Evidence for two homologous, but nonidentical, Ia molecules determined by the I-EC subregion.

Abstract

Sequential immunoprecipitation, 2-dimensional gel electrophoresis and peptide mapping analyses of B10.A(3R), 35S-methionine-labeled, I-EC subregion products were performed. Evidence was presented here for the presence of 2 structurally homologous, but nonidentical, gene products of the I-EC subregion. These 2 Ia molecules are independently immunoprecipitable, identical in molecular size and charge, but differ by .simeq. 20% in their peptides obtained by partial digestion with Staphylococcus aureus protease V8.