BEHAVIOR OF THE IDIOTYPIC NETWORK IN CONVENTIONAL IMMUNE-RESPONSES .2. AFFINITY AND HETEROGENEITY OF IDIOTYPIC AND ANTIIDIOTYPIC ANTIBODIES FOLLOWING IMMUNIZATION WITH T-INDEPENDENT AND T-DEPENDENT ANTIGENS

The relative affinity and heterogeneity of affinity of idiotypic and anti-idiotypic antibodies in mice immunized with the T-independent antigen DNP-Ficoll and the T-dependent antigen DNPHGG were measured by a plaque inhibition assay. Idiotypic plaque-forming cells (PFC) were detected by a conventional assay utilizing DNP-coated SRBC. Anti-idiotypic PFC were detected with SRBC coated with affinity-purified anti-DNP antibody of rabbit origin. It was found that both idiotypic and anti-idiotypic antibodies elicited by immunization with the T-independent antigen had lower affinity and were less heterogeneous than the corresponding antibodies originating in mice immunized with the T-dependent antigen. In addition, the affinity and heterogeneity values of the idiotypic antibodies were correlated with the affinity and heterogeneity values of the anti-idiotypic antibodies from the same mice. This finding indicates that idiotypic and anti-idiotypic antibodies mutually regulate each other, thus pointing to internal immunoregulatory effects of the idiotypic network with respect to these parameters. © 1992.