A Preclinical Immunogenicity Study of the Recombinant Human Papillomavirus Nine-Valent Virus-like Particle Vaccine

Background: Cervical cancer is associated with persistent infection of high-risk human papillomaviruses (HPVs). Prophylactic HPV vaccines have been recommended and have significant efficacy in preventing cervical cancer. Multivalent HPV vaccines have a better preventative effect on HPV-related diseases. However, there is currently only one nine-valent HPV vaccine on the market: Gardasil (R) 9. The development of new HPV vaccines is still urgent in order to achieve the goal of eliminating cervical cancer as proposed by the WHO. Methods: In this study, we developed a nine-valent recombinant HPV virus-like particle (VLP) vaccine (HPV-9 vaccine) containing HPV type 6, 11, 16, 18, 31, 33, 45, 52, and 58 antigens, with an adjuvant of aluminum phosphate (AlPO4). The type-specific L1 proteins were recombinantly expressed using Pichia pastoris, followed by self-assembly into VLPs. Immunogenicity studies of the HPV-9 vaccine were performed using rodents (mice and rats) and non-human primates (macaques) as animal models. Results: Immunogenicity studies showed that the HPV-9 vaccine is able to elicit a robust and long-lasting neutralizing antibody response in rodents (mice and rats) and non-human primates (cynomolgus macaque) models. The HPV-9 vaccine shows immunogenicity comparable to that of Walrinvax (R) and Gardasil (R) 9. Conclusions: In summary, this study provides a comprehensive investigation of the immunogenicity of the HPV-9 vaccine, including its immune persistence. These findings, derived from using models of diverse animal species, contribute valuable insights into the potential efficacy of the vaccine candidate in clinical settings.