Papain-solubilized HL-A antigens from cultured human lymphocytes contain two peptide fragments

HL-A 2 and HL-A 7 antigens have been solubilized from cultured human lymphocytes by papain and purified on a small radioactive scale after formation of immune complexes, or on a large scale by column chromatographic methods. In both cases, it has been shown that the materials obtained consist of two noncovalently bound fragments. One fragment is a glycopeptide of molecular weight 30,000-31,000, the other is a peptide of molecular weight 11,000-12,000. In polyacrylamide gels containing 8 M urea, the large fragments of HL-A 2 and HL-A 7 exhibited different electrophoretic mobilities, while the small fragments were the same. The relationship of these materials to the native HL-A molecule is discussed.