Experimental transmission of bovine papilloma virus (BPV) extracted from morphologically distinct teat and cutaneous lesions and the effects of inoculation of BPV transformed fetal bovine cells.

Bovine papilloma virus (BPV) was extracted from five cattle each affected with only one of five morphologically distinct lesion types. When inoculated into experimental calves either by scarification or intradermal injection, the BPV extracts produced lesions macroscopically and microscopically similar to those from which individual extracts were made. Fetal bovine cells, transformed in vitro with BPV, failed to produce fibromas, fibropapillomas or papillomas when inoculated into experimental calves. When calves inoculated with virus or BPV transformed cells were challenged with the five original BPV extracts, a differential immunity was demonstrated, while control calves were susceptible to all extracts. Post mortem examination revealed the presence of upper alimentary tract papillomas in three of eight calves forming one group. These results suggest that different strains of BVP, causing morphologically separable lesion types, exist. There may be additional BPV variants causing fibropapillomas of the teat and anogenital regions of cattle. The inoculation of BPV transformed fetal bovine cells conferred a relative immunity to later challenge with some but not all BPV extracts.