The use of staphylococcal protein A in the mixed agglutination test

A mixed agglutination (MA) test employing staphylococcal protein A (SpA) instead of an antiglobulin reagent has been developed for the detection of IgG antibodies bound to cell-surface antigens. In the SpA MA test, a single indicator system may be used for the detection of IgG antibodies from several mammalian species. The sensitivity of this test compares favorably with that of the conventional MA test in the detection of most mammalian IgG. The main advantage of the conventional SpA MA test is its usefulness in the study of antigens on cells because of adherence of antibody-coated indicator erythrocytes.