Oncogenic activity of the BK type of human papova virus in newborn Wistar rats

The oncogenic potential of the human papova virus BK (= BKV) has been examined in newborn Wistar rats. 12 of 37 animals inoculated with BKV s.c. and 7 of 40 animals inoculated with BKV i.c. developed tumors of various histological types. The latency periods ranged from 6 to 18 months. The BKV etiology of tumors was supported by detection of BKV T antigen in cells of established tumor lines by means of indirect immunofluorescence. No tumors appeared in animals given injections of saline instead of virus. BKV T antibodies were detected in sera of 100 per cent of animals bearing tumors but no in sera of control animals. Only 3 of 77 BKV infected and none of the control animals developed spontaneous tumors (adenomas).