Immune - Biology 111 Reading: 944-967 plus box about cancer...

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Biology 111 The Immune System Reading: 944-967 plus box about cancer on 816. Nonspecific immune defenses Passive barriers Active defenses Specific immune defenses Specificity, diversity, memory, danger recognition, and self/nonself recognition Humoral immunity Cell-mediated immunity Complement Protection of self, autoimmunity, and allergies Two diseases—AIDS and cancer Major Ideas
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Nonspecific Immune Defenses 1. Unbroken skin with antimicrobial peptides called defensins, plus lysozyme, a bacteriocidal enzyme found on the skin. 2. Bleeding, running nose, cough, abundant vaginal secretions. 3. Acidity of stomach, cilia in lungs. 4. Normal bacterial flora of gut, mouth, vagina, etc. 5. Filtering of lymph in lymph nodes. 6. Phagocytic cells (especially macrophages) in lungs, vagina, uterus, liver. These have "Toll-like receptors" on their surfaces that recognize "pathogen-associated molecular patterns" like bacterial flagella and double-stranded viral RNA. 7. Natural killer cells, a type of lymphocyte that punches holes in cancer cells and cells infected with viruses, some bacteria, and some fungi. 8. Complement, a series of proteins that make holes in the membranes of invading pathogens, make them easier to phagocytize, and attract white blood cells. 9. Interferon, a cytokine that that helps cells resist viral attack. 10. Tumor necrosis factors, cytokines that initiate inflammation responses and fever as well as attack tumors. 11. The inflammation response, including: a) increased blood flow to a damaged area and increased permeability of capillaries due to release of histamine from damaged tissues; b)action of complement; c) attraction of phagocytic macrophages and neutrophils. 12. For systemic infections, fever. This retards the growth of pathogens, increases the activity of defensive cells, and sequesters iron in the liver. Cytokine - a general name for a molecule (usually a glycoprotein) that stimulates cells to divide or become active. Interferon and interleukins are cytokines. Specific immune defenses - immune mechanisms that mount a very vigorous attack against a particular invader. Specific immune defenses involve either antibodies, killer T cells, or complement. Specificity - ability to attack only a certain invader. Diversity - ability to attack a wide (perhaps infinite) variety of invaders. Danger recognition - ability to ignore harmless foreign molecules and respond to those that pose a threat, usually because they cause tissue damage. Memory - ability to attack an invader even more quickly and forcefully the second time it appears, even if this is years later. Self/nonself recognition - ability to mount attacks against invaders while not attacking the body's own tissues. This ability is lost in autoimmune diseases.
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Specific Immune Defenses Antibody-mediated immunity - a kind of specific immunity in which B cells secrete antibodies. These bind to antigens that are usually outside the cells of the body (e.g., bacteria in the blood or lymph). T cells help with B cell activation.
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This note was uploaded on 04/03/2009 for the course CH 102 taught by Professor Staff during the Spring '08 term at Clemson.

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Immune - Biology 111 Reading: 944-967 plus box about cancer...

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