Epitope analysis with monoclonal antibodies directed against class II molecules subdivides HLA-DR2, DR3 and DR4: correlations with cellularly defined Dw specificities

Monoclonal antibodies (Mabs) defining 14 distinct polymorphic epitopes have been produced against the class II antigens of HLA-DR3Dw3DQw2 cells. Population analysis indicates that Mab C1 is directed against the DQw2 specificity and Mab M6 against the DRw52 specificity. The remaining Mabs define epitopes shared by the class II molecules of DR3 and various other specificities. Seven DR3Dw3 DQw2 haplotypes were examined and could be divided into two types based on the presence of the epitope defined by Mab M3. Analysis of DR2 and DR4 homozygous cells with these Mabs revealed several distinct patterns of epitope expression. These subdivisions were found to correlate with the cellularly defined Dw specificities.