Duplication of the Rabies Virus Glycoprotein Enhances the Virus Propagation Rate and Immunogenicity

The most effective approach to control and prevent rabies is by proper pre- and post-exposure immunization. Glycoprotein (G) is a structural protein of the rabies virus that plays a crucial function in host protection against the virus. This study assessed the effects of integrating an extra copy of the glycoprotein gene into the rabies virus genome using reverse genetics on the immunogenicity and titer of the recombinant virus.

The expression of the recombinant viral glycoprotein was compared to the PV strain using qRT-PCR and western blot techniques. The virus titers were studied using a fluorescent antibody test (FAT). The inactivated recombinant virus was administered to BALB/c mice as a vaccine, and the immunogenicity was assessed using the rapid fluorescent focus inhibition test (RFFIT).

Glycoprotein overexpression was observed using qRT-PCR (2.47-fold increase) and confirmed by western blot analysis (3.4-fold increase). The double G virus showed significantly higher virus titers than the PV strain. The immunogenicity of the double G virus was also considerably increased. The VNA titers induced by the double G virus were approximately two and three times higher at 14 and 21 days post-inoculation, respectively.

Based on our findings, the PV strain's G gene duplication showed greater viral titers, better VNA induction, and higher G expression levels. Both the development of rabies vaccines and the investigation of various cellular processes involved in the virus's life cycle may be advanced by characterizing the recombinant double G strain.