ABSTRACT
Rift Valley fever virus (RVFV) is an arthropod-borne pathogen that often results in severe morbidity and mortality in both humans and livestock. As its geographic range continues to expand, it presents a real threat to naïve populations around the world by accidental introduction (e.g., the result of increased travel) or intentional release (e.g., a bioterror event). While there is a clear need for a safe and efficacious vaccine against this emerging and re-emerging pathogen, no FDA-approved vaccine is currently available. This need was addressed by the establishment of novel mammalian and insect suspension cell line systems for the efficient production of RVF virus-like particle (VLP)-based vaccine candidates. A direct comparison of the production of RVF VLPs in these systems was performed. Optimization and characterization resulted in a production platform suitable for scale-up. Furthermore, RVF VLP-based vaccines were tested in a lethal challenge model and showed full protection, demonstrating that RVF VLPs present promising RVFV vaccine candidates.
Subject(s)
Rift Valley fever virus/growth & development , Viral Vaccines/biosynthesis , Animals , Cell Culture Techniques/methods , Cell Line , Disease Models, Animal , Humans , Rats , Rats, Inbred WF , Rift Valley Fever/immunology , Rift Valley Fever/prevention & control , Rift Valley fever virus/genetics , Spodoptera , Survival Analysis , Vaccines, Virosome/biosynthesis , Vaccines, Virosome/genetics , Viral Vaccines/geneticsABSTRACT
To display antigenic protein on the surface of virus-like particles (VLPs) presents a potentially powerful strategy for vaccine development. We genetically engineered the major capsid protein VP1 of foot-and-mouth disease virus (FMDV) into the predominant epitope C of HBV core gene to yield a chimeric core-VP1 VLP. The VLP was successfully expressed in HeLa cells transfected with core-VP1 DNA construct. Compared with a regular VP1 DNA construct, immunization with core-VP1 DNA induced significantly higher levels of antigen-specific IgG production, T cell proliferation, cytotoxic T lymphocyte response, and cytokine production in mice. Most importantly, the level of neutralizing antibody elicited by core-VP1 immunization was significantly higher than that with VP1 DNA immunization, which correlated well with animal protection level from subsequent live FMDV challenge. Thus, immunization with chimeric VLP induces higher efficacy and provides an attractive DNA vaccine strategy for controlling FMDV infection in future.
