Local immune reaction in syngeneic mice against tumorigenic and nontumorigenic BPV-transformed mouse cell lines.

The role of cytotoxic T cells in immune response to Bovine Papillomavirus type 1 (BPV1)-transformed mouse cell lines was assessed. The chromium release assay was used to follow the induction of cytotoxicity in local lymph nodes of syngeneic C57BL/6J (B6) mice after injection of BPV1-transformed cell lines tumorigenic in nude mice but tumorigenic or nontumorigenic in B6 mice. The nontumorigenic cell line B6B31.C-NuT.A induced cell line-specific cytotoxicity with a maximal activity on day 7 after subcutaneous inoculation of one million B6B31.C-NuT.A cells. After injection of nontumorigenic B6B31.J or tumorigenic B6B31.J-NuT.A or B6B31.A cell lines, only low levels of nonspecific cytotoxicity were observed. These results suggest a role for cytotoxic T cells only in rejection of B6B31.C-NuT.A cells. One reason for the poor immunogenicity could be the lack of transformation-induced/virus-specific antigens on most of the present BPV1-transformed cell lines. However, in a transplantation rejection experiment, protection was induced in B6 mice against a challenge of the highly tumorigenic B6B31.A-B6T.1 line by repeated injections of BPV1-transformed cells. These results suggest the expression of common transplantation rejection antigens on the three BPV1-transformed cell lines used in the immunization experiments.