Vaccine: Unit I Flashcards

Question

What would happen if all children were vaccinated and why isn’t that the case?

Answer 1

o If all children received the vaccines recommended for children in the US

Answer 2

o What is (are) the target population(s)? • Children may have blocking maternal antibodies • Elderly adults or immunocompromised persons may not respond well • Are there potential compliance or accessibility issues? o Is there an animal reservoir for the pathogen? • Will the vaccine work in animals? o Are there side effects or (if live attenuated) risks of reversion? o Is antigenic variation an issue? o How will it be made, stored, and delivered? Can enough be made? o How much will it cost and who will pay for it? Will it divert resources from other efforts?

Answer 3

o Affordable worldwide (less than 1$ per dose) o Heat stable (requires no refrigeration) o Single-dose efficacy o Efficacy against multiple diseases o Administered without needles o Suitable for administration early in life o No side effects o **No currently available vaccine has all of these features

Answer 4

Because there is no natural immunity conveyed by the infection; for chicken pox and measles, the disease itself conveys a natural immunity. But for HIV (and malaria), there is no person who has HAD the disease and survived; no case of an immune system successfully clearing infection; not a disease you get only once. Problem for vaccine creation because usually vaccines based off of natural immunity antibodies

Answer 5

* Any substance that causes the immune system to produce antibodies * Each antibody is specifically produced by the immune system to match the antigen; allows precise identification of antigen and tailored response

Answer 6

* A procedure designed to induce or convey an IMMUNE RESPONSE to a specific antigen * designed to increase the concentration of antibodies and/or lymphocytes (B-cells/T-cells) that are reactive against the immunogen * May be ACTIVE or PASSIVE

Answer 7

* ACTIVE immunization performed for the specific purpose of inducing an immune response that is protective or therapeutic against a given infectious disease * not all immunizations are technically vaccines (immunization of animals for monoclonal antibody or antitoxin production) * name derives from vacca (cow) in order to honor Jenner's use of cowpox (vaccinia) to protect against smallpox

Answer 8

* Performed BEFORE (in some cases shortly after) exposure to an infectious agent * intended to PREVENT infections or disease * Most current vaccines are of this type

Answer 9

* Performed DURING an active infection * Intended to treat or CURE the infection * certain passive immunizations are of this type (i.e. antitoxins)

Answer 10

* Transfer of performed antibodies to a recipient, conveying INSTANT immunity * Transient protection; no memory induced

Answer 11

1. Natural: maternal antibodies passed on to child; antibodies cross placenta during pregnancy -->antibodies conveyed orally through breast milk after birth 2. Artificial: injection of antibodies into recipient; antibodies may be produced by animals or other humans-->may act on WHOLE organism, toxins (antitoxin), or venums (antivenins)

Answer 12

* Immunodeficiency affecting antibody production * Immunoprophylaxis in at-risk populations (ex. RSV, Rh-mom) * Rapid immunity needed (ex: traveling, have had recent exposure, etc.)

Answer 13

Four different blood types; each is further classified based on the presence or absence of proteins on the surface of RBCs that indicate the Rh factor; if you have this protein, you are Rh positive. * most people are Rh positive * If a woman who is Rh NEGATIVE has a child with a man who is Rh positive, and the baby is Rh positive, could pose risk; for FIRST child, Rh incompatability shouldnt be a problem because the fetuses blood doesn't enter mothers circulatory system; during DELIVERY however, blood can mingle and mother might create antibodies against Rh proteins * SECOND CHILD: if 2nd has Rh positive, her Rh antibodies will recognize Rh proteins on surface of babies RBC and will attack those cells-->causes babies blood count to get dangerously low

Answer 14

1. Maternal (transplacental & via milk) 2. blood or blood products (e.g. plasma); have to have compatible blood types to transfer plasma with another person 3. pooled human antibody (Human Immune Globulin) 4. Human hyperimmune globulin (e.g. human rabies immune globulin; HRIG) 5. heterologous hyperimmune serum (animal derived antitoxin/antivenin) 6. monoclonal antibodies

Answer 15

IMMUNE GLOBULIN: produced by combining the IgG antibody fraction from thousands of adult donors in the US; because it comes from many different donors, it contains antibody to many different antigens; human Ig comes from PLASMA

Answer 16

antibody products that contain HIGH titers of specific antibody; these products are made from the donated plasma of humans with high levels of antibody of interest; since hyperimmune globulins are from humans, they will contain other antibodies in lesser quantities

Answer 17

ANTITOXIN: product produced in animals (often horses) that contains antibodies against only one antigen; potential problem of SERUM SICKNESS, which is an immune reaction to the horse protein

Answer 18

Produced from a single clone of antibody producing B cells, so products contain antibody to only ONE ANTIGEN or closely related groups of ANTIGEN * mAbs are used for diagnosis and therapy of certain cancers and autoimmune and infectious diseases * MOST mAbs used in humans are mouse antibodies that have been engineered to be more human in structure; put sequences that code CDRs into human antibody so have human constant region of the antibody

Answer 19

Is it ethical to create antitoxin/antivenin using people? No. so use animals. Do you need a large quantity of a specific antibody, then use hyperimmune. do you need to protect against various strains, then use normal human Ig.

Answer 20

If someone gets bit by a rabid animal, dont just juse pooled human ABs (HIG), use the Abs with HIGH-affinity for the rabies virus (HRIG)

Answer 21

NOT necessarily; it just transfers immunity, hence why you dont form memory and dont recall memory if secondary infection occurs

Answer 22

he mother has an intramuscular injection of anti-Rh antibodies (Rho(D) Immune Globulin). This is done so that the fetal Rhesus D positive erythrocytes are destroyed before her immune system can discover them. This is passive immunity and the effect of the immunity will wear off after about 4 to 6 weeks (or longer depending on injected dose) as the anti-Rh antibodies gradually decline to zero in the maternal blood.

Answer 23

Antisera prepared in animals, while lifesaving, can induce isotypic reactions in human recipients, leading to serum sickness

Answer 24

Immune complexes deposit in blood vessels, joins and organs, activating complement and leading to tissue damage

Answer 25

DESPECIFICATION: the digestion of antibodies with pepsin to remove MOST of the Fc region, significantly reducing the risk of serum sickness

Answer 26

Complementary determining regions: part of the variable chains in Ig (antibodies): where these molecules BIND to their specific antigen *The most variable parts of the molecule; crucial to the diversity of antigen specificities

Answer 27

DRUG; brand name is Synagis. *It is a monoclonal antibody produced by recombinant DNA technology, and used to prevent RSV infections *Humanized mAb directed against antigenic site of the F protein of respiratory syncytial virus (RSV), a common infection of children *Delivered by monthly intramuscular injection *doesnt interfere with response to other vaccines *indicated for premature infants, children less than 2 years of age with congenital heart or chronic lung disease, and children with compromised immune systems >1000$ per dose-->biologicals are a LOT more expensive to make

Answer 28

INDUCES immune response and/or memory (T-cells & B-cells) that will protect against subsequent exposure to a pathogen

Answer 29

Infection with certain pathogens (e.g. smallpox) conveys immunity against subsequent infection (if it doesnt kill you the first time)

Answer 30

* Injection, ingestion, or inhalation of immunogen to educate the immune system * vaccines in current use include live attenuated, whole inactivated, toxoid, subunit and conjugate * next generation vaccines include DNA and recombinant vectors

Answer 31

* pre-existing antibodes (e.g. maternal antibodes) * poor responders, but "herd" immunity may compensate * compliance issues (lack of resources or will) * like all medical interventions, active vaccination carries certain risks that vary depending on vaccine type: BENEFITS OUTWEIGH RISKS

Answer 32

the more similar a vaccine is to the disease-causing form of the organism, the better the immune response to the vaccine

Answer 33

*Newly developed meningitis vaccine could save 150,000 lives in Sub-Saharan Africa by 2015; people got together to develop vaccine specifically for aAfrica and with Africas most common strain-->EXTREMELY CHEAP AT .40$$ A DOSE

Answer 34

* T Helper Cells * Lymphocyte (subset of Leukocytes) * Mature Th cells express the surface protein CD4 * promote innate and adaptive immune responses, especially ADAPTIVE

Answer 35

WHITE BLOOD CELL: a colorless cell that circulates in the blood and body fluids and is involved in counteracting foreign substances and disease * All white blood cells are produced and derived from a multipotent cell in the bone marrow known as a hematopoietic stem cell. * All white blood cells have nuclei, which distinguishes them from the other blood cells, the anucleated red blood cells (RBCs) and platelets.

Answer 36

*Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm

Answer 37

Basophil granulocytes Eosinophil granulocytes Neutrophil granulocytes

Answer 38

A type of white blood cell. it is a granulocyte derived from the myeloid stem cell that is a part of the immune and neuroimmune systems and contains many granules rich in histamine and heparin. *Best known for their role in allergy and anaphylaxis

Answer 39

* is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways. * Most cytotoxic T cells express T-cell receptors (TCRs) that can recognize a specific antigen

Answer 40

An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. In other words, the epitope is the specific piece of the antigen that an antibody binds to.

Answer 41

* where mature B lymphocytes proliferate, differentiate, and mutate their antibody genes (through somatic hypermutation), and switch the class of their antibodies (for example from IgM to IgG) during a normal immune response to an infection. * Germinal centers are an important part of the B cell humoral immune response, acting as central factories for the generation of affinity matured B cells specialized in producing improved antibodies that effectively recognize infectious agents

Answer 42

* Somatic hypermutation (or SHM) is a cellular mechanism by which the immune system adapts to the new foreign elements that confront it * Somatic hypermutation involves a programmed process of mutation affecting the variable regions of immunoglobulin genes.

Answer 43

T regulatory cells are a component of the immune system that suppress immune responses of other cells. This is an important "self-check" built into the immune system to prevent excessive reactions.

Answer 44

Increasing numbers of microbes and increasing diversity

Answer 45

Consists of a complex community of microorganisms that live in the digestive tract of the animal. Different people and animals have different types of microorganisms in their guts. The composition of the gut flora also changes over time, when the diet changes.

Answer 46

An aggregate of all the genomes of the microbiota

Answer 47

As infants we (and our guts) come into this world with a blank slate of sorts, awaiting our first contact with the microscopic organisms which surround us. Our first exposure via the birth canal, followed by a gut-nurturing concoction of mother’s milk, is nature’s way of establishing the foundation on which we will build our microbiome. Familial, dietary, and environmental exposure throughout our developing years cultivates an ecosystem which will play a starring role in the determination of our health for a lifetime. *the vagina

Answer 48

Starting with our immune system, our microbiome establishes the parameters in which our bodies judge whether or not something is friend or foe. It maintains harmony, balance, and order amongst its own communities, ensuring that opportunistic pathogens are kept to a minimum, while also keeping the host system from attacking itself. It is our first, second and third line of defense – starting with our skin, then our mucus membranes, and finally our gut, providing a living barrier that is able to be modified and transformed to suit individual needs and unique environments.

Answer 49

Our gut microbiota is fundamental to the breakdown and absorption of nutrients. Without it, the majority of our food intake would not only be indigestible, but we would not be capable of extracting the critical nutritional compounds needed to function. Our symbiotic cohorts not only provide this service, but also secrete beneficial chemicals as a natural part of their metabolic cycle.

Answer 50

Antibiotics and an obsession to sterilize our environments have resulted in a significant rise in gut-related illnesses and pressure on the medical community to finally explore this long-ignored aspect of human biology. Research has uncovered an intricate web connecting our gut flora to virtually every process in our body. As such, imbalances in our microbial communities have been implicated in countless health issues, including immune health, psychological well-being, and some of the deepest chronic health issues of our times.

Answer 51

Viruses Bacteria Fungi Parasites

Answer 52

when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response. Artificially acquired active immunity can be induced by a vaccine, a substance that contains the antigen.

Answer 53

highly infectious disease caused by the Variola Virus; had a 30% mortality rate. *survivors were left permanently scarred; blindness and sterility often occurred

Answer 54

Innate immunity refers to nonspecific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body. Individual is BORN with this and requires no prior experience. These mechanisms include physical barriers such as skin, chemicals in the blood, and immune system cells that attack foreign cells in the body. Limits/contains/controls infections and generates signals that activate and enhance the adaptive immune response

Answer 55

Adaptive immunity refers to antigen-specific immune response. The adaptive immune response is more complex than the innate. The antigen first must be processed and recognized. Once an antigen has been recognized, the adaptive immune system creates an army of immune cells specifically designed to attack that antigen

Answer 56

1. specificity 2. Diversity: able to react with an almost limitless variety of antigens 3. Memory: ability to remember a previous encounter with a pathogen; secondary response is induced more quickly and is more vigorous than original response 4. Self/Non-Self

Answer 57

T-Cell receptors; produced by helper and cytotoxic T lymphocytes; they are surface bound to a cell and not secreted. * recognize PROCESSED antigens PRESENTED on specific molecules known as MHC; cannot recognize antigens in the NATIVE FORM * antigen is presented on MHC complex by an antigen-presenting cell (APC) * helper T-cells need MHC class II, and cytotoxic T need MHC class I

Answer 58

B and T cells; they are a subset of leukocytes which mediate adaptive immune responses; these are generated; generated in the primary lymphoid organs (bone marrow and thymus) and enter the bloodstream

Answer 59

1. Vaginal: passage through birth canal *babies born via C-section have higher frequency of developing allergies and autoimmune diseases; smaller microbiomes 2. Cutaneous: contact with skin 3. Mammary: through breastfeeding REDUCTION as more and more babies are being born via Caesarean section, being bottle fed, given early-life antibiotics, and being extensively bathed and cleaned

Answer 60

From birth to a year, have increasing numbers and increasing diversity of microbiome. Microbial stability is established after one year. After a year, the # of bacteria remains the same, but bacteria diversity greatly increases as the composition of bacteria evolves continuously. Composition is influenced by host genetics, antibiotics, diet, lifestyle, environment, etc. Over time as diversity increases, interindividual variability decreases because we all will have a lot of the same bacteria

Answer 61

1. Increases the metabolic capacity of the HOST; digestion of otherwise UNUSED food components 2. completion of the bile-salt cycle 3. protect the host from colonization with pathogenic bacteria (colonization resistance) * If didnt have GOOD bacteria, would be more susceptible to infection by pathogenic bacteria

Answer 62

Most microbes have genomes that are full of genes that allow them to metabolize certain carbohydrates; dont code for pathogenic material but have genes that are advantageous to the host

Answer 63

"Known life"--all the forms of life within an organism can be accounted for *Gnotobiotic animals are born in aseptic conditions, which may include removal from the mother by Caesarean section and immediate transfer of the newborn to an isolator where all incoming air, food and water is sterilized.[2] Such animals are normally reared in a sterile or microbially-controlled laboratory environment, and they are only exposed to those microorganisms that the researchers wish to have present in the animal. These gnotobiotes are used to study the symbiotic relationships between an animal and one or more of the microorganisms that may inhabit its body.

Answer 64

*MICROBIOLOGICALLY STERILE *healthy, breed normally *consume 1/3 more calories than conventionally colonized mice Germ-free animals are animals that have no microorganisms living in or on it. Such animals are raised within germ-free isolators in order to control their exposure to viral, bacterial or parasitic agents. *Comparing germ free w/ conventional mice; pinpoint immune differences that exist between mice and illustrates that bacteria and our gut microbiome influence our immune system greatly; germfree mice have fewer of everything, fewer germinal centers, intestinal epithelial cells, T cells, etc.

Answer 65

1. rRNA sequencing: group sequences into OTU's (operational taxonomic unit), compare to database, and identify species and abundance of species within microbiome sample 2. Total microbiome DNA sequencing; filter HOST DNA sequences and compare microbial sequences to databases; identification of species, relative abundance within sample, genes, and functional information

Answer 66

* Mucosal surfaces such as the intestinal tract are continuously exposed to both potential pathogens and beneficial commensal microorganisms. This creates a requirement for a homeostatic balance between tolerance and immunity that represents a unique regulatory challenge to the mucosal immune system. Recent findings suggest that intestinal epithelial cells, although once considered a simple physical barrier, are a crucial cell lineage for maintaining intestinal immune homeostasis. * Microbiota regulates intestine immune responses via microbe associated molecular patterns (MAMPS) and bacteria derived metabolic products.

Answer 67

Microbe-associated molecular patterns (MAMPs) are molecular signatures typical of whole classes of microbes, and their recognition plays a key role in innate immunity. TLRs on host cells recognize these, and TLR signaling has been shown to enhance epithelial barrier function. IECs also secrete a broad range of antimicrobial peptides to maintain an immunological barrier.

Answer 68

* immune cells exist within intestinal tissue; intestinal tissue is MOST immunogenic organ; the whole paradox of situation is that you have so many immune cells and exist SO CLOSE to the bacteria that they potentially could react with * INTESTINAL are the first cell type that come in contact with commensal bacteria and products derived from commensal bacteria * *innate immunity functions as a result of receptors that exist on cell surface or within the cells * receptor are capable of binding to bacterial products; components of the mammalian innate immune system are constantly sampling the dynamic composition of commensal communities.

Answer 69

Bacteria will produce SCFA (short chain fatty acids produced by bacterial metabolism), LPS, Sphingolipids, and Flagellin. Binding of some of these to intestinal cells TLRs can produce proinflammatory cytokine release, or RegIII-gamma that is an antibacterial lectin that is responsible for promoting the spatial segregation of microbiota and host in the intestine.

Answer 70

the task of differentiating between pathogens and commensal microflora and eliciting the appropriate action is the responsibility of a single layer of intestinal epithelial cells (IECs) that line the intestinal tract and are in direct contact with luminal contents.Under noninflammatory conditions, the intestinal epithelium not only performs its normal functions (i.e., barrier against bacteria, nutrient absorption), but also continuously “prepares” for an unexpected encounter with a pathogen. Even in the absence of pathogens, IECs are known to continually present antigens to T lymphocytes (11) and express Fc receptors on their apical surface.

Answer 71

Beneath the intestinal epithelium is a layer of mucosal tissue that has immune cells. in a healthy gut, the intestinal epithelium barrier will prevent penetration of any commensal bacteria, preventing excessive immune response

Answer 72

studies show that the physical separation of microbiota from the intestinal surface is critical for limiting immune activation and maintaining mutualistic host-bacterial associations *A plausible mechanism by which intestinal epithelial cells could limit bacterial-mucosal contact is through the production of secreted antibacterial proteins.

Answer 73

Microbiota stimulation leads to B cell switching and production of IgA, regulatory T cell induction, and T cell differentiation to Th17 * *antigen presenting cell that has seen bacteria and sensed it can signal to a B cell, also specialized dendritic cells; get signaled to B cells and can generate plasma cells or IgA secreting cells * with B cell help get specific IgA; without, generic IgA—>secreted into GUT LUMEN

Answer 74

IgA is produced by B cells and plasma cells located on mucosal surfaces. As a result, IgA is produced and secreted in large amounts into the upper respiratory tract, the GI tract, tears, sweat, etc. In these locations, it complements the physical barriers of the body and prevents microbial invasion. *through a process known as immune exclusion, SIgA promotes the clearance of antigens and pathogenic microorganisms from the intestinal lumen by blocking their access to epithelial receptors, entrapping them in mucus, and facilitating their remova

Answer 75

Important part of the adaptive immune response at intestine-bacteria surface. They are a subset of pro-inflammatory cytokine producing T helper cells; serve to help maintain mucosal barriers and contributes to pathogen clearance at mucosal surface

Answer 76

M cells are specialized epithelial cells that sample and uptake antigens at their apical membrane, encase them in vesicles to transport them to the basolateral membrane of M cells, and from there deliver antigens to the nearby lymphocytes. *many pathogens exploit the M cells as a conduit to invade the host and establish an infection.

Answer 77

KEY COMPONENTS OF CROSS-TALK. immune system is sensing NOT ONLY just the bacterial cell wall but also bacterial metabolites; future therapy of instead of probiotics could take metabolite and have desired effect.

Answer 78

Disease considered the result of inappropriate activation of intestinal mucosal immunity in genetically susceptible hosts. However, increasing evidence suggests that the intestinal microbiota play a role in initiating, maintaining, and determining the phenotype of IBD * Genetic and environmental factors induce IMPAIRED BARRIER function * translocation of bacteria and bacterial products * immune activation and proinflammatory cytokine production * Chronic inflammation leads to tissue desctriction and complications * proinflammatory responses due to defects in host genetics and microbiota can lead to mucosal damage, which will lead to dysbiosis; this means greater loss of barrier integrity, induction of proinflammatory cytokines, lesions in the intestinal epithelium, and therefore profuse GI bleeding

Answer 79

genetics & environment where you live is regulating microbiome; if have genetics that makes you susceptible to inflammatory diseases (A lot of genes that are defective have to do with anti-microbial protection or section; defective in innate immunity, in phaogcyototic genes, etc). * if these genes are defective, host is not able to keep bacteria away from barrier and so immune system gets inflated * If there is abnormal microbiota composition, can lead to Reactive oxygen species development, clastogens, and increased acid, leading to cytotoxicity, and DNA damage, which yields carcinogenesis

Answer 80

many changes in the bacterial composition of the gut microbiota have been reported in colorectal cancer, suggesting a major role of dysbiosis in colorectal carcinogenesis.

Answer 81

Certain microbiota can cause: 1. DNA damage leading to increased apoptosis at gastric mucosa 2. abnormal DNA transcription 3. Inflammatory milieu; increased T cells and Th1 cells All leads to METAPLASIA (conversion in cell type due to change of milieu) and TUMORIGENESIS

Answer 82

* strongly linked to gastric cancer; a bacteria that grows in the mucus layer of the stomach; pylori are so effective because the embed themselves into stomach mucus/lining and attach to gastric mucosa, where they upregulate inflammatory T cells that can feed into making epithelial cells cancerous * if H. pylori infection was the main cause of stomach ulcers and chronic inflammation, and inflammation a pre-cursor to stomach cancer, then it stood to reason that infection with the bugs could be a leading cause of cancer.

Answer 83

1. Use of antibiotics that will eradicate H pylori itself 2. anti-inflammatory drugs that decrease the negative effect that H pylori has, reducing chronic inflammation and therefore reducing the chance of getting cancer 3. if have developed cancer, more aggressive treatment, like actual removal of the tumor, may be needed.

Answer 84

A clastogen in biology is a mutagenic agent giving rise to or inducing disruption or breakages of chromosomes, leading to sections of the chromosome being deleted, added, or rearranged.

Answer 85

* misalignment of microbiota linked to metabolic diseases like OBESITY * microbiota has also an impact on the way calories are absorbed and how fat cells develop * obesity is being seen as a kind of inflammation (low-grade) in your body that leads to to accumulation of fat * the composition of the gut microbiota has been shown to differ in lean and obese humans and animals and to change rapidly in response to dietary factors. * Dietary changes have been shown to have significant effects on the microbiota. Shifting mice to a high-fat, high-sugar “Western” diet, from a low-fat, plant polysaccharide-rich diet, changed the microbiota within 24 h * the subjects’ ratio of Firmicutes to Bacteroidetes was substantially higher than that of the normal-weight controls. Importantly, in those subjects who had successful and sustained weight loss, the ratio returned to normal.

Answer 86

There is growing evidence that dysbiosis of the gut microbiota is associated with the pathogenesis of both intestinal and extra-intestinal disorders. Intestinal disorders include inflammatory bowel disease, irritable bowel syndrome (IBS), and coeliac disease, while extra-intestinal disorders include allergy, asthma, metabolic syndrome, cardiovascular disease, and obesity.

Answer 87

* Gut microbiota (and diet-induced changes in microbiota composition) may contribute to low-grade inflammation, which is associated with obesity & metabolic dysfunction * The gut microbiota has been identified as a potential contributor to metabolic diseases. It has been shown that obese individuals present different proportions of bacterial phyla compared with lean individuals, with an increase in Firmicutes and a decrease in Bacteroidetes. * This alteration seems to interfere with intestinal permeability, increasing the absorption of lipopolysaccharide (LPS), dietary lipids, and peptidoglycan, which reaches circulation and initiates activation of Toll-like receptor (TLR) & other immune cells, leading to increased activation of inflammatory pathways. Along with these activations, an impairment of the insulin signaling is observed;The insulin signaling may be impaired by altered secretion of cytokines and chemokines. * immune cells can start secreting inflammatory cytokines; as a result of this, increase overall inflammatory status of the tissue * some inflammatory molecules can end up in regions other than the gut (liver, brain, muscles, fat); immune cytokines may show up in organs and cause changes in metabolic pathways in these tissues

Answer 88

they are found in the outer membrane of Gram-negative bacteria, and elicit strong immune responses in animals; known as endotoxins. * The presence of endotoxins in the blood is called endotoxemia. It can lead to septic shock * purified endotoxin from Escherichia coli can induce obesity and insulin-resistance phenotypes when injected into germ-free mouse models; acts through inflammatory pathways * Weight gain has been associated with a higher gut permeability and subsequent systemic exposure to mildly increased LPS circulating levels. demonstrated that a high-fat diet promotes LPS absorption across the intestinal barrier, increasing its plasma levels by two to three times * TLR4 is a subclass of TLRs that can be activated by lipopolysaccharide (LPS), a major component of the outer membrane in Gram-negative bacteria, and by nonbacterial agonists, such as saturated fatty acids [73,94]. The activation of TLR4 signaling induces upregulation of inflammatory pathways related to the induction of insulin resistance

Answer 89

* increased SCFA may increase FAT STORAGE * Diet induced changes in microbiota suppresses expression of fasting-induced adipose factor (FIAF), which then promotes lipoprotein lipase (Lpl) activity and increases fat storage * increased LPS levels can stimulate eCB1 receptors, which activates the endocannabinoid pathway and promotes adipogenesis

Answer 90

1. increased SCFA: increased lipogenesis and fat storage 2. Decreased FIAF: increased LPL and fat storage 3. Increased Gut permeability: increased LPS; leads to increased proinflammatory cytokines and adipogenesis 4. Decreased AMPK: oxidation of fatty acids; increased adipogenesis; AMPK is a master nutrient and energy sensor that maintains homeostasis

Answer 91

Peptidoglycan (PGN) and some of the dietary lipids (LPS) can activate immune cells that underlie the gut activity; they can do that if the barrier is compromised; epithelial cells have mechanisms to keep bacteria away from epithelial cells, but sometimes mechanisms fail * *microbiotic bacteria can modify junctions between epithelial cells; bacteria can down-regulate proteins that are responsible for tight junctions, allowing bacteria to seep into inner layer where immune cells reside * immune cells can start secreting inflammatory cytokines; as a result of this, increase overall inflammatory status of the tissue * some inflammatory molecules can end up in regions other than the gut (liver, brain, muscles, fat) * changes in gut microbiota can then translate into immune activation and immune cytokines showing up in organs and cause changes in metabolic pathways in these tissues

Answer 92

It is linked to feelings of SATIETY, decreased body weight, and decreased energy intake

Answer 93

Inflammation: good tactic to help conserve energy and fatten up host so if there is sickness, you can live longer SCFA:good ways to increase fat storage; potentially good in past when food sources were scarce but in more developed societies makes us more prone to obesity

Answer 94

if take microbiota from obese mice and put it in germ free WT mice, see obesity effect take hold, so microbiome itself is likely regulating these hormones *phenotype of obesity was transferred to mice who had microbiome of obese people

Answer 95

``` Fecal transplantation (or bacteriotherapy) is the transfer of stool from a healthy donor into the gastrointestinal tract for the purpose of treating recurrent C. difficile colitis. FMT involves restoration of the colonic microflora by introducing healthy bacterial flora through infusion of stool, e.g. by enema, orogastric tube or orally in the form of a capsule containing freeze-dried material, obtained from a healthy donor. ```

Answer 96

*ones diet greatly effects microbiome; if have diet based largely on simple sugars, have simple microbiome, so tend to have more inflammation and a greater likelihood of gut microbiota problems *malnutrition—>large part of the world suffers from—impairs microbiota COMPLEX DIET IMPORTANT FOR COMPLEX AND DIVERSE MICROBIOME *food additives and emulsifiers can change pigments of mucus layer and that can cause low grade inflammation and metabolic diseases

Answer 97

*Gut microbiota is being linked to liver pserosis caused as a result of binge drinking Whenever mice were fed ethanol, there was a decrease in anti-microbial epithelial secretions, so the host-microbiome interface is not protected that well —>allows microbes to end up in liver, causing liver problems

Answer 98

Diet or obesity induced changes in the micobiota leads to increased deoxycholic acid (secondary bile acid) * DCA reaches LIVER via portal vein * Increased DCA leads to DNA damage, which promotes senescence-associated secretory phenotype (SASP) in HSC (hepatatic stellate cell) * Combined with activation of oncogenic signaling pathways, promotes HCC development (HCC=hepatocellular carcinoma; liver cancer) * HSC exhibit proinflammatory phenotype phenotype during senescence

Answer 99

Cellular senescence is a tumor-suppressive mechanism that permanently arrests cells at risk for malignant transformation. * accumulating evidence shows that senescent cells can have deleterious effects on the tissue microenvironment. * The most significant of these effects is the acquisition of a senescence-associated secretory phenotype (SASP) that turns senescent fibroblasts into proinflammatory cells that have the ability to promote tumor progression. * A plethora of stresses can provoke cellular senescence, like DNA damage

Answer 100

*babies delivered by C-section, tend to have microbitioa that remsebled peoples hands or on the skin; babies delivered naturally had a much greater microbiota diversity; kids born by C section had higher prevalence of developing allergic diseases; model supported by mice; did study of mice that were germ free v. those with microbiome; not having complex microbiota while getting birthed leads to development of stunted immune response that can lead to autoimmune diseases later on

Answer 101

Massive increase in prevalence of allergic diseases in westernized countries (>20% over 10 year period) * Allergic disease is attributed to both genetic predisposition and environmental factors * Genetic drift over such a short period of time cannot explain increased incidence of disease * Westernized life style has introduced several environmental risk factors that disturb the homeostatic balance of GUT microbiota

Answer 102

1. excessive antibiotic use, especially during early life and pregnancy 2. shift towards more formula-fed babies 3. shift towards more C-section babies 4. western diet; food emulsifiers and additives causing low-grade inflammation

Answer 103

Dietary antigens are normally rendered nonimmunogenic through a poorly understood “oral tolerance” mechanism that involves immunosuppressive regulatory T (Treg) cells; constantly being sampled by the IEC *tolerance built into immune system so unselect T and B cells that are selective for food antigens so we can eat stuff

Answer 104

* Certain types of bacteria produce SCFAs, which can drive induction of regulatory T cells, which reduce cytokine production by down-regulating T cells activity * Certain types of bacteria promote IL-22 production by CD4+ and ILC, which promotes barrier protection-->Il-22 strengthens the barrier and makes it impermeable to some food antigens that might cause food allergies

Answer 105

Patients with T1D exhibit a less diverse and less stable gut microbiome compared to healthy controls and changes of the ratio of Firmicutes to Bacteroidetes have been observed in the patients. Prediabetic children harbor more Bacteriodetes compared to controls * these alterations could explain increased gut permeability, subclinical small intestinal inflammation, and dysregulation of oral tolerance in type 1 diabetes. * Generally beleived that the altered microbiota and subsequent leaky gut have led to increased permeability to dietary antigens, yielding greater cytokine release and therefore abnormal epithelial activation, as well as ALTERED mucosal immunity, leading to an autoimmune process (induction of T cells and antibodies), generating pancreatic islet inflammation, beta cell destruction, and Type I diabetes

Answer 106

Type 1 Diabetes (T1D) is one of the most common metabolic disorders in children and young adults. This autoimmune-mediated disease results in a progressive loss of insulin-producing beta cells in the islets of Langerhans in the pancreas.

Answer 107

Associated with intestinal micriobiota dysbiosis

Answer 108

``` altered micriobiota linked to arthritis *A chronic inflammatory disorder affecting many joints, including those in the hands and feet. body turns on itself to attack the joints Rheumatoid arthritis (RA) is the most common type of autoimmune arthritis. It is triggered by a faulty immune system (the body’s defense system) and affects the wrist and small joints of the hand, including the knuckles and the middle joints of the fingers. *potentially a missing microbe species that upregulates Treg and decreases immune system activity and attack so the immune system attacks too much at joints *animal models of arthritis were exacerbated or rescued depending on gut microbiota ```

Answer 109

physicochemical barrier composed of a thick mucus layer, antimicrobial proteins, and secretory IgA antibodies51 coalesces to minimize the contact between the commensal microbes in the gut lumen and intestinal epithelial cells that line the gut wall. Bacteria escaping this initial 'buffer zone' encounter a second defense strategy, a physical boundary provided by the tight junctions formed between the intestinal epithelial cells. These cells are not only an anatomical boundary, but also exhibit active antibacterial properties *epithelial cells present Toll-like receptors (TLRs) in their cellular membrane, which allow for the recognition of PAMPs and induction of downstream inflammatory responses. The lamina propria innate immune cells, constantly surveying the contents of the gut lumen in search of undesirable antigens, constitute another defense mechanism

Answer 110

Bi-directional communication between microbiome, gut, and brain * bacterial waste products can also influence the brain--for example, at least two types of intestinal bacterium produce the NT gamma-aminobutyric acid (GABA) * mice born by C-section, which hosted different and less diverse microbes from mice born vaginally, were significantly more anxious and had symptoms of depression-->animals inability to pick up mothers vaginal microbes during birth, the first bacteria they would normally encounter, may cause lifelong changes in mental health

Answer 111

1. Peripheral serotonin: cells in the gut produce large quantities of serotonin which may effect brain signaling 2. Immune system: intestinal microbiome can prompt immune cells to produce cytokines that can influence neurophysiology 3. Bacterial molecules: microbes produce metabolites such as butyrate that can alter the activity of cells in the blood-brain barrier * *neural communication by vagal and sympathetic nerve * *systemic communication by HPA axis, NT, bacterial metabolites and cytokines

Answer 112

1. can the microbiota be altered to improve vaccine responses? 2. can microbiota be used to deliver vaccine antigens? 3. Can specific vaccines be designed to target particular microbiota strains?

Answer 113

Because of vaccination, relatively FEW PEOPLE have had personal experience with the diseases they prevent; so there is lower risk tolerance by the public because are less aware of alternative (disease) *public confidence in vaccines is also lower because new communication technologies have allowed the dissemination of INCORRECT information that is difficult to retract; increased attention on vaccine RISK

Answer 114

141 people infected in Disneyland with measles; this is NOT a problem of the measles vaccine not working but rather it NOT BEING USED * the majority of people who got measles were unvaccinated * herd immunity is compromised because not enough people with measles vaccine * measles has a basic reproductive number of 18; so on average, each person infected with measles will infect 18 other people before they recover

Answer 115

Vaccines may provide INDIRECT immunity to unvaccinated through herd immunity by protecting those for whom vaccines are contraindicated or for those who have religious objections; having most of the population get vaccine allows some to NOT get vaccine because disease cannot spread if most people cannot get it ❁Relationship between how contagious disease I is and what % of people needs to be vaccinated for herd immunity

Answer 116

* in vitro and in silico (computer-based) studies * animal studies * Phase I, II and III clinical trials on HUMANS * Pre-licensure studies will detect COMMON side effects, but not rare or late side effects * Only after a vaccine is shown to be safe and efficacious may a manufacturer apply for licensing

Answer 117

1. product license: the vaccine itself and procedure for how it is to be made and administered 2. establishment license: where it is made; Physical building where it is made; make sure facilities are really secure and are protecting people and public from deadly things getting OUT

Answer 118

* Phase I: 20-100 volunteers; initial safety studies--looking for adverse side-effects & undesirable toxicity * Phase II: hundreds of volunteers; optimization of dosage and schedule * Phase III: hundreds to thousands of volunteers; determines efficacy; may last several years

Answer 119

* Post-licensure surveillance is CRITICAL to ensure that rare events are identified and quantified * monitor increases in known reactions * identify risk factors or conditions associated with reactions * identify vaccine batches with unusual rates or types of adverse events * identify adverse reactions that require further study

Answer 120

* passive reporting by healthcare providers * ad hoc studies of adverse reactions/events * Phase IV trials * Large Linked Databases (LLDBs) * CISA Network

Answer 121

* More than 10,000 participants * better than phase III trials; larger scope and greater understanding of more rare side effects and what subgroups of people are more likely to have adverse reactions/events

Answer 122

* Link immunization and medical records from defined populations (done by large companies with computerized medical records like HMOs and Medicare) * Aimed at addressing limitations to passive reporting systems which are: inability to determine causality, lack of timelines, underreporting, and recall bias * ACA includes incentives to increase the usage of electronic medical records which will increase denominator of LLDBs * Helpful in finding adverse reactions that people might not remember or associate with the vaccine * Helps with timeliness question; reports are well documented because see DATES of things so allow connections between certain things, like when you got the vaccine and when you got onset of symptoms * Because have verified record, can do better epidemiological studies and make a case for causality

Answer 123

* Established in 2001 to improve understanding of vaccine safety issues at the individual level * Evaluates person who experienced adverse health events following vaccination * major goal is to study the pathophysiological basis of adverse events, study the risk factors associated with adverse events, and develop evidence-based guidelines for healthcare providers. * Group of researchers from CDC go and check VAERS claims; academically focused; fly to where adverse events are reported and investigate you * Concerned with finding NEW biologically plausible causational adverse reactions that we didn’t know before

Answer 124

* Advisory body consisting of medical and public health experts across many disciplines that develops recommendations about vaccines * role is to provide ADVICE that will lead to a reduction of vaccine preventable diseases in the USA * ACIP develops RECOMMENDATIONS for routine administration of vaccines (age, dosing intervals, precautions & contraindications) * insurance companies tend to follow & abide by ACIP decisions, often forcing doctors to do the same because going against ACIP means going out of insurance bubble meaning cost is out of pocket

Answer 125

* The safety and effectiveness of the vaccine when given at specific ages (immune responses can vary depending on age) * the NUMBER of children who get the disease if there is no vaccine; vaccines that dont provide benefits to MANY children may not be recommended for ALL children * the severity of the disease * only vaccines LICENSED by the FDA are recommended; thus vaccine manufactureres must conduct studies to show that a vaccine is SAFE and EFFECTIVE at specific ages

Answer 126

* ACIP members CANNOT have a conflict of interest; researchers and clinicians who lead vaccine studies at their respective institutions may become ACIP members but NOT comment or vote on their own vaccines or vaccines associated with the company they work for; must excuse themselves * Those who serve on a board of directions of a vaccine manufacturer, those who hold patents on vaccines or related products, and those who are directly employed by a vaccine manufacturer or have immediate family members so employed are EXCLUDED from membership

Answer 127

*inappropriate effect caused by a vaccine that is unrelated to its primary purpose of producing immunity; a SIDE EFFECT

Answer 128

* any medical event following vaccination | * may be true adverse reaction and may be coincidental (fell down stairs after vaccination)

Answer 129

* Due to intrinsic characteristics of the vaccine and the individuals response * event would NOT have occurred without the vaccine

Answer 130

* event would have occurred anyway but was precipitated by the disease * ex: vaccine may cause slight fever which may induce febrile seizures that would have occurred anyway but now occur earlier because of fever

Answer 131

*event due to errors in vaccine storage, preparation, handling or administration

Answer 132

*event was not caused by vaccination but occurred by change or as the result of underlying illness

Answer 133

* BRADFORD-HILL CRITERIA developed as a checklist for causality * TIMELINE: did the adverse event occur within a plausible time frame? * BIOLOGICALLY PLAUSIBLE * POSITIVE RECHALLENGE: does event recur upon administration of the vaccine * have there been any laboratory evidence, clinical trials, or epidemiological studies indiciating a h`igher level of adverse events among vaccinated v. unvaccinated

Answer 134

1. Local 2. Systemic 3. Allergic

Answer 135

Pain, swelling, redness at SITE of injection * common with inactivated vaccines * usually mild and self-limited

Answer 136

* fever, malaise, headache, muscle pain, loss of appetite, etc. * some LIVE vaccines may cause a mild form of the illness as a result of replication

Answer 137

Rare allergic reaction to the vaccine antigen, or to some other component of the vaccine itself (some allergic to egg-based vaccines) * may be life-threatening if not immediately treated * classified differently from systemic response because it’s a different mechanism; more of a known quantity rather than an issue with a vaccine itself (like systemic)

Answer 138

* Vaccine Adverse Event Reporting System * System created in 1990s to collect reports of adverse events * passive system that ACCEPTS reports from healthcare providers, vaccine manufacturers, and the general public (does not solicit) * Receives 15,000 reports per year * collects data on patient, vaccine administered, and suspected adverse event, and WHO is reporting; if doctor is reporting, given greater weight * VAERS detects new or rare events, increases in rates of known side effects, patient risk factors, etc. * additional studies REQUIRED to confirm VAERs signals; cannot get causality from these, especially given subjectivity of patient reports

Answer 139

Follows up on all reports of SERIOUS adverse events *serious adverse events defined as an event involving or prolonging hospitalization, life threatening illness, permanent disability, or death

Answer 140

1. Underreporting: common to all surveillance systems which require voluntary reporting; occurs more frequently with LESS serious adverse events 2. Differential reporting: reporting is increased in the first few years after vaccine licensure; increased reporting of events occurring soon after vaccination 3. Stimulated reporting: reporting increases after a KNOWN or alleged type of adverse event is brought to public; like if SOMETHING happens or celebrity speaks out or somethings is in the news 4. Reporting of coincidental events 5. Data quality; data not always complete or accurate 6. No denominator data: VAERS does not collect data on # of vaccine doses administered so don't know exact RATES of adverse events

Answer 141

* Parent, Guardians, and patients should be informed of the risks and benefits of vaccines in understandable language * Vaccine concerns should be anticipated and discussed in empathetic manner using clear and factual language * importance of VACCINE INFORMATION STATEMENTS (VISs)-->per federal law, MUST be provided before each dose of vaccine; available in multiple languages

Answer 142

Contraindication is a condition in a recipient that greatly increases the change of a SERIOUS adverse reaction *Vaccine should NOT be given

Answer 143

A precaution is a condition that MIGHT increase the chance of a severe reaction or that might compromise efficacy * vaccine should NOT be given * in SOME cases the benefit may outweigh the risk sufficiently so as to indicate vaccination in case of precaution

Answer 144

* mild acute illness * Mild/moderate local reaction * antimicrobial therapy * breastfeeding * multiple vaccines, etc.

Answer 145

* Moderate to severe illness (fever, respiratory issues, cardiac problems) * pregnant * severe allergy to vaccine component or an allergic reaction following a prior dose of vaccine * immune disorder like autoimmune disease of immunosuppression

Answer 146

Salk inactivated polio vaccine (IPV) was declared SAFE and effective following a trial conducted in 1.8 million children (POLIO pioneers) * within HOURS, five pharmaceutical companies were granted licenses to manufacture IPV * millions of doses were quickly produced and administered, mostly to children

Answer 147

* Reports began to surface of children becoming paralyzed after receiving IPV manufactured by Cutter Laboratories * Vaccine was immediately recalled * Later determiend that 120,000 doses of vaccine produced by Cutter contained LIVE POLIO VIRUS due to a manufactoring error * Of the children vaccinated, 40,000 developed abortive polio, 51 were permanently paralyzed, and 5 died * vaccine started a polio epidemic that paralyzed 113 and killed 5 more

Answer 148

Cell debris in the vaccine prevented adequate exposure of the virus to formaldehyde * they miscalculated the extrapolation; expected that for a given increase in temperature, the amount of live polio virus in the vaccine would decrease logarithmically, but at very high temperatures, begins to taper off and so the same temperature increment has smaller effect, so they did not heat it enough because based on extrapolation of what graph SHOULD look like, the heat they used should be sufficient * now they WAY overdo it to ensure that virus is KILLED

Answer 149

* manufacturing requirements for IPV were revised * cutter laboratories was sued by many of the affected families; the company was found to be financially liable but NOT NEGLIGENT--legal precedent of liability without fault made it easier for courts to rule against pharmacuetical companies in other cases * by the 1980s, liability issues caused increases in the price and a dwindling number of manufacturers, threatening the supply; tension caused establishment of VICP

Answer 150

Vaccine Injury Compensation Program * major goals: to provide JUST compensation to those injured by rare adverse events and provide liability protection for VACCINE manufacturers, helping to ensure adequate vaccine supply * no fault program: no need to prove negligence on part of provider or manufacturer * Settlements are based on a vaccine injury table; if event not listed on table, must PROVE vaccine caused it

Answer 151

* in 1998, British Gastroenterologist Wakefield published article in the Lancet saying that MMR vaccine caused INTESTINAL INFLAMMATION, which allowed the movement of otherwise nonabsorbed peptides into the bloodstream and subsequently to the brain where they affected development * studied only 12 children; believed that MMR vaccine led to children developing autism * Hypothesized neurological mechanism for immunological event; he studied 12 children; hypothesized that there was intestinal inflammation in stomach called leaky gut allowing absorption of proteins into bloodstream, crossing BBB and in the brain, causing autism in the baby

Answer 152

* Following media reports on the wakefield paper, MMR immunization rates dropped and reached a low of 80% (way below what is necessary for herd immunity) * measles cases dramatically increased during this period * immunization rates have subsequently increased but are STILL below the 95% threshold needed to prevent outbreaks * the Wakefield paper was FORMALLY retracted in 2010 after Wakefield was found to have engaged in multiple ethics violations while conducting study

Answer 153

* 12 people is not enough people to draw a conclusion; no statistical significance or power * 3 of children reported with regressive autism did NOT have diagnosed autism * 5 of the children had DOCUMENTED pre-existing developmental concerns * in 9 cases, unremarkable colonic histopathology results were changed to NON-specific colitis * patients were recruited through anti-MMR vaccine campaigners, and the study was commissioned and funded for planned litigation

Answer 154

1. MMR Hypothesis 2. Thimerosal Hypothesis 3. "Too Many Vaccines" Hypothesis

Answer 155

MMR vaccine causes inflammation that damages the intestinal lining, allowing the entrance of encephalopathic peptides **DEBUNKED: the MMR vaccine has NOT been shown to cause intestinal inflammation or loss of barrier function & the putative autism-inducing encephalopathic peptides have NOT been identified

Answer 156

The MERCURY containing preservative thimerosal found in some vaccines is toxic to the CNS *DEBUNKED: well described signs and symptoms of mercury poisoning are DISTINCT from those of autism; furthermore a tuna can has more mercury in it than vaccine

Answer 157

The simultaneous administration of multiple vaccines OVERWHELMS or weakens the immune system and creates a pathological interaction with the nervous system * debunked because number of proteins and ANTIGENS in vaccines has decreased drastically over the years while autism has increased; know it is antigens that activates immune system so fewer antigens=less activation * DEBUNKED: the immune system can and DOES respond to many more antigenic challenges than vaccines represent; multiple vaccinations do NOT weaken the immune system and even as the # of childhood vaccines has increased, the # of antigens in them has declined

Answer 158

scientific community is poor at speaking colloquially and understandably about situation while the anti-vaccine campaign tends to speak using colloquial language and famous personalities and preys on fears people already have

Answer 159

* many vaccine preventable disease are unfamiliar to parents and increasingly clinicians (so less risk aversion driving use of vaccines) * # of recommended vaccines has increased considerably * Vaccine mandates can fuel distrust; American individualism is strong and resists this impetus * misinformation about vaccines has equal access to the internet and popular media, and greatly exceeds the volume of reputable information; misplaced trust in celebrities expressing scientifically UNFOUNDED POSITIONS

Answer 160

Although the terms are often used interchangeably, not all immunizations are technically vaccines; immunization of animals for monoclonal antibody or antitoxin production is not to treat the animal and provide a protective or therapeutic response, but just to get antibodies that can be used to treat OTHERS

Answer 161

Can make plasmid better, the specific gene better, use adjuvants, and deliver to the right part of the body where it will be most efficacious. Can make gene easier to express and more stable when it gets into a cell. P

Answer 162

* Integration: DNA vaccines integrate into cellular DNA owing to optimized expression plasmids, which could result in chromosomal instability or inactivation of tumor suppressor genes. * Autoimmunity: development of autoimmune disorders against patient DNA or immune adjuvants * Antibiotic Resistance: potential risk that antibiotic resistance could be transferred to patients receiving vaccines through the unintentional transfer of bacteria. * Low immunogenicity: first generation DNA plasmids elicit low levels of T and B cell memory

Answer 163

1. Integration studies are done for DNA vaccines before human trials are done 2. Autoimmunity is unlikely 3. Antibiotic resistance; antibiotics used are those not commonly used to treat human infections/ have a bacterial, not mammalian origin of replication 4. Increasing immunogenicity using plasmid adjuvants

Answer 164

1. Design: simple engineering; easy to manufacture and modify; antigen genes could be combined with genes for cytokines, TLR ligands, etc. 2. Time: rapid production & large-scale production 3. Safety: cant revert into virulent forms and no significant adverse events to date 4. Stability: long shelf life 5. Mobility: ease of storage and transport; doesnt require cold chain & can be administered without needles 6. Immunogenicity; similar to live attenuated; induce humoral and cell-mediated immunity 7. Antigens expressed in natural form in myocytes and DCs (myocytes are muscle cells); DNA is typically injected into muscle cell; some muscle cells will take up DNA and express it, which then allows immune system to respond to it * could theoretically express antigen right in antigen presenting cell

Answer 165

* the first DNA vaccine was the for West-Nile virus for HORSES * if horses get west nile it can be really bad for them so there is a DNA vaccine that works really well (94% efficacy)

Answer 166

Device for injecting cells with genetic information (transgenes) * The payload is an elemental particle of a heavy metal coated with plasmid DNA. * *Gene gun uses high pressure to blast microparticles into pig * not any human DNA vaccine available yet; SOME are approved for vetinary use

Answer 167

They cannot be used for NON-protein antigens

Answer 168

*DNA is very stable; easy to make and store and easy to change it mid-stream; if it turned out that during flu season a different flu came up or different strain emerged, could theoretically change vaccine very easily

Answer 169

1. Vaccine supplies are insufficient; there is inadequate research and development, and few manufacturers making current vaccines 2. Financial barriers at multiple levels; research and development costs are high, they are not as profitable as drugs, and once produced, have to be affordable; drugs need long-term, vaccines shorter term and only once 3. Safety, efficacy, and compliance issues

Answer 170

* study conducted with over a million active military personnel * Vaccination with TIV (trivalent INACTIVATED vaccine) was associated fewer medical encounters related to pneumonia than LAIV (intranasal live attenuated) * authors suggest that in a highly immunized adult population, inactivated is more affective than live attenuated in preventing pneumonia and influenza-related morbidity * If have had flu vaccine, could potentially clear out live attenuated vaccine which doesnt give it enough time to create a really strong memory * live attenuated potentially better for those with NO prior immunizations

Answer 171

IgA will bind and surround pathogen, preventing it from interacting with the intestinal epithelium * Through a process known as immune exclusion, SIgA promotes the clearance of antigens and pathogenic microorganisms from the intestinal lumen by blocking their access to epithelial receptors, entrapping them in mucus, and facilitating their removal * IgA can come from ones own gut or mothers milk * *if enough IgG is in serum, some will cross surface and be protective; it doesnt last as long as IgA because not as stable, but IgG can act on the mucosal surface and be protective sometimes

Answer 172

Mucosal immunology is the study of the portion of the immune system which provides protection to an organism's various mucous membranes from invasion by potentially pathogenic microbes.

Answer 173

TOLERANCE. * the essential difference between antigenic challenge by food compared with that by pathogens is that the pathogens cause inflammation, whereas food does not. Both the antigens within food and the antigens within pathogens are presented by antigenpresenting cells to T lymphocytes, but the contexts in which these two sources of antigen are presented are quite different. * anergy: process in which T cells presented with peptide in the absence of co-stimulatory signals become refractory to further stimulation with antigen; happens with food stimuli

Answer 174

* The primary reason for using a mucosal route of vaccination is that most infections affect or start from a mucosal surface, and that in these infections, topical application of a vaccine is often required to induce a protective immune response. * These infections represent an enormous challenge for development of vaccines targeted to induce immunity that can either prevent the infectious agent from attaching and colonizing at the mucosal epithelium (noninvasive bacteria), or from penetrating and replicating in the mucosa (viruses and invasive bacteria) * But despite the many attractive features of mucosal vaccination, it has often proven difficult in practice to stimulate strong SIgA immune responses and protection by mucosal administration of antigens.

Answer 175

1. oral (enteric) 2. intranasal 3. aerosol 4. transcutaneous (patches, microneedles, powder)--topical

Answer 176

* intravenous | * intramuscular

Answer 177

* The idea was to stably insert one or more genes of other pathogens into the genome of vaccinia virus while retaining the infectivity of the latter. Moreover, the large capacity of vaccinia virus for foreign DNA raised the possibility of polyvalent vaccines against multiple diseases. * In principle, recombinant vaccinia viruses would have many of the properties of live attenuated virus vaccines and would present antigens in natural ways so as to stimulate humoral immunity to native protein conformation as well as cell-mediated immunity * take vaccinia virus (has large genome so not hard to get other genomes in there for size purposes), and introduce with DNA technology the gene from the pathogen into the genome of the vaccina * so vaccina is also now expressing some other pathogens protein (ex: rabies protein) * dont have any vaccines like this for human USE * many viral coat proteins will self-assemble under appropriate conditions

Answer 178

* Understanding of disease pathogenesis * first step towards the development of vaccine strategies * allows assessment of protection in vaccinated individuals * permits new vaccines to be developed without having to form large field efficacy trials * it provides an objective criterion for protection of individual vaccinees, and even more practically, it permits the licensure of a vaccine without demonstration of field efficacy in situations where clinical trials are dangerous or when new combinations of existing vaccines are tested. Although the literature is rich in attempts to define correlates for particular vaccines, few synthetic analyses have been published.

Answer 179

*an immune response that is responsible for and statistically interrelated with PROTECTION

Answer 180

A specific level of immune response highly correlated with protection; a threshold * situations in which a certain level of response almost guarantees protection

Answer 181

A level of immune response variably correlated with protection *Although an absolute correlate of protection is highly desired, unfortunately, many correlates are relative—that is, protection is usually achieved at a certain level of response, but breakthroughs occur even at nominally protective levels.

Answer 182

One of two or more factors that correlate with protection in alternative, additive, or synergistic ways *There may be >1 correlate of protection for a disease, which we term “cocorrelates.” E

Answer 183

An immune response that substitutes for the true immunologic correlate of protection, which may be unknown or not easily measurable * often antibody measurements that must suffice as predictors of protection by vaccines * surrogates are immunological measurements that are feasible to make but that are only indirectly related to the true correlate of protection

Answer 184

* it should be understood that each correlate must be qualified as to the end point. Is it a correlate of protection against infection, disease, hospitalization, or death? These may be very different for the same vaccine. * Correlates may differ quantitatively and qualitatively, depending on whether the objective is to prevent systemic infection, mucosal infection, disease, or severe disease/death * Lastly, it is crucial to understand that the correlate of protection induced by vaccination is not necessarily the same correlate that operates to close off infection. for instance a certain dose could protect against clinical signs of the disease not not the actual infection * Correlates may vary according to individual charac-teristics, such as age, gender, and major histocom-patibility complex (MHC) group

Answer 185

* Large challenge doses may overwhelm vaccine-induced immunity and confuse the identification of correlates * The mechanism of protection (e.g. antibodies) is not necessarily the mechanism of recovery from infection (e.g. cellular responses

Answer 186

* Most vaccines available today act through antibodies * This is evident from the frequent efficacy of passive antibodies and transplacental antibodies * Given that the immune system has evolved to be redundant, vaccines, like prior natural infection, may protect through multiple mechanisms

Answer 187

Viremia; viruses in the blood * mucousal and skin invasion & virus replication * toxin production

Answer 188

* ELISA * neutralization * Interferon * HAI

Answer 189

Hemagglutination Inhibition * Influenza virus particles have an envelope protein called the hemagglutinin, or HA, which binds to sialic acid receptors on cells. The virus will also bind to erythrocytes (red blood cells), causing the formation of a lattice. This property is called hemagglutination, and is the basis of a rapid assay to determine levels of influenza virus present in a sample. * The red blood cells that are not bound by influenza virus sink to the bottom of a well and form a button. The red blood cells that are attached to virus particles form a lattice that coats the well.

Answer 190

* The HA assay can be easily modified to determine the level of antibodies to influenza virus present in serum samples. * The basis of the HI assay is that antibodies to influenza virus will prevent attachment of the virus to red blood cells. Therefore hemagglutination is inhibited when antibodies are present. The highest dilution of serum that prevents hemagglutination is called the HI titer of the serum. If the serum contains no antibodies that react with the new H1N1 strain, then hemagglutination will be observed in all wells. Likewise, if antibodies to the virus are present, hemagglutination will not be observed until the antibodies are sufficiently diluted.

Answer 191

A serum IgG HAI titer of 1/40 (indicated by the red line) is generally considered acceptable, but efficacy varies and in some cases may be as low as 50%, making this a relative correlate * The relevance of antibodies to other antigens for protection is poorly understood * Serum IgG antibodies are a good correlate in adults under 50; in the elderly cellular responses may be a better correlate

Answer 192

A substance that when included as part of a vaccine has the effect of enhancing the immune response to the vaccine antigen(s) * May be aluminum salts, emulsions, proteins, lipids, small molecules, particles, etc. * Promote “stronger, longer” responses * Often allow reduction in antigen dose and/or number of immunizations required * Enhance protective efficacy of vaccines, especially in populations that may be “immune challenged” * Generally cause little or no toxicity on their own * May be intentionally added or be present as a natural (intrinsic) part of a vaccine * May be combined in vaccines for added effect

Answer 193

*Memory induced by vaccination may be crucial to protection Particularly in long-incubation diseases (e.g. Hepatitis B) Loss of antibody after vaccination may render vaccinees susceptible to some infections, but central memory established by vaccination is sufficient under certain circumstances to confer protection

Answer 194

Viral shedding refers to the expulsion and release of virus progeny following successful reproduction during a host-cell infection. Once replication has been completed and the host cell is exhausted of all resources in making viral progeny, the viruses may begin to leave the cell by several methods.

Answer 195

* if have low levels of antibodies, below a certain threshold, antibody levels are not high enough to preevnt invasive disease if colonized * If above threshold for infection but below threshold for colonization; antibody levels are high enough to prevent invasive disease but not colonization; while only some, a small fraction of kids, may be colonized, a much greater number has the potential to be colonized becasue dont have enough antibodies * IF above colonization threshold, antibody levels are high enough to prevent colonization

Answer 196

Isolate the microorganism Attenuate or Inactivate it Inject it into patient

Answer 197

*Traditional vaccine development methods have generally involved the cultivation of pathogenic microorganisms in the laboratory The cultured organisms may serve as live attenuated vaccines, inactivated (killed) whole vaccines, or sources of acellular “subunit” vaccines

Answer 198

*Not applicable to organisms that cannot be cultivated in the laboratory *Cultivated organisms may not express full repertoire of infection-associated antigens There may be thousands of antigens to analyze, and those that are protective may not be abundant or immunodominant

Answer 199

The ability of rapid sequencing technology allows all possible proteins of a given pathogen to be predicted and analyzed “in silico”, making “reverse vaccinology” possible

Answer 200

1. ORF (open reading frame) prediction on the genomic sequence 2. Database searches for all the predicted ORFs 3. If hits are found, look up assigned function. , if localized in the cytoplasm or is an already known antigen, discard it. Look for homology to bacterial surface-associated proteins 4. If no hits found, make localization predictions for the hypothetical proteins; discard those located in cytoplasm and select secreted outer membrane & inner membrane proteins

Answer 201

* Mutant strains are generated and each is “tagged” with a unique DNA sequence * Tagged mutant strains are pooled together and inoculated into an animal * After infection is established, bacteria are recovered from the infected animals * Attenuated mutants will not be recovered from the animals * Technique identifies attenuated mutant strains that fail to cause productive infection, which may be used as live vaccines * Also allows identification of proteins essential for infection or disease which may be used as subunit vaccines * Since virulence genes are either directly or indirectly associated with various stages of the infection process, their inactivation may lead to complete loss of virulence or a decrease in the level of infection. One of the main tools to identify virulence factors is to use gene disruption strategies, such as random transposon mutagenesis and to analyze the individual mutants that carry a single gene deletion.

Answer 202

*Thousands of pathogen DNA sequences are applied to a solid “chip” to make a microarray *RNA from pathogens grown under various conditions (e.g. in vivo and in vitro) is prepared and used to probe the chip *By comparison with a control it is possible to identify pathogen genes whose transcription is upregulated or downregulated during host-pathogen interaction Technique may also be employed to study host genes involved in the response to infection

Answer 203

* A protein extract prepared from the pathogen is first separated into its individual components using 2D electrophoresis, chromatography, etc. * Once separated, each protein may be analyzed by mass spectroscopy, N-terminal sequencing, immunoreactivity, etc. * Sequence results may be used to search the pathogen’s genome (if available) or those of other species to identify and/or predict proteins * The protein(s) of interest may be cloned and evaluated as vaccine candidates * Advantage over DNA & RNA-based methods is that the proteins are known to be expressed

Answer 204

* Reverse-Phase High-Performance Liquid Chromatography of Adult A. ceylanicum Excretory/Secretory (ES) Products * Each “fraction” collected off the HPLC column was tested for immunoreactivity against infected hamster serum; a subset were subjected to mass spectrometry and N-terminal sequencing

Answer 205

* A reverse vaccinology approach where you start from the WHOLE genomic sequence and then use a computer to predict novel antigens and then use in silico analysis to narrow down antigens and then use a plasmid to express the recombinant proteins and then do immunogenicity testing. It is a 1-2 year process. * was successfully employed to develop a candidate vaccine for Meningococcus B * Genome of virulent strain had many ORFs * Computer predictions identified fewer ORFs corresponding to surface-exposed secreted antigens * of those, even fewer were successfully expressed in E. Coli, purified, and used to immunize mice * antisera tests by ELISA to evaluate surface localization of antigens * antiseria tested for bactericidal antibodies, which correlate with protection in humans

Answer 206

* a blood serum containing antibodies against specific antigens, injected to treat or protect against specific diseases. * Antisera will have everything in it: specific (polyclonal) antibodies raised against antigen, antibodies that cross-react with similar antigens, antibodies that do not react with with the antigen at all. * s blood serum containing polyclonal antibodies and is used to pass on passive immunity to many diseases. * The most common use of antiserum in humans is as antitoxin or antivenom

Answer 207

*An antitoxin is an antibody with the ability to neutralize a specific toxin. Antitoxins are produced by certain animals, plants, and bacteria. Although they are most effective in neutralizing toxins, they can kill bacteria and other microorganisms. Antitoxins are made within organisms, but can be injected into other organisms, including humans. This procedure involves injecting an animal with a safe amount of a particular toxin. Then, the animal’s body makes the antitoxin needed to neutralize the toxin. Later, the blood is withdrawn from the animal. When the antitoxin is obtained from the blood, it is purified and injected into a human or other animal, inducing passive immunity. To prevent serum sickness, it is often best to use antitoxin generated from the same species

Answer 208

* The enzyme-linked immunosorbent assay (ELISA) is a common laboratory technique which is used to measure the concentration of an analyte (usually antibodies or antigens) in solution. * The purpose of an ELISA is to determine if a particular protein is present in a sample and if so, how much. There are two main variations on this method: you can determine how much antibody is in a sample, or you can determine how much protein is bound by an antibody. The distinction is whether you are trying to quantify an antibody or some other protein.

Answer 209

1. Computer analysis of the whole genome identifies genes coding for predicted antigens and eliminates antigens with homologies to human proteins. 2. The identified antigens are screened for expression by the pathogen and for immunogenicity during infection. 3. The selected antigens are used to immunize animals and test whether immunization induces a protective response. 4. Protective antigens are tested for their presence and conservation in a collection of strains representative of the species (molecular epidemiology). 5. Selected antigens are manufactured in large scale for clinical trials, and candidate vaccines are tested for safety and protective immunity in humans using established correlates of protection or efficacy studies. 6. Scientific, clinical, and technical information is then analyzed and approved by regulatory agencies 7. Policy-making bodies, such as the ACIP, make the recommendation on how the vaccine should be used. 8. The approved vaccine is then commercialized and used in large scale. At this point, phase IV clinical studies confirm safety.

Answer 210

Immunogenicity is the ability of a particular substance, such as an antigen or epitope, to provoke an immune response in the body of a human or animal. In other words, immunogenicity is the ability to induce a humoral and/or cell-mediated immune responses. * Wanted immunogenicity is typically related with vaccines, where the injection of an antigen (the vaccine) provokes an immune response against the pathogen (virus, bacteria...) aiming at protecting the organism. Vaccine development is a complex multistep process, immunogenicity being at the center of the vaccine efficiency. * In silico screening. T cell epitope content, which is one of the factors that contributes to the risk of immunogenicity can now be measured relatively accurately using in silico tools.

Answer 211

* LOTS of PAMPS=NO NEED TO ADD ADJUVANTS * FEW PAMPS=ADD ADJUVANT * Adjuvants in immunology are often used to modify or augment the effects of a vaccine by stimulating the immune system to respond to the vaccine more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionarily conserved molecules, so called PAMPs

Answer 212

Pathogen-associated molecular patterns, or PAMPs, are molecules associated with groups of pathogens, that are recognized by cells of the innate immune system. These molecules can be referred to as small molecular motifs conserved within a class of microbes. * PAMPs activate innate immune responses, protecting the host from infection, by identifying some conserved nonself molecules. Bacterial lipopolysaccharides (LPSs), endotoxins found on the cell membranes of bacteria, are considered to be the prototypical class of PAMPs. * they are recognized by Toll-like receptors (TLRs) and other pattern recognition receptors (PRRs) in both plants and animals.

Answer 213

*Many act directly or indirectly on antigen- presenting cells (APCs), especially dendritic cells (DCs) *Vehicles --Some have “depot” effect (controlled Ag release) --Some deliver the antigen (or other adjuvants) to APCs *Immunostimulants *Many act by engaging the pathogen recognition receptors (PRRs) of the innate immune system such as TLRs May affect DC migration, maturation, APC activity, or expression of costimulatory molecules and cytokines Cytokine adjuvants may act on T-cells, B-cells, or APCs

Answer 214

* An antigen-presenting cell (APC) or accessory cell is a cell that displays antigen complexed with major histocompatibility complexes (MHCs) on their surfaces; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs). These cells process antigens and present them to T-cells. * Professional antigen-presenting cells, including macrophages, B cells, and dendritic cells, specialize in presenting foreign antigen to T helper cells, while other cell types can present antigen originating inside the cell to cytotoxic T cells. * Antigen presentation allows for the extreme specificity of adaptive immunity and can contribute to immune responses against both intracellular and extracellular pathogens.

Answer 215

* A set of cell-surface proteins essential for immune system * The main function of MHC molecules is to bind to peptide fragments derived from pathogens and display them on the cell surface for recognition by the appropriate T-cells. * Each MHC molecule on the cell surface displays a molecular fraction of a protein, called an epitope.The presented antigen can be either 'self' or 'nonself', thus preventing an organism's immune system targeting its own cells. In its entirety, the MHC population is like a meter indicating the balance of proteins within the cell.

Answer 216

*By interacting with CD4 molecules on surfaces of helper T cells, MHC class II mediates establishment of specific immunity (also called acquired immunity or adaptive immunity). By interacting with CD8 molecules on surfaces of cytotoxic T cells, MHC class I mediates destruction of infected or malignant host cells, the aspect of specific immunity termed cellular immunity.

Answer 217

* Safe for use regardless of age, health status, immune status, etc. * Stable (no refrigeration a plus) * Biodegradable in vivo * Selectively induces desired immune responses * Mechanism of action understood * Inexpensive and easy to produce * Compatible with a range of vaccine antigens and other adjuvants * Can be administered by various routes

Answer 218

* Not consistently immunogenic in children younger than 2 years old * No booster response (No T cell involvement, so no memory induced) * Activates antibodies with less functional activity (mostly IgM and SOME IgG) * Immunogenicity of polysaccharide may be improved by conjugation to carrier protein * An unconjugated polysaccharide vaccine does NOT ALLOW T CELL HELP, thus little IgG can be utilized * Conjugation of polysaccharide allows B cells to receive signals 1 and signals 2 * Conjugated polysaccharide allows T cell help, thus HIGH LEVELS of IgG are produced * A conjugate vaccine for streptococuss pneumoniae has greatly reduced invasive pneumococcal disease in children

Answer 219

* toxins: typically the way toxins work is they have a toxin domain and binding domain; binding domain will bind to host cell and toxin cell will do badness to cell * Toxoid: PREVENT it from getting into the cell by making antibodies that are inactivating binding domain; if it cant get in the door its not going to wreck the party * toxoids have traditionally been produced by treatment with heat or fixatives, but can be engineered via recombinant DNA technology

Answer 220

*There is a relative LACK of licensed & effective oral vaccines which are able to give LIFE LONG protective immunity

Answer 221

* Diarrheal diseases remain a significant worldwide health issue * the gold standard would be development of vaccine * development of vaccines for mucosal pathogens has been a major challenge b/c 1: there is poor understanding of the determinants of gut immunity, 2: vaccines have reduced efficacy & immunogenicity in developing countries were diarrheal diseases are the most problematic

Answer 222

Most cases of acute, watery diarrhea are caused by viruses (viral gastroenteritis). The most common ones in children are rotavirus and in adults are norovirus. Bacteria are a common cause of traveler’s diarrhea. *Exposure to infectious agents is the major risk factor for acute diarrhea. Bacteria and viruses are often transmitted by the fecal-oral route, so hand washing and hygiene are important to prevent infection.

Answer 223

* Antibiotics, also called antibacterials, are a type of antimicrobial used in the treatment and prevention of bacterial infection. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the common cold or influenza, and may be harmful when taken inappropriately. * Antibiotics revolutionized medicine in the 20th century, and have together with vaccination led to the near eradication of diseases such as tuberculosis in the developed world.

Answer 224

Antibiotics and vaccines are both used to fight germs but they work in different ways. While vaccines are used to prevent disease, antibiotics are used to treat diseases that have already occurred. In addition, antibiotics do not work on viruses or viral illnesses such as common cold or flu.

Answer 225

*Variolation or inoculation was the method first used to immunize an individual against smallpox (Variola) with material taken from a patient or a recently variolated individual in the hope that a mild, but protective infection would result. The procedure was most commonly carried out by inserting/rubbing powdered smallpox scabs or fluid from pustules into superficial scratches made in the skin. The patient would develop pustules identical to those caused by naturally occurring smallpox, usually producing a less-severe disease than naturally-acquired smallpox. Eventually, after about two to four weeks, these symptoms would subside, indicating successful recovery and immunity. The method was first used in China and the Middle East before it was introduced into England and North America in the 1720s in the face of some opposition.

Answer 226

1. PRODUCTION: A=selection of avirulence by culture or mutagenesis, I=virulent organism or toxin inactivated by exposure to heat, chemicals, or radiation 2. BOOSTING: A=0-1 booster (usually), I=requires multiple boosters 3. STABILITY: A=limited, needs refrigeration; I=generally more stable than attenuated 4. DOSAGE: A=injected or mucosal, no adjuvants needed, I=injected only, adjuvants often required 5. TYPE OF IMMUNE RESPONSE: A=humoral (mucosal) antibodies and cell-mediated responses (CTL and/or DTH), I=induces mainly humoral (serum) antibodies, DTH possible, but generally POOR CTL 6. RISKS: A=in rare cases, may revert to virulent form which can cause disease and spread to others; I=cannot cause disease if PROPERLY inactivated, and allergic reactions are POSSIBLE but rare

Answer 227

* Cytotoxic T lymphocytes (CTLs) are generated by immune activation of cytotoxic T cells (Tc cells). They are generally CD8+, which makes them MHC class I restricted. CTLs are able to eliminate most cells in the body since most nucleated cells express class I MHC molecules. * Most cytotoxic T cells express T-cell receptors (TCRs) that can recognize a specific antigen. An antigen is a molecule capable of stimulating an immune response, and is often produced by cancer cells or viruses. Antigens inside a cell are bound to class I MHC molecules, and brought to the surface of the cell by the class I MHC molecule, where they can be recognized by the T cell. If the TCR is specific for that antigen, it binds to the complex of the class I MHC molecule and the antigen, and the T cell destroys the cell.

Answer 228

* delayed type hypersensitivity takes two to three days to develop. Unlike the other types, it is not antibody mediated but rather is a type of cell-mediated response. * An inflammatory response that develops 24 to 72 hours after exposure to an antigen that the immune system recognizes as foreign. This type of immune response involves mainly T cells rather than antibodies (which are made by B cells). Also called DTH. * CD4+ helper T cells recognize antigen in a complex with Class II major histocompatibility complex. The antigen-presenting cells in this case are macrophages that secrete IL-12, which stimulates the proliferation of further CD4+ Th1 cells. CD4+ T cells secrete IL-2 and interferon gamma, further inducing the release of other Th1 cytokines, thus mediating the immune response. Activated CD8+ T cells destroy target cells on contact, whereas activated macrophages produce hydrolytic enzymes and, on presentation with certain intracellular pathogens, transform into multinucleated giant cells.

Answer 229

Specific gut microbial species affect the immune system; a shift in the intestinal microbiota composition could alter the functioning and development of the immune system * the presence of a complex microbiota promotes development of the intestinal immune system

Answer 230

* Reduced numbers and size of Peyer's patches * decreased lamina propria CD4+ T-cell numbers * Reduced levels of class-switching atnibodes IGA and IgG * Lack of a developed Gut-associated lymphoid tissue * DO NOT develop tolerance

Answer 231

* The gastrointestinal tract's immune system is often referred to as gut-associated lymphoid tissue (or GALT) and works to protect the body from invasion. * The digestive tract is an important component of the body's immune system. In fact, the intestine possesses the largest mass of lymphoid tissue in the human body. The GALT is made up of several types of lymphoid tissue that store immune cells, such as T and B lymphocytes, that carry out attacks and defend against pathogens.

Answer 232

* They are aggregations of gut associated lymphoid tissue that are usually found in the lowest portion of the small intestine * Because the lumen of the gastrointestinal tract is exposed to the external environment, much of it is populated with potentially pathogenic microorganisms. Peyer's patches thus establish their importance in the immune surveillance of the intestinal lumen and in facilitating the generation of the immune response within the mucosa. * Pathogenic microorganisms and other antigens entering the intestinal tract encounter macrophages, dendritic cells, B-lymphocytes, and T-lymphocytes found in Peyer's patches and other mucosa-associated lymphoid tissue (MALT). Peyer's patches thus act for the gastrointestinal system much as the tonsils act for the respiratory system, trapping foreign particles, surveilling them, and destroying them.

Answer 233

Peyer's patches are covered by a special epithelium that contains specialized cells called microfold cells (M cells) which sample antigen directly from the lumen and deliver it to antigen-presenting cells (located in a unique pocket-like structure on their basolateral side). T cells, B-cells and memory cells are stimulated upon encountering antigen in Peyer's patches.

Answer 234

* The lymphatic system is part of the circulatory system and a vital part of the immune system, comprising a network of lymphatic vessels that carry a clear fluid called lymph directionally towards the heart. * Associated organs composed of lymphoid tissue are the sites of lymphocyte production.; lymphocytes= subtypes of white blood cell in a vertebrate's immune system. Lymphocytes include natural killer cells (NK cells) (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells (for humoral, antibody-driven adaptive immunity).

Answer 235

* The lamina propria is a thin layer of loose connective tissue, or dense irregular connective tissue, which lies beneath the epithelium and together with the epithelium constitutes the mucosa. * The connective tissue of the lamina propria is very loose allowing it to be very cell rich. The cell population of the lamina propria is very varied including, for example, fibroblasts, lymphocytes, plasma cells, macrophages, eosinophilic leukocytes, and mast cells * The lamina propria is also rich in immune cells known as lymphocytes. A majority of these cells are IgA-secreting B cells.

Answer 236

Yes. It is early days in microbiome research however. But there is potential that our newfound knowedge of the impact of the gut microbiota could be the missing link in improving oral vaccine efficacy.

Answer 237

Many studies show that responses to polio, potavirus, cholera, dysentery and typhoid are less in developing countries * Nicaraguan children have blunted antibody responses to oral cholera vaccine when compared to developed countries * Small intestinal bacterial overgrowth contributes to lower antibodies to cholera vaccine

Answer 238

* increased antigen exposure * Malnutrition * Nutrient deficiency (vitamin A, zinc) * Antibiotics * Breast milk antibodies * parasites * however, all of these feed into microbiota composition * studies DO SHOW that microbiota is different in children from developed and developing countries; microbiota could be implicated in why vaccines show reduced efficacy in developing countries; in developed, have more firmicutes, while in developing African village, have more bacteroidetes microbres.

Answer 239

Probiotics and prebiotics could POTENTIALLY be used as vaccine adjuvants responsible for modulating the flora to enhance the adaptive immune response. Have been studies done where taking probiotics has led to improved immunogenicity & enhanced vaccine efficacy *Probiotics could potentially be USED to deliver VACCINE ANTIGEN--NO DATA in animals or humans for this yet

Answer 240

* Probiotics have been found to increase responses to parenteral vaccines diptheria, tetanus, and hep. B * Particularly important early in life (C-section/formula feeding can decrease probiotic microbiota constituents) * No long term follow up studies and studies show variable effectiveness * Mechanism as yet unclear

Answer 241

* Very difficult to study small intestinal and mucosal-associated microbiota in humans, but there is a SIGNIFICANAT GAP between animal and human studies in microbime and vaccine research, so we need mice with humaized immune systems so they are more translatible to HUMAN VACCINE RESEARCH * Human microbiome studies are more relevant but correlative and hard, while animal models are poor translations to human vaccines but allow more mechanistic study; need balance of both * Also fecal microbiota composition is not always reflective of function at mucosal sites

Answer 242

* *Definite need as we begin to identify keystone species and pathobionts * we only have blunt tools at our disposal to alter specific species/pathobionts in our microbial community * ex: antibiotics, diet, prebiotics, phage therapy, etc.

Answer 243

May cause community ripple-down effect * difficult to predict, need for more basic science on community interactions * Microbial ecosystem is a complex and adaptive system that is non-linear, so small changes could have profound effects

Answer 244

ANTIBODY: Neutralization, Opsonization, Complement activation, Antibody-Dependent, Cellular Cytotoxicity (ADCC), Mast cell degranulation CELL-MEDIATED: Phagocytosis (Neutrophils, Macrophages, etc.), Cytotoxic T-Cells (CTLs), Natural Killer Cells (NKs), NKT Cells, Delayed-Type Hypersensitivity (DTH), Antibody-Dependent Cellular Cytotoxicity (ADCC)

Answer 245

respiratory syncytial virus (RSV) * usually causes mild, cold-like symptoms, but CAN cause SEVERE lung infections like pneumonia, especially in infants * Medicine is PALIVIZUMAB, which is a series of monthly shots given to at-risk infants during RSV season * example of passive immunization because providing temporary protective immunity but creating no memory

Answer 246

*Influenza, commonly known as "the flu", is an infectious disease caused by an influenza virus. Symptoms can be mild to severe.The most common symptoms include: a high fever, sore throat, muscle pains, headache, coughing, and feeling tired. *Three types of influenza viruses affect people, called Type A, Type B, and Type C.[4] Usually, the virus is spread through the air from coughs or sneezes *Influenza spreads around the world in a yearly outbreak, resulting in about three to five million cases of severe illness and about 250,000 to 500,000 deaths. *At least four pandemics in the 19th century, three in the 20th, and one (so far) in the 21st *In the 20th century three influenza pandemics occurred: Spanish influenza in 1918, Asian influenza in 1958, and Hong Kong influenza in 1968, each resulting in more than a million deaths *Virus first isolated in 1933 and cultured (in embryonated chicken eggs) in 1936 This enabled the development of the first flu vaccines

Answer 247

* Enveloped virus with two major surface antigens, Hemagglutinin (H) and Neuraminidase (N) * Three genera: Influenza A, Influenza B, and Influenza C * Type A viruses are further classified based on what combination of H and N they have (H1N1 or H3N2 for example)-->18 H subtypes and 9 N subtypes discovered so far * The viral genome consists of single-stranded, negative-sense RNA * The RNA is segmented, with roughly one protein encoded by each segment * This gives Influenza A viruses their special ability to undergo “antigenic shift”

Answer 248

* Know that influenza is an enveloped virus with a segmented genome and two immunologically-important surface glycoproteins. * Because hemagglutinin (aka H or HA) is more abundant on the viral surface than neuraminidase (N or NA), the majority of our protective antibodies (from a natural infection) tend to be anti-HA. * This is why we’ve traditionally focused on anti-HA antibodies when we measure vaccine efficacy.

Answer 249

* Infects both humans and animals * Circulates in nature by infecting waterfowl * Moderate to severe illness in humans * Affects all age groups * High degree of antigenic variation * Influenza A is the big threat: it’s the only one with an animal reservoir, which means it’s the only one that can undergo antigenic shift

Answer 250

* Infects humans only * Milder disease, primarily affects children * Less genetic variability

Answer 251

* Rarely reported in humans | * No epidemics

Answer 252

Virus type, Geographic origin, strain number, year of isolation, virus subtype

Answer 253

Flu vaccines work by Inducing production of neutralizing antibodies

Answer 254

* Flu virus hemagglutinin (red) binds sialic acids (green) to attach itself to the cell membrane * The virus is endocytosed. Its envelope fuses to the vesicle membrane, releasing viral RNA into the cell. The virus begins to replicate. * Newly-produced virus particles have to escape the cell. Neuraminidase (yellow) cleaves attachments to sialic acid, allowing viral release.

Answer 255

* Antibodies bind to the head region of hemagglutinin, inhibit binding to sialic acids. * Antibodies bind to the stalk region of hemagglutinin prevent the virus from fusing and releasing its contents. * Antibodies to neuraminidase prevent it from cleaving hemagglutinin-sialic acid attachments. Newly-produced viruses are stuck to the cell.

Answer 256

* HA-Head reactive antibodies inhibit HA binding to sialic acids * HA-stalk reactive antibodies inhibit HA conformational change and membrane fusion * NA-reactive antibodies inhibit cleavage of sialic acids and viral release after budding

Answer 257

* Hemagglutinin and neuraminidase antigens expressed by circulating virus strains change with time under the influence of selective pressure exerted by host immunity * Epidemiological impact of antigenic changes depends on extent of change (more change usually means larger impact)

Answer 258

1. Point mutations in the virus gene (antigenic drift) | 2. Exchange of a gene segment with another subtype of influenza virus (antigenic shift)

Answer 259

* Minor change. Subtype remains the same * Caused by point mutations which may lead to amino acid substitutions * Mutations in H and N proteins happen slowly but steadily, and may result in epidemics if the cumulative change is substantial * Drift happens particularly quickly in RNA viruses like flu, because RNA polymerase has no proofreading function. * Due to degeneracy in the genetic code, some mutations are “silent”…. * But other mutations change the codon and thus the amino acid at that position in the protein!

Answer 260

* The majority of viral mutations happen in the two proteins that are subject to selective pressure by immune attack-->HA and NA mutate the most * In turn, changes in the HA protein cluster in regions that neutralizing antibodies can easily access * Most naturally-generated antibodies against hemagglutinin (HA) will attack the exposed “head” region of this protein. The “stalk” region (below the hinge in this picture) is hard to get to, so tend to mutate head more

Answer 261

* Major changes that introduce new genes, including new H and N subtypes, into the pool of viruses circulating in humans * Caused by exchange of gene segments between animal and human flu viruses * Only Type A flu viruses can infect multiple species and experience shift! * Occurs at irregular intervals (10-40 yr) * May result in pandemics * The Segmented Genome of Influenza Virus Allows for Antigenic Shift

Answer 262

*Out of the 19 H subtypes, only H1, H2, and H3 allow viruses to infect humans efficiently. (Remember that hemagglutinin is what allows the virus to attach and get into cells.) *Matters because ANTIGENIC SHIFT: it’s bad news when an avian virus acquires H1 through shift. That virus, adapted to cause mild disease in birds, might be devastating in humans who have no previous immunological experience with it. Pigs are great mixing bowls for human and avian viruses, because they are easily infected with both.

Answer 263

*200 million people could be infected ~200,000 deaths *Direct economic impact could exceed $100 billion

Answer 264

* The 1918-19 Influenza pandemic killed at least 21 million people * (World War I had killed 16 million from 1914-18)

Answer 265

Seasonal flus (like the 1928 flu) often cause the highest mortality in the elderly and very young children. The 1918 flu was unusual because it killed a lot of young, healthy adults.

Answer 266

* Virus is transmitted by respiratory aerosols and direct contact with contaminated objects * Replication in respiratory epithelium with subsequent destruction of cells * The virus almost always stays contained in the respiratory tract, though symptoms are systemic * Viral shedding in respiratory secretions persists for 5-10 days

Answer 267

* About 50% of infected persons will develop classic clinical symptoms * Incubation period 2 days (range 1-4) * Abrupt onset of fever, prostration, myalgia, (muscle aches) sore throat, nonproductive cough, rhinorrhea (runny nose), headache * Severity of illness depends on prior experience with related variants (including both natural infections and vaccines)--Severity isn’t all or none: viruses closely related to strains we have memory against will elicit some cross-reactivity, and perhaps cause a shortened infection. * Major symptoms usually last 2-3 days, but some persons may have asthenia (lack of strength or energy) for weeks

Answer 268

* Pneumonia: Secondary bacterial, or Primary influenza viral-->Flu can kill you directly or indirectly. And researchers now think that secondary pneumonia was responsible for a lot of the deaths in the 1918 pandemic. * Reye’s syndrome in children given aspirin: A rare but serious condition that causes confusion, swelling in the brain, and liver damage. * Myocarditis: Myocarditis is usually caused by a viral infection. A severe case can weaken the heart, which can lead to heart failure, abnormal heartbeat, and sudden death. * Worsening of pulmonary disease * Death: 0.5-1 per 1,000 cases

Answer 269

* Approximately 36,000 influenza-associated deaths during each influenza season * Average of more than 200,000 influenza-related excess hospitalizations * Highest rates of complications and hospitalization among young children and persons >65 years * Persons >65 years of age have typically accounted for more than 90% of deaths * Higher hospitalizations and mortality during seasons when influenza type A (H3N2) viruses predominate * Cost of severe epidemics estimated at $12 billion

Answer 270

* Influenza-Like Illness * We don’t do a great job of diagnosing or quantifying flu incidence and death; ILI is just a proxy measure, and many of these cases might not actually have been flu * ILI is one way to measure flu activity. Most of the time, flu is not actively diagnosed. During flu season, people who come down with flu-like symptoms are usually assumed to have the flu. You can isolate the virus, antigens, or anti-flu Ig from a sample, but that’s not usually done. * “Seasonal” peaks (typically in winter)

Answer 271

*Infections 61 million* *Hospitalizations 274,000* *Deaths 12,470* The majority of infections, hospitalizations, and deaths in the 2009 pandemic occurred in persons under 65 years old By comparison, seasonal influenza leads to about 200,000 hospitalizations and 36,000 deaths annually, mostly in persons above 65 years old

Answer 272

* Strain prevalence fluctuates * We don’t know exactly why this happens * This makes it difficult (though not impossible) to predict the dominant circulating strains each year

Answer 273

* Labs just started testing more patient samples as the 2009 H1N1 strain emerged. The amount of tests they run usually parallels the number of cases the clinicians see. But surveillance got into higher gear with the emergence of this new strain. Higher sampling = greater detection rate. Hence, the upswing in incidence of the unrelated Influenza B strain around the same time. They also started subtyping a greater proportion of samples (being more careful). * Note that the 2009 H1N1 strain displaced the previously circulating H3N2 and B strains during the 2009-10 season * 2009 H1N1 has now become one of the regular seasonal variants. But the other subtypes are back now.

Answer 274

*Inactivated Vaccines-->delivered by intramuscular injection have traditionally been trivalent (A/A/B). Quadrivalent (A/A/B/B) vaccine approved in 2012-13. “Split virus” and subunit types. Duration of immunity 1 year or less. *Live Attenuated Influenza Vaccine (LAIV) Delivered by intranasal route Trivalent/quadrivalent (same strains as TIV) Duration of immunity at least 1 year Approved for healthy persons aged 2-49 years-->LAIV seems to work well in kids, but not as well as the inactivated vaccine in adults. It was never tested in the >50 age group. The only reason why the age cutoff happens there * Most people get the inactivated vaccine * Immunity really only lasts as long as the Ig titer stays high.

Answer 275

viruses whose membranes has been disrupted by detergent

Answer 276

* Most U.S. vaccines have been grown in fertilized chicken eggs since the 1940s: This is not a quick process: it takes about six months from time that included strains are decided to time the vaccines are ready to ship. It’s not easy to change course and include new strains. * 1 egg per strain, 3 per dose * Contain residual egg proteins * Requires about 6 months of lead time * Cell culture-grown vaccines were approved in 2012-->Vaccines made from viruses grown in cell culture: faster, cheaper, and more flexible than growing virus in eggs. * DNA-based vaccines are in clinical trials * “Universal” vaccines would target nonvariable epitopes: could target viral antigens that are less variable

Answer 277

* We keep special “master strains” of flu virus chosen for their ability to grow to high titer in eggs * Coinfect an egg with this master strain and our target strain * For the vaccine, a “reassortant” strain is selected that contains HA and NA from the target, with other genes coming from the master strain. * Goal: a strain that grows well in eggs while resembling the target strain to the immune system * This process must be repeated for each strain to be included in the vaccine

Answer 278

* Because the vaccine production process takes so long, we have to predict the following year’s circulating subtypes around 7-9 months before vaccination actually begins. * World health officials analyze and identify the dominant circulating strains; the FDA distributes seed viruses to manufacturers to begin the production process

Answer 279

*Protection against clinical flu depends on maintenance of high circulating antibody levels *Duration of protection is less than one year due to waning antibodies and antigenic drift *The killed vaccine can induce only antibodies that circulate in the blood (IgM, IgG). This can prevent symptomatic flu (what we’re aiming for in most cases), but it actually doesn’t stop the infection process. You need mucosal antibodies (IgA) to do that. *When well matched to circulating strains, 70%-90% effective among healthy persons younger than 65 *In elderly populations (>65 years): 30%-40% effective in preventing infection among frail elderly persons 50%-60% effective in preventing hospitalization 80% effective in preventing death

Answer 280

34% of African Americans and 25% of Latinos considered the 2009 H1N1vaccine unsafe, compared with 14% of whites and 16% of Asians 65% of African Americans said they had no plans to get vaccinated, compared with 52% of whites, 50% of Latinos and 41% of Asians

Answer 281

* Note that current ACIP recommendations call for all persons 6 months and over to be vaccinated * Healthcare providers, including home care * Employees of long-term care facilities * Persons with chronic medical conditions * Household contacts of high-risk persons * Providers of essential community services * Persons traveling outside the U.S. * Persons in institutional settings (e.g. students who reside in a dormitory; persons in a correctional facility)

Answer 282

Has ranged from 48% to 88%; begs the question of whether healthcare workers should be mandated to get vaccinations

Answer 283

* You might know it as FluMist * Contains the same strains as TIV * Indicated for healthy, non-pregnant persons 2-49 years of age * Induces mucosal IgA that can block flu viruses from infecting in the first place * Can be administered concurrently with other live or inactivated vaccines (multiple vaccination isn’t a contraindication)

Answer 284

Children *87% effective against culture-confirmed influenza in children 5-7 years old *Decreased fever and otitis media in vaccine recipients who developed influenza Adults *20% fewer severe febrile illness episodes *24% fewer febrile upper respiratory illness episodes *27% fewer lost work days due to febrile upper respiratory illness *18%-37% fewer days of healthcare provider visits due to febrile illness *41%-45% fewer days of antibiotic use *The point: it works. For both kids and adults. But LAIV seems to be less effective in adults, who have previously been exposed to flu virus (natural or vaccine). Perhaps our preexisting antibodies cross-react with the weakened live virus and clear it from the system before we get the chance to develop protective immunity?

Answer 285

* LAIV replicates in the nasopharyngeal mucosa * Mean shedding of virus 7.6 days, longer in children * One instance of transmission of vaccine virus documented in a child care setting * Transmitted virus retained attenuated, cold- adapted, temperature-sensitive characteristics * No transmission of LAIV reported in the U.S.

Answer 286

``` Local reactions 15%-20% *Soreness, redness, etc) Systemic Rare (Related to egg proteins) Neurological reactions--> Very rare ```

Answer 287

*Children No significant increase in URI symptoms, fever, or other systemic symptoms Increased risk of wheezing in children 6-23 months of age *Adults Significantly increased rate of cough, runny nose, nasal congestion, sore throat, and chills reported among vaccine recipients No increase in the occurrence of fever

Answer 288

1.Serological criteria -->Anti-HA serum titers (IgG) as measured in a hemagglutination assay are generally used as a marker of vaccine efficacy; this approach is limited by its inability to measure cellular immunity, mucosal antibodies (IgA), and anti-NA responses 2. Clinical criteria Ideally, should be by randomized clinical trials with defined clinical outcomes, but this is not generally practical; Observational studies are often used, although these have methodologic limitations and may be influenced by case definitions (confirmed influenza vs. “influenza-like illness”) *Serum IgG levels are the standard correlate of protection for flu vaccines

Answer 289

*New influenza vaccines should provide higher level, broader protection than currently employed vaccines but with comparable safety The scientific and medical communities should agree on study design, case definitions, and serological assays so that vaccine trials are more comparable *need to work on efficacy and access *Vaccine effectiveness depends on multiple factors: protective efficacy of the vaccine, transmission rate and disease severity, vaccination practices and policies *A highly protective vaccine will provide limited benefits to a population if underutilized, but a modestly protective vaccine can provide consider- able benefits if widely used, especially for vulnerable populations *Improved control of influenza should be approached from two directions: #1. increase utilization of currently existing vaccines #2. Develop vaccines with improved efficacy

Answer 290

#1. Natural immunity: Epidemiologically significant drift thought to be associated with more severe, early onset epidemics #2. Vaccine-induced immunity Every year, we must predict the most significant circulating strains to vaccinate against Danger of additional drift during production. It takes a long time to grow vaccines in eggs Vaccine effectiveness may be impacted (depending on the degree of mismatch, certain flu seasons can be worse) Different populations (e.g. the elderly) may be impacted to varying degrees *Increased disease burden may result if drift coincides with a particularly pathogenic strain

Answer 291

* Takeaway: the better the vaccine strains match actual circulating strains (in terms of antigenic similarity), the more effective the vaccine will be. * Note how the dark bars (better match between circulating and vaccine strains) correlate with higher vaccine efficacy (Y axis).

Answer 292

* Thanks to drift, we have to start over from scratch every year when picking vaccine strains. But developing vaccines against pandemic flu is also harder when we have to worry about drift * Use of alternative antigens that are more conserved may allow for broad spectrum vaccines: M2 ion channel protein or Nucleoprotein (NP) * Use of less variable regions of H or N antigens * Intranasal immunization using live attenuated vaccines (LAIV) * LAIV has higher efficacy against drifted strains in children * Adjuvanted vaccines * Alternative approaches such as virosomes, DNA vaccines, etc.

Answer 293

*Perhaps we can make a “universal” flu vaccine (protective against many different strains) by designing vaccines against the less-variable stem region instead. Still, we don’t know whether this will actually work. Neutralizing antibodies can’t easily reach the stem regions.

Answer 294

* Adjuvanted vaccines: Alum, MF59, and AS03 are good candidates - -improve immune response, especially for vulnerable populations - -allow for lower antigenic doses (antigen sparing) * Cross-protective (“universal”) vaccines * Improved mucosal vaccines (IgA responses) * Alternative delivery strategies - -Intradermally-delivered vaccines may enhance protection in elderly persons and may allow for antigen sparing - -Skin patches may allow for remote self-vaccination * Alternative production methods - -Cell-culture based methods (mammalian or insect) - -Could allow for faster turnaround time for vaccine production - -Safer for those with allergies to current vaccine components - -Less vulnerable - egg supply could be disrupted by avian strains

Answer 295

*Not typically required for live attenuated vaccines and many killed whole vaccines These contain “intrinsic” adjuvants (PAMPs!) Most subunit vaccines need adjuvants These are safer than attenuated or killed whole organisms but immunogenicity is typically lower Basic Classification *Vehicles: present or deliver the antigen to the immune system in an optimal manner Examples include mineral salts, emulsions, and various nanoparticles *Immunostimulants: act directly on various components of the immune system Examples include TLR ligands, cytokines, saponins, and bacterial toxins

Answer 296

*What immune response(s) does it induce? *Most approved adjuvants are more effective at stimulating antibody responses than cellular immunity *Future vaccines for diseases such as HIV/AIDS, malaria, and tuberculosis will likely require strong cellular responses *Is it compatible with your vaccine antigen(s)? *Will it alter its stability, bioavailability or immunogenicity? *Is it stable before and after being included in the vaccine? *Can it be administered by the desired route? *What are its production requirements? Cost Ease of manufacture *What side effects does it cause? *Can it be used in your target group?

Answer 297

* Non-crystalline gels based on aluminum salts * Has been used for over 70 years, found in about 80% of currently used vaccines * Mechanism of action still incompletely understood but may include: - -Controlled antigen release (depot effect) - -Enhancement of phagocytosis by APCs via particulate formation - -Localized inflammation that recruits APCs and upregulates MHC, costimulatory molecules, etc. * Promotes strong Th2-dependent humoral responses * Not a good inducer of Th1 responses so useful-ness for certain future vaccines may be limited * Stable and easy to manufacture but cannot be frozen * Generally safe and well tolerated but can cause granulomas at the injection site

Answer 298

Monophosphoryl lipid A (MPL) is a non-toxic derivative of lipopoly- saccharide (LPS) from Salmonella minnesota Like LPS, MPL binds TLR4 LPS signals through MyD88 and TRIF dependent pathways following TLR4 engagement, generating high levels of inflammatory cytokines MPL signaling seems to be biased toward the TRIF pathway MPL may have other anti-inflammatory effects that cause it to be less toxic than LPS Potent stimulator of Th1 responses Not generally used as a standalone adjuvant but is combined with alum (AS04 adjuvant system), the purified saponin QS-21 (AS02), or liposomes and QS-21 (AS01) Good safety profile; adverse reactions similar to alum Employed in the HepB vaccine Fendrix and the HPV vaccine Cervarix Has been evaluated in clinical trials for vaccines against malaria, TB, leishmaniasis, HIV, and vesicular stomatitis virus Licensed in Europe as a treatment for allergies

Answer 299

Codelivery of antigens and PRR ligands enhances effectiveness Adjuvants can work through both direct and indirect actions on APCs Multiple innate stimuli can be better than one Formulations and PRR ligands can be combined to develop the most appropriate response Animal models and in vitro systems have important limitations

Answer 300

* Adjuvants are not approved by the FDA as stand-alone products but only as parts of individual vaccines * Regulations have become more stringent * High development costs and regulatory issues limit the motivation of for-profit entities * Many commercial adjuvants are expensive and proprietary, limiting research and clinical access * Lack of standardization in adjuvant formulation makes it difficult to compare results obtained by different research groups * There is no reliable computer-assisted way to predict an ideal adjuvant for a given antigen

Answer 301

Highly contagious viral illness (one of the most contagious diseases we know of); it is an airborne disease that can spread via coughs and sneezes Before we developed a vaccine, basically everyone caught the measles 90% infected by the age of 15 *has an Ro of 18; meaning that the number of people that ONE SICK PERSON will infect (on average) is Ro

Answer 302

WORLDWIDE: but transmission has been interrupted in the USA

Answer 303

Humans only & there is no asymptomatic carrier state

Answer 304

Primarily via large respiratory droplets | Can occur in closed spaces via aerosolized droplets for up to 2 hrs

Answer 305

Peaks in late winter and spring in temperate areas

Answer 306

*communicability period is the time during which the patient is infectious to others. Highly contagious, >90% attack rate among susceptible persons Maximal from onset of prodrome through first 3-4 days of the rash * a prodrome is an early symptom (or set of symptoms) that might indicate the start of a disease before specific symptoms occur. It is derived from the Greek word prodromos, meaning "precursor".

Answer 307

*Incubation period Exposure to prodrome period 10-12 days *Prodrome Gradual onset of high fever Cough, runny nose, and conjunctivitis ``` *Rash & Other Symptoms 14 days after exposure characteristic rash appears Begins on face and head Persists for 5-6 days Also can get anorexia, diarrhea & swelling of lymph nodes ```

Answer 308

Complications: Most common form of death in children is pneumonia Most common form of death in adults is encephalitis; encephalitis is an acute inflammation of the brain * Subacute sclerosing panencephalitis (SSPE) - Caused by persistent measles infection of the brain - rare and chronic form of progressive brain inflammation caused by a persistent infection with measles virus - Progressive cerebral deterioration and eventual death * Hemorrhagic measles - 105° F fever, seizures, delirium, respiratory distress and hemorrhage into skin and mucous membranes * During pregnancy - Premature labor, spontaneous abortion, low birth weight *In an immunocompromised person Severe disease with prolonged course

Answer 309

It takes an average of 10–12 days from exposure to the first symptom, which is usually fever. The measles rash doesn’t usually appear until approximately 14 days after exposure, 2–3 days after the fever begins

Answer 310

Symptoms include fever, runny nose, cough, loss of appetite, “pink eye,” and a rash. The rash usually lasts 5–6 days and begins at the hairline, moves to the face and upper neck, and proceeds down the body.

Answer 311

Measles can be a serious disease, with 30% of reported cases experiencing one or more complications. Death from measles occurs in 2 to 3 per 1,000 reported cases in the United States. Complications from measles are more common among very young children (younger than five)

Answer 312

Diarrhea is the most common complication of measles (occurring in 8% of cases), especially in young children. Ear infections occur in 7% of reported cases. Pneumonia, occurring in 6% of reported cases, accounts for 60% of measles-related deaths. Approximately one out of one thousand cases will develop acute encephalitis, an inflammation of the brain. This serious complication can lead to permanent brain damage. Measles during pregnancy increases the risk of premature labor, miscarriage, and low-birth-weight infants, although birth defects have not been linked to measles exposure. Measles can be especially severe in persons with compromised immune systems. Measles is more severe in malnourished children, particularly those with vitamin A deficiency. In developing countries, the fatality rate may be as high as 25%.

Answer 313

People previously receiving immune globulin or infants with residual maternal antibody Get modified measles - longer incubation and generally milder illness

Answer 314

Occurs in persons previously vaccinated with inactivated measles vaccine (1963-1967) *The new, atypical measles, occurring in the vaccinated was characterized by high fever, unusual rash and pneumonia, often with history of vaccination with killed measles vaccine. Such persons are hypersensitive to measles antigens and can develop severe disease if subsequently infected May be prevented by revaccination with live vaccine *AMS occurs in persons who were incompletely immunized against measles. This may happen if a person were given the old killed-virus measles vaccine (which does not provide complete immunity and is no longer available); or the person were given attenuated (weakened) live measles vaccine that was, by accident, inactivated during improper storage. Immunization with inactivated measles virus does not prevent measles virus infection. It can, however, sensitize a person so that the expression of the disease is altered, resulting in AMS.

Answer 315

*Measles virus (MeV) is a single-stranded, negative-sense, enveloped (non-segmented-meaning genome is all in one piece) RNA virus *humans are the natural host of the virus *The measles virus has two envelope glycoproteins on the viral surface—hemagglutinin (H) and membrane fusion protein (F). These proteins are responsible for host cell binding and invasion. *The measles virus evolved from the formerly widespread rinderpest virus, which infects cattle *F (fusion) and H (hemagglutinin) proteins are important surface antigens One antigenic type Rapidly inactivated by heat, light and acid

Answer 316

* Positive-sense (5' to 3') viral RNA signifies that a particular viral RNA sequence may be directly translated into the desired viral proteins. Therefore, in positive-sense RNA viruses, the viral RNA genome can be considered viral mRNA, and can be immediately translated by the host cell. * Negative-sense (3' to 5') viral RNA is complementary to the viral mRNA and thus must be converted to positive-sense RNA by an RNA polymerase prior to translation. Negative-sense RNA (like DNA) has a nucleotide sequence complementary to the mRNA that it encodes. Like DNA, this RNA cannot be translated into protein directly. Instead, it must first be transcribed into a positive-sense RNA which acts as an mRNA. Some viruses (Influenza, for example) have negative-sense genomes and so must carry an RNA polymerase inside the virion.

Answer 317

Measles replicates in the nasopharynx – this can be inhibited by local secretory IgA and/or transudated IgG Inhibit the viremia that occurs during the incubation period by circulating abs to neutralize the virus Cellular responses are also protective Kids with primary agammaglobulinemia don’t have more severe measles infections than other kids These kids can also develop lasting immunity after infection, indicating that cell-mediated immunity alone is adequate to prevent measles *Agammaglobulinemia is a disorder where you have low levels of immunoglobulin; make you more likely to get infections Immune suppression: Decrease of CD4+ lymphocyte counts that begins before the onset of rash and lasts for up to 1 month Suppression of the production of IL-12 in response to general stimuli *IL-12 is a cytokine that stimulates the growth and function of T cells and the production of IFN-gamma and TNF-alpha from T cells *IFN-y is a cytokine important in innate & adaptive immunity TNF-alpha is a cytokine involved in systemic inflammation Immune activation: Activation of virus-specific CD8+ T cells, which are important for viral clearance Type 2 CD4+ T cells, which provide help for optimal antibody production Recovery from infection: Serum and secretory antibodies Establishment of cellular immunity Immunity after natural infection is believed to be lifelong

Answer 318

Relying on secreted IgA or transudated IgG in the local region as the essential immune response for blocking transmission

Answer 319

Despite the importance of both humoral and cellular responses, antibody responses are most often measured Correlate of protection from symptoms = Plaque reduction neutralization (PRN) antibody titers >120 Correlate of protection from infection = PRN titers (e.g. >1000)

Answer 320

1954: Measles virus isolated by Enders 1963: Live attenuated and killed vaccines licensed 1965: Live further attenuated vaccine (Schwarz strain) 1967: Killed vaccine withdrawn 1968: Live further attenuated vaccine (Moraten) 1971: Licensure of measles-mumps-rubella vaccine (MMR) 1989: Two dose MMR schedule recommended 2005: Licensure of measles-mumps-rubella-varicella vaccine (MMRV)

Answer 321

Today’s vaccine is live attenuated virus grown in chick embryo fibroblast culture at 32oC Produces a mild, non-communicable infection Efficacy 95% protective efficacy after a single dose at 12 months 98% protective efficacy after a single dose at 18 months Long-term, likely lifelong immunity

Answer 322

Maternal Antibodies 1960s studies indicated that maternal abs persisted in some infants up to 11 months of age Passively acquired anti-measles abs may neutralize the vaccine before a complete immune response develops

Answer 323

Antibodies induced by vaccination are typically at lower titers than those by measles disease Studies have suggested that infants whose mothers have vaccine-induced immunity may thus receive less maternal antibody than infants whose mothers had natural measles

Answer 324

Vaccinated before the first birthday MMR given before 12 months should not be considered a valid dose Vaccinated with killed measles vaccine (KMV) Remember atypical measles? Vaccinated prior to 1968 with an unknown type of vaccine More concerns about atypical measles Immunized with immune globulin in addition to one of the further attenuated strains or vaccine of unknown type Attenuates your response – think of the problem of maternal antibodies when vaccinating infants against measles

Answer 325

Highly contagious viral illness Spread through droplets of saliva or mucus from the mouth or throat Clinical features Starts with a fever, headache, muscle aches, tiredness and a loss of appetite for a few days Followed by swelling of the salivary glands Complications Most common is inflammation of the testicles in males Rare complications include encephalitis, inflammation of the ovaries or breasts, deafness

Answer 326

Live attenuated vaccine was introduced in 1967 Prior to this, there were 100K’s of cases every year Approximately a 99% reduction in Mumps cases Though there are still outbreaks of cases in recent years 1967: 186,000 cases 2014: 1,151 people were reported to contract mumps 88% effective after two doses First dose between 12-15 months Second dosed 4-6 years

Answer 327

How did this happen? Teams live in close quarters for long periods of time (like schools) Most players are born between 1970 and 1992 – a time when only one MMR shot was common (but that is less effective) Mumps in the NHL All started with the Anaheim Ducks – some players lived where an outbreak in OC, CA occurred Soon spread & over the next three months over 20 players were diagnosed with the mumpsMumps in the NHL Mumps at Harvard? Sucks to be them…

Answer 328

Viral illness called by rubella virus Also known as “German measles” but it’s not related to measles Spread by airborne droplets from the upper respiratory tract Symptoms: fever and rash for 2-3 days About ½ of people with Rubella will have no symptoms Major complication: congenital rubella syndrome High chance of injury to the fetus if the woman is infected within the first two trimesters of pregnancy Affected infants may exhibit deafness, cataracts, hear defects, mental retardation, and liver & spleen damage

Answer 329

Live attenuated vaccine introduced in 1969 Prior to this, there were epidemics that could involve millions of cases every 6-9 years in the US 1964-1965: 12 million cases 2009: 3 reported cases First dose provides 90-95% immunity

Answer 330

Indicated for: All children Susceptible adolescents and adults without documented evidence of immunity Primary dose 12-15 months old In high transmission nations, the WHO recommends that the first dose be given at 9 months with a second dose at 15-18 months Second dose Recommended at 4-6 years (but can be given as soon as 4 weeks after the first dose) Intended to produce measles immunity in people who failed to respond to the first dose (primary vaccine failure) May transiently boost antibody titers in some people

Answer 331

Lack of immunity against measles, mumps, or rubella in a vaccinated person 2-5% of recipients do not respond to the first dose Genetic factors implicated (e.g. HLA types) Caused by passively acquired antibody, damaged vaccine, record errors, etc. Most people will respond (>90%) will respond to a second dose

Answer 332

FEVER (5-15%), Rash (5%), Joint Symptoms (25% of adult women), Thrombocytopenia (

Answer 333

``` Severe allergic reaction to vaccine component or following prior dose Pregnancy (but not breastfeeding) Immunosuppression Moderate or severe acute illness Recent antibody-containing blood product ```

Answer 334

Recent epidemiological trends Record low annual total in 2004 (37 total cases) 2015 started off poorly with >100 cases in the first few months (year total=189) Endemic transmission interrupted in the U.S. Most cases imported or linked to importation and then spread easily in pockets of unvaccinated individuals Measles is a leading global cause of death among children even though a safe and cost-effective vaccine is available (

Answer 335

Measles resurgence in 1989-1991 55,622 cases in this period Shift in age distribution, 45% of cases in

Answer 336

Peptide Conjugate Measles Vaccine Problem: live measles vaccine is poorly immunogenic in infants Persistence of maternal antibodies Immaturity of the immune system Premature waning of maternal immunity leaves many infants vulnerable to infection before they reach vaccination age A peptide-conjugate vaccine using a non-measles carrier protein (tetanus toxoid) could fill the gap Provide bridging protection until vaccinated with live measles vaccine is indicated No risk for atypical measles (mediated by measles-specific Th2 cells), since the anti-measles response would be entirely humoral with the T cell responses directed at the carrier only

Answer 337

Next Frontier: Immunogenetics? About 90% of variation in immune response to measles appears to be genetic in origin Remember why the 2nd dose of measles vaccine is necessary? Vaccine failure Allow the one-size (and dose) fits-all vaccine approach to be abandoned in favor of an individualized strategy More accurate prediction of the likelihood of a significant adverse event to a vaccine Help decide the number of doses likely to be needed to induce a sufficient response to a vaccine But…genetic testing will have to become much faster and cheaper for any of this to be feasible

Answer 338

*The Plaque reduction neutralization test is used to quantify the titer of neutralizing antibody for a virus. *A titer is a way of expressing concentration *Currently it is considered to be the "gold standard" for detecting and measuring antibodies that can neutralize the viruses that cause many diseases. It has a higher sensitivity than other tests like hemagglutination and many commercial Enzyme immunoassay without compromising specificity. However, the test is relatively cumbersome and time intensive (few days)

Answer 339

* Helminths are parasitic worms. They are the most common infectious agents of humans in developing countries and produce a global burden of disease that exceeds better-known conditions, including malaria and tuberculosis. * includes nematodes and other major intestinal worms * The high medical, educational, and economic burden of helminth infections, together with their coendemicity with malaria and AIDS, provides an important rationale for launching a global assault on parasitic worms * According to the 1993 report, intestinal helminths ranked among the leading cause of DALYs lost annually, i.e. more than malaria * about 25% of the world's population are infected with soil-transmitted helminths (World Health Organization). * For reasons not well understood, compared with any other age group, school-aged children (including adolescents) and preschool children tend to harbor the greatest numbers of intestinal worms and schistosomes and as a result experience growth stunting and diminished physical fitness as well as impaired memory and cognition-->Over 270 million preschool-age children/600 million school-age children live in areas where these parasites are transmitted.

Answer 340

* The disability-adjusted life year (DALY) is a measure of overall disease burden, expressed as the number of years lost due to ill-health, disability or early death. * A measure that combines healthy life years lost because of premature mortality with those lost as a result of disability * It "extends the concept of potential years of life lost due to premature death...to include equivalent years of 'healthy' life lost by virtue of being in states of poor health or disability."[2] In so doing, mortality and morbidity are combined into a single, common metric.

Answer 341

Neglected Tropical Diseases * Viral, parasitic, and bacterial diseases that mainly affect the world's poorest people * includes Hookworm infections, Schistosomiasis, Dengue Fever, etc. * In 2010, it was estimated that NTDs collectively caused 26 million DALYs worldwide, with worms contributing the greatest to this burden * The geographical burden of NTDs varies significantly, with the greatest burden occurring in Sub-Saharan Africa and Asia.

Answer 342

*A disease caused by infection with freshwater parasitic worms in certain tropical and subtropical countries. NTD The freshwater becomes contaminated from infected animal or human urine or feces. The parasites penetrate human skin to enter the bloodstream and migrate to the liver, intestines, and other organs.

Answer 343

* World Health Assembly (WHA) passed a resolution affirming that the control of schistosomiasis and soil-transmitted helminthiasis should be considered as a public health priority; the resolution set a global target of scaling up intervention to regularly treat 75% of school age children at risk (398 million) by 2010. * Recommended single dose treatment for soil transmitted helminth infections with any of the four anthelmintics on the WHO list of essential drugs (albendazole, levamisole, mebendazole, and pyrantel), which costs less than 3 cents. In 2011, the WHO Strategic and Technical Advisory Group for Neglected Tropical Diseases and partners adopted a roadmap for control, elimination and eradication. The roadmap sets targets for the period 2012–2020. Preventive chemotherapy aims at optimizing the large-scale use of safe, single-dose medicines, currently against four helminthiases (lymphatic filariasis, onchocerciasis, schistosomiasis and soiltransmitted helminthiases).

Answer 344

Anthelmintics or antihelminthics are a group of antiparasitic drugs that expel parasitic worms and other internal parasites from the body by either stunning or killing them and without causing significant damage to the host

Answer 345

preventive chemotherapy, an intervention that allows the regular and coordinated administration of quality-assured, safe, single-dose medicines on a large scale *Preventive chemotherapy – Preventive chemotherapy aims at optimizing the large-scale use of safe, single-dose medicines, currently against four helminthiases

Answer 346

- Today, 13 pharmaceutical companies and other global health organizations announced a new, coordinated push to accelerate progress toward eliminating or controlling 10 neglected tropical diseases (NTDs) by the end of the decade. * Uniting efforts with NTD-endemic countries, partners pledged to bring a unique focus to defeating these diseases and to work together to improve the lives of the 1.4 billion people worldwide affected by NTDs, most of whom are among the world’s poorest. In the largest coordinated effort to date to combat NTDs, the group announced at an event at the Royal College of Physicians that they would: sustain or expand existing drug donation programs to meet demand through 2020; share expertise and compounds to accelerate research and development of new drugs; provide more than US$785 million to support R&D efforts and strengthen drug distribution and implementation programmes.

Answer 347

$72,100 USD *Drug costs: $20,000 cost of the product, its international transport and custom clearance Financial costs: $33,000 training of personnel, drug transport, social mobilization and monitoring Economic costs: $19,100 time spent by teachers and health personnel at central, provincial and district level to provide service as part of their routine work

Answer 348

*We evaluate a Kenyan project in which school-based mass treatment with deworming drugs was randomly phased into schools, rather than to individuals, allowing estimation of overall program effects. The program reduced school absenteeism in treatment schools by one-quarter, and was far cheaper than alternative ways of boosting school participation. Deworming substantially improved health and school participation among untreated children in both treatment schools and neighboring schools, and these externalities are large enough to justify fully subsidizing treatment. Yet we do not find evidence that deworming improved academic test scores. ***** Did pure replication of prior study *In this pure replication, we re-analysed the original data according to the methods used by the original authors and compared results with those presented in the original paper. Although most results were reproduced as originally reported, there were discrepancies of several types between the original paper and re-analysis. In contrast to the original study, re-analysis found little evidence for an effect on anaemia or for indirect effects on school attendance for children in non- intervention schools; other results were largely unchanged.

Answer 349

*"Treating children known to have worm infection may improve weight gain but there is limited evidence of other benefits. For routine deworming of schoolchildren in endemic areas, there is quite substantial evidence that deworming programs do not show benefit in terms of average nutritional status, haemoglobin, cognition, school performance, or death. ….the belief that deworming will impact substantially on economic development seems delusional when you look at the results of reliable controlled trials.

Answer 350

*Because of rapid reinfection, anthelminthics need to be administered at least 3X/yr to achieve sustainable impact on growth and development

Answer 351

* More than 500 million people infected * Prevalence approaches 90% in endemic areas ``` *Major clinical symptoms Anemia due to red blood cell loss Hypoproteinemia due to serum loss Intestinal malabsorption Growth delay and cognitive deficits ``` *Impact on maternal child health At least 44 million pregnant women infected worldwide Anemia in pregnancy contributes to perinatal mortality, IUGR, early child development *Impact on other infectious diseases Increased HIV viral load Enhanced susceptibility to TB Impaired response to routine immunizations

Answer 352

*4 communities (292 subjects) in the Kintampo North district Questionnaire and fecal samples Single dose albendazole (400mg) Follow-up examination 11-22 days *Hookworm prevalence: 45.4% Males/females equally distributed Age distribution similar to other reports from Africa *Hookworm-Malaria coinfection highest in school-age children 87% with one or both infections

Answer 353

*Overall fecal egg count reduction rate: 81% *39% of subjects (n=37) failed therapy *Among those who failed No statistically significant difference between pre- and post-treatment egg counts: 307 vs 202 EPG (p=0.3) *50% of subjects had higher egg counts post-treatment *Potential causes of reduced efficacy Pharmaceutical (albendazole) stability Adherence High intensity infections Anthelminthic resistance

Answer 354

* This eggs-per-gram number is a standard measure and, depending on the number, we know whether the horse in question is carrying a low, moderate or high worm burden, and can then act accordingly. * allows the the presence of anthelmintic resistance can be detected * ERR is much greater than cure rate

Answer 355

*Benzimidazoles are variably active against the 3 major STNs (soil transmitted nematodes) Reduced efficacy of albendazole, mebendazole, pyrantel against hookworm Reduced efficacy of albendazole against Trichuris *Potential for resistance is high with increased delivery to endemic communities Documented resistance in Mali, Australia Suspected resistance in Tanzania, Ghana *Limited commercial market for traditional pharmaceutical and biotechnology companies Only 4 new drugs have been recommended for clinical trials since the 1970s (ivermectin, oxibendazole, nitazoxanide, amidantel/tribendimidine)

Answer 356

``` *Impact of chronic, even low intensity, infection is high Nutritional status and development Perinatal mortality/morbidity Productivity Susceptibility for other diseases ``` * Drugs are only moderately effective * Emerging resistance

Answer 357

*No acquired immunity to infection Reinfection occurs quickly following therapy Hookworm associated immunosuppression *Basis of natural “resistance” poorly understood “wormy” vs “non-wormy” people, ie overdispersion Role of antibodies unclear * Cumbersome animal models * Few immunologic reagents *Pathogenesis and virulence factors are poorly defined

Answer 358

1. Ancylostoma or N. americanus L3 larvae penetrate skin, enter blood vessels 2. L3 larvae migrate to lungs by day 3, break out into alveoli 3. L3 migrate up trachea, are coughed up and swallowed, reach intestine by day 7 4. L3 -> L4 -> adults Worms mate in small intestine (5-6 weeks), feed on mucosa and blood-->LEADS TO ANEMIA; Blood loss caused by hookworms attached to the intestinal mucosa 5. Eggs pass out with feces and hatch in the soil in 1-2 days, releasing L1 larvae 6. L1 -> L2 -> L3 over 5-8 days, L begin “questing”for a new host

Answer 359

Dow (1959) attenuated hookworm larvae with radiation Miller showed that administration of irradiated A. caninum larvae subcutaneously protected dogs against challenge 88-97% protection Vaccine licensed in 1973, but discontinued in 1975 Failure to induce sterile immunity hindered commercial success Labor intensive to produce

Answer 360

*Miller showed that antiserum from vaccinated dogs reacted with larval antigens, and protection could be transferred with serum A caninum L3 stimulated with host serum secrete three major proteins Zinc metalloprotease Ancylostoma secreted protein (ASP)-1 and ASP-2 (pathogenesis related protein (PRP) superfamily) PRPs are produced by invertebrates, vertebrates, and plants in response to stress. No known function, but homology to vespid venom allergens

Answer 361

DOG MODEL: Expensive Labor intensive Suited for culturing larvae but not adult stages MOUSE MODEL: Larvae don’t develop, so only larval antigens can be tested Non-permissive host: no “disease” Cannot follow clinical features, eg anemia, weight loss, egg excretion, intestinal worm burden

Answer 362

When administered to mice, Ancylostoma caninum or Necator americanus L3 migrate to lungs, where they arrest and are cleared Lungs are harvested (48-72 hrs post-infection) and larvae recovered – 500 L3 inoculum ~ 50 lung larvae (10% yield)

Answer 363

ASP-1 (A. caninum) confers partial protection (~60%) from lung migration in mice Less protection afforded in permissive models of hookworm (dog, hamster) Cross-protection is not conferred, despite significant amino acid sequence similarity species specific immunity may be required for vaccine induced protection Murine model may not be applicable to human disease

Answer 364

*Public–private partnership of the Sabin Vaccine Institute •Established ~ 2000, based in Washington, DC, then Houston TX * Discovery and clinical development of protein based, injectible hookworm vaccines * Previously funded by BMGF

Answer 365

7 subjects immunized with rNa-ASP-2 following deworming 3 developed urticaria of head/neck/upper torso and systemic symptoms within 2 hrs of vaccination 2 subjects experienced severe injection site erythema (9x6 cm) Mild nausea and mild/moderate headache common Study was terminated due to unacceptable rate of side effects

Answer 366

*A. ceylanicum is a human parasite ``` Mesocricetus auratus (golden Syrian hamster) is a fully permissive host for ceylanicum ``` Infection and disease similar to humans Retarded growth/weight loss Anemia *Mice and rats are not fully permissive for hookworms *hamsters infected with A. ceylanicum exhibit retarded weight gain and anemia *The A. ceylanicum hamster model reproduces the major sequelae of human infection *Antibody (IgG) response to hookworm antigens following primary A. ceylanicum infection; shows that the antibody response to hookworm antigens is increasing w/ days post infection *found that Previously infected hamsters are resistant to weight loss and anemia following secondary challenge

Answer 367

* *Passive Transfer Protocol: Serum prepared from hamsters twice infected with A. ceylanicum (H-2x); Day 0: naïve hamsters infected with 50 A. ceylanicum L3; Day 11: inject each hamster subcutaneously with 0.5 ml H-2x or normal hamster serum (NHS); Follow hamsters for weight gain and anemia * Passive transfer of twice infected serum (H2X) improves blood hemoglobin and weight gain

Answer 368

Procedure: subcutaneously immunize 3x with 100 kg of HEX protein in alum; then challenge by putting hookworms into body; then sacrifice after about a month * during this time, weigh & collect blood at regular intervals * with individual sera: ELISA * with pooled sera: WESTERN BLOT Findings: Humoral immune responses in hamsters vaccinated with soluble hookworm extract (HEX); found that there was a massive increase in the number of Hex-specific antibodys in hamsters vaccinated compared to alum control * Subcutaneous vaccination with hookworm proteins confers partial protection against disease; see vaccinated animals had greater weight than unvaccinated and had higher levels of Hemoglobin days postchallenge * *Adult worm burdens are not reduced in HEX vaccinated hamsters relative to alum controls

Answer 369

*Primary A. ceylanicum infection leads to retarded weight gain and anemia in hamsters These hamsters develop vigorous specific humoral responses and are resistant to weight loss and anemia upon secondary challenge Passive transfer of serum from the twice-infected hamsters is associated with improved weight gain and hemoglobin status in infected animals Active vaccination with soluble hookworm extract (HEX) leads to partial protection from hookworm disease in the absence of measurable reduction in adult worm burden

Answer 370

Oral vaccination with hookworm proteins confers partial protection against disease

Answer 371

* very high levels of serum IgA & IgG | * higher levels of flush IgA compared to flush IgG

Answer 372

* Intestinal worm burden: challenge only had a high worm burden while MTI + challenge had low worm burdens (even 0 in some cases) * Serum IgG titers: challenge only had low serum IgG levels, while MTI + challenge were found to have significantly more IgG * Flush IgA titers: no IgA titers were detected in challenge only, while MTI + challenge illustrated high IgA levels

Answer 373

Intestinal flush prepared from infected hamsters is enriched in IgA specific for A. ceylanicum excretory-secretory (ES) products. Mucosal IgA responses detect a broad range of hookworm ES proteins. Increasing parasite-specific fecal IgA responses are coincident with significant reductions in intestinal worm burdens over time. Hamsters repeatedly exposed to drug terminated infections have enhanced serum IgG and mucosal IgA responses, as well as a high level of protection from challenge infection. Mucosal immune responses (IgA) may play a role in protective immunity against hookworm infection and disease.

Answer 374

``` Summary Elevated systemic (IgG) and mucosal (IgA) immune responses directed at adult A. ceylanicum ES are associated with reduced intestinal worm burden and fecal egg output. ``` Intranasal vaccination with adult A. ceylanicum ES induces both serum IgG and intestinal IgA responses that correlate with significant protection against infection and disease. **Future directions Identify specific secretory antigens that mediate protection via mucosal vaccination Develop oral vaccination strategy using native and recombinant hookworm ES proteins NOTA BENE: As bloodfeeding intestinal parasites, hookworms could be targeted by serum and mucosal immune responses

Answer 375

Virus-Like Particles Virus-like particles resemble viruses, but are non-infectious because they do not contain any viral genetic material. The expression of viral structural proteins, such as Envelope or Capsid, can result in the self-assembly of virus like particles (VLPs). VLPs are useful as vaccines. VLPs contain repetitive high density displays of viral surface proteins which present conformational viral epitopes that can elicit strong T cell and B cell immune responses. Additionally, since VLPs cannot replicate, they provide a safer alternative to attenuated viruses

Answer 376

LIVE ATTENUATED VACCINES * live attenuated vaccines (LAV)Live attenuated vaccine (LAV)A vaccine prepared from living micro-organisms (viruses, bacteria currently available) that have been weakened under laboratory conditions. LAV vaccines will replicate in a vaccinated individual and produce an immune response but usually cause mild or no disease. are derived from disease-causing pathogensPathogenAny disease-causing substance. Most commonly used for organisms (e.g., bacteria, viruses) and their biological products (e.g. toxins). (virusVirusAn ultramicroscopic infectious agent that consists of genetic material surrounded by a protein coat. A virus can replicate themselves only within cells of living hosts. or bacteriaBacteriaSingle-celled life-forms that can reproduce quickly on their own. Some bacteria cause disease.) that have been weakened under laboratory conditions. * n an attenuated vaccine, live virus particles with very low virulence are administered. They will reproduce, but very slowly. Since they do reproduce and continue to present antigen beyond the initial vaccination, boosters are required less often.

Answer 377

Some of the most common methods involve passing the disease-causing virus through a series of cell cultures or animal embryos (typically chick embryos). Using chick embryos as an example, the virus is grown in different embryos in a series. With each passage, the virus becomes better at replicating in chick cells, but loses its ability to replicate in human cells. A virus targeted for use in a vaccine may be grown through—“passaged” through—upwards of 200 different embryos or cell cultures. Eventually, the attenuated virus will be unable to replicate well (or at all) in human cells, and can be used in a vaccine. All of the methods that involve passing a virus through a non-human host produce a version of the virus that can still be recognized by the human immune system, but cannot replicate well in a human host. When the resulting vaccine virus is given to a human, it will be unable to replicate enough to cause illness, but will still provoke an immune response that can protect against future infection.

Answer 378

* Viruses may be attenuated via passage of the virus through a foreign host * The initial virus population is applied to a foreign host. One or more of these will possess a mutation that enables it to infect the new host. These mutations will spread, as the mutations allow the virus to grow well in the new host; the result is a population that is significantly different from the initial population, and thus will not grow well in the original host when it is re-introduced (hence is "attenuated"). This process is known as "passage" in which the virus becomes so well adapted to the foreign host that it is no longer harmful to the vaccinated subject. This makes it easier for the host's immune system to eliminate the agent and create the immunological memory cells which will likely protect the patient if they are infected with a similar version of the virus in "the wild"

Answer 379

* allows body to break it down so it doesn’t cause disease (SAFETY) * also has to do with efficacy of vaccine; IgA is in the mucus membranes; allows body to make IgA and that can confer protection from infection instead of protection from disease * Because most would have difficulty getting past the hostile environment that is our gastro-intestinal tract. The stomach acid, enzymes, gut bacteria and other potential antigen killers in our gut would render them useless.

Answer 380

Intramsuscular vaccines do NOT confer protection against infection, only confer protection against disease; in order to get protection against infection, need protection in mucus membrane; need mucus membrane protection in order to confer *Vaccines taken orally (like the oral polio vaccine and rotavirus) will induce production of IgA antibodes. Vaccines injected intramuscularly will induce IgG. Vaccines have been studied and tested to ensure the best route to provide the best immune response with the least side effects.

Answer 381

This circulating IgG means that on exposure, a person will be protected from systemic polio infection, as pretty much the whole circulatory system has some anti-polio antibodies, but that person could still get a gut infection, and pass it on, before developing enough of a local response to clear it from their system, whereas the IgA response from the oral vaccine helps prevent that initial colonisation in the first place.

Answer 382

VLP vaccine was found to protect against H3N2 canine influenza virus in dogs * Biggest result is that they actually made the VPL; process of folding is really hard to do so starting out with polypeptides and making protein spontaneously fold takes forever * Multiple antigenic epitopes GOLDEN RULE:The closer something looks to the original disease, the better the vaccine is going to be; because we have multiple genetic epitopes, it looks closer to the disease; better than just throwing protein around * Goal for multiple antigen epitopes to look enough like a whole cell; goal is it to act like a whole killed * found that the addition of an adjuvant greatly increased the immunogenicity of the vaccine *MAJOR BENEFIT IS NO EGGS: Benefits on Virus like particles is that there are no eggs; right now we GROW virus and either attenuate it or KILL IT; growing viruses now is for eggs and it takes about 6 months; takes 6 months to create vaccine even if we already know what vaccine is going to be; difficult for flu because takes a while

Answer 383

Puppy influenza virus found in 2004 * Found different types: Specific type we’ll look at is H3N2 * Goes from birds to dogs * Puppy flu acts like human flu – snotty puppy, coughing puppy, etc. * Epidemiologically could be dangerous for puppies so they want to study H3N2 * wanted to determine immunogenicity and efficacy of vaccine; vaccine could put up an immune response but it might not be the right stuff to protect you (so not efficacious)

Answer 384

Adjuvant: helps make immune response more immunogenic; they aren't used in live attenuated vaccines because you don’t need it if its live because its already very immunogenic; body sends inflammation to site of infection; immune cells sense presence of immune markers and follow up the concentration gradient of inflammatory markers This needs adjuvant because its not alive *Gave Oil adjuvent or saline because found from #1 that oil was best; gave vaccine and waited four weeks

Answer 385

Made H3 HA VPLs H3 = type of hemagglutanin HA = Hemagglutinin VLP = Virus Like Particles Made vaccines without adjuvant, with oil adjuvant, and with aluminum adjuvant

Answer 386

* gave vaccine with oil adjuvant or saline, and then waited 4 weeks * the first hump of immune response takes a week to hump up so wanted to make sure that they had waited for the primary response to be almost over and that the vaccine had had enough time to generate memory * after a month, gave (up the nose) H3N2 virus, and then waited for 4 days; Waited for four days because that’s how long the virus takes for it to ramp up and generate high viral load * then measured clinical signs and did PCR to quantify viral shedding; measurement of amount of virus in puppy

Answer 387

* Vaccines made antibodies! * Little bit of vaccine made antibodies, vaccine without any adjuvant made antibodies; The reason they wanted to use as little vaccine as possible is because VPL are hard to make and hard to fold so want to figure littlest amount you can use * See amount of antibodies, H Ig titers (the amount of antibody against the H3 in the puppies; it is high- that’s good) * Oil adjuvant better than aluminum; Adjuvants allowed them to use fewer VPLs * vaccinated group found to have LOWER VIRAL LOADS; graph showing the viral load (logarithmic Y-axis) compared to the vaccine dosage; the 15 that is the upside down triangle has in general the lowest viral load which makes sense since it is the greatest/highest dosage of VPL; get a lot of vaccine means you have a less amount of virus; for circles, if you don’t have a lot of vaccine you DO have a lot of virus * Viral shedding not completely eliminated from the vaccinated group (bummer!) goal to provide sterile immunity

Answer 388

*No runny noses in vaccinated groups Fevers lower in the vaccinated groups--graph showing the body temperature of the puppies days Post-inoculation, and found that in the vaccinated group, the body temperatures decreased to more normal levels *Had fewer symptoms Pathology; tried to quantify; the lungs of the un-vaccinated puppies are BAD; in general more purple if looking at slides Lungs show biggest different in amount of vaccine Clinical signs of respiratory illness not present in vaccinated groups lungs of non vaccinated looked bad, vaccinated a little still looked not super hot, vaccinated a lot no lesions or bleeding or other “morphologic changes in the lungs”

Answer 389

BIG: multicellular and mobile; cannot be devoured by phagocytes; Worms are BIG & Too large to phagocytize TOUGH: worms are resistant to digestion and many immune effector mechanisms SMART: have gone through millions of years of host-parasite co-evolution; capable of evading and even manipulating the host's immune response; have thousands of genes *however, human intestinal worms do not have an animal reservoir b/c animal nematodes have a different morphology than human ones *Penetrate the blood vessel in a foot → capillary → heart → lungs → crawl up your trachea and crawl into your intestinal tract through your throat All the hookworm’s nutritional needs are met by red blood cells (the picture of is of red blood cells in their gut)

Answer 390

Leishmaniasis is a parasitic disease that is found in parts of the tropics, subtropics, and southern Europe. It is classified as a Neglected Tropical Disease (NTD). Leishmaniasis is caused by infection with Leishmania parasites, which are spread by the bite of phlebotomine sand flies. There are several different forms of leishmaniasis in people. The most common forms are cutaneous leishmaniasis (CL; dominantly caused by L. Major), which causes skin sores, and visceral leishmaniasis (VL; dominantly caused by L. Infantum), which affects several internal organs (usually spleen, liver, and bone marrow). * VL and CL are not mutually exclusive (one can potentially cause manifestation of the other) * It's hard to vaccinate against parasites because they're so much more complicated genetically than most bacteria and viruses.

Answer 391

* *VL and CL are not mutually exclusive (one can potentially cause manifestation of the other) * CL: Cutaneous Leishmaniasis; Symptoms: skin sores, ulcers, possibly swollen glands; L. Major * VL:Symptoms: swelling of spleen and liver, fever, anemia, low WBC count, low platelet count; slightly less common but far more severe; L. infantum

Answer 392

*Mice had far fewer parasites in their tissues if they had been vaccinated *Mice had less foot swelling *Mice had MORE pro-inflammatory cytokines; they were able to get a higher Th1 response which is difficult to do in vaccines; had higher levels of IFN-gamma (Th1) compared to IL-4 (Th2); very happy about this *Mice had FEWER mature granulocytes; more mature granulocytes is indicative of more disease; If have more granulocytes, means immune system is fighting disease; so less granulocytes means you are okay (less=better) Vaccinated mice had a lot more of the small granulocytes and almost no mature granulocytes *control groups: PBS (injected buffer did nothing), plasmid (injected plasmid had no effect)

Answer 393

*Vaccine is effective in prolonging life of infected mice in this test environment However: no sterile immunity achieved; mice still get infected, just with fewer parasites This technology is an important step in the right direction, but efficacy would have to be increased before it becomes a viable clinical therapeutic. Future possibilities could include enhancing the plasmid with an adjuvant, adding more epitopes, and testing in different model systems. *It is effective at treating, but doesn’t fulfill gold standard of what vaccine is but they still have managed to get TH1 response (Hard) Not all vaccines achieve sterile immunity; there are some vaccines that don’t achieve sterile

Answer 394

Vaccines induce an IMMUNOLOGICAL RESPONSE that typically involves a population of activated T and B cells, and the production of antibodies *activated cells are typically short lived, persisting for days to weeks *simiarly, the half-life of serum antibodies is typically on the order of days to weeks BUT in some cases, antibodies CAN be detected YEARS after vaccination *VACCINES also usually generate a population of memory T and B cells; although there is SOME decay over time, memory cells typically persist for the life of an individual *the memory cells will be specific for epitopes found on the pathogen of interest, and can be activated in response to an actual infection *the timeline for induction of memory and memory recall are similar to that of anynormal immunological response

Answer 395

ALL VIRAL infections produce their antigens INTRACELLULARLY, although many antigens are externally exposed (e.g. coat proteins & secreted molecules) * bacterial and protozoal infections may be intracellular or extracellular, depending on species * parasitic worm infections are almost always extracellular

Answer 396

respiratory, orally, sexually, bloodborne, vector borne, mother-to-child, etc.

Answer 397

1. Neutralization: antibodies can neutralize; surround pathogen and keep it from coming in and interacting with receptors; can be done for toxins or WHOLE pathogens 2. Opsonization of antigens or cells via FcR; make antigens or cells seem more delish to phagocytes; often antibodies when BOUND to something serve as signals for phagocytic cells to take them out; macrophages actually have receptors for the part of an antibody called the Fc region and can tect when antibody is boudn to someething and then takes it up 3. COMPLEMENT ACTIVATION; can lyse or kill cells by having antibodies activate complement system and generate membrane attack complexes 4. ADCC: antibody dependent cellular cytotoxicity: signal to kill cell 5. Mast Cell degranulation (IgE): rapid inflammatory response;

Answer 398

1. Phagocytosis; neutrophils, macrophages, etc. 2. Cytotoxic T-Cells (CTLs) 3. Natural Killer Cells (NKs) 4. NKT Cells 5. Delayed- Type Hypersensitivity (DTH) 6. Antibody Dependent Cellular Cytotoxicity

Answer 399

Balto the sled dog helped to bring diptheria antitoxin to the children of Nome, Alaska during a diptheria outbreak in 1925

Answer 400

During primary response, naive B cells will bind to pathogen; this will activate B cell and generate production of antibodies, yielding pathogen eradication

Answer 401

* Memory B cells will bind to pathogen and become activated; B cells that are specific to the epitopes encountered in the past will be re-activated * Naive B cells will bind to the pathogen, but the Fc region of the antibodies that are already bound to the pathogen will bind to the FcR (Fc Receptor) on the naive B cell, inactivating it; negative signal will prevent b cell activation

Answer 402

Immune responses to NEW EPITOPES tend to be inhibited during subsequent exposures to a pathogen until the pathogen expresses a significant # of unique epitopes such that memory cells can no longer eradicate pathogen **Can explain why we have epidemics and pandemics; once it makes the last change (3rd to 4th) that was protective, you’ve basically hit the resest immunologically speaking and so have to start over because now there is no memory for this mutated infection Not a problem when immunizing with multiple pathogens because they are their own entity, ore a problem when you have a single type of pathogen and its changing

Answer 403

Viruses are obligate parasites; they have to bind to host cells and invade them in order to replicate; take charge of host cell machinery *viruses are typically acquired by ingestion or inhalation, through mucus membranes, or the bite of an insect or animal

Answer 404

OUTER COAT: containing multiple copies of a protein required to bind to a host-cell receptor *examples of specific cell membrane binding sites: CD4+ chemokine receptors, sialic acid, etc. INNER COAT: containing DNA or RNA: genes that encode for essential proteins *genes: genes for enzymes like polymerase, reverse transcriptase, and protease, and also proteins like regulatory/evasive proteins, core proteins, surface proteins

Answer 405

* Innate Mechanism: alternative complement pathway for free virus; NK cells or IFN-alpha/beta for infected cells; NK cells are a type of WBC and a major component of the innate immune system; huge role in host-rejection of virally infected cells--able to recognize stressed cells; * antibiotics & complement: Antibodies block target cell binding (neutralization);C'-mediated lysis of enveloped viruses via MAC; FcR & C3R promote phagocytosis; ADCC of virally infected host cell (killing host cell but also virus within it) * Th1-dependent cellular responses: cytokines like IL-2, IFN-gamma, and TNF promote an antiviral state, activate CTLs and macrophages * CTLs: recognize virus infected host cells (MHC-1 + peptides) and lyse them; kill them

Answer 406

``` Interferons (IFNs) are a group of signaling proteins made and released by host cells in response to the presence of several pathogens, such as viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses. IFNs belong to the large class of proteins known as cytokines, molecules used for communication between cells to trigger the protective defenses of the immune system that help eradicate pathogens. Interferons are named for their ability to "interfere" with viral replication by protecting cells from virus infections. IFNs also have various other functions: they activate immune cells, such as natural killer cells and macrophages; ```

Answer 407

0-4 days: IFN-alpha + IFN-beta (peak first at day 2) 0-12 days: NK cels (peak 2nd, around day 3-4) 2-12 days: virus-specific CTLs; reach peak a week or so post-infection *CTLs are the first time you see a specific response; antibodies follow similar kinetics as CTL responses; might even come up later Innate responses are there to keep you alive (IFNalpha and beta and NK); they buy you time to engage adaptive response; some viruses are killed off by early responses efficiently, but if have to use adaptive response, must buy yourself time

Answer 408

*LCMV infections in mice are typically cleared within 2 weeks (red line), but serum IgG responses persist much longer *A stable population of radiation-resistant LCMV-specific antibody secreting cells (ASCs) is found in the bone marrow and spleen *Detectable levels of memory B cells are not found in the bone marrow *Study suggests that these are long-lived plasma cells *In theory, you shouldnt see much circulating antibody after a couple of months; however we can detect antibody responses years after someone has been vaccinated with vaccine or have had a particular infection Examined in LCMV virus in mice; used commonly when looking at viral specific immune responses; know that within two weeks, an animal will clear out an LCMV infection (red line on top graph); found that there was a stable population of specific antibody secreting cells that went back to the bone marrow and spleen; these cells form stable population *there is a mechanism that your immune system uses to keep producing antibodies that may be useful to you in the future; can have persistent protective antibody responses; for specific infections that require high level of antibody when exposed, couldn’t vaccinate well if didn’t have long lived antibody responses **SOME PLASMA CELLS ARE LONG-LIVED: Tend to retain plasma cells that are most useful to you; if exposed to things consistently, will replenish pool with more plasma cells specific for that pathogen; should maintain a population of long-lived cells *mechanism to adjust which responses will persist longer; provides us with mechanism to have longer lasting immune response

Answer 409

RESULTED in catastrophic inflammation and mortality after challenge with a persistent strain of virus *immunopathology required antigen-specific CD4 T cells and was associated with a CYTOKINE STORM, generalized inflammation, and multi-organ system failure *virus-specific CD8 T cells or antibodies abrogated the pathology *data demonstrates that vaccine-elicited CD4 T cells in the absence of effective antiviral immune responses can trigger LETHAL IMMUNOPATHOLOGY *found animals made a ridiculous amount of inflammatory cytokines *Impaired virus-specific antibodies *Impaired virus-specific CTLs *Fewer germinal centers in spleen *Higher levels of virus in the blood (PFU/mL; virus quantification) TAKE HOME POINT: Inducing the “wrong” immune response(s) with a vaccine could actually do more harm than no vaccine at all!

Answer 410

1. Inhibition of IFN-alpha/beta action; a virus may prevent translation or secretion of these viral-replication-inhibiting cytokines 2. Inhibition of antigen presentation; can prevent antigen from being moved to surface so T cells can recognize it; inhibition of TAP (Transporter associated with antigen) 3. Interference/inhibition of MHC expression; some viruses inhibit MHC I expression, and others inhibit MHC II expression 4. Interference with Complement activation; means less phagocytosis and cell lysis 5. Antigenic Variation that affects both B and T-cell epitopes; antigenic drift due to error prone polymerase, antigenic shift due to segmented genome 6. General immune suppression; infect immune cells & generally downregulate immune response

Answer 411

HA1 and NA vary more than others; because they are under a lot of immune pressure because making antibodies to clear them out so creating a lot of selection pressure for viruses to be varying surface proteins; happen to be TWO MAJOR targets of protective immunity so virus changes them constantly

Answer 412

* Bacteria are unicellular prokaryotic microorganisms * Surrounded by a complex outer structure of a lipid membrane(s) containing proteins & polysaccharides, supported by a cell wall * DNA genome encodes most or all proteins required for growth & replication. * May have external organelles (e.g. pili, flagella) * Some infectious bacteria are obligated to live within cells; others live extracellularly * Can be acquired by ingestion or inhalation, mucosally, from a vector, or via a wound

Answer 413

1. SIZE of inoculum; the dosage/# of pathogenic microorganisms entering the host 2. VIRULENCE of pathogens 3. extracellular v. intracellular bacteria

Answer 414

1. Toxin neutralization by antibodies 2. Bacterial agglutination by antibodies (agglutination=clumping of particles) 3. antibodies (i.e. sIgA) block bacterial attachment 4. Complement mediated lysis (CP or AP) 5. Opsonization by antibodies & complement 6. Complement mediated mast cell degranulation 7. Complement mediated neutrophil/macrophage chemotaxis

Answer 415

When an infection occurs, the parasite and damaged tissue release chemical factors that attract white blood cells to the site of infection. The attraction of white blood cells is called chemotaxis. The primary white cells attracted are neutrophils and macrophages

Answer 416

1. NK: stimulated by early cytokines; early source of IFN-gamma 2. DTH: macrophage activation via IFN-gamma produced by Th1 cells; DTH is a form of cell-mediated immunity, and the effector cell of DTH is the activated macrophage 3. CTL's: activated if bacteria is in cytoplasm * cellular effector responses against intracellular bacteria: involves killing bacteria in phagolysosomes and killing of infected cells

Answer 417

1. Enhanced adhesion to host cells; use specialized structures such as PILI or secrete adhesion molecules 2. Inhibition of phagocytosis: can acquire host proteins to masquerade as host cell or have polysaccharide capsule (equivalent of catching a greased pig) 3. Targeting of antibodies: some bacteria species are capable of secreting an IgA degrading protease 4. Antigenic variation: some bacterial species use gene rearrangement to vary pilin proteins 5. Inhibition of Complement: cell wall structure of some gram-negative bacteria resists lysis; some bacteria release enzymes that cause proteolytic degradation of complement proteins 6. Survival within phagocytic cells; some bacteria can escape from phagocytic lysosomes

Answer 418

Anti-capsular antibodies play an important role in defense against invading strep species; the polysaccharide capsule is variable between strains with mroe than 90 serotypes currently identified; the variability of the capsule allows a different bacterial strain to escape humoral responses generated against a previous infecting strain; the polysaccharide capsule also masks epitopes and interferes with phagocyte receptors due to the negative charge; this also prevents bacteria from entrapment in mucus; colonization of the upper respiratory tract is inhibited by IgM and IgA antibodies secreted across the epithelium * penetration of the bacteria into the submucosa can be reversed by opsonisation with IgM or dimeric IgA secreted by B lymphocytes; the polymeric immunoglobulin receptor (PigR) binds to the J chain of antibodies already bound to antigen and facilitates the excretion of pathogens by transcytosis

Answer 419

neutrophils play an important role in innate immune control of bacteria; neutrophils classically employ phagocytosis and release of antimicrobial granules to control extracellular pathogens; recently discovered innate defense mechanism known as NEUTROPHIL EXTRACELLULAR TRAP (NET); chromatin (DNA & histone proteins) with attached antimicrobial granules are extruded from the neutrohpils into the environment and serve to trap pathogens; the neutrophil dies during this process *bacteria may evade this by expressing a DNA endonuclease, that cleaves DNA and permits escape from the trap

Answer 420

*Diphtheriais an infection caused by the bacterium Corynebacterium diphtheriae. *Symptoms often come on fairly gradually beginning with a sore throat and fever. *The neck may swell in part due to large lymph nodes. *Diphtheria is usually spread between people by direct contact or through the air. * The symptoms are due to a toxin produced by the bacteria. *In respiratory tract, formation of “pseudomembrane” interferes with breathing and may lead to suffocation Heart and neurological damage also seen

Answer 421

Pathology mediated by a secreted exotoxin Injection of toxin in absence of bacteria causes disease in absence of actual diptheria; if put toxin in, will cause symptoms like actual infection Once internalized, toxin interferes with protein synthesis A single toxin molecule may kill a cell

Answer 422

Treatment & prevention * May be treated by passive immunization with antitoxin * Active immunization employs formaldehyde-inactivated toxoid, which retains the protective epitopes but cannot cause disease * Could get immunized prophylactically with activated toxic molecule called toxoid; allow you to make your own antibodies and they will neutralize toxin if you were to be exposed to it subsequently * Once a feared killer of children, vaccination against diphtheria has essentially eliminated disease from U.S. * ANTITOXIN: In the 1890s von Behring and Kitasato demonstrated that antiserum against diphtheria toxin could serve as a therapy for diphtheria; techniques were quickly developed to prepare large quantities of diphtheria antitoxin from horses

Answer 423

*Worked with Pasteur on cholera, anthrax and rabies Isolated C. diphtheriae Purified diphtheria toxin Developed methods to prepare antitoxin in horses Cofounder of the Pasteur Institute, served as its director for almost 30 years

Answer 424

*TB, consumption, the white plague *Bacteria: mycobacterium tuberculosis *The classic symptoms of active TB are a chronic cough with blood-containing sputum, fever, night sweats, and weight loss *Tuberculosis is spread through the air when people who have active TB in their lungs cough, spit, speak, or sneeze. * Antibiotic resistance is a growing problem with increasing rates of multiple drug-resistant tuberculosis (MDR-TB). *Tuberculosis is the second-most common cause of death from infectious disease (after those due to HIV/AIDS). *Leading cause of death from an infectious agent 1.5 million deaths per year worldwide Over 2 billion are currently infected Although largely eliminated as a public health threat from U.S. in mid 20th Century, TB re-emerged in 1990s as a result of the HIV/AIDS pandemic

Answer 425

Disease 90% of those infected mount effective CD4+ mediated response in the lung that contains bacteria in a granulomatous tubercle (Tubercle is simply a hard round structure and the term granuloma indicates that it is formed of macrophages. So it is both a tubercle and a granuloma.) 10% develop chronic TB, leading to extensive pulmonary lesions and disseminated bacteria Diagnosis Typically by PPD skin test and pulmonary X-ray Treatment Various antibiotics for at least 6 months Lapsed treatment has allowed multidrug resistant TB (MDR-TB), XDR-TB and TDR-TB to emerge Prevention Traditionally by public heath measures and quarantine BCG vaccine effective in some areas, but complicates skin testing so is not used in U.S.

Answer 426

Employs an attenuated bovine tuberculosis bacillus, Mycobacterium bovis * Attenuated by long-term culture in artificial medium (hundreds of passages over many years) * Virulence is lost but antigenicity retained

Answer 427

Efficacy and use Highly efficacious against tuberculous meningitis and miliary (disseminated) TB, but its efficacy against pulmonary TB varies with geography and seems to be positively associated with distance from the equator Trials in the U.K. have found efficacy against pulmonary TB as high as 84%, others in the U.S. and India have shown little protective effect Has never been widely used in the U.S., U.K. stopped routine use in 2005 WHO currently recommends BCG be given to all children born in countries highly endemic for TB Why variable efficacy? Genetic variability in BCG strains and/or human populations? Interference by environmental mycobacteria or parasitic infections? Exposure to UV light? (decreased efficacy in UV-exposed guinea pigs)

Answer 428

* Chronic activation of CD4+ T-cells * Accumulation of macrophages * Formation of a granuloma * Tissue necrosis

Answer 429

*Protozoa are unicellular eukaryotic organisms with a plasma membrane and a nucleus containing the genomic DNA Also may have other specialized organelles, both extracellular (e.g. flagella) or intracellular (e.g. kinetoplast) Some infectious protozoa are obligated to multiply within cells (e.g. malaria and Leishmania); others multiply extracellularly (e.g. African trypanosomes) Often have a complex life cycle, involving an intermediate host in which they display different forms with new antigens Usually acquired by ingestion or from a vector Immune response depends on location Extracellular: antibody-mediated mechanisms Intracellular: cell-mediated immunity There are no commercially available vaccines

Answer 430

*Caused by Plasmodium species; P. falciparum most virulent 600 million infected, causes at least 1 million deaths per year (mostly in African children) Fever, chills, and organ damage due to capillary blockage (e.g. cerebral and placental malaria) Rapid development of drug resistance Sporozoite: infective stage, requiring years of exposure to develop protective antibodies Cryptozoite: in hepatocytes, protective CTL responses can be experimentally induced Merozoite: released from liver to infect RBC where they replicate, mediating symptoms Gametocytes: produced from some infected RBC, taken up by feeding mosquitoes to continue the life cycle. Antibodies can interrupt escape from mosquito gut No vaccine yet, but development active

Answer 431

Trypanosoma brucei subspecies Agents of African sleeping sickness in humans and Nagana of domestic animals Millions are at risk in 36 countries of sub-Saharan Africa War, poverty, and displaced populations may increase transmission The WHO estimates that there are currently 50,000-70,000 cases of sleeping sickness per year * Disruption of the sleep cycle is a leading symptom of this stage and is the one that gave the disease the name 'sleeping sickness.' Infected individuals experience a disorganized and fragmented 24-hour rhythm of the sleep-wake cycle, resulting in daytime sleep episodes and nighttime periods of wakefulness *Antigenic Shift in Surface Proteins Leads to “Waves” of Parasitemia; parasites in the blood

Answer 432

Single-celled protozoan parasites that infect macrophages | Cause cutaneous, mucocutaneous, and visceral (internal organ) leishmaniasis

Answer 433

Th1 response: LESION HEALS: elvated IFN-gamma and IL-2 TH2 response: elevated IL-4 and LOW IFN-gamma; lesion fails to heal, infection visceralizes, and mouse dies

Answer 434

TH1: cell-mediated immunity: CTL, NK, DTH, some Abs; secretion of IL2, IFN-gamma, TNF-beta TH2: humoral immunity; mostly Abs; secretion of IL-4, IL-5, etc. Treg: contact-dependent regulation; tampens immune response

Answer 435

* *Cell mediated immunity: SOME antibodies * Cytokines: IL-2, IFN-gamma, TNF-beta * Cell types activated: macrophages, CD8 T cells,, some B cells * most effective gainst: INTRACELLULAR PATHOGENS * mechanism of action: cytotoxicity to infected cells through perforin-granzyme, IgG3-mediated ADCC and other mechaisms

Answer 436

* HUMORAL (antibody-mediated) immunity * cytokines: IL-4, IL-5, IL-10 * cell type activated: B cells * most effective against: extracellular pathogens * mechanism of actiion: antibodies neutralizizing toxins and pathogens, opsonize pathogens, and clear them throuh immune complexes

Answer 437

*The only currently employed vaccines that can elicit an effective Th1 response are live attenuated *These vaccines, while generally safe, do tend to carry more risk and logistical challenges than nonliving vaccines *Further knowledge of how these responses are polarized can lead to better understanding of how to elicit a Th1 response in other vaccine types *Humoral responses are effective against a wide range of pathogens This includes many, but unfortunately not all, intracellular pathogens *Many pathogens (and vaccines that would protect against them) require a strong cell-mediated response for solid protection, such as: Tuberculosis Rhinovirus Leishmania HIV

Answer 438

1. Nematodes “Roundworms” 2.Cestodes “Tapeworms” 3.Trematodes (FLATWORMS) “Flukes”

Answer 439

*Usually complex, depending upon Stage of infection (stage-specific antigens) Location of the parasites (gut, tissue, etc.) Nature of the antigen (surface, excretory, secretory) May be inadequate and/or pathological Example: sclerosing keratitis caused by Onchocerca volvulus CTL responses are not generally possible and the size of worms largely negates phagocytosis Antibodies (via ADCC, C’, or mast cell activation) or encapsulation via DTH may provide some protection Many worm species evade the immune response by secreting immunoregulatory factors or shrouding their surfaces, often with the host’s own proteins Defining which antigens are significant as targets for protective immunity and the proper type of immune response are major challenges for vaccine development

Answer 440

Major cause of liver and bladder disease in the developing world Sterile immunity does not develop following infection Drugs are expensive No viable human vaccine *Schistosomiasis is Acquired by Contact with Contaminated Fresh Water *Infected freshwater snails release cercariae, which penetrate the skin and develop into adult worms

Answer 441

Preferred route: worm pair gives rise to eggs, which go to intestine and then out through feces pathological route: worm pair go to egg: washback to liver (~50% of total eggs), eggs induce inflammation in liver; pliver pathology; worms will live in bladder and cause urinary tract pathology

Answer 442

*no antifungal vaccines About 400 fungal species cause disease Classification Site of infection: superficial, cutaneous, subcutaneous, deep/systemic Route of acquisition: exogenous or endogenous Virulence: primary or opportunistic Innate immunity controls most fungal infections Commensal organisms outcompete Phagocytosis by neutrophils Activation of alternative and lectin complement pathways by fungal cell walls Pattern recognition (e.g. TLR2 & TLR4) Acquired immunity develops against some fungi Anti-fungal antibodies develop Certain fungal infections are more prevalent in HIV/AIDS (e.g. oral thrush caused by Candida albicans), suggesting need for CD4+ T-cells

Answer 443

*Recall that memory B cells require a few days (2-5) to be reactivated What occurs if memory response is not recalled fast enough to deal with an infection? Toxins (e.g. diphtheria) can often incapacitate a host quicker than a memory response can be recalled Quickly replicating pathogens, such as influenza or Ebola virus, are able to incapacitate and/or kill their host before memory B cells can be reactivated, presenting a significant challenge for development of vaccines In these cases, vaccines must induce high levels of preformed antibodies

Answer 444

Live attenuated vs. subunit/inactivated vaccines Stronger primary responses in live attenuated vaccines over subunit/inactivated vaccines Stronger innate responses cause better priming of cells Ability for a live attenuated pathogen to replicate allows for higher amounts of overall antigen available to cells in a primary response Choice of adjuvant (nonliving vaccines) Certain adjuvants modulate the immune response to a vaccine one way or another (T helper cell polarization) Certain adjuvants exhibit a “depot” (slow release) effect, limiting the amount of antigen available to the immune system and allowing it to persist This can strengthen immune responses by increasing the amount of time the immune system has to respond to the antigen Conversely, the lower antigen dose can lower strength of primary responses

Answer 445

*Higher antigen dosage generally correlate with better immune responsiveness More antigen for initial B cell activation More antigen available for association with follicular dendritic cells However, very high antigen doses can cause tolerization Enough antigen processed by APCs in the absence of costimulatory molecules can lead to anergy of potentially reactive cells* What determines how much antigen is too high or too low for a given vaccine? Often this must be determined empirically (i.e. by trial and error).

Answer 446

Anergy is a term in immunobiology that describes a lack of reaction by the body's defense mechanisms to foreign substances, and consists of a direct induction of peripheral lymphocyte tolerance.

Answer 447

Vaccine doses are generally spaced at least two weeks apart, often a month or more Often the first dose primes against the most immunogenic epitopes available in the vaccine It is important to note that these epitopes are not necessarily the most protective. Furthermore, the most “immunogenic” epitopes may vary between individuals Subsequent doses will elicit primary immune responses against the less immunogenic, but potentially more protective epitopes What do you expect would occur if doses were spaced too closely together?

Answer 448

MHC alleles & haplotypes Recall that an individual’s collection of MHC alleles (haplotypes – one from each parent) determine what T cell epitopes can be loaded and presented to T cells This dictates what your T cells “see” and thus what you respond to Epitope coverage The set of epitopes in a vaccine must encompass a fairly wide range of MHC haplotypes in order to ensure maximal coverage of the human population as a whole This can be a problem for subunit vaccines, which generally contain a limited number of antigens (and thus epitopes)

Answer 449

*. If the presence of antibodies is sufficient to prevent colonization of mucosal surfaces, vaccines can produce “sterile” immunity.