Exam 4 (Ch. 15, 16, & 17) Flashcards
T/F: Rabies has several animal reservoirs
True - especially in Idaho with bats!
In Lyme disease, which is the reservoir, the host organism, and the vector?
RESERVOIR: Birds, mice
HOST: Deer
VECTOR: Ticks
List the 3 Mechanisms of Transmission
-
Contact Transmission
-direct contact (e.g., rabies)
-indirect contact by fomites (e.g, common cold)
-droplets (e.g., influenza, common cold) -
Vehicle Transmission
-waterborne
-foodborne
-airborne -
Vector Transmission
-mechanical (on insect body parts, Salmonella)
-biological (tick, flea)
List some of the Portals of Exit
-Ear (earwax)
-Broken skin (blood)
-Skin (flakes)
-Anus (feces)
-Eyes (tears)
-Nose (secretions)
-Mouth (saliva, sputum)
-Mammary Glands (milk, secretions)
-Vagina (secretions, blood)
-Urethra (urine)
-Seminal Vesicles (semen, lubricating secretions)
Define Epidemiology
The study of the mechanisms involved in the frequency and spread of disease
-not just infectious disease, but also cancer, heart disease, etc.
Why is it important to study the Epidemiology of a disease?
It can aid in designing strategies to prevent disease
Define Incidence
number of NEW cases within a population in a specific period of time
Define Prevalence
TOTAL number of people INFECTED within a population at a given time
What is the Morbitity Rate?
Diseased Individuals / Total Population
What is the Mortality Rate?
Deaths from Disease over Specified Time / Total Population
What is a Sporadic Disease?
disease that occurs in RANDOM, UNPREDICTABLE pattern
Differentiate Endemic, Epidemic, and Pandemic
Endemic = constantly in population in low numbers (e.g., Influenza)
Epidemic = incidence of disease suddenly becomes higher than normal (e.g., measles)
Pandemic = worldwide epidemic (e.g., COVID-19, Spanish Flu)
What is an example of both a common-source outbreak and a propagated epidemic?
Common-Source Outbreak: Food Poisoning
Propagated Epidemic: Common Cold
What happens to normal flora when a pathogen is prominent?
Normal flora live in harmony with the host during healthy times, but it can become PATHOGENIC when host defenses are lowered
e.g., S. aureus
If an organism that is NOT part of the normal flora is able to colonize human tissues, it is ___________
Pathogenic
What are Opportunistic Pathogens?
Organisms that are pathogenic only in IMMUNOCOMPROMISED HOSTS
How do you determine the Causative Agent
Koch’s Postulates!
- The microorganisms must be present in every case of the disease
- The organisms must be isolated from the diseased host and grown in culture
- The pure culture must cause the same disease when introduced to a new host
- The microorganism must be recovered from the experimentally infected host
What are the Molecular Postulates?
- The virulence factor gene or its product should be FOUND in pathogenic strains but NOT in non-pathogenic strains
- Introduction of a virulence gene should CHANGE a non-pathogenic to a pathogenic strain; disruption of the virulence gene should REDUCE virulence
- Virulence genes must be EXPRESSED during disease process
- Antibodies of immune cells specific for the virulence gene products SHOULD be PROTECTIVE
How does a microbes “break through” the body’s defenses?
Adhesions allow binding to certain cell types (e.g., E. coli strains contain a special pili that binds to cells lining the bladder)
Toxoplasma gondii
What are some facts about this Eukaryotic parasite?
-Eukaryotic
-Single-Celled
-Parasite
-Can infect ANY NUCLEATED CELL
-Cousin to Malaria
-Also found in fish, cows, sheep…
-Mice are attracted to cat urine that is infected with this parasite, where they usually are repelled
Toxoplasma gondii
Explain how Toxoplasma gondii spreads
CATS!…specifically cat poop
also may be found in:
-soil
-water
-plant material
-undercooked meats
-blood transfusions
-organ transplant
-trans-placentally from mother to fetus
T/F: 2 BILLION people are infected with Toxoplasma gondii worldwide
TRUE
Toxoplasma gondii
What are the vulnerable populations to this parasite?
-Mothers
-Fetus’
-AIDS/other autoimmune diseases
-Immunocompromised
-Compromises to the immune system can cause REACTIVATION
Toxoplasma gondii
What are some signs and symptoms of this?
Toxoplasmic Encephalitis
-swelling of the brain, often presents with cysts
Ocular Toxoplasmosis
-lesions within the eye
Neurologic Issues
-cysts in the brain act SIMILARLY to brain tumors
T/F: There was interest in active toxoplasmosis in the 2000s as a cause for mental illness
True - this was considered due to the behavioral changes that occurred in mice prey, who were attracted to cat urine that was infected
Toxoplasma gondii
Describe what happens in Congenital Toxoplasmosis
-Intracranial calcifications
-Hydrocephalus: water in the brain cavities
-Delayed mental development and epilepsy
-Ocular toxoplasmosis
Toxoplasma gondii
In what ways is Toxoplasmosis treated or prevented?
Drug Therapies
-pyrimethamine, sulfadiazine, and folinic acid
Thoroughly cooking meat (NO undercooked or raw, sushi)
Freezing meat
Washing fruits and vegetables
Avoiding gardening/litter box when pregnant
REVIEW QUESTION
Who is at greatest risk for toxoplasma infection?
Pregnant women
REVIEW QUESTION
What is unique about toxoplasma?
Can infected ANY NUCLEATED CELL
What is a neglected Tropical Disease?
A disease that infects a large amount of people in an area and there is little to no money going into treating or researching it well
What is the Method of Infection for Parasites?
First - they infect and cause disease in OTHER ANIMALS
Then - these animals transmit disease to HUMANS
What are Helminths?
worm-like parasites
Definitive host : where the parasites reproduce sexually and intermediate host for maturation and development with tape worms humans can act as either the definitive and intermediate host
Can involve many sites
Lymphatic filariasis….Elephantitis
How is this disease acquired, and what are the symptoms?
Acquired via FEMALE AEDES MOSQUITO BITE in childhood
-transmit of Nematode (thread-like filarial worms) larvae
-Adult worms NEST in the LYMPHATIC VESSELS
-Can live for approximately 6-8 years and produce MILLIONS of immature larvae that circulate in the blood
SYMPTOMS:
-asymptomatic at infection
-Lymphodema
-Skin thickening
-Stigma and decline in mental health as mobility and livelihood can be LIMITED
Lymphatic filariasis….Elephantitis
Wuchereria Bancrofti (90% of cases) is diagnosed by collecting blood at night. Why?
The filarial worms are most active during the night
Also, it prevents spread by controlling mosquitos
Lymphatic filariasis….Elephantitis
How does Lymphoedema occur within this disease?
Filarial parasites release toxins that lodge within the lymphatic vessel during immune response
causes valves to become insufficient or non-functional, causing retrograde and impaired lymph flow and a dilated vessel
Lymph leakage leads to Lymphoedema
Lymphatic filariasis….Elephantitis
How is this disease treated and prevented?
TREATMENT
-DEC used to be used worldwide, but is no longer approved by the FDA, so must get it DIRECTLY FROM THE CDC following a POSITIVE INFECTION
PREVENTION
-sleep under a mosquito net (dusk to dawn)
-wear long sleeves and pants
-mosquito repellent
What are the THREE Lines of Defense against microorganisms?
1st Line: Physical and Chemical Barriers
2nd Line: Innate Defenses
-Phagocytes
-Inflammation
-Complement
3rd Line: Acquired Immunity
-Recognition by lymphocytes
-Effector mechanisms (how the immune system KILLS microorganisms)
List some of the Anatomical and Chemical Barreris against microorganisms
-Antimicrobial factors in saliva (lysozyme, peroxidase, lactoferrin
-Lysozyme in tears and other secretions and phagocytes
-Skin-physical barrier, fatty acids, sweat, normal flora
-Rapid pH change from stomach to upper intestine
-Acid in stomach (low pH)
-Flushing of urinary tract
-pH and normal flora of vagina
How does Mucociliary Escalator act as an Anatomical Barrier against microorganisms?
-Ciliated columnar epithelium lines the respiratory system
-between these epithelial cells there are “Goblet cells” that release mucus outside onto a mucus layer
-pathogens are caught into this mucus layer and are directed to the pharynx to be coughed out via cilia
How does sweat act as a barrier against microorganisms?
The saltiness of the sweat lowers the osmotic tolerance for microbial growth
Describe how the following chemical barriers defend against microorganisms:
- Saliva
- Stomach Acid
- Sebum
- Saliva - washes microbes from teeth and gums; contains the antibacterial enzyme LYSOZYME and immunoglobulin IgA
- Stomach Acid - digests microbes
- Sebum - low pH inhibits growth of some bacteria
What are Defensins?
Amphipathic molecules/proteins that can INSERT into membranes and DISRUPT them
-host defense peptides, with members displaying either direct antimicrobial activity, immune signaling activities, or both.
-secreted at mucosal surfaces, skin, in neutrophils, etc.
What type of bacteria are Defensins better against?
Gram-Negative - because of its greater membrane
REVIEW QUESTION
T/F: When infected with filarial worms, the only place the worms are found is in your lymphatic system
False - they are also found in the blood…this is how it transfers to person-to-person via mosquitos as the vector
REVIEW QUESTION
Why do we not have many cases of Lymphatic filarial diseases in the United States?
The mosquito is not native to the U.S.
REVIEW QUESTION
What are 4 chemical barriers>
Saliva
Tears
Sweat
Stomach Acid
Bile
Urine
Sebum
REVIEW QUESTION
How do Defensins work?
They INSERT into phospholipid bilayers and DISRUPT it, REDUCING the structure’s osmotic tolerance
What are Dermcidins?
Anti-microbial peptides constitutively expressed in sweat
-broad activity against both Gram+ and Gram- organisms
-6 molecules bind together to form a pore in membranes
How do Dermcidins remain on the skin?
They are resistant to salt and low pH which ensures they remain active on the skin
What are the cells involved in the 2nd Line of Defense? Which one is the major player?
MAJOR PLAYER: Neutrophils
-PMNs
-Macrophages
-Natural Killer Cells
-Mast Cells
-Eosinophils
During Hematopoiesis, which cells eventually mature into the Granulocytes?
Stem cells -> Myeloblasts -> Granulocytes (Eosinophil, Basophil, and Neutrophil)
Which is the major WBC found in the blood?
Neutrophils
Describe the function of Neutrophils
Phagocytize and digest engulfed material
Describe the function of Eosinophils
Participate in inflammatory reaction and immunity to some parasites
Describe the function of Basophils
Release histamine and other inflammation-causing chemicals from the granule
Describe the function of Macrophages
Phagocytize and digest engulfed material
-present in virtually all tissues, given various names based on where they are found in the body (e.g., pulmonary macrophages)
Describe the function of Dendritic Cells
Gather antigen from the tissues and PRESENT it to the lymphocytes that congregate in the secondary lymphoid organs
THE TATTLER
What are the two main Lymphocytes?
T Lymphocytes
B Lymphocytes
If you have allergies, you may carry a higher number of ___________ in the blood
Eosinophils
Describe the process of Phagocytosis by a Macrophage
- Bacterium becomes ATTACHED to pseudopodia, membrane evaginations
- Bacterium is INGESTED, forming a PHAGOSOME
- Phagosome FUSES with lysosome
- Lysosomal enzymes DIGEST captured material
- Digestion products are RELEASED from the cell, later being cleaned up by other cells
There are several factors secreted by activated macrophages.
What does IL-1 do?
Promotes INFLAMMATORY RESPONSES and FEVER…inhibits bacterial growth
There are several factors secreted by activated macrophages.
What does IL-6 do?
Promote INNATE IMMUNITY and ELIMINATION of pathogens
There are several factors secreted by activated macrophages.
What do Complement Proteins do?
Promote INFLAMMATORY RESPONSE and ELIMINATION of pathogens
There are several factors secreted by activated macrophages.
What do Hydrolytic Enzymes do?
Promote INFLAMMATORY RESPONSE
There are several factors secreted by activated macrophages.
What does Interferon Alpha do?
Activates cellular genes, resulting in the PRODUCTION of proteins that CONFER an ANTIVIRAL state on the cell
Neutrophils are considered professional _________, because this is ALL they do
professional PHAGOCYTES
-they undergo respiratory bursts to create reactive oxygen molecules…these can be produced on the membrane an act by simply contacting the pathogen
When a neutrophil dies, how does it continue to trap and kill microorganisms?
Neutrophil Extracellular Traps (NETS)
these are released and grasp onto microbes, and microbicidal proteins help kill them
Macrophages exist throughout the body.
What is an example of one and its relevance?
Alveolar Macrophages in the lungs
-these are the important in engulfing TB
What is the function of Kupffer Cells?
remove damaged RBC from circulation
How do cells recognize microorganisms?
PATTERN RECOGNItiON RECEPTORS - scavanger receptors and toll-like receptors
-these recognize bacterial components like LPS, peptidoglycan, and flagellin that are found in many types of bacteria
-there are a LIMITED number of receptors, thus a LIMITED number of structures are recognized
How do Pattern Recognition Receptors work?
Some INDUCE PHAGOCYTOSIS while others lead to activation signals that RESULT IN CYTOKINE PRODUCTION
Describe a Toll-like Receptor (TLR)
THIRTEEN HAVE BEEN FOUND SO FAR (10 in humans)!
Each receptor RECOGNIZES a molecule UNIQUE to microorganisms
Signaling pathways are DIFFERENT, thus the activation of different receptors can CONTROL the TYPE OF RESPONSE ELICITED
ESSAY QUESTION: KNOW TWO TOLL-LIKE RECEPTORS (TLR)
Describe where TLR5 is found and its natural microbial binding partner
LOCATION: Cytoplasmic Membrane
NATURAL MICROBIAL BINDING PARTNER: Flagellin (bacterial flagella)
ESSAY QUESTION: KNOW TWO TOLL-LIKE RECEPTORS (TLR)
Describe where TLR7 is found and its natural microbial binding partner
LOCATION: Phagosome Membrane
NATURAL MICROBIAL BINDING PARTNER: Viral ssRNA
What are some of the EXTERNAL and INTERNAL structures that are recognized by TLRs?
EXTERNAL:
-Flagellin
-LPS
-GPI anchor
INTERNAL:
-dsRNA
-ssRNA
-DNA
Where would you expect to find a TLR that recognizes LPS?
Cytoplasmic membrane
Where would you expect to find a TLR that recognizes dsRNA?
Phagosome membrane
After the recognition of a TLR, what happens?
Activated macrophages secrete a range of cytokines
LOCAL EFFECTS SUCH AS: activates lymphocytes, increases antibody production, activates vascular endothelium, activates NK cells, etc.
SYSTEMIC EFFECTS SUCH AS: fever, mobilization of metabolites, production of IL-6
Where are Mast Cells located and what do they do?
Near blood vessels in sites EXPOSED to the environment
Produce different mediators depending on different signals
Where are Dendritic Cells located and what do they do?
LOCATED: skin, oral/respiratory/genital mucosal areas, intestine, lymphoid tissues/nodes
FUNCTION: TRAP antigens and carry them to lymph nodes to ACTIVATE adaptive immunity (i.e., the tattler)
What do Natural Killer (NK) cells do?
Have NO pathogen-specific receptors, but INDIRECTLY recognize and KILL several types of pathogens and tumor cells
Also secrete cytokines that ACTIVATE macrophages
REVIEW QUESTION
What are the steps to phagocytosis?
WILL BE ON THE EXAM!
- Bacterium becomes ATTACHED to pseudopodia, membrane evaginations
-ATTACHMENT - Bacterium is INGESTED, forming a PHAGOSOME
-ENGULFS - Phagosome FUSES with lysosome
-FUSES - Lysosomal enzymes DIGEST captured material
-DIGESTS - Digestion products are RELEASED from the cell, later being cleaned up by other cells
-RELEASES
REVIEW QUESTION
What is the role of Neutrophils (PMNs)?
1st Line of Defense
Phagocytosis
REVIEW QUESTION
How do Neutrophils trap bacteria?
If it can’t keep up, they trap and kill bacteria with their Neutrophil Extracellular Traps (NETS) - its like velcro!
REVIEW QUESTION
What does a Toll-Like Receptor (TLR) in the CYTOPLASM detect?
Detect virus particles INSIDE the cell
NOTE: outside/membrane toll-like receptors detect bacteria and parasites…only cytoplasmic ones detect viruses
What are the Hallmarks of Inflammation?
Redness: increased blood flow, vasodilation
Heat: increased blood flow, vasodilation
Swelling: increased vascular permeability…so fluid is leaving vessel and going into the tissue
Pain: swelling and chemical mediators
What occurs during the Innate Defense?
- Pathogen crosses the physical barrier
- Phagocytes and Natural Killer Cells arrive on the scene, cytokines recruit immune cells, and the pathogens are phagocytized
- Inflammatory Response
At the site of active inflammation, what is pus?
collection of dead WBCs/phagocytes, tissue debris, and the dead pathogen
What occurs during Inflammation?
VASODILATION and INCREASED VASCULAR PERMEABILITY
Magnifies Response: interleukins, histamine, chemokines, prostaglandins
Vascular Permeability and Promotion of Adherence of Cells to Vessels: leukotrienes
The migration of phagocytes from blood to tissue is VERY RAPID (within minutes)
IL-2 is an important cytokine. What does it do?
Secreted by Macrophages and Epithelial cells
Proliferation of Lymphocytes; Macrophage production of cytokines, induces adhesion molecules for PMNs on blood vessel cells; induce fever
TNF-a is an important cytokine. What does it do?
From Macrophages, T Lymphocytes
Initiates inflammatory response; Cytotoxicity for some tumor cells; Regulation of certain immune functions; Induce fever; Chemotactic for granulocytes
What complement component initiates the Membrane Attack Complex?
C5b
What complement component is CENTRAL to the function of the Complement Cascade?
C3
-present in serum in an inactive form
The innate immune activation CLEAVES c3 into C3a and C3b
C3a = a chemoattractant, RECRUITS phagocytes
C3b = an opsonin, TAGS bacterium for DESTRUCTION
Describe the steps in the Innate Immunity Complement.
-
INITIAL ACTIVATION
-Classical: IgG and IgM antibodies
-Lectin: bacterial glycoproteins
-Alternative: PAMP recognition -
AMPLIFICATION OF INFLAMMATION
-Cleavage of complement C3
-C3a: recruits phagocytes, neutrophil influx
-C3b: tags bacteria to aid phagocytosis -
MEMBRANE ATTACK
-C5-C9: form the “membrane attack complex”, which come together to form a pore (hole) in the cellular membrane of bacteria, allowing water to move into the bacteria causing it to swell and die.
In the Complement Cascade, which complements cause the following end results:
- Inflammation/Attract Phagocytes
- Lysis of Foreign Cells
- Tagging of Pathogens
Inflammation: C3a, C5a
Lysis of Foreign Cells: C5b - C9
Tagging of Pathogens: C3b
Describe opsonization and its relationship to phagocytosis
Opsonization, like C3b, coats the organism, “tagging” it for destruction by a phagosome
the C3b surrounding the organism attaches to C3b receptors on the phagocyte, allowing for the engulfing to occur
What are the two main opsonins?
complement C3b and antibodies
What happens to an organism that has been phagocytosed?
- The phagosome fuses with the lysosome within the phagocyte, and lysosomic enzymes are produced to kill and degrade the organism (now called a phagolysosome)
- The organism continues to breakdown within the phagolysosome
- The contents are eliminated by exocytosis and cleaned up by other cells
Why do we need an adaptive immune response?
faster response, not always constantly having symptoms of infection (fever, pain)
What are the Hallmarks of Acquired Immunity?
- Antigen specificity: recognizes specific part of the virus
- Diveristy
- Immunologic memory
- Self/non-self recognition
Around how long does it take for antibodies to form from a new infection?
around 3 weeks
the innate immune response is pretty instant, but the adaptive immune response doesn’t kick in until later
Describe the Clonal Selection Theory
Naive B cells have different specific antigen receptors
When a B cell is exposed to its certain antigen, it begins to release growth factors and divide
Division forms Memory B cells as well as Plasma cells, which then leads to the secretion of large amounts of antibodies
BE ABLE TO DESCRIBE/DRAW!
What are the components that consist of the antibody structure?
FROM TOP TO BOTTOM
Antigen-binding site
Light Chain (part of variable region: binds to complementary shape of antigen, detect sugar, protein fold, etc.)
Heavy Chain (part of constant region: determines the mechanism used to destroy antigen
Y shaped
Give an example of a virulence factor that:
Shows the ability of an organism to bind and colonize a tissue
P pili of E. coli that allows to to bind to cells lining the bladder
Give an example of a virulence factor that:
Shows the ability of an organism to evade the host immune response or phagocytosis
S. pneumonia production of a capsule, makes it harder to be engulfed
Give an example of a virulence factor that:
Shows the ability of an organism to disperse to other hosts
TB proliferation after granuloma rupture…promotes coughing to release the bacteria from the lungs in respiratory droplets to infect other hosts
What is the role of lymphatics and lymph nodes?
This is where T cells and B cells are formed
REVIEW QUESTION
How does a WBC migrate into the tissue from the blood? Which WBC is most likely to migrate?
WBCs recruited by histamine and cytokines
an increase in vascular permeability allows for entry into the tissue
WBCs are hooked like Velcro on the sticky vascular wall, tumbling and acting as “bloodhounds” to the chemical signal
Neutrophils are most likely to be the first to migrate
REVIEW QUESTION
What is the impact of the Membrane Attack Complex?
PLAN TO DRAW THIS ON THE EXAM!
- Inflammation
- Lysis of Foreign Cells
- Opsonization
C3 cleaves into C3a and C3b
-C3a = induces changes that contribute to local vascular permeability and attract phagocytosis (inflammation)
-C3b acts as opsonin binding to microbial cells as a tag that aids in phagocytosis), and cleaves to C5
C5 cleaves into C5a and C5b
-C5a is a chemo attractant, like C3a
-C3 cleaves into C5b-C9
C5-C9 form the Membrane Attack Complex, which creates PORES in cell membranes, DISRUPTING the integrity of the cell
T/F: Each antibody is formed from its own unique B cell.
True
Which cells are considered the “Antibody Factories?”
Plasma Cells - they are the ones secreting large amounts of antibodies, as seen in the clonal selection theory
____________ of Ig receptors on B cells is IMPORTANT for activation
Cross-linking of Ig receptors - this leads to rapid activation
What are some antibody-mediated effector functions?
- Neutralization
- Opsonization
- Immobilization and Prevention of Adherence
- Complement Activation
- Agglutination and Precipitation Agglutination
- Antibody-Dependent Cellular Cytotoxicity (ADCC)
How is there a generation of antibody diversity?
The IgG heavy chains consist of four parts:
THINK LIKE A SANDWICH
- Constant Region Gene (stays the same) - “Bread”
- Variable Region Genes (changes) - “Meat”
- Diversity Regions (also changes) - “Condiments”
- Joining Sequences - “Tomato”
*2, 3, and 4 are variable and can change…creating the diveristy
Is our antibody response stable or does it improve with each exposure?
Improves with each exposure
Initial Infection = takes 2 weeks to form antibodies and create Activated B Cells
Memory B Cells are formed and remain present, identifying subsequent infections…Activated B cells form a GREATER response so they immune system is able to recognize and attach this pathogen more effectively
What is IgM
First antibody produced during the immune response
Functions: agglutination, precipitation, complement activation
A big Pentamer structure (five antibodies)…can’t be everywhere due to its size
What is IgG
Antibody that has specific attachment to phagocytes; complement fixation
Functions: agglutination, precipitation, opsonization, ADCC, complement activation
Monomer structure
Which antibody is able to cross the placenta?
IgG
What is IgE?
Antibody that attaches to mast cells and basophils, causing them to release their granule contents
involved in many ALLERGIC REACTIONS, functions in ADCC, helps to expel parasites
When is an infant most vulnerable to infection, and why?
After 3-6 months after birth
They begin losing their maternal IgG after birth during this period, and their body does not have the best time making their own at first.
It is best to wait around 4 months before vaccinating the child to allow for this innate immune system to build
Diptheria
Describe this infection?
Organism: Corynebacterium diptheriae
Spread: respiratory droplets, close contact, secretion from infected skin/mouth
Symptoms: weakness, fatigue, swollen glands in the neck, mild fever, Toxin Kills heathy tissues in respiratory system; 2-3 days after infection dead tissue forms a thick grey coating that builds up in nose/throat called a Pseudomembrane..
Treatment:
-Antitoxin = prevents further damage
-Antibiotics = kill remaining bacteria and limit toxin formation
Prevention: vaccination, TDAP
Anti-toxins are an example of _______ immunization.
Passive immunization
Describe why Balt and Togo rose to fame.
These two led a team of sled dogs on the 1925 serum run to Noma, Alaska in which DIPTHERIA ANTITOXIN was delivered by train to Nenana, Alaska and needed to be rushed by sled to Nome, Alaska
Staph species produce several enterotoxins that can lead to __________
Food poisoning
What are some examples of superantigens?
-SEA, SEB, SED, SEE = staphylococcal enterotoxins that lead to food poisoning
-Exfoliative-dermatitis toxin = scalded-skin syndrome
-Streptococcal pyrogenic exotoxins = shock
How does WBC migrate into the tissue from the blood? Which WBC is most likely to migrate
Margination: inflammatory signals or chemotactic factors released by damaged tissues. WBC adhere to lining of blood vessels by adhesion molecules on both the WBC and endothelial cells. Once adhered, the blood cells follow chemotactic gradients of inflammatory mediators, cytokines.
What is the impact of the Membrane Attack Complex? (MAC)?
MAC is a mechanism of the complement system that plays a critical role in eliminating pathogens and infected cells from the body. MAC is formed through a cascade of complement activation pathways and ultimately results in the assembly of a pore-forming complex on the surface of target cells. —> disrupting osmotic pressure and membrane integrity.
Describe innate immunity complement.
1.) initial activation
-classical: IgG igM antibodies
-lectin: bacterial glycoproteins
-alternative: PAMP recognition
2.) Amplification of inflammation
-cleavage of complement 3
- C3a neutrophil influx
-c3b coats bacteria to aid phagocytosis
3.) membrane attack
- C5-C9 form a pore on the cell surface
-can attack our cells too/sacrifice
describe phagocytosis of opsonized bacterium?
a.) chemoattractants such as C5a, attract phagocyte to organisms to be ingested
b.)C3b coats organisms and attaches to C3b receptors on phagocyte
c.) organism is engulfed into a phagosome
d.) phagosome fuses with lysosome to produce phagolysosome
e.) organism is killed within the phagolysosome
f.) digestion and breakdown of organism within phagolysosome
g.) contents of phagolysosome eliminated by exocytosis
