Polyoma virus infection in neonatally thymectomized hamsters

Summary Inoculation of polyoma virus into weanling hamsters, thymectomized as neonates, has resulted in the production of tumors. In contrast, the sham operated litter mates developed no demonstrable neoplasms over a 12–18 month period of observation. Thus, it has been confirmed in these studies that neonatal thymectomy may render some resistant animals susceptible to the effects of an oncogenic virus.When inoculated with high titers of polyoma virus, both the thymectomized and sham operated animals developed hemorrhagic lesions, primarily of the liver. The histology of these hemorrhagic lesions has revealed no neoplastic features.It is suggested that the hemorrhagic and neoplastic responses to polyoma virus infection in hamsters may representin vivo, respectively, lytic and proliferative cellular responses to the infection.Dedicated to ProfessorJohn F. Enders on the occasion of his 70th birthday.Supported in part by U.S. Public Health Service general research support grant FRO5486.