Reduced transplantability of syngenic mouse tumors superinfected with membrane viruses in nu/nu mice.

Transplantability of mouse tumors superinfected with various kinds of membrane viruses was investigated in syngeneic hosts. Methylcholanthrene-induced fibrosarcomas in BALB/c mice, Meth A, and in C57BL/6 mice, BMT-, superinfected with Friend lymphatic leukemia virus in mice given neonatal injection of the virus, grew more slowly than uninfected tumors. The retardation of growths was not observed in mice that had been given injections of the virus at birth. Similarly, Meth A and a hepatoma in C3H/He mice, MH134, superinfected with Moloney murine sarcoma virus in nu/nu mice, had reduced their transplantability in respective syngeneic mice. Further, Meth A and MH134 superinfected with endogenous rat leukemia virus and human measles virus, respectively, in nu/nu mice also showed reduced transplantability, and some of the former were actually rejected by normal syngeneic hosts. On the other hand, the reduced transplantability was not found in irradiated mice, suggesting that the phenomenon was due to immunological events. However, a myelogenous leukemia in C57BL/6 mice, C1498, superinfected with Moloney sarcoma virus in nu/nu mice grew like uninfected tumor and did not show reduced transplantability at all.