Induction of Malignancy in vitro in Newborn Hamster Kidney Tissue Infected with Simian Vacuolating Virus (SV40)

Summary

Cell cultures derived from explants of newborn hamster kidney infected with simian vacuolating virus (SV40) consisted of sheets of rapidly growing polygonal, cuboidal and elongated cells. Cultures derived from similar explants free of SV40 consisted initially of slowly growing polygonal and elongated cells, and, after 12 weeks in vitro, only a few scattered elongated cells remained. Cell suspensions from infected cultures injected into newborn hamsters produced tumors at the sites of injection, the tumors becoming apparent as early as 17 days after injection of cells. Histologically, in contrast to the sarcomas produced after malignant transformation of hamster tissue in vitro by polyoma virus, the tumors were predominantly undifferentiated carcinomas with areas of adenocarcinoma, sarcoma and, in one animal, well-differentiated epidermoid carcinoma. SV40 was recovered from the infected cultures and from one of 2 tumors tested.