Infection of human embryonic skin-muscle tissue culture cells with adenovirus type 12

,The effect of infection of human embryonic skin-muscle cell cultures with adenovirus type 12 has been studied. When maintained in YLE containing 20 per cent bovine serum, human embryonic skin-muscle tissue culture cells developed little or no cytopathogenic effect for about 50 days after inoculation of adenovirus type 12, though a small amount of virus was always detected in the overlying medium. From day 50∼60, CPE started appearing and spread over 90 per cent of cells accompanied with the increase of virus in the overlying medium. The addition of human serum to the maintenance medium inhibited the virus release. After removal of human serum about 16∼37 days after its addition, virus-and, later, CPE also-again started appearing. The second virus release-and CPE also-was inhibited by addition of human serum to the medium. When maintained in the medium with human serum for about 200 days, the removal of human serum did not result in the appearance of virus or CPE. The virus isolated from the overlying medium of these cells during the whole process of the experiment was always highly oncogenic to newborn hamsters. Diluted adenovirus-12-immune rabbit serum also showed the effect similar to that of human serum. But, regardless of its much higher antibody titer, the effect of this diluted adenovirus-12-immune rabbit serum was weaker than that of human serum. In one of cell cultures, rapidly growing cells appeared 212 days after virus inoculation. But the available data suggest that these are the cells transformed rather spontaneously in tissue culture than by adenovirus type 12.