Induction of an HPV 6bL1-specific mucosal IgA response by DNA immunization.

Human papillomavirus (HPV) plays a crucial role in the development of human anogenital dysplasia. To prevent infection, it is important to induce an HPV-specific mucosal immune response. We investigated whether DNA vaccination would induce an intravaginal mucosal antibody response against HPV 6bL1. New Zealand White rabbits were immunized with an HPV 6bL1 DNA vaccine by one of the three routes: muscular, vaginal, or rectal. We found that vaginal immunization of rabbits with HPV 6bL1 DNA induced 6bL1 virus-like particle-specific lgA antibodies in vaginal secretions. They were detectable until at least 14 weeks after the first immunization. The antibodies also showed neutralizing activity in a hemagglutination inhibition assay. No mucosal immune response was detected in vaginal secretions of rabbits immunized intramuscularly or intrarectally. Our data suggest that vaginal immunization with HPV 6bL1 DNA induces long-lasting IgA responses with neutralizing activity in vaginal secretions of rabbits.