Papain-solubilized HL-A antigens. Chromatographic and electrophoretic studies of the two subunits from different specificities.

Papain-solubilized HL-A antigens contain two subunits, a glycoprotein of molecular weight 30,000 to 31,000 and a small protein of molecular weight 11,000 to 12,000. These subunits have been studied in six different specificities (HL-AZ, HL-A3, HL-A7, HL-AlO, HL-AK?, and W-27) obtained from normal peripheral lymphocytes and from cultured lymphoblastoid lines. The electrophoretic and chromatographic mobility of the small subunits in a variety of systems was identical, but the large glycoprotein subunits of several specificities could be distinguished by electrophoresis in urea gels at either pH 8.7 or at pH 4.5. It is particularly noteworthy that HL-A7 and W-27 which show a high degree of immunological cross-reactivity were nevertheless distinguishable by electrophoresis at pH 8.7.