A sindbis virus replicon-based DNA vaccine encoding the rabies virus glycoprotein elicits immune responses and complete protection in mice from lethal challenge

A sindbis virus replicon-based DNA vaccine encoding rabies virus glycoprotein (G) was developed by subcloning rabies G gene into a sindbis virus replicon-based vaccine vector (pAlpha). The self-amplification of RNA transcripts and translation efficiency of rabies G was analyzed in pAlpha-Rab-G-transfected mammalian cells using RT-PCR, SDS-PAGE and Western blot analysis. The transfected cells also showed induction of apoptosis which is an important event in the enhancement of immune responses. Further, immune responses induced with replicon-based rabies DNA vaccine (pAlpha-Rab-G) was compared with conventional rabies DNA vaccine and commercial cell culture vaccine (Rabipur) in intramuscularly injected mice. The mice immunized with replicon-based rabies DNA vaccine induced humoral and cell mediated immune responses better than conventional rabies DNA vaccine however, comparable to Rabipur vaccine. On challenge with rabies virus CVS strain, replicon-based rabies DNA vaccine conferred complete protection similar to Rabipur. These results demonstrate that replicon-based rabies DNA vaccine is effective in inducing both humoral and cellular immune responses and can be considered as effective vaccine against rabies.