A phase 1 study of a recombinant viruslike particle vaccine against human papillomavirus type 11 in healthy adult volunteers

Viruslike particles (VLPs) produced from the L1 protein of several papillom aviruses have induced protection from infection after live challenge in ani mal models. In the present study, the safety and immunogenicity of a human papillomavirus (HPV)-11 L1 VLP candidate vaccine were measured in a phase 1 , dose-finding trial in humans. The vaccine was well tolerated and induced high levels of both binding and neutralizing antibodies. Marked increases i n lymphoproliferation to HPV-11 L1 antigens were noted after the second vac cination. In addition, lymphoproliferation was induced after vaccination in peripheral blood mononuclear cells (PBMC) stimulated with heterologous L1 VLP antigens of HPV types 6 and 16. Statistically significant increases in HPV antigen-specific interferon-gamma and interleukin-5 production were mea sured from PBMC culture supernatants. This candidate HPV VLP vaccine induce d robust B and T cell responses, and T cell helper epitopes appear to be co nserved across HPV types.