The Effect of Unheated Normal Bovine Serum on the Complement-Fixing Activity of Heat Inactivated Bovine Antiserum with Homologous Antigen: III. Immunodiffusion Studies.

Examination by immuno-diffusion methods in agar gel plates demonstrated that the supplementing fraction precipitated from normal bovine serum by dialysis against dilute buffer, pH 5.0 to 6.6, contains at least three main antigens, and a weaker fourth. Two of these antigens or antigen determinants appeared to be present in globulin fractions prepared by dilution with distilled water or differential precipitation with ammonium or sodium sulphate.