ch. 15 – Microbiology – Flashcards
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| adaptive immunity |
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| protection by immune response that mature throughout life; involves b cell and t cells |
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| antibody |
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| y shaped protein that binds antigen |
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| antigen |
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| molecule that reacts specifically with either an antibody or antigen receptor on lymphocyte |
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| antigen presenting cells |
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| cells such as b cells, macrophages, and dendritic cells that can present exogenous antigedns to naive or memory t cells activating them |
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| b cell |
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| type of lymphocyte programmed to make antibodies, responsible for humoral immunity |
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| cell mediated immunity |
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| deals with antigens residing within a host cell, such as a virus |
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| clonal selection |
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| process in which a lymphocyte's antigen receptor binds to an antigen, allowing the lymphocyte to proliferate |
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| cytotoxic t cell |
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| type of lymphocyte programmed to destroy infectious or cancerous self cells |
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| dendritic cell |
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| cell type responsible for activating naive t cells |
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| helper t cell |
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| programmed to activate b cells and macrophages and assist in other parts of adapative immune response |
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| lymphocytes |
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| group of white blood cells that have antigen specific receptors on their surface, includes b and t cells |
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| MHC molecules |
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| cell surface molecules that present antigen to t cells (class I and class II) |
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| memory lymphocytes |
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| long lived descendants of activated lymphocytes that can quickly respond when a specific antigen is encountered again |
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| plasma cell |
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| effector form of b cell, functions as antibody secreting factory |
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| Tc cell |
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| effector form of cytotoxic t cell, induces apoptosis in infected or cancerous self cells |
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| Th cells |
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| effector form of helper t cell, activates b cells and macrophages, releases cytokines that stimulate other immune responses |
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| characteristics of adaptive immunity |
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| memory, specificity, tolerance (ability to ignore self molecules) |
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| 2 basic strategies used to adaptive immunity to counter foreign material |
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| humoral & cell mediated immunity |
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| humoral immunity |
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| works to eliminate extracellular antigens (bacteria, toxins, viruses in blood or tissue) |
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| antibody anatomy |
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| 2 identical arms (Fab regions) that bind to specific antigens, 1 stem (Fc region) that functions as red flag tagging antigen bound by antibodies and enlisting other immune system components to eliminate antigen |
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| how b cell responds to extracellular antigens |
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| triggered to proliferate --> become plasma cells --> produce and secrete antibodies, some become memory b cells |
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| hoe antibodies directly protect the host |
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| bind antigens, coating it and preventing it from attaching to host cell |
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| how antibodies indirectly protect host |
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| red flad stem tagging antigen for elimination |
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| how naive b cell knows when to respond |
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| its surafce has many copies of b cell receptors, if it encounters an antigen that it binds to, it is triggered to multiply after it is activated by another lymphocyte such as a t helper cell |
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| 3 subsets of t cells and their functions |
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| cytotoxic t cells- programmed to destroy cancerous or infectious self cells helper t cells- activate b cells regulatory t cells- helps prevent immune system from mounting a response on itself |
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| difference between BCR and TCR |
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| TCR doesn't recognize free antigens, the antigens must be brought to it by one of the body's cells |
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| cells responsible for naive t cell activation |
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| dendritic cells (part of innate immunity) |
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| similarities of T and B cells |
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| both form memory cells, both need "confirmation" of foreign material to multiply, both have many receptors |
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| lymphatic system |
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| collection of tissues and organs that bring the population of b cells and t cells into contact with antigens |
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| secondary lymph organs |
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| where lymphocytes gather to contact various antigens and trade cytokines lymph nodes, spleen, tonsils, appendix |
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| peyer's patch |
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| important secondary lymph organ in intestinal wall |
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| primary lymph organs |
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| bone marrow (where b and t cells originate and b cells mature) and thymus (where t cells mature) |
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| immunogen |
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| antigen that elicits an immune response |
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| t-dependent antigens |
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| responding b cell requires help from t helper cell in order to become activated, has protein component |
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| example of t-independent cells |
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| LPS, some carbs |
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| antigenic |
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| ability of antigen to elicit immune response, proteins are best at doing this, lipids are least effective |
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| epitopes |
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| regions of a molecule that the adaptive immune system recognizes |
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| neutralization |
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| coats toxin or virus with antibodies so that it cannot bind to host cell |
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| opsonization |
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| phagocytic cells have receptors for Fc region of IgG antibodies making it easier for phagocyte to engulf antigen |
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| complement system activation results in... |
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| production of opsonin C3b, initiation of inflammatory response, formation of membrane attack complexes |
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| cross-linking |
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| when each arm of an antibody grabs on to separate antigens, linking them to form one large complex that is easier for phagocyte to engulf |
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| antibody dependent cellular cytotoxicity (ADCC) |
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| when multiple IgG molecules bind to infected cell and makes it a target for natural killer cells which attach to Fc region of antibody |
