HPV prophylactic vaccines: Second-generation or first-generation vaccines

Abstract

High-risk genotypes of human papillomavirus (HPV) are associated with genital cancers especially cervical cancer. United State Food and Drug Administration (USFDA) has recently licensed two first-generation prophylactic vaccines (i.e., Gardasil and Cervarix), for control of HPV 16 and 18 infections. Both vaccines are able to generate neutralizing antibodies against major capsid protein L1 assembled as virus-like particles (VLPs). To enhance protection against other HPV genotypes, second-generation vaccines are underway. A HPV L1-based nonavalent vaccine showed is potent and safe in prevention of precancerous lesions associated with HPV types 16/18/31/33/45/52/58, as well as anogenital warts associated with HPV types 6/11. This vaccine is in the advanced stage of phase III clinical trials. Other second-generation vaccines were based on L1-pentameric subunits and also the minor capsid protein L2 that have shown to be effective in preclinical studies. The L2 protein co-assembles with the L1 protein for VLP formation increasing virion aggregation. This mini-review describes two vaccination strategies including first-generation and second-generation vaccines against HPV infections.