Idiotype suppression. I. Influence of the dose and of the effector functions of anti‐idiotypic antibody on the production of an idiotype

Parameters that influence the effect of passively administered anti‐idiotypic antibody on the expression of idiotype‐positive and of idiotype‐negative antibodies were investigated in adult A/J mice immunized with Group A streptococci. The results suggest: 1. idiotype‐positive antibodies are eliminated from the spectrum of humoral antibodies as a consequence of the elimination of the idiotype‐forming cell precursors. 2. The heterogeneity of the idiotype‐negative compensatory response of individual suppressed mice is as restricted as that of the idiotype‐positive normal response. The isoelectric spectra of idiotype‐negative antibodies are individually specific, whereas the isoelectric spectra of idiotype‐positive antibodies are individually specific, whereas the isoelectric spectra of idiotype‐positive antibodies are shared between individual mice. 3. Suppression is transient in mice treated with low and with high doses of anti‐idiotypic antibody, but is maintained in mice treated with intermediate doses. 4. Suppression is mediated by complement and macrophage fixing (guinea pig IgG 2 ) anti‐idiotypic antibody only. IgG 1 anti‐idiotypic antibody appears to have an enhancing effect on the production of the idiotype. The results are discussed with respect to possible regulatory functions of idiotype‐anti‐idiotype interactions in the immune response.