| anaphylatoxin | <protein> Originally used as an antigen that reacted with an IgE antibody thus precipitating reactions of anaphylaxis. Now restricted to defining a property of complement fragments C3a and C5a, both of which bind to the surfaces of mast cells and basophils and cause the release of inflammatory mediators. (18 Nov 1997) |
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| anaphylatoxin inactivator | An alpha-globulin (MW 300,000) which destroys the activity of the anaphylatoxic complement fragments. See: anaphylatoxin. (05 Mar 2000) |
| anaphylatoxins | The family of peptides c3a, c4a, c5a, and c5a des-arginine produced in the serum during complement activation. They produce smooth muscle contraction, mast cell histamine release, affect platelet aggregation, and act as mediators of the local inflammatory process. The order of anaphylatoxin activity from strongest to weakest is c5a, c3a, c4a, and c5a des-arginine. The latter is the so-called "classical" anaphylatoxin but shows no spasmogenic activity though it contains some chemotactic ability. (12 Dec 1998) |