Differences in the capacity of simian virus 40 (SV40) tumor antigens on cells, membranes and in soluble form to induce transplantation immunity in hamsters and mice.

The immunogenicity of the SV40 tumor-specific transplantation antigen (TSTA) on cells, cell particulates and solubilized membranes was studied in mice and in Syrian hamsters. Immunizations were done with various concentrations of tissue-culture-passaged, non-virus-releasing transformed cells, purified cell membranes and in some cases purified nuclei and papain-solubilized membranes obtained from several species, including the mouse, hamster, man, and sheep. All transformed cell lines were T-antigen-positive. The immunosensitive mKSA line of BALB/c mice and the immunosensitive SV34 cell line of the hamster were used for tumor challenge. All materials, regardless of source and of type of preparation, were strikingly immunogenic in the mouse but only SV40 virus and SV34 (hamster) cells provided protection against tumor cell challenge in the hamster. Also, in a limited study, BKV-transformed hamster cells and purified cell membranes and JCV-transformed hamster cells were found to be immunogenic by the tumor rejection assay in the mouse but not in the hamster. SV40 immunization did not protect the hamster against BKV- and JCV-transformed hamster cells. These results are discussed in terms of possible different specificities resident on the TSTA molecule.