In vitro generation of secondary cell-mediated cytotoxic response against a syngeneic Gross virus-induced lymphoma in rats.

Cell-mediated cytotoxic responses against a syngeneic Gross virus-induced lymphoma, (C58NT)D, in W/Fu rats were generated in vitro by using mixed lymphocyte-tumor cell cultures. The source of responding cells was either spleens from normal rats or spleens from rats carrying or having rejected (C58NT)D tumors. Mitomycin C-treated (C58NT)D tumor cells were used as stimulating cells. The secondary anti-tumor cytotoxic response occurred more rapidly and reached higher levels than the primary response, and it was antigen specific. T cells, but nor B cells or macrophages, were essential for both the induction and the effector phases of the secondary anti-tumor responses. These data suggest that specific memory T cells persist for long periods of time in the lymphoid organs of (C58NT)D immune rats, which can rapidly become cytotoxic upon re-exposure to antigen.