Cytotoxic T cells directed against HLA-DR antigens and their surface proteins

The authors review their recent research involving the generation of cytotoxic T lymphocytes (CTL) directed against HLA-DR antigens. A mouse anti-human xenogeneic system first suggested that HLA-DR antigens could be recognized by CTL. Human allogeneic CTL specific for HLA-DR6 were generated and found to be OKT4+. The fact that these CTL were OKT4+ while anti HLA-A,B CTL were OKT8+ suggested that these T cell surface antigens may be involved in MHC antigen recognition; ie, they may be part of the T cell receptor. These OKT4+, HLA-DR specific CTL were further used to generate monoclonal antibodies (1) which block cytolysis and define novel antigens involved in the CTL-target interaction and (2) which define an antigenic complex on alloantigen activated T cells.