Cloned cytotoxic T lymphocytes recognize cells expressing discrete fragments of the SV40 tumor antigen.

Thirteen cloned long-term lines of H-2k anti-SV40 cytotoxic T lymphocytes were established by limiting dilution and analyzed for functional specificity. All thirteen clones are H-2Kk-restricted and require expression of the SV40 early region in target cells for cytolysis. By using adeno-SV40 hybrid virus-infected or plasmid-transfected target cells expressing known fragments of T antigen, we found that lysis by ten of these clones requires expression in target cells of determinants within the carboxy-terminal 185 amino acids of T antigen, whereas lysis by the three remaining clones requires expression in target cells of amino-terminal determinants on a 33K fragment of T antigen. None of the clones require determinants in the "mid-region" (amino acids approximately 246 to approximately 523) of the molecule. No correlation was observed between recognition by these clones and expression in target cells of the 53K cellular protein that binds to T antigen.