Papovavirus in epitheliomas appearing on lymphoma-bearing hamsters: lack of association with horizontally transmitted lymphomas of Syrian hamsters.

Several epizootics of lymphoma occurred in a colony of LVG hamsters contaminated with an unusual, horizontally transmitted, subviral, lymphomagenic agent. Hamsters with horizontally transmitted lymphoma, or others housed with these hamsters, occasionally developed epitheliomas bearing an unclassified papovavirus. The possibility that the virus present in the wart-like structures in our hamster colony could activate lymphoma was tested, and a search was conducted for mature virions in passaged epitheliomas and lymphomas. The agent responsible for the skin epitheliomas in our hamster facility was an icosahedral, 36-nm virion compatible with the morphology of a polyomavirus or simian virus 40. Horizontally transmitted lymphoma cells and epitheliomas contained hamster papovavirus (HaPV) DNA sequences detected by dot hybridization; however, such sequences were not found in extracts of lymphomas with oncogenic potential. In contrast to reports by other investigators, infection of hamsters with the papovavirus present in primary epitheliomas produced epitheliomas in good yield but was not reproducibly associated with lymphoma induction. These data confirm the observation that the HaPV is the causative agent of epitheliomas, but they suggest clearly that HaPV is not the agent responsible for lymphomagenesis.