Simian Vacuolating Virus (SV40) infection in Cell Cultures Derived From Adult Human Thyroid Tissue

Abstract

Explants of adult human thyroid tissue infected in vitro with simian vacuolating virus (SV40) were grown in tissue culture, and a strain of rapidly multiplying pleomorphic cells was derived from the infected explants. Large amounts of virus were recovered from the cultures more than 4 months after they had been initiated, and intranuclear localization of SV40 in approximately 5 percent of the cells was demonstrated by electron microscopy and fluorescent-antibody techniques. Cells from infected cultures grew more rapidly in vitro than cells from cultures derived from noninfected explants of the same thyroid tissue; however, cells from both sources grew poorly when transplanted to the cheek pouches of Syrian hamsters. Limited growth of cells from infected cultures was observed in the brains of cortisone-treated African green monkeys after intracerebral injection of cell suspensions. No evidence of proliferation of cells from infected cultures was found in the brains of hamsters after intracerebral injection of cell suspensions on the day of birth. Three months after intracerebral injection of cells from infected cultures, however, 2 of 22 hamsters developed papillary ependymomas histologically identical with the tumors produced in hamsters by intracerebral inoculation of SV40 grown in kidney cell cultures from African green monkeys. This result indicates that SV40 can retain its oncogenic activity in hamsters even after passage in human cells in vitro.