Development of Tumors in Hamsters Inoculated in the Neonatal Period with Vacuolating Virus,SV 40 ∗

Abstract

Summary

Intracerebral and subcutaneous injection into newborn hamsters of vacuolating virus, SV₄₀, grown in renal cell cultures of grivet monkey resulted in single or multiple fibrosarcomas at site of injection which were histologically of varying degree of malignancy. These occurred 3 1/2 to 8 months post-inoculation and in both sexes. Animals injected with appropriate control materials or held uninoculated failed to develop tumors. Tests to exclude mouse polyoma virus as a factor were clearly negative. Evidence for the role of SV₄₀ virus as a primary oncogenic agent was provided by recovery of the virus from the tumor and by demonstration of SV₄₀ antigen in tumors by fluorescent antibody staining. The agent appeared to be localized in the tumors since the virus was not detected in blood or excretions, since antibody response was minimal or lacking, and since gross metastases were lacking. Transplantation and serial passage of SV₄₀-induced tumors were accomplished with ease. The data represent the first definitive evidence implicating a virus of primate origin as a malignant oncogenic agent in experimental animals. The findings relate to observations of oncogenesis in hamsters and do not warrant extrapolation to oncogenesis in other mammalian species.