Division of Animal Biotechnology, Indian Veterinary Research Institute, Izatnagar-243122, India.
RNA interference (RNAi) represents an emerging technology, which can cause non-cytopathic viral clearance, hence, is most suitable for the treatment of viral infections affecting vital tissues. Rabies is 100% fatal untreatable disease caused by a neurotropic virus. Its negative sense RNA genome consists of genes namely N, M, P, G and L. The L gene, coding viral polymerase is indispensable for virus multiplication which makes it attractive target for inhibition of virus multiplication by RNAi. In this study, the ability of specific siRNAs targeting L gene to inhibit rabies virus multiplication in BHK-21 cells was studied. Four siRNA sequences (siL1, siL2, siL3 and siL4) targeting the conserved region of L gene were synthesized using SilencerTM siRNA Construction Kit. Rabies infected BHK-21 cells were transfected with four different siRNAs to evaluate and compare their antiviral potency. By using fluorescent spot count of transfected cells after immunofluorescence staining and titration of supernatant progeny virus harvest, it was observed that virus multiplication was inhibited and viral clearance was evident in cells that were already infected. The siRNA, siL1, was found most potent with 98.36% reduction in fluorescent spot count and 163.33 fold reduction in supernatant progeny virus harvest titre. These results indicate that RNAi is promising for control of rabies virus multiplication and clearance of viruses from already infected cells and hence has a potential to develop as an effective therapeutic strategy against clinical rabies infection.
