The properties of a potent murine sarcoma virus (MSV), which was isolated after in vivo passage of a spontaneous tumor arising in an NZW/NZB F1 hybrid mouse, are described. The agent had the morphological and growth characteristics of a type C virus, and contained the group‐specific (gs) antigen of the murine leukemia‐sarcoma viruses. The virus induced discrete, focal lesions of transformed cells in mouse tissue‐culture cells. Focus formation usually followed a “two‐hit” titration pattern, and sarcoma virus preparations contained a large excess of an accompanying non‐transforming type C virus. The MSV was stable when stored at — 70° C; it was ether‐sensitive and had a buoyant density of 1.16g/cm3 when centrifuged in sucrose density gradients. These properties are similar to those of the Moloney (M‐MSV), Harvey (H‐MSV), and Kirsten (Ki‐MSV) isolates of MSV. When inoculated into hamsters, the new strain of MSV rapidly induced sarcomas. While the viruses produced by hamster and mouse tumors both contained the murine gs antigen, the host range of the MSV was altered by hamster passage. It failed to induce focal lesions in mouse and hamster cells, and did not induce sarcomas or leukemias when injected into newborn mice and hamsters. The antigenic properties and infectivity of the virus produced by hamster tumor cells were significantly different from the properties of the hamster leukemia pseudotype viruses obtained from hamster tumors induced by the other strains of MSV.
ASJC Scopus subject areas
- Cancer Research