Abstract
Polyoma virus-induced neoplasms in C57BL strain mice were totally prevented through adoptively acquired immunity. Sensitized lymphoid cells inoculated intravenously were effective if administered as late as 30 days after virus infection. Sensitized allogeneic lymphoid cells, killed syngeneic cells, and serum from hyperimmunized donors were ineffective. The antigenic difference between tumor and host can be used to control primary tumors. Clones of neoplastic cells induced by virus and containing TR [trans-plantation-resistance]/antigen are eliminated by an immune reaction of the homograft type.