Recognition by cytotoxic T lymphocytes of cells expressing fragments of the SV40 tumor antigen.

Recognition by cytotoxic T lymphocytes (CTL) of syngeneic cells transformed with simian virus 40 (SV40) was examined by using cells expressing known portions of the SV40 early region both as sensitizing cells for stimulation of CTL development and as targets for lysis by CTL. LMTK- cells transfected with a plasmid specifying a 33K amino-terminal fragment of the SV40 tumor (T) antigen served both to stimulate syngeneic CTL capable of lysing SV40 transformed cells and as target cells for CTL generated against syngeneic transformants. The same is true for cells infected with the adenovirus 2-SV40 hybrid viruses, Ad2+ND1 and Ad2+ND2, which produce proteins homologous with carboxy-terminal regions of the SV40 T antigen. These findings indicate that on cells transformed by SV40 virus, and expressing the entire T protein, determinants in both the amino- and carboxy-terminal regions of the molecule are exposed on the cell surface. Furthermore, determinants in both these regions are recognized independently in the polyclonal CTL response to SV40.