Induction of Fibrosarcomas in Rabbits by Polyoma Virus

Summary

Within 2 months after inoculation of polyoma (Py) virus into newborn rabbits, small subcutaneous nodules occurred which eventually regressed; however, 1 year later, in 2 of the 12 inoculated rabbits, large fibrosarcomas developed at the site of inoculation. In addition, multiple metastases were found in the lung, liver, spleen, kidney, and mesentery. These late-appearing tumors were devoid of the lymphoid infiltration characteristic of primary regressing nodules; serum from these 2 rabbits had Py T antibody. Tissue cultures were initiated from the subcutaneous and metastatic nodules. These aneuploid lines have been maintained for over a year in tissue culture without the detection of Py virus; however, all lines are positive for the intranuclear Py T antigen. Attempts to transplant these cells into noninbred rabbits have been unsuccessful.