Correlating immunity with protection for HPV infection

Abstract

Background: Cervical cancer is one of the most common types of cancer in women and is largely attributable to persistent infection with high-oncogenic risk human papillomavirus (HPV) types. Most HPV infections resolve spontaneously over 5 years, but, in a small fraction of women, persistent infection with high-risk HPV results in cervical intraepithelial neoplasia (CIN) grade 2/3 and eventually cervical cancer. Perspectives: Prophylactic vaccines based on HPV virus-like particles (VLPs) exploit the propen- sity of the immune system to protect against HPV infection and resulting diseases, including cancer. The quadrivalent (HPV types 6, 11, 16, 18) vaccine was 100% effective in preventing HPV 16- and 18-related CIN 2/3 in young, HPV-naïve women and possessed similar efficacy against anogenital warts and vaginal and vulvar neoplasias. HPV VLP vaccine-induced protection is mediated by anti-HPV antibodies specific for conformational "neutralizing" determinants on the HPV capsid. Conclusions: The quadrivalent vaccine is highly immunogenic in human subjects; induces per- sistent, high-titer, neutralizing antibodies for at least 5 years; and induces immune memory responses. The quadrivalent HPV vaccine induces the greatest immune response in prepubertal children (9 to 12 years). Long-term follow-up studies are planned through the Nordic cancer registries to assess duration of HPV protection. © 2007 International Society of Infectious Diseases.