The intracellular association of B700 and B50 murine melanoma antigens and their role in tumor rejection.

B700 and B50 are melanoma-specific antigens originally isolated from B16 murine melanoma. B700, which elicits a strong tumor rejection response, is present on all murine melanomas tested to date. We now demonstrate the presence of B50 in the other murine melanomas and find that the 2 molecules are non-covalently complexed with each other within the cells. We also show that hosts immunized with intact, irradiated melanoma cells produce antibodies that specifically recognize the B700 and B50 tumor antigens. These results suggest that B50 may also participate in the host response to melanoma growth.