A. Rai

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.

Induction of immune responses and protection in mice against rabies using a self-replicating RNA vaccine encoding rabies virus glycoprotein

A self-replicating RNA vaccine encoding rabies virus glycoprotein gene was developed utilizing sindbis virus RNA replicon. The in vitro transcribed RNA (Sin-Rab-G RNA) was transfected in mammalian cells and analysed for self-replication and expression of rabies glycoprotein. To generate immune responses against rabies, mice were immunized with 10microg of Sin-Rab-G RNA and immune responses developed were compared with mice immunized with rabies DNA vaccine and commercial cell culture vaccine (Rabipur). The self-replicating rabies RNA vaccine generated cellular and humoral IgG responses similar to rabies DNA vaccine. On challenge with rabies virus CVS strain, rabies RNA vaccine conferred protection similar to rabies DNA vaccine. These results demonstrated that replicon-based self-replicating rabies RNA vaccine with 10microg dose was effective in inducing immune responses and protection similar to rabies DNA vaccine.

Sequence Analysis of VP2 Gene Hyper Variable Region of a Cell-culture Adapted Indian Classical Infectious Bursal Disease Virus of Chicken

Abstract Kataria, R.S., Tiwari, A.K., Butchaiah, G. and Rai, A. 2007. Sequence analysis of VP2 gene hyper variable region of a cell-culture adapted Indian classical infectious bursal disease virus of chicken. J. Appl. Anim. Res., 32: 49–54. An Indian classical infectious bursal disease virus (IBDV), adapted to grow in primary chicken embryo fibroblast culture, was characterized by RT-PCR/RFLP and sequence analysis of VP2 gene hyper variable region. The Indian classical virus displayed restriction profile similar to that already reported for attenuated IBDV strains. Sixteen nucleotide changes in Indian classical virus were revealed as compared to majority consensus with four unique changes 797A-T, 887C-A, 953A-C and 1017A-G. Deduced amino acid sequence analysis showed two unique changes 270A-K and 296I-V. Presence of amino acid changes 253Q-H, 279D-N and 284A-T, as well as 330S-R indicated this virus to have undergone attenuation after serial passaging in cell-culture. Phylogenetic analysis further confirmed this virus to be most closely related to attenuated strain, PBG-98. Antigenic index analysis and hydrophilicity plots clearly show differences in the peaks of cell culture adapted, classical and very virulent viruses. The present study confirmed that Indian very virulent viruses having not originated from Indian classical virus.