Partial Chemical Characterization of T Lymphocyte I-Region Associated Antigens

Abstract

Murine major histocompatibility complex I-region genes encode macrophage and B cell surface molecules of 34.0 (A_α) 26,000 (A_β), 28,000–29,000 (A_e), and 31,000-34,000 (E_α) daltons (I). Helper T cell factors carrying I-A subregion determinants appear to be dimeric proteins with 15–20,000 and 40–50,000 dalton chains (2). A single 70,000 dalton polypeptide factor was also reported (2). Low molecular weight Ia antigens of T cell origin were described; these were dialyzable serum glycolipids (3). We described four I-region T cell unique determinants (Iat molecules) and produced monoclonal antibodies specific for an I-A^k -encoded Iat structure (4). Cellular I-A^k -encoded T cell molecules are chemically uncharacterized.