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21 Cards in this Set
- Front
- Back
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What are the three major things that antibody does
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Opsonization,
Neutralization, Complement activation. |
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Early defense mechanisms against virus
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Natural Killer cells
Type I Interferons (alpha and beta) *early anti-viral defenses. |
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Later defense mechanisms against virus
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Antibody
Cytotoxic T-cells *takes time to activate and replicate. **left shift if the 2nd time you encounter the virus b/c of memory cells. |
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which antibody is responsible for anti-parasitic defenses?
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IgE!!!!
when you think about IgE, you think about 1)allergic reactions and 2)anti-parasitic defenses |
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How do you combat a huge parasitic worm if you cannot phagocytize it?
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Act on the surface of the organism. IgG and IgE can bind to antigens on the surface of the worm, cells bind to the Fc region of the Ab, and release a toxic substance on the surface of the organism. Cells such as neutrophils, macrophages, and eosinophils (esp. with IgE).
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What do the parasitic defense cells (neutrophils, macrophages, eosinophils) release onto the surface of the parasite?
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Reactive Oxygen Intermediates (ROI) and Nitric Oxide.
Mast Cells also have a high affinity for IgE, so when it's in contact with IgE, it releases its granules (histamine, etc), as well as get more eosinophils to the organism |
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Interferon Gamma is released by_____ and activates ________
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Th1 T cells ; macrophages
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What are the oxygen dependent mechanisms of killing by macrophages and neutrophils?
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Since they are phagocytic cells, they will engulf an organism. It kills with NADPH OXIDASE (most important step), superoxide dismutase, and myeloperoxidase.
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What problem happens if you have an NADPH oxidase problem?
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neutrophils can't kill the organism well once they're phagocytized. this will cause Chronic Granulomatous Disease.
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Name two types of KILLER cells
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Cytotoxic T Cells
-CD8+ T cells, MHC I resricted peptide recognition, induce target cell apoptosis Natural Killer Cells -mediate ADCC, MHC I send NEGATIVE signal, induce target cell apoptosis |
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What does MHC Class I do to Natural Killer Cells?
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MHC Class I turns off natural killer cells.
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What does Cytotoxic T cell have for killing?
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Fas Ligand- membrane protein receptor
TNF- cytokine released from the cell Perforin- just like C9 of complement, puts a hole in the target cell. |
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What does a CD8+ Cytotoxic T cell see on the target cell? What does it do?
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MHC Class I peptides on the surface of the target cells. It kills the cell because the target cell has a protein called Fas (CD95) which binds to the Fas ligand on the T cell, this activates the CASPASE enzyme, leading to apoptosis.
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What is a granuloma?
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A space-occupying chronic inflammatory lesion that form due to cell-mediated immune reaction. Certain infections tend to lead to granuloma formation, like tuberculosis, leismaniasis, schistosomiasis. Involves macrophages and T cells.
When an infection is not easily cleared, altered macrophages accumulate, forming a ball. The macrophages form multi-nucleated giant cells, and epithelioid cells. |
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What is ADCC?
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Antibody Dependent Cellular Cytotoxicity. It's a mechanism where antibody acts as a bridge between the target cell and a killing cell (ex NK cell, macrophage, et al). The Killer cells need an Fc receptor to bind to the antibody (which is coating the target cell), then release toxic granules to kill the target cell.
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Th1 makes
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IFN-gamma (for macrophage activation), and helps B cells make IgG.
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Th2 makes
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Produce IL-4, IL-10, 5,13,. Cytokines that help B-cells proliferation and differentiate. IL-4 and 13 help B-cells make IgE.
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Regulatory (inhibitory) T cells make
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TGF-beta and IL-10; shut down the immune response.
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Predominant immunoglobulin in mucosal immune system is?
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Secretory IgA
-mad Igs since this is at the openings of the body, so you want a good defense -does NOT cross placenta -does not activate complement via classical pathway (not much inflammation at mucosal membranes) |
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What are M-cells?
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gate-keeper from things that activate lymphocytes. Found ontop of epithelial cells in the GI and respiratory tracts. Sample the lumen, let certain antigens through to lymphoid tissue underneath. Prevent inappropriate response to everything you eat.
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T and B cells stay in one place, right?
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No, they tend to migrate throughout the body. This is particularly true for the T-cells. If you have a T-cell in the GI tract/peyer's patch and recognize something, they hone back to mucosal tissue.
Because of this, you can take an oral vaccine that generates an immune response that circulates sytemically to mucosal membranes of the resp tract, etc. The immune response can go anywhere the virus may go. |
