HPV vaccines: preclinical development.

The knowledge about immune biology of human papillomaviruses stems mainly from animal models that also formed the basis for establishing the strategy for the current vaccines. They consist of virus-like particles (VLP) that are DNA-free virus particles composed of 360 molecules of the major structural protein L1. Protection against virus infection depends upon neutralizing antibodies that prevent the interaction between the virus and its host cell, i.e., the keratinocyte at the basal layer of the epithelium. Despite the good performance of the current vaccines (prevention of infection with the high-risk HPV types 16 and 18 and the anogenital lesions induced by them), development of second-generation product(s) is mandatory, in particular in view of the medical need in areas of the highest burden of cervical cancer.