[Structural and immunochemical studies on the immunoglobulin of carp (Cyprinus carpio L.). III. Valence and affinity of antidinitrophenyl-antibodies].

Carps were immunized with DNP conjugated to human serum albumin, bovine gamma globulin and Brucella abortus. The antibodies were isolated by immunoadsorption. The intrinsic average association constant (Ko) of the antibodies was determined by equilibrium dialysis and ammonium sulphate precipitation employing the monovalent hapten tritiated epsilon-DNP-L-lysine. The tetrameric carp IgM possesses four measurable combining sites per molecule. The affinity (Ko) of the isolated antibodies varied from less than 10(4) M-1 to 2,5-10(5) M-1. The highest determined affinity in the whole serum was 4,4-10(5) M-1. The affinity of antibodies, which was determined in the whole serum was 1,1--1,45 times higher than the affinity of specifically purified antibodies. The selective influence of the antibody isolation procedure was unimportant. The affinity of these IgM antibodies increased twice during the first stage following immunization and did not change significantly over a 25-month period.