Immuno - Midterm 1

ktepps's version from 2015-10-04 20:15


Question Answer
What is CMI? Cells required?Cell mediated immunity. Need CD8+ (cytotoxic T-cells) & CD4+Th1
What are CTLs (CD8's?) what is required for their activation?Cytotoxic killer T cells. They need MHC1's, interleukin 2 & interferon gamma
What do CD8's do? How do they recognize & respond to antigen? (How do they get activated to become effector cells?)(LYSE CELLS). An APC presents antigen in context of a MHC1. A CD4 (Th1) recognizes the presented antigen & secretes IL2 & IF gamma (cytokines). The CD8 follows the cytokines & w/ the guidance of the CD4Th1, the CD8 lyses the infected APC cell presenting the antigen
What is an effector cell?Cell that can kill another cell
How do you tell the difference b/t Th1 & Th2?Only by the cytokines they make
What is a CD4-Th1?Helper T-cell involved in the CMI response. The Th1 cytokines activate the CD8 cells to effector (killing) cells
Th1 - immune response involved? Cytokines secreted? Activates what? For what type of antigen?CMI response. Cytokines are Interleukin 2 & Interferon Gamma. Th1's activate CD8s. INTERCELLULAR antigens
Th2 - immune response involved? Cytokines secreted? Activates what? For what type of antigen?Humoral response. Cytokines are Interleukin 4+5. Th2's activate B-cells (antibody production). EXTRACELLULAR antigens
What is DTH response? How is it generated?Delayed-type-hypersensitivity response. Memory Th1 cells encounter antigen, release cytokines (IL2, IF gamma) which recruit & activate macrophages & CTLs (CD8s) TYPE 4
How does antigen specificity fit into the DTH response/cells responsible for antigen recognition?Th1 responsible for antigen recognition in DTH - "Memory Th1 cells" can remember
What is the role of macrophages in the DTH response? What activates them in the DTH response?Macrophages phagocytize the antigen when signaled by the Th1 cells to do so. They also granulate & cause inflammatory response
Describe the DTH test for TB in cattle. Pos/Neg response?The TB skin test in cattle has you inject an inactivated TB antigen into the caudal skin fold (below tail). Wait 48 hours (hence delayed) & if positive, it means the Th1 memory cells have been exposed before (to mycobacterium)& remember the antigen & thus have a reaction via degranulation (discoloration, swollen, etc). Negative sign = no reaction = never before exposed
What is the IGRA? How is it conducted?Interferon-gamma release assay. To replace DTH TB test in cattle. Take blood of cow, squirt in TB antigen & culture. Then measure IF gamma...if IF gamma high it's a positive test
Advantages of the IGRA are?It's FAST, poses less risk to the cow & prior vaccination doesn't cause a false positive
Pos & neg control for an IGRA?Pos control = Simultaneously test known positive test along w/ unknown sample being tested. Compare IF gamma levels
Neg control = Same except w/ known negative
What is used in BCG vaccine for humans? Why would someone vaccinated w/ BCG test positive on human TB skin test?MYCOBACTERIUM BOVIS used in human vaccine. Might show up positive bc skin test is not specific (mycobact. protein common to all mycobacteriums) the reaction would show for any mycobacterium (cross reaction)
Activation & clonal expansion of antigen-specific B-cell?APC shows Th2 cell an antigen, Th2 cell tells naive B-cell that it is an antigen via IL4+5, B-cell then proliferates, differentiates & starts to make antibodies
What is class switching of Ab? How is it done?Class is determined by the CONSTANT REGION (aka heavy chain aka Fc region) which is what attaches to the self-immune-cell, not the antigen. This region expresses different genes so that it may attach to a different immune cell (ex: attach to B-cell instead of T-cell)
What is affinity maturation?Ab increases affinity to its antigen (it gets stickier)
Polyclonal antibody versus monoclonal?Monoclonal when only one type of antibody around. This is IN VITRO ONLY. Polyclonal is when there are many diff types of antibodies
Explain antibody against antibody terminology"Mouse anti-dog" means an antibody made by a mouse will attach to a dog's antibody
Serum electrophoresis pattern is what? Where is Ig in this?Put serum in well, add electricity to gel, Ig's will migrate to NEGATIVE cathode (Lg proteins to positive anode) high indication of inflammation
Fab fxn & structure?Attach to antigen, "light chain" portion. (The two "tips" of the Y)
Fc fxn & structure?Attach to somatic cell, "heavy chain" portion. Class switching happens here
Stuff about IgM?Pentamer. 1ST RESPONDER! Every response everywhere involves IgM. They bind to antigens so that antigens can be opsonized
Stuff about IgG?Monomer. IN COLOSTRUM. Also in blood. Binds to Ag & toxins. Long-term fighters & signal phagocytosis. (G-I-joe)
Stuff about IgE?Monomer. Responds to parasites & allergens, stimulate degranulation, stimulate sm. mm. motility. Involved in Type-1 hypersensitivity
Stuff about IgA?Dimer. In MILK & MUCOSA. (Buy milk at IgA)
Ab that opsonizes?IgM
Ab that neutralizes?IgG
Which Abs activates (classic) compliment cascade? Results?IgM or IgG → activate cascade → eventually Membrane Attack Complex formed to lyse cell.
Ab for mast cell degranulation?IgE
What is ADCC?Antibody dependent cell cytotoxicity = killing of antibody coated target cells by cytotoxic cells (usually NKs) w/ surface receptors for the antibody
What characterizes a T-independent antibody response? What’s produced?Antigen must be simple repeating polymers. Fast but weak response. B-cells activated to make Ab by the antigen binding to the BCR. ONLY IgM PRODUCED. humoral,no class switching, primary response, no memory
What characterizes a T-dependent antibody response?Abs formed can class switch & affinity maturate. Require the thymus & Th cells. Th cell cytokines affect which type of antibody is made. Can make memory B-cells Th1=ifn-gamma,IL-2(intracellular) Th2=IL4,IL5,IL6(extracellular)
What is a 1⁰ antibody response? (Major class produced?)Has lag, log, plateau & decline phase. Looks like a bell curve. (IgM IS MAJOR CLASS PRODUCED)
What is a 2⁰ antibody response? (Major classes involved?)Has lag, log, plateau & decline phase. However unlike 1⁰, lag is short, log is rapid & HIGHER & decline is slow & may persist for a long time (up to a lifetime) (IgG major class produced) (sometimes IgA or IgE is the major class but not as much as IgG)
What is a memory B cell?Allows a 2⁰ antibody response. Formed following 1⁰ infection. Doesn't produce antibodies, but produces plasma cells which do. Long term cell waits for infection of same antigen it learned in the 1st place
What determines the outcome of a FIP infection?If it has a Th1 or a Th2 response
Th2 response to FIP?Wet form. Th2 trigger B-cell to form antibodies. Antibodies form immune complexes. This causes immune complex vasculitis & fluid leaks into body cavities. Usually fatal
Th1 response to FIP?Dry form. Th1 has CD8 lyse affected cell. Lower mortality rate
What is the compliment system?Proteins in blood - no cells. It's a system whose activation leads to a sequence of events which will lyse a pathogen w/ NO CD8 INVOLVED!
What do complement proteins do?Ab & non-Ab mediated lysis of cells/Bact/viruses/parasites, facilitate phagocytosis via opsonization (make it sticky), induce inflammation in tissues, promote mast cell degranulation, clear immune complexes from circulation & deposit them in the liver/spleen
How is compliment system activated?(1) Classic pathway (antibody-mediated)
(2) Alternate pathway (includes lectin pathway)
How is alternate pathway (lectin pathway) activated?Activated w/o Ab. certain polysaccharides on bact. wall can activate system (often, lectins bind the carbs). Occur immediately, no prior exposure needed
How is classical pathway activated?IgG or IgM*(better) bind to antigen. Fc portion of Ab activates C1 (1st compliment protein in chain to activate system)
The end result of the compliment system is a what? Which does what?MAC (membrane attack complex). It is various parts of cascade assembled into a pore to lyse the pathogen
(Bird) IgY stuff?Analogous to IgG. 2⁰ immune response. Comes from yolk. Is "main military man" antibody & ALSO does a little of IgE's job (anaphylactic shock etc)[anaphlaxis]
(Bird) IgM stuff?Analogous to IgM. 1⁰ immune response. In egg WHITE
(Bird) IgA stuff?Analogous to IgA. In egg WHITE. (Mucosal antibody)
Passive transfer of antibody of birds?Though egg white & yolk - chick receives IgY via yolk so in circulation & IgM & IgA in its intestine. Has all when it hatches

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