Immunity to melanoma in mice immunized with transfected allogeneic mouse fibroblasts expressing melanoma-associated antigens.

Transfection of genomic DNA from B16 mouse melanoma into LM(TK-) fibroblasts led to the generation of several clones of transfected cells that strongly expressed B16 melanoma-associated antigens (MAA). The transfected cells retained their H-2k markers and served as allogenic cells with expressive MAA in C57BL/6 mice, syngeneic with the melanoma. The cells were capable of eliciting primary anti-B16 immune responses in vitro in spleen cells from C57BL/6 mice. Immunization of C57BL/6 mice with the transfected cells led to the generation of anti-B16 cytotoxic activity in spleen cells, and C57BL/6 mice immunized with the MAA-positive transfected cells were partially resistant to a lethal challenge with B16 melanoma cells. Under similar conditions, B16 cells were nonimmunogenic. Therefore, transfected allogeneic LM(TK-) fibroblast cells expressing MAA served as more potent anti-melanoma immunogens than the parental B16 tumor cells themselves.