specific-1 - 1 SPECIFIC RESISTANCE (SPECIFIC IMMUNITY)...

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1 SPECIFIC RESISTANCE (SPECIFIC IMMUNITY) Specific Resistance (Immunity ) A. Effective against only ONE organism B. Acquired following exposure C. Two types: 1. Humoral immunity - antibody mediated a. Due to production soluble proteins - antibodies b. Occur in body fluids, primarily plasma 2. Cellular immunity - cell-mediated a. Due to production T-lymphocytes b. Occur primarily in tissues D. Often develop simultaneously Antigens A. Definition: 1. Foreign material which when introduced in body 2. Stimulates an immune response (cellular, humoral, or both). B. Characteristics of antigens 1. Foreign to host - chemical groupings (markers) must be different from those on host cells (receptors) - called antigenic determinants 2. Possess 2 or more antigenic determinants (2 - bivalent, many - multivalent) 3. Molecular weight - 10T or more 4. May be soluble, particulate, cellular 5. Examples: a. Soluble - toxins, enzymes, venom, plant extracts, medications, foods, foreign serums (proteins), b. Particulate - cell structures (cell walls, flagella, capsules, pili), viruses, mold spores, pollen, house dust c. Cellular - microorganisms, viral infected host cells, foreign tissue cells, neoplastic cells, altered host cells
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2 C. Haptens 1. Foreign chemicals that cannot initiate immune response (incomplete Ag.) 2. If hapten combines with carrier protein complete Ag. initiates immune response 3. Once immunity develops, will react with hapten alone (without carrier protein) Cells of Immune system A. Macrophage - tissue phagocyte 1. Antigen processing cell a. “Processes” the Ag. – engulfs and digests antigen b. “Presents” Ag. deter. on surface of cell membrane - Ag. deter. attach to sites on cell membrane 2. Secretes Interleukin I - attract additional macrophages and lymphocytes B. Lymphocytes - two types B-lymph. and T-lymph. 1. B-type lymphocyte - mature in bone marrow, GALT (gut associated lymphoid tissues) a. Possess surface receptors (immune receptors - IgD) - react with about 100T different Ag. b. Function - development humoral immunity c. 20 - 25% total lymphocytes in blood, tissue 2. T-type lymphocytes - mature in thymus a. Secrete soluble proteins - lymphokines b. 75 - 80% total lymphocytes c. Four subgroups: 1) T H lymph. (CD4, T 4 ) - helper - initiates immune responses 2) T S lymph. - suppressor - downgrades immune response; # T H T S 3) T C lymph. (CD8, T 8 ) - cytotoxic - responsible for cellular immunity 4) T DH lymph. - delayed hypersensitivity 3. Plasma cells a. Arise from B lymph. following antigenic stimulation (clonal selection theory) b. Produce soluble proteins - antibodies (humoral immunity).
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3 Humoral Immunity A. Due to production of soluble proteins - antibodies occurring in body fluids (primarily plasma) B. Develops in response to bacterial cell components, toxins, enzymes, viruses
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specific-1 - 1 SPECIFIC RESISTANCE (SPECIFIC IMMUNITY)...

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