LABORATORY PRODUCTION OF INFECTIOUS STOCKS OF RABBIT ORAL PAPILLOMAVIRUS

Several small, raised lesions from the underside of the tongue of dome stic rabbits were isolated, and an extract prepared and tested for the presence of rabbit oral papillomavirus (ROPV), Two weeks after inocul ation of this extract into the underside of rabbit tongues, multiple s mall discrete, grey-white nodules were observed that reached a maximum size of 2 mm in diameter by 5 weeks, These lesions showed typical ROP V pathology, and nuclei stained positive for papillomavirus (PV) group -specific antigen (GSA) by immunocytochemistry, Tissue fragments from rabbit tongues were incubated with a suspension of ROPV and placed sub renally into athymic mice. After 60 days, cysts were removed, sections cut for histology, and a virus stock prepared, GSA staining and in si tu hybridization demonstrated that the xenografts were morphologically transformed with areas showing strong nuclear staining for viral caps id antigen and ROPV DNA, Extracts prepared from the pooled xenografts contained infectious ROPV as demonstrated by inoculation into the unde rsurface of tongues of nonimmune New Zealand White rabbits, The result s demonstrated that stocks of infectious ROPV can be prepared in the a thymic mouse xenograft system for use in studies on the experimental t ransmission of a mucosal-targeting animal papillomavirus.