The α and β subunits of the murine I-A alloantigens from several H-2 haplotypes were examined by comparative tryptic peptide mapping by using double label (3H and 14C) techniques. Significant structural variation between alleles was detected in both subunits. Tryptic digests of the α polypeptides from s, b, and d showed only 65% co-elution with k; β-chains from s, b, d, and r were about 50% similar to the k β subunit. Peptide analysis of the Ak subunits from intra-H-2 recombinant strains indicated that both the α and β polypeptides are encoded within the I-A subregion.
This work was supported by National Institutes of Health Grants AI-12127, AI-13448, AI-11851, AI-10967, AI-12796, AI-14742; National Science Foundation Grant PCM-22411; and American Cancer Society Grant IM-140.