Proliferative T cell clones directed at a human minor antigen.

Clones directed against a human minor antigen were isolated from an interleukin-2-dependent cytotoxic T cell line. As expected, some clones exhibiting cytotoxicity for HLA-identical minor antigen-positive cells were detected. In addition, some clones were detected which, though not cytotoxic, were able to proliferate in the primed lymphocyte typing (PLT) test in response to stimulation by cells from some HLA-identical sibs and certain DR 2+/ve unrelated cells. These clones expressed the Leu 3a cell surface antigen. DR 2 was one of the class II determinants expressed by the responding cell used to generate the cytotoxic T lymphocyte line. These results are consistent with the interpretation that helper T cells are able to recognize minor antigens in the context of self-class II HLA determinants and respond in PLT.