In vitro HPV-11 infection of human foreskin

Study of the infectious process of human papillomavirus type 11 (HPV-11) has been facilitated by the discovery that HPV11-infected neonatal human foreskin epithelium can proliferate as xenografts into condyloma-like growths within athymic nude mice. Here we describe detection of HPV-11 infection of neonatal human foreskin-derived keratinocytes, infected and cultured entirely in vitro, by use of the polymerase chain reaction and primers straddling the splice donor/ acceptor site of the most prevalent early gene HPV-11 transcript (E1^E4). Expression of the E1^E4 HPV-11 mRNA is abrogated by 60°C heat inactivation of the inoculum. HPV-11-infected foreskin explants continue to produce the E1^E4 mRNA for up to 5 weeks in culture, and second-passage keratinocytes derived from infected explant outgrowths continue to produce the E1^E4 mRNA. The in vitro system described here provides a new way to study HPV-11 infection and may be useful in evaluating early events of infection.