Homozygous typing cell-defined HLA-Dw specificities correlate better than serologically defined HLA-DR specificities with restriction elements for influenza virus-specific proliferative human T lymphocyte clones.

Human T lymphocyte clones with specific proliferative response to influenza A virus were derived by limiting dilution from peripheral blood lymphocytes (PBL) after in vitro stimulation with autologous irradiated, virus-infected PBL. Four OKT3+4+8- T lymphocyte clones (TLC) that showed HLA-restricted antigen-specific proliferative responses were used for a detailed analysis of the restriction elements for antigen presentation. None of the clones showed alloreactivity and all required the presence on the antigen-presenting cell of HLA class II antigens of one or other haplotype of the donor. Restriction elements for two clones were correlated with Dw1 rather than DR1, and for two others with Dw6 rather than DRw6. These latter clones showed differential recognition of HLA-Dw6 subtypes as defined tentatively by homozygous typing cells, without relationship to putative serological "splits" of DRw6. One of the Dw6-restricted clones was specific for a Dw6.1 (now Dw18) "subtype," confirmed by family segregation analysis, the other for a broad Dw6 (Dw18 and Dw19) specificity. Studies with a panel of monoclonal antibodies against monomorphic determinants of HLA class II antigens revealed heterogeneous patterns of blocking activity, distinguishing between clones of different restriction specificity. Inhibition patterns were partly as predictable from the known activity of the monoclonal antibody in alloantigeneic PLT systems. These results provide evidence that certain structures that function as restriction elements for antigen presentation also carry alloantigeneic determinants.