T cell clones restricted to "hybrid" HLA-D antigens?

The genetics of T lymphocyte/accessory cell interactions were studied by using antigen-specific monoclonal T cell lines from human peripheral blood and X-irradiated non-T cells (E rosette-depleted) as accessory cells. The T cell lines were obtained by expanding single colonies from soft agar-cloned E rosette-positive lymphocytes, previously incubated for 3 days in liquid culture with 30% autologous X-irradiated non-T cells and antigen (PPD). When investigated with both autologous and allogeneic accessory cells of various HLA-D genotype, different sets of PPD-specific T cell lines were obtained from HLA-D heterozygous individuals; two sets restricted to each one of the two HLA-D antigens, and a third set responding to PPD only when presented by accessory cells carrying both HLA-D antigens possessed by the T cell donor. A few cell lines responded to PPD only in the presence of autologous accessory cells.