HIGH-EFFICIENCY INDUCTION OF PAPILLOMAS IN-VIVO USING RECOMBINANT COTTONTAIL RABBIT PAPILLOMAVIRUS DNA

Plasmids containing cottontail rabbit papillomavirus (CRPV) DNA can in duce papillomas in vivo, but efficiency has been low. The aim of the p resent investigation was to explore some of the technical variables in volved in inoculation of rabbits with recombinant CRPV DNA in attempts to improve both yield and consistency of papilloma induction. It was found that induction of epidermal hyperplasia, with either a mixture o f turpentine and acetone or phorbol esters, produced a marked increase in papilloma yield. An additional powerful factor was the use of very vigorous, cutaneous scarification, sufficient to penetrate the papill ary dermis and produce bleeding. When used in combination, papilloma y ields were consistent and often reached 90-100% of inoculated sites. A number of other variables which did not consistently affect papilloma yield were tested. These included bleb and puncture injections, plasm id dose, vector type, occlusive dressings, lipofection reagent, carrie r DNA, and different methods for plasmid DNA extraction and purificati on. It is concluded that the most important variables in improving pap illoma yields were prior induction of epidermal hyperplasia and vigoro us cutaneous scarification.