Human Allospecific TLCs Generated Against HLA Antigens Associated with DR1 Through DRw8

To study the fine specificity of the HLA-D region, a panel of human T-lymphocyte clones (TLCs) was generated against alloantigens associated with HLA-DR1 through DRw8. HLA-DR-homozygous peripheral blood lymphocytes (PBLs) were stimulated with DR-heterozygous PBLs in primary mixed lymphocyte cultures for 4 days. Blasts were cloned by limiting dilution at 0.3 cells/well in the presence of 20% T-cell growth factor and irradiated stimulator cells. Viable clones were subsequently tested in proliferation assays against the original stimulator and a limited panel of stimulators bearing relevant DR specificities. Initial primings produced approximately 800 clones; some recognized DR-associated antigens, 70 recognized only their original stimulator, and approximately 50% were nonresponsive. Analysis on extended stimulator panels revealed alloantigenic complexity within similar DR-associated antigens as recognized by TLCs. The data are consistent with evidence that extreme heterogeneity exists within the HLA-D region.