[Xenogenization of rat tumor cells by transfection with envelope gene derived from Friend murine leukemia virus].

The highly tumorigenic rat hepatocellular carcinoma cell line cKDH-8-cl-11 was xenogenized by transfection with an envelope (FV-env) gene derived from Friend murine leukemia virus. The transfected tumor cells, expressing the FV-env gene product on the cell surface, were injected into normal and immunosuppressed (irradiated) syngeneic rats. All the irradiated rats developed tumors at the injection site. Thirteen out of fifteen normal rats rejected the xenogenized cells and acquired tumor transplantation resistance to the parent (nontransfected) cell line. The tumor cells that grew in normal rats failed to express th FV-env gene product during growth in vivo, but resumed expression during in vitro primary culture. These results suggest that the FV-engine product, when expressed on tumor cell surfaces, displays biological characteristics which are immunologically recognized by normal rats and induces tumor rejection. Moreover the results show that the FV-env gene product is a good candidate for the xenogenization of tumor cells.