Virus-like particles expressing the nucleocapsid gene as an efficient vaccine against Rift Valley fever virus.

Rift Valley fever virus (RVFV), a member of the family Bunyaviridae, regularly accounts for large and severe outbreaks among humans and livestock in Africa and Arabia. Therefore, safe and efficient vaccines are highly needed. Here, we report the production of recombinant virus-like particles (VLPs) that, in addition to their similarity to RVFV particles, are able to express the viral nucleocapsid (N) gene. A single inoculation of 1 × 10(6) of these N-VLPs was sufficient to protect 100% of mice from infection with a lethal dose of 1 × 10(5) PFU of RVFV. Our study demonstrates that N-VLPs can be considered as a safe and efficient vaccine against the emerging pathogen RVFV, and that VLPs that actively produce a viral antigen may be considered a strategy to improve the immunogenicity of VLPs in general.