Heterogeneity of rabbit IgM antibody as detected by C'1a fixation.
The C'1a-fixing properties of purified rabbit IgM anti-benzenearsonate antibody were determined. When tested with sheep erythrocytes to which hapten had been coupled by diazo linkage, the number of C'1a molecules fixed was 21% of the number of IgM antibody molecules bound to the erythrocyte surface. This was not due to loss of C'1a-fixing capacity during the purification procedure. Preparative electrophoresis of the antibody concentrated C'1a-fixing molecules in the anodal region so that antibody fractions with greater C'1a-fixing capacity were obtained. The demonstration that C'1a fixation is a property of a subpopulation of IgM molecules provides evidence for previously unrecognized micro-chain heterogeneity.
D000818:Animals; D000906:Antibodies / Q000032:analysis*; D001152:Arsenicals; D001554:Benzene; D002845:Chromatography; D003168:Complement Fixation Tests; D004589:Electrophoresis, Disc; D004912:Erythrocytes; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera; D007122:Immunoelectrophoresis; D007456:Iodine Isotopes; D011506:Proteins / Q000032:analysis; D011817:Rabbits; D014461:Ultracentrifugation; D005719:gamma-Globulins / Q000032:analysis*
D000906:Antibodies; D001152:Arsenicals; D007106:Immune Sera; D007456:Iodine Isotopes; D011506:Proteins; D005719:gamma-Globulins; D001554:Benzene