Human papillomavirus vaccines

Virus-like particle (VLP) subunit vaccines composed of the major capsid protein L1 of the genital human papillomaviruses (HPVs) are under test in phase I and II clinical trials. The vaccines are immunogenic and safe but no data on efficacy are yet available. VLPs induce strong cell-mediated as well as humoral immune responses, and chimeric VLPs, including an HPV early protein, may have therapeutic potential. Polynucleotide and recombinant viral vaccines encoding nonstructural viral proteins show therapeutic and prophylactic efficacy in animal models and are candidate immunotherapies for established low-grade benign genital infections. Recombinant virus, peptide, protein, polynucleotide and dendritic cell vaccines designed to elicit cytotoxic T-lymphocytes specific for the HPV oncoproteins E6 and E7 show immunogenicity and efficacy in transplantable tumor models in rodents. Immunogenicity, but no efficacy, has been demonstrated in small clinical trials with some of these approaches.