An alphavirus replicon-derived candidate vaccine against Rift Valley fever virus

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Rift Valley fever virus (RVFV) poses significant threats to livestock and human health, causing severe disease.
• Existing vaccines for RVFV have limitations, necessitating the development of improved alternatives.

Purpose of the Study:

• To evaluate the efficacy of Sindbis virus replicon vectors expressing RVFV glycoproteins (Gn, Gc) and nsM protein as a potential vaccine candidate.
• To assess the ability of these vectors to induce protective immune responses against RVFV.

Main Methods:

• Construction of Sindbis virus replicon vectors encoding RVFV antigens.
• In vitro assessment of glycoprotein expression.
• Evaluation of anti-RVFV antibody responses (ELISA, FAT, neutralization assays) in immunized mice and sheep.
• Assessment of protection against lethal RVFV challenge in mice via intraperitoneal and intranasal routes.

Main Results:

• Replicon vectors efficiently produced RVFV glycoproteins in vitro.
• Vaccination induced robust systemic anti-RVFV antibody responses, including neutralizing antibodies, in mice.
• 100% protection against lethal RVFV challenge was achieved in mice.
• Preliminary data indicated RVFV-specific neutralizing antibody responses in vaccinated sheep.

Conclusions:

• Alphavirus-based replicon vectors are capable of inducing protective immunity against RVFV.
• This approach demonstrates potential for developing novel RVFV vaccines and warrants further investigation.