T-cell clonal analysis of HLA-DR2 haplotypes.

Individuals carrying the serologically-defined DR2 haplotypes can be further subdivided by utilizing T cell response to define several HLA-Dw/LD clusters: Dw2, Dw12, LD-5a, and a related group composed of FJO, AZH, and MN2. We have used cytotoxic T cell clones generated against these DR2 haplotypes to define the DR and DQ associated Dw/LD polymorphisms. Clones were categorized as DR, DQ, DP, or class I-directed based on monoclonal antibody (MoAb) inhibition studies. We analyzed the distribution of the determinants detected by these clones based on analysis with panels of cells. Some DR-directed clones only lysed cells positive for the Dw subtype of the sensitizing cell. A few DR-directed clones lysed most DR2 positive cells. Other DR-directed clones detected determinants shared by cells of different subtypes: determinants shared by Dw2 and Dw12 positive cells and determinants shared by MN2, FJO, AZH, and LD-5a positive cells. The majority of the DQ-directed clones only lysed cells positive for the sensitizing HLA-Dw subtype. A group of clones primed against an LD-5a HTC, whose cytolytic activity was not blocked by any monoclonal antibodies tested, lysed some, but not all, DR2 positive cells as well as Dw1 and Dw10 positive cells. The results suggest the detection of determinants on these molecules which may be shared by cells of specific Dw subgroups and determinants shared by most cells of the sensitizing serological specificity. The basis of this observed polymorphism and influence on the allogeneic response are discussed.