A DC-specific cytolytic T lymphocyte line is OKT8⁺

A human cytotoxic T lymphocyte (CTL) line, A9, was generated by limiting dilution and was selected because of its apparent DC specificity. A9 is 100% OKT3⁺, 90% OKT4⁺, and 10% OKT8⁺, but by negative selection the CTL present are entirely OKT8⁺. These OKT8⁺ CTL are totally inhibitable by Genox 3.53, an anti-DC1 monoclonal antibody (mAb), and Leu-10, an anti-DC subgroup mAb, but are not inhibitable by a panel of anti-HLA-DR mAb. These CTL are also inhibitable by anti-OKT3 and anti-LFA-2 but not by OKT4 or OKT8 mAb. These findings extend previous studies that showed that OKT8⁺ CTL recognize HLA-A,B antigens, whereas OKT4⁺ CTL recognize HLA-DR and SB antigens. It is possible that an as yet undefined T cell surface molecule is involved in DC recognition.