IgM and IgG Anti-Hapten Antibody: Hemolytic, Hemagglutinating And Precipitating Activity.

Abstract

Summary Hemolytic and hemagglutinating activities of IgM and IgG antibody against the p-azobenzenearsonate (Rp) group were compared using purified antibody preparations. IgM antibody showed a considerably higher activity in both hemolytic and hemagglutinating systems. The hemolytic and hem-agglutinating activities of IgM antibody were both 180 to 60 times higher on a molar basis than those of IgG antibody when measured with erythrocytes to which Rp-groups were attached. The reduced-alkylated product of IgM antibody showed little activity in both hemolytic and hemagglutinating systems, although the reduced-alkylated product had been shown previously to retain hapten-binding activity. IgM antibody also lost precipitating activity with a polyvalent hapten-protein conjugate upon reduction and alkylation. Loss of hemagglutinating and precipitating activities is probably due to univalency of 6S subunits produced by reduction.