Variants of HLA-DRw52 defined by T lymphocyte clones

Polymorphism within the gene encoding the DRw52 allospecificity was studied with DRw52-specific proliferative T lymphocyte clones. Three clones, C6, E3 and ZUK16, were generated by intra-DRw52 priming in mixed lymphocyte culture and tested against an HLA-D homozygous reference cell panel. The reactivity of each clone could be specifically inhibited by anti-DR, but not anti-DQ or anti-DP, monoclonal antibodies. Clone C6 identified a DRw52 variant termed 52a that was predominantly expressed by HLA-B8,DR3+ and DRw13,Dw18+ cells. Clone E3 identified a variant termed 52b which was predominantly expressed by HLA-B18,DR3+,DRw11,Dw5+ and DRw14,Dw9+ cells. Clone ZUK16 identified a variant termed 52c which was predominantly expressed by DRw13,Dw19+ cells. The DRw52a, 52b and 52c variants correspond to the Dw24, Dw25 and Dw26 alleles defined by the WHO HLA 1987 Nomenclature Committee. Together, clones E3 and ZUK16 appeared to identify a fourth DRw52 variant termed 52d which was expressed by two cells, one DR3, Dw"3.3"+ and one DRw14,Dw"9.2"+. A fifth Drw52 variant termed 52e, expressed by a DRw13,Dw"OMW"+ cell, was suggested by the absence of reactivity with any of the three T cell clones. These data thus demonstrate the existence of three well-defined allelic variants of DRw52 and indicate that there are at least two additional variants. The recognition of these polymorphisms by alloreactive T cells provides one measure of their functional significance.