Virus-cell interaction with a tumor-producing virus

The polyoma(PY) virus or parotid tumor agent (1,2) -- a DNA-containing virus (3,4) -- is characterized by a duality of action: it produces neoplasias of various types in different species of rodents (5), and causes cell degeneration in mouse embryo tissue cultures (6). In the experiments to be reported here, it was possible to obtain in cellular cultures in vitro the oncogenic effect of the virus; this afforded the possibility of studying the relationship between the oncogenic and cytocidal effect of the virus. The results so far obtained reveal a situation novel in animal viruses and suggest the existence of a host-virus interaction with characteristics reminiscent of temperate bacteriophage.