Protein analysis of HLA-DR2.3 haplotype

Abstract

The human major histocompatibility antigens (HLA-DR, HLA-DQ, and HLA-DP), consisting of alpha and beta chains, show extensive polymorphism. Based on differences of T-cell responses, the serologically defined DR2 specificity has been divided into Dw2, Dw12, and several putative additional "Dw subtype" specificities (AZH, FJO, and MN2, which we shall designate as "DR2.3", and LD-5a). To investigate the relationships of these specificities, DR and DQ molecules were analyzed by two-dimensional gel electrophoresis (2D-PAGE). The 2D-PAGE patterns of the DR molecules are identical among DR2.3 cells. Three DR beta chain polypeptides are expressed on DR2.3 cells. The electrophoretic mobilities of two of these beta chains are different from those of beta chains from the Dw2 and Dw12 cells. The DR molecules of the LD-5a cells show similar 2D-PAGE patterns with those of DR2.3 cells. The 2D-PAGE patterns of DQ molecules are identical among DR2.3 cells. The electrophoretic mobilities of DQ beta chains are different for Dw2, Dw12, LD-5a, and DR2.3 cells. These results indicate that the AZH, FJO, and MN2 cells have identical or very similar DR and DQ molecules and constitute a third, and relatively homogeneous, subgroup ("DR2.3") of the DR2 specificity. In addition, DR2.3 cells have a unique characteristic in that they express three DR beta chains.