Relationship of polyoma virus and tumor in vivo

Abstract

The results of a serum protection test in newborn hamsters infected with polyoma virus indicated that tumor induction took place rapidly and directly. Protection against tumor induction occurred only if antibody was present at the time of virus inoculation. Even at that time, some animals developed subcutaneous sarcomas at the site of virus inoculation and most of these tumor-bearing animals did not produce hemagglutinin-inhibiting (HI) antibodies. Although the virus was necessary for tumor induction, direct evidence that it was required for tumor maintenance was lacking. A previously established transplantable hamster tumor in its thirteenth passage showed virus in the tumor and antibody in the host, whereas all other passages were negative. This transplant line was not induced to produce virus by in vivo treatment with X-ray, cortisone, or starvation, nor by X-ray and ultraviolet irradiation of tissue cultures made from the tumor. Two transplantable tumor lines were established in C57 BL mice from subcutaneous sarcomas developing as the result of virus inoculation of newborns. In one line, tumors were consistently negative for virus and donor adults negative for antibody. The other line was consistently positive for virus. Cells in tissue cultures of either line were susceptible to virus challenge.