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20 Cards in this Set
- Front
- Back
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Intracellular Cytoplastmic infection requires what protective immunity?
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Cytotoxic T cells, NK cells, T cell dependent macrophage activation
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Intracellular Vesicular infection requires what protective immunity?
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T cell and NK cell dependent macrophage activation
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Entracellular - intestinal spaces, blood, lymph infection requires what protective immunity?
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antibodies, complement, phagocytosis, neutralization
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Extracellular Epithelia cell infection requires what protective immunity?
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antibodies expecially IgA, inflammatory cells
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What is the innate immune response to viruses?
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Soluble factors - enzymes in GI tract, mucus, complement interferon alpha or beta
Cells - NK cells and phagocytes (may accidentally spread virus) |
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Mechanism of action for Interferons Alpha and beta?
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virus infection stimulates IFN alpha and beta secretion by host cell which binds to receptors on other cells and eventually ihibits protein synthesis by those cells so virus is not synthesized
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Natural Killer Cells
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Large granular lymphocytes
CD!^ 5-10% of lymphocytes No Ag receptor so no clonal selection Stimulated to divide by IFN alpha, beta, gamma, and 12 |
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NK cell granules contain?
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Perforin and Granzymes
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How do NK cells recognize altered self cells?
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KIR and/or CD94/NKG2 binds to Class I MHC if present - then doesn't kill
If there is no MHC I to bind to then kills because virus infected cells have decreased MHC I NK cells also have AR that binds to AR-ligand on cells |
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How do NK cells target cells?
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Perforin - pokes holes in target cells
Granzymes - induce apoptosis in target cells |
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Activation requirements for T cytotoxic cell response?
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1. TCR binds to MHC I / foreign Ag
2. CD28 on Tc binds to B7 on target cell 3. IL-2 from Th1 cell binds IL-2R on Tc |
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What is a CTL-P?
What is a CTL? |
CTL-P = cytotoxic T lymphocyte precursor (no granules)
CTL= activated cytotoxic T lymphocyte - has granules and killing function |
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What are T cytotoxic cell killing mechanisms?
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1. Granules with perforin and granzymes
2. Fas ligand on CTL binds to Fas receptor on target cell - induces apoptosis in target cell |
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What antibodies do to stop viruses?
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Abs block receptor from attaching to target = neutralization
Block fusion of virus envelope with CM Activate complement (MAC, C3b, C5b-9) Agglutination Opsonization |
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What are viruses evasion tactics?
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Inhibit interferon - adenovirus, epstein barr
block C3b - herpes Immunosuppress your victim - HIV Antigenic Drift and Antigenic Shift |
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Bacterial Evasion tactics?
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Extracellular bacteria
- change surface proteins - destroy antibodies - inhibit phagocytosis - resist complement Intracellular bacteria - escape from the lysosome into the cytoplasm - prevent lysosomes from fusing with the phagosome |
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Other Virulence mechanisms of bacteria?
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1. secretion of enzymes that enhance infection
2. Using host cells to spread infection |
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Which cells help in extracellular and intracellular infections?
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Extracellular - Th2, Ab
Intracellular - Tc, Th1, macrophages - cell mediated |
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Evasion tactics used by parasites? - protozoa?
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Variable surface glycoproteins - change them constantly
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Evasion tactics used by parasites? worms?
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Motile - can swim away from buildup of immune system cells
Decrease expression of worm Ag Acquire a coat of human proteins Communicate with T regulatory cells - to suppress inflammation |
