AMINO TERMINAL SEQUENCE STUDIES ON THE IA ANTIGENS OF THE GUINEA-PIG

The partial amino acid sequence of three β (25,000 daltons) chains from guinea pig Ia antigens have been determined. The radiolabeled Ia polypeptide chains were isolated from lymphocytes cultured with [3H]-amino acids and subjected to automated Edman degradation. The sequence analysis data suggest the assignment of 8 residues out of 17 positions in the β chain from the Ia molecule bearing the 4, 5 marker (strain 2); 4 or 7 from Ia. 7 (strain 13); and 10 of 16 from Ia. 3,5 (strain 13). Comparison of the tentative partial sequences indicates that although similar, each β chain is encoded in a separate gene. The guinea pig β chains show some homology to the human HLA-D analogue but little or none to three murine la β chains. © 1979.