[Regulation of the IgM immune response. I. Changes in the affinity of carp anti-DNP-antibodies during immunization depending on the antigen dose].

The affinities of anti-DNP-antibodies (IgM) of carp, immunized with different doses of dinitrophenylated human serum albumin in complete Freund's adjuvant, were determined by a modified Farr-technique using the hapten epsilon-DNP-L-Lysine. Very low affinity antibodies were formed in the early immune response (Ko = 0.2 - 1.0-10(5) M-1). A progressive increase in IgM antibody affinity occurred during the immune reaction. After immunization with low doses of antigen (0.01 and 0.1 mg) the affinity increased up to four weeks (Ko = 3.2 and 9.1-10(5) M-1) and decreased in the subsequent three weeks (K = 0.8 and 1.2-10(5) M-1). Following immunization with a higher dose of antigen (1 and 10 mg), the affinity increased up to seven weeks (Ko = 4.9 and 11.9-10(5) M-1). The highest antibody concentration in all groups were observed at the maximum of affinity.