complement fixation

complement fixation
complement fixation n the process of binding serum complement to the product formed by the union of an antibody and the antigen for which it is specific that occurs when complement is added to a mixture (in proper proportion) of such an antibody and antigen

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the binding of complement to the complex that is formed when an antibody reacts with a specific antigen. Because complement is taken up from the serum only when such a reaction has occurred, testing for the presence of complement after mixing a suspension of a known organism with a patient's serum can give confirmation of infection with a suspected organism. The Wassermann reaction for diagnosing syphilis is a complement-fixation test.

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fixation of complement the consumption of complement upon reaction with immune complexes containing complement-fixing antibodies; this is the basis of complement fixation tests, two-stage procedures in which heat-inactivated antiserum (or antigen) is reacted with the test material in the presence of a known amount of complement. If the homologous antigen (or antibody) is present in the test material, complement is fixed. Then sheep red blood cells and antisheep erythrocyte antibody are added; lack of hemolysis indicates complement fixation, i.e., a positive test result. Quantitative results are obtained by determining the highest dilution of antiserum or test material that gives a positive reaction. Called also Bordet-Gengou phenomenon or reaction.

Medical dictionary. 2011.

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  • Complement fixation test — Diagnostics MeSH D003168 The complement fixation test is an immunological medical test that can be used to detect the presence of either specific antibody or specific ant …   Wikipedia

  • complement-fixation test — n a diagnostic test for the presence of a particular antibody in the serum of a patient that involves inactivation of the complement in the serum, addition of measured amounts of the antigen for which the antibody is specific and of foreign… …   Medical dictionary

  • complement fixation — noun Date: 1906 the process of binding serum complement to the product formed by the union of an antibody and the antigen for which it is specific that occurs when complement is added to a suitable mixture of such an antibody and antigen and that …   New Collegiate Dictionary

  • complement fixation — Binding of complement as a result of its interaction with immune complexes (the classical pathway) or particular surfaces (alternative pathway) …   Dictionary of molecular biology

  • complement fixation — Immunol. the binding of complement to immune complexes or to certain foreign surfaces, as those of invading microorganisms. [1905 10] * * * …   Universalium

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  • complement-fixation test — noun : a test for the presence of a particular antibody made by addition of complement and an indicator system to a mixture of known antigen and a serum suspected to contain the specific antibody for this antigen and used especially in the… …   Useful english dictionary

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