Microbiology Exam Final Review Flashcards
What is the definition of infection?
entry or growth of mircoorganisms of a host and can have one of two outcomes
What are the two possible outcomes of infection?
- disease: microorganism produces symptoms and causes damage
- colonization: when microorganisms persist without causing disease
What is the difference between a primary pathogen and an opportunistic pathogen?
- Primary pathogen: regularly causes disease in at least some individuals with normal defenses
- Opportunistic pathogen: usually doesn’t cause disease except in people with compromised defenses (p. originosa)
What is the definition of virulence?
Degree of pathogenicity
What is a virulence factor?
- specific properties of a pathogen that promote infection/disease
- high resistance to pathogen=means pathogen has a low virulence
From an ecological perspective, what types of symbiotic associations between different organisms can occur, and what type does a pathogen host interaction represent?
Symbiosis:
- ecological perspective on an disease
- 2 or more organisms living together in close association
Mutualism, commensualism, parasitism
Mutualism
both organisms benefit (ex, lichens)
Commensualism
one organism benefits and other is not affected (ex. bactria in GI tract)
Parasitism
- One organism benefits (parasite) at expense of other (host)
- changes in parasite or host may alter balance between health and diseases
What are the portals of entry into the host?
- microbial entry into host
- 1st step in infection
Examples: respiratory tract, gastrointestinal tract, genitourinary tract, skin wounds, eyes and ear, placenta
What are the specific virulence factors discussed in lecture?
capsule, toxin, toxin: a. endotoxin, toxin: b. exotoxin, extracellular enzymes
What 2 microbial activities do many virulence factors promote during growth and spread of the microbe within the host?
- scavenge nutrients (e.g., siderophores)
- penetrate host tissues (e.g., invasins)
- counter host defenses (e.g., IgA proteases)
What is the difference between endotoxin and exotoxins?
- endotoxin is a lipopolysaccharide: Shedding of endotoxin induces fever (Salmonella tyhi)
- exotoxin is a soluble protein
What are the five different types of exotoxins discussed in lecture?
botulinum neurotoxin, cholera enterotoxin, diphtheria cytotoxin, hemolysins, leukocidins
Exotoxin botulinum neurotoxin
blocks neurotransmitter release (Clostridium botulinum)
Exotoxin cholera enterotoxin
promotes massive fluid loss from intestinal epithelium (Vibrio cholerae)
Exotoxin diphtheria cytotoxin
kills cells by inactivating translation
Corynebacterium diphtheriae
Exotoxin hemolysins
lyse red blood cells by forming pores in membranes (Streptococcus pyogenes)
Exotoxin leukocidins
lyse white blood cells by forming pores in membranes
Staphylococcus aureus
How do microorganisms attach to the surface tissues of the host?
pili and other (non-pilus) adhesins
What are the major physical and chemical barriers to infection?
Tissue integrity, flushing mechanisms, antimicrobial substances
What are examples of antimicrobial substances produced by specific host cells and tissues?
- Cationic antimicrobial peptides,
- antibacterial fatty acids in perspiration,
- lysozyme in tears and saliva,
- lactoferrin in tears, saliva, and milk, gastric acid in stomach,
- bile salts in intestine, antiviral proteins in tissues,
- antimicrobial proteins in blood and lymph,
- transferrin in blood and lymph
Tissue integrity (physical and chemical barriers)
- Unbroken skin and mucous membranes
- Sloughing cells (removes adherent bacteria)
- Mucus secretion (traps microorganisms)
Flushing mechanism (physical and chemical barriers)
Urination, peristalsis, coughing, sneezing, perspiring, tearing, salivating
Antimicrobial substances (physical and chemical barriers): Cationic antimicrobial peptides
- (defensins and cathelicidins)
- Positive
- Bond to the negatively charged bacteria, basically lyse the bacteria because they open pores in the membrane and lyse it
Antimicrobial substances (physical and chemical barriers): Lysozyme
- found in tears and saliva (degrades peptidoglycan)
- Breaks the bond between the NAM and the NAG, if there is no wall barrier water can rush in and burst
Antimicrobial substances (physical and chemical barriers): Gastric acid in stomach has a….
low pH
Antimicrobial substances (physical and chemical barriers): bile salts
found in intestine (detergent action)
Antimicrobial substances (physical and chemical barriers): antiviral proteins
- (interferons) in tissues
- interferons are produced by cells
Antimicrobial substances (physical and chemical barriers): Antimicrobial proteins
- found in blood and lymph
- B-lysins and complement
Antimicrobial substances (physical and chemical barriers): transferrin
found in blood and lymph (binds iron)
What are the major biological barriers to infection?
Biological barriers: Genetic resistance (species, subspecies, and individual), normal microbiota, phagocytosis, inflammation
In what ways does the normal microbiota benefit the host?
Protects the host by: -limiting nutrient availability
- preventing pathogen attachment to host cell surfaces
- synthesizing antimicrobial agents (e.g., bacteriocins)
What are the four steps in the phagocytosis process?
- Chemotaxis
- attachment
- engulfment
- digestion
Phagocytosis process: chemotaxis
- Microorganism releases some type of compound and the compound serves as chemoattractants
- Chemoattractants follow the trail back to the site of the infection
Phagocytosis process: attachment
When white blood cell comes into contact with the bacteria
Phagocytosis process: engulfment
Membrane pinches off in a vacuole, and referred to as a phagosome
Phagocytosis process: digestion
- Lysosomes are packed with enzymes like protiases and halogens and superoxide generating molecules
- Phagosytic cells clean up damage from host cells, like vaccum cleaners
What are the 3 major types of cells in whole blood?
- erythorcytes (red blood cells) that carry oxygen to other body tissues, hold hemoglobin
- leukocytes (white blood cells)
- thromobocytes (platelets)
How are leukocytes further classified according to their appearance in the Wright stain?
- White blood cells stain different colors
- Can categorize them into different sub categories
- Can distinguish some white blood cells if they have a lot of granuales, and the granuales have little speckles on them
- Called granulocytes: basophils, eosinophils, neutrophils (first cells that are there when there is damage or infection and start the inflammatory response) (they are also phagosytic)
- Agranulocytes: monocytes and lymphocytes
What is the fluid portion of blood called (a) before and (b) after the clotting factors are removed?
- Plasma: the fluid portion of blood after the cells are removed
- Serum: the fluid portion of blood that remains after the cells and clotting factors are removed (by letting them coagulate naturally)
What are mediators in the inflammation response, and what specific examples were mentioned in lecture?
Cells in damaged tissues release mediators (histamine (benadryl), bradykinin, prostaglandins, leukotrienes, serotonin).
What are the three basic characteristics of adaptive immunity?
- Recognition of self from non self
- Memory of past infections
- Specificity (adaptive immunity is a specific response whereas inflammation is non specific response) (each virus or infection is different, and the body will recognize the specific action needed to get rid of it)
What is autoimmunity, and what specific examples of autoimmune diseases were discussed in lecture?
- An immune response triggered against the body’s own tissues
- Rheumatoid arthritis, lupus erythematosus, rheumatic fever, autoimmune uveitis, multiple sclerosis, alopecia
What is an antigen?
-Any molecule that is immunogenic (induces an immune response)
What is an epitope, and how many epitopes does a good antigen usually need to have?
- Patches that the immune system does recognize
- To be a good antigen, it needs multiple epitopes
- Found in animal
- Immune system does not recognize the entire cell but recognizes small patches called epitopes
What is an antibody?
soluble proteins that are synthesized in response to the presence of an antigen. They recognize and bind to the antigen at specific epitopes
What can an antibody also be called?
immunoglobulins (lg) (another name for antibodies)
What is the structure of an antibody molecule?
- 4 polypeptide, 2 light and 2 heavy chains that are all connected by the disulfide bonds
- 4 separate amino acid chains, 2 longer chains than the other one
- The two shorter amino acids are half the size of the longer amino acids
- 2 longer chains are called heavy chains and 2 shorter chains are called light chains
- The two heavy chains are covalently linked together by disulfide bond and there may be more than two disulfide bonds
- The light chains are also covalently attached to heavy chains
- The amino acid sequence will be the same in all antibodies for about 3/4ths up the chain
- Constant region- lower half of the light chains/ constant region
- Variable region- higher half of the light chains
What are the 5 classes of antibodies?
IgG, IgM, IgA, IgD, IgE
Function of Antibody Class: IgG
- is the most abundant antibody in blood serum. Maternal IgG confers immunity to the fetus and in newborns
- Depends on mother to provide protections
- IgG has the ability to cross the placenta and go to the baby and protect it
- The unborn child does have antibodies and most of them are IgG, usually not until after birth does the child start making its own antibodies
- Major response that comes along a bit later after IgM
Function of Antibody Class: IgM
- is the earliest antibody to appear in blood serum during a primary immune response
- They are the first to get to an antigen, rapid deployment force of the immune system
- First responders
Function of Antibody Class: IgA
- is the major antibody found in secreted body fluids (mucus, saliva, urine, tears, and breast milk).
- Like a UTI infection, IgA is usually the one that goes to help fight the infection
- Gonorrhea
Function of Antibody Class: IgD
-is involved in activating antibody production during a primary immune response
-Very small amounts
Thought to have helped with antibodies in infants???
Function of Antibody Class: IgE
participates in allergic reactions
What are the 5 different types of antigen-antibody reactions?
precipitation, agglutination, complement fixation, opsonization, neutralization
Antigen-Antibody Reactions: Precipitation
antibodies react with soluble antigens and form aggregates that precipitate out of the solution
Antigen-Antibody Reactions: Agglutination
- antibodies react with particulate antigens, causing cells to agglutinate (clump).
- Instead of participation you get a clumping type of action called aglutination reaction
- Getting them out of the solution, and makes it easier for the phagosytic cells to consume the antigen
Antigen-Antibody Reactions: Complement fixation
- binding of antibodies to participate antigens activates complement (a set of blood serum proteins) to lyse the microbial cell.
- What happens when the antibodies bind to the bacterial cells, can lyse the bacterial cell
Antigen-Antibody Reactions: Opsonization
- antibody binding stimulates phagocytosis
- Comes from the Greek word meaning to prepare food, really it is preparing it for phagocytosis
Antigen-Antibody Reactions: Neutralization
- antibody binding blocks the harmful activities of exotoxins, viruses, etc…
- Toxins like botulism
- If you bind antibodies to them, it blocks them from being a toxin and the virus can no longer attach to a host cell and cannot reproduce
- When the antibodies bind to it then it blocks the toxins or viruses from being harmful and it neutralizes it
What is the difference between humoral immunity and cell-mediated immunity?
Humoral immunity functions primarily for the defense of body fluids
- Humor is a body fluid such as blood, lymph, etc… (Latin for "moisture") - Humoral immunity is mediated by soluble factors in the body fluids. Cells of the immune system are involved only indirectly.
- Cell mediated immunity functions primarily for the defense of body tissues.
- Cells of the immune system are involved directly.
What are B lymphocytes and T lymphocytes? What organ processes the latter?
-B lymphocytes:
Synthesized in bone marrow and released directly into the body and blood stream
-T lymphocytes:
Also synthesized in bone marrow and released into the thymus gland for further processing and then go into the body and blood
How is a primary immune response induced? Identify the steps in the process.
- Phagocytic cell (e.g., macrophage or dendritic cell) makes contact with antigen.
- Phagocytosis of antigen
- MHC proteins bind small pieces of digested antigen, carry them to the cell surface, and display them in the cell membrane
- The phagocytic cell migrates to lymphoid tissue and “presents” the antigen fragment-MHC complex to a “naïve” CD4+ T lymphocyte. The activated T cell turns into a helper T lymphocyte, which then assists in the activation of a second lymphocyte
- The activated second lymphocyte divides (increases in number) and differentiates (acquires specialized functions in the immune response).
What cells are produced in a humoral immune response, and what cells are produced in a cell-mediated immune response?
B lymphocytes (humoral)
- Are responsible for antibody synthesis
- If you have an activated helper T lymphocytes, it can activate the naïve B lymphocytes
- This can be done directly by cell to cell contact
- It sometimes can be done indirectly by chemicals
- Plasma cells make the specific antibodies for that antigen
CD8+ T lymphocytes (cell mediated)
-The cytotoxic kill the virus infected cells, tumor cells
-Memory (CD8+) T lymphocytes are longer-lived, memory function
Can remember a virus that you had years ago
What 3 types of cell mediated immune responses were discussed in lecture?
- Protection against certain infectious agents, especially those that multiply intracellularly: tuberculosis, leprosy, brucellosis, some viruses
- Tumor cell destruction (immune surveillance)
- transplant tissue rejection
What is immune surveillance?
Tumor cell destruction
- Immune system goes down hill as you get older, and more likely to get cancer when you get older because your immune system is declining (it is a hypothesis of some/most forms of cancer)
- Cell mediated immune responses help destroy tumor cells
What are the different types of transplants?
Autograft, isograft, allograft, xenograft
Transplant: autograft
- a transplant to another part of the same body
- Ex.) If you burned part of your arm and they take some of the tissue from your leg to help it
Transplant: Isograft
a transplant between genetically identical individuals (Greek isos=eqal)
Transplant: Allograft
- a transplant between genetically non-identical individuals (Greek allos= other, different)
- Most common transplant
- Have to do tissue typing
- MHC
- Tissues must match, or else could get a cell mediated immune response
Transplant: Xenograft
- a transplant between individuals of different species
- Tissues come from different species
- Ex.) Heart valves that come from pig hearts
- A downside is that the animal could have a unknown virus that could then be transmitted to the human recipient
What is hypersensitivity?
primarily antibody-mediated, a fast response (minutes to hours)
Anaphylactic hypersensitivity
- primarily mediated by IgE antibodies
1. IgE antibodies not as important in an immune response, but they are still there
2. IgE antibodies used to be used to fight against certain bacteria found in GI tract
3. Humoral immune response
Cytotoxic hypersensitivity
IgM and IgG antibodies react with cellular antigens. Example: blood transfusion
- Cell mediated response
- Example: blood transfusions
- Carl Langsteiner, studied blood, more specifically transfusions and tried to figure out why people were dying from blood transfusions
Immune-complex hypersensitivity
IgM and IgG antibodies react with soluble antigens, forming immune complexes of antigens and antibodies
Delayed hypersensitivity
- primarily cell-mediated, a slow response (over several days).
- Example: contact dermatitis
What is Epidemiology?
the study of where and when diseases occur and how they are transmitted.
-A population study of disease
The goals of epidemiology are…
- To identify the cause of the disease
- To identify the risk factors for contracting the disease, and
i. Maybe age or restaurant or food - To provide information to health care professionals about the prevention and treatment of disease
What is the difference between endemic and epidemic diseases?
An endemic disease: is constantly present in the population, usually at a low level. (example: The mumps, A year round basis disease)
An epidemic disease: causes a localized outbreak that affects many people within a short time
- Breaks out all of a sudden and a bunch of people get sick with the same disease
- Very rapid
What is a pandemic disease?
- is a worldwide epidemic
- One country gets it and then another does
What are the definitions of the following epidemiological term: fomite
-can be spread indirectly by contact with contaminated inanimate objects called fomites (beddings, towels)
What national and international agencies oversee programs related to disease control and prevention at the population level?
CDC, FDA, NIH, United Nations World Health Organization, office of the secretary of health and human services, office of the deputy secretary of health and human services, office of the assistant secretary for health
What type of infectious disease accounts for the greatest number of deaths on a global scale?
Upper respiratory and lower respiratory tract infections (pneumonia and TB)
What bacterium causes anthrax and its main virulence factors?
Gram-positive endospore- forming rod Bacillus anthracis
What is the characteristic symptom of anthrax?
malignant pustule (black scab surrounded by inflamed tissue) at site of entry: bacteremia. High mortality rate.
What bacterium causes tetanus and its main virulence factor?
a potent neurotoxin
What is the characteristic symptom of tetanus?
extremely painful voluntary muscle spasms, especially in the neck and jaws.
What bacterium causes leprosy?
acid fast-positive rod Mycobacterium leprae
What are the characteristic symptoms of leprosy?
skin lesions, gradual loss of sensation due to nerve damage
Can often hurt themselves like burn themselves on a burner without even knowing it
What are the only natural hosts in which this bacterium (leprosy) causes the disease?
Mycobacterium leprae has a slow generation time and cannot be cultivated in vitro. The only known natural hosts are humans and armadillos, it can also be studied in genetically engineered mice.
What bacterium causes plague, and what is the vector?
- small Gram – rod Yersinia pestis
- flea, Bites of infected fleas introduced Y. pestis into human host
What are the two forms of the plague?
bubonic plague and pneumonic plague
What is the characteristic symptom of one of these forms?
swollen lymph nodes (buboes). Fever, headache, chills, delirium, hemorrhaging, black lesions appear under the skin.
♣ -Untreated cases have 50% mortality.
What bacterium causes Rocky Mountain spotted fever, and what is the vector?
- obligate intercellular parasite Rickettsia rickettsii
- arachnid (not insect) vector: ticks, Infected tick bites transmit R. rickettsii to humans
What bacterium causes Lyme disease, and what is the vector?
- the spirochete Borrelia burgdorferi
- Arachnid vector: tick (genus Lxodes)
What virus causes rabies, and how is it transmitted to humans?
- Caused by rabies virus, a bullet-shaped member of the rhinovirus family
- animals (racoons, skunks, foxes, bats, coyotes, dogs, etc…)
What is the mortality rate in untreated rabies cases?
100% mortality rate in untreated cases. The direct cause of death is respiratory and cardiac failure.
What bacterium causes diphtheria and its main virulence factor?
- Gram + nonspore-forming rod Corynebacterium diphtheriae
- diphtheria cytotoxin blocks protein synthesis.
What is the characteristic symptom of diphtheria?
-Damaged throat tissue forms a pseudomembrane, which can obstruct the airway, causing asphyxia and death.
What annual event commemorates a 1925 outbreak of diphtheria?
Iditarod Dog Sled Race in Alaska (Anchorage to Norma) commemorated an emergency relay of antiserum during a 1925 diphtheria outbreak in Nome.
What bacterium is the most common cause of pneumonia and its main virulence factors?
- Streptococcus pneumoniae (90% of bacterial infections)
- Other bacteria (10% of bacterial infections)
-Virulence factors: capsule and hemolysins
What bacterium causes pertussis?
Gram-negative rod Bordetella pertussis
What is the characteristic symptom of pertussis?
coughing fits with a “whooping” sound
What bacterium causes TB?
acid fast-positive rod Mycobacterium tuberculosis
What are the characteristic symptoms of TB?
chronic cough, fever, and fatigue
What major concern about treatment has arisen in recent outbreaks of TB?
Multidrug-resistant strains have appeared in recent outbreaks.
What is the difference between a food infection and food poisoning?
- Food infection: bacterial growth and spread cause symptoms of disease.
- Food poisoning: toxin produced by bacteria causes symptoms.
What microbe causes the most common type of food infection associated with ingestion of inadequately cooked, contaminated meat and eggs?
- Salmonella food poisoning (salmonellosis)
- Salmonella Typhimurium, Enteriditis, Newport, and other closely related nontyphoidal serotypes.
What is the most important virulence factor associated with Salmonella?
heat-labile enterotoxin (NOT heat stable).
What microbe causes the most common type of food poisoning associated with ingestion of uncooked or inadequately cooked, contaminated foods with a starch or cream base, especially if left unrefrigerated?
Staphylococcus (aureus) food poisoning
What is the most important virulence factor associated with Staphylococcus food poisoning?
Heat-stable enterotoxin.
What microbe causes the most common type of food poisoning associated with ingestion of improperly canned foods, especially veggies?
Clostridium botulinum
What is the most important virulence factor associated with Clostridium botulinum?
botulinum neurotoxin affects central nervous system.
What microbe causes typhoid fever, and what is the most important virulence factor associated with this organism?
-Salmonella typhi
- endotoxin (lipopolysaccharide).
- Infection may also develop into bacteremia (systemic infection in the bloodstream)
What is the most characteristic symptom of typhoid fever?
-Incubation period up to 2 weeks, followed by high fever and malaise
Who was a notorious carrier of typhoid fever?
- Mary Mallon, aka Typhoid Mary
- Mary Mallon was a notorious carrier (carries the infectious bacterium but doesn’t show symptoms)
- She was an Irish cook who got 51 people in NY sick.
What microbe causes cholera?
- Vibrio cholerea
- Toxin encoded by a lysogenic bacteriophage.
What is the most characteristic symptom of cholera?
serve dehydration and pale watery diarrhea (“rice water” diarrhea). Eventual shock and then death
What is unusual about the origin of the most important virulence factor associated with this organism?
enterotoxin that causes massive loss of fluids and electrolytes from the intestinal lining.
What microbe causes gonorrhea?
Gram-negative coccus Neisseria gonorrhoeae
What are the most important virulence factors associated with gonnorrhea?
1) Pili
2) IgA protease (cleaves IgA antibodies)
3) Antigenic variation: periodic alteration of cell surface antigens to avoid host defenses
What are the characteristic symptoms of this disease?
inflammation of genital tract, discharge of pus
What microbe causes syphilis?
spirochete Treptonema pallidum
What are the characteristic symptoms of syphilis? (3 stages)
1) Primary: a usually painless sore (chancre) at site of infection that heals spontaneously
2) Secondary: multiple skin sores and rash, fever, fatigue, and swelling of lymph nodes several weeks or months after infection
3) Tertiary: in about 30% of untreated cases, formation of granulomatous skin lesions called gummas and degeneration of the central nervous system several years after infection. Complications may include blindness, deafness, insanity, and damage to the heart and other major organs
What types of extracellular enzymes can be produced?
- Hyaluroniclase- degrades hyaluronic acid (hyaluronic acid keeps tissues together, acts like glue) (with the breakdown of the acid, it breaks down tissue and makes it easier bacteria to get into the tissue)
- Collagenase- degrades collagen (collagen also found in skin and tissues, degrading it makes it easier to penetrate)
- Coagulase- promotes blood clot formation (Staphyloccocus aureus causes this)
- Streptokinase- it dissolves blood clots (bacteria only want this to happen if the body forms a blood clot and the bacteria is trapped in the blood clot)
IgA Portease- degrades the IgA antibody (major antibody found in your secreted body fluids, blood, saliva, sweat) (N. gonherea)
What are the portals of exit from the host?
respiratory tract, gastrointestinal tract, genitourinary tract, skin wounds, eye, ear, placenta
What is the definition of phagocytosis?
engulfment and destruction of bacterial cells
What are the two major categories of leukocytes?
agranulocytes, granulocytes
What is the inflammation response?
- Damage to host tissues injured and dead cells (necrosis)
- Cells in damaged tissues release mediators (histamine, bradykinin, prostaglandins, leukotrienes, serotonin).
- Mediators provoke a variety of biological responses, including:
- Tissue repair and regeneration occurs
- Inflammation response is shut down
How does vaccination work?
Vaccine wont cause symptoms of disease, but your immune system will recognize it if you ever do get the disease because your body will have already make antibodies that will attach to the disease
What are the two major forms of antigens?
Proteins and polysaccharides are large molecules and could be seen as an antigen if they are foreign
What cells are primarily responsible for turning off the immune response when it is no longer needed?
eosinophils
How does a secondary immune response differ from a primary immune response?
- 2nd time being exposed to the same thing
- happens faster
- a lot more IgG antibodies
What role do major histocompatibility antigens?
- used for tissue typing
- if not similar, MHC will recognize as foreign and develop an immune response
What are immunodeficiency disease examples?
Example: AIDS, severe combined immunedeficiency disease (SCID)
-weak immune system against diseases
What are mast cells?
- granulated cells that contain mediators
- found in respiratory tract, and blood vessels
What role do mast cells play in anaphylactic hypersensitive reactions?
- causes the IgE goes to the mast cells in the anaphylactic hypersensitive response
- after second response, and the IgE goes to the mast cells they degranulate and they release mediators
What class of antibodies is involved in the mast cell/anaphylactic hypersensitive reaction?
IgE
What is the definition of the following epidemiology term: reservoir
- any continuing source of infection
- includes, animal, soil, water, and people
- if people are the reservoir then they are called carriers
What is the definition of the following epidemiology term: vector
an animal, especially insects, that act as intermediate carriers of infection
What is a notifiable disease?
- all diseases that government agencies want to keep track, just because, or to be more aware if a lot of people are getting it
- if you go to your doctor, they may have to notify the gov. that you got this disease
What region of the U.S. has the highest incidence of Rocky Mountain spotted fever?
Maryland, Virginia, and the Carolina’s
What microbe causes cholera?
Vibrio cholerae
What is unusual about the origin of the most important virulence factor associate with this organism?
- enterotoxin that causes massive loss of fluids and electrolytes from the intestinal lining:
- Toxin encoded by a lysogenic bacteriophage.
- you can be contaminated with the cholera cells, but if the bacteriophage cells do not infect the bacteria cells in the body then you will not get sick
What are cytokines?
they are the chemicals exchanged in the immune response
What are the general functions of cytokines?
- promote immune response and kill infection
- promote macrophages
- tries to stop infection by promoting immune response
What are the specific examples of cytokines discussed in lecture?
macrophage activation factor, migration inhibition factor, interleukins, chemokines, lymphotoxins, colony stimulating factors, interferons
Cytokines: Macrophage activation factor (MAF)
(MAF: the most common is interferon-y): enhances killing by macrophages
-It is a phagosytic cell
-Are laid back and migrate slowly through the body in regular environment
-If you culture them, you can see that they move slowly
-If you put them in a petri dish though, they start moving faster and are considered “angry macrophages”
Pumps up the phagosytic activity
Cytokines: Migration inhibition factor (MIF)
(MIF): inhibits migration of macrophages from the site of infection
You want all of the phagosytic cells to converge on the infected site
Cytokines: Interleukins
have a wide range of activities in inflammatory and immune response
Cytokines: chemokines
(including interleukin-8): attract leukocytes to antigen
Cytokines: Lymphotoxins
(especially tumor necrosis factor-B): kill cells
Cytokines: colony stimulating factors
stimulate cell division, including granulocytes and macrophages
Cytokines: interferons
- inhibit viral replication
- Used to help prevent viral replication
