An idiotypic cross‐reaction between two streptococcal antibodies from an individual rabbit

Abstract

Abstract A rabbit immunized with Group C streptococcal vaccine produced two antibodies with specificity for the Group C carbohydrate. Structural, idiotypic, and allotypic comparisons were made between these two antibodies. The use of recombinant molecules prepared from isolated H and L‐chains showed the L‐chains of the antibodies to be idiotypically identical while the H‐chains were extensively cross‐reactive, but distinct. The idiotypically identical L‐chains differed in electrophoretic mobility in alkaline urea gels and in sequence at one position among the first 22 N‐terminal residues. The H‐chains could be differentiated not only idiotypically, but also by the subspecificities of their group a (a3) allotypic determinants.