Molecular Dissection of DRw6

The complex HLA-DRw6 specificity was first described at the Seventh Histocompatibility Workshop according to the reactivity of a set of polyspecific sera (DR2 + w6; DR3 + w6). While the DR specificities 1 to 5 and 7 were clearly defined during the following workshop, no monospecific anti-DRw6 sera were found. HLA-DRw6 was therefore only defined by a serie of supertypic sera. These include anti-DQw1, which react with DR1, DR2, and DRw6; anti-DRw52 which react with DR3, DR5, DRw6, and DRw8; and sera with shorter reactivity: anti-DR2+w6, anti-DR3+w6, anti-DR5+w6, anti-DR3+5+w6. DRw6 specificity was thus assigned to cells reacting with the above supertypic sera but negative with monospecific sera anti-DR1, 2, 3, 5, and w8. Subdivisions of DRw6 were proposed following combinations of reactivities with clusters of supertypic sera as reviewed in a recent report [7]. Because of the absence of monospecific DRw6 sera the existence of the DRw6 molecule itself has been a matter of controversy. We investigated the molecular nature of the DRw6 antigens in 15 individuals and four families using a monomorphic monoclonal anti-HLA-DR antibody and two-dimensional gel electrophoresis (2D-PAGE).