A predominant idiotype on anti-hen egg white lysozyme antibodies from diverse mouses strains.

A predominant idiotype was detected on almost all antibody molecules directed against the multideterminant antigen, hen egg white lysozyme (HEL). This idiotypic set was defined by rabbit and quinea pig antiidiotypic antisera raised against a rare cross-reactive antibody population isolated and from a heterogeneous BALB/c anti-human lysozyme (HUL) humoral response. This isiotype was fond on the majority of all HEL-reactive antibody from all strain tested; its presence was independent of Ig-1 allotype of H-2 haplotype. The idiotype was also present on the majority of anti-HEL antibody from nonresponder mice immunized with keyhole limpet hemocyanin coupled to HEL. The idiotype was not found on normal mouse immunoglobulin or on antibodies specific to two other proteins, HUL and ribonuclease, which are similar to HEl in size and charge. Individual idiotype-positive anti-HEL antibody populations exhibited specificity differences when analyzed for reactivity toward other avian lysozymes, suggesting that distinct clonal products shared the idiotype specificities. Fractionation of heterogeneous anti-HEL antibodies by preparative isoelectric focusing yielded distinct antibody fractions that were demonstrated to share the relevant idiotype determinants. The data are discussed in terms of the HEL peptide specificites of idiotype-positive and -negative antibodies.