deck_2671127 Flashcards
Antibody-dependent cell-mediated cytotoxicity
one of the type II hypersensitivity reactions; leukocytes become attached to the antibody-coated target cells and cause cell lysis without phagocytosis
Antigen/antibody complex
A combination of antigena and antibody; when both are present in about equal amounts these complexes are poorly soluble and often precipitate in tissue.
Autoimmune reaction/disease
a phenomenon in which the body develps and immune reaction that is directed against it’s own organs/tissues
Complement
A series of proteins activated by aggregated antibody, bacteria, or cell-attached antibody, which form a complex that damages cell membranes leading to lysis (also releases chemotactic proteins C5a and C3a)
Hypersensitivity
a relative term, in which an individual shows evidence of response to a stimulus greater than that of the average person
Type 1 Hypersensitivity
Caused by interaction between an allergen and IgE antibodies attached to a mast cell leading to release of histamine and other inflammatory factors. Characterized by allergic reactions or by anaphylactic shock
Type II Hypersensitivity
Caused by antibody attachment to cells. This may lead to complement activations, “killer cell” response, or inhibition/stimulation of cellular function
Type III Hypersensitivity
Antigen and antibody produce insoluble complexes that deposit in tissues and incite an inflammatory response
Type IV Hypersensitivity
Caused by interaction between an antigen and T-lymphocytes only; no antibody response present. In some cases, where antigen is not destroyed by response, it results in the formation of granulomas (think caseus necrosis, giant cells, and epitheloid cells)