Tumor induction in newborn and adult Syrian hamsters infected with SV40 temperature-sensitive mutants.

Newborn and adult Syrian hamsters were injected with wild-type SV40 and its temperature-sensitive (ts) mutants A30, A209, A239, B201 and BC210. Wild-type SV40 and ts B201 were highly oncogenic for newborn but not adult animals; ts A239, ts A30 and ts BC210 also induced tumors in some adult hamsters. Unexpectedly, the number of tumors induced by ts A209 and ts A239 in newborn animals was very low. The number of tumors observed was also low in adults infected with ts A30, ts A239 and ts BC210. The duration of the latent period of tumors induced in adult animals was the same as in the newborns. The data obtained are discussed in connection with the defectiveness of the mutants to induce tumor-specific transplantation antigen activity in hamster cells.