• Vaccine Name: Rabies Virus Vaccine pAlpha-Rab-G
• Target Pathogen: Rabies virus
• Target Disease: Rabies
• Type: DNA vaccine
• Status: Research
• Host Species for Licensed Use: None
• Antigen: G (Saxena et al., 2008)
• G gene engineering:
  • Type: DNA vaccine construction
  • Description: (Saxena et al., 2008)
  • Detailed Gene Information: Click Here.
• Preparation: The full length rabies G gene was isolated from conventional rabies DNA vaccine, pTargeT-Rab-G. To construct replicon-based rabies DNA vaccine (pAlpha-Rab-G), the DNA fragment containing full length rabies G gene was isolated by digesting pTargeT-Rab-G with NheI and SmaI restriction endonucleases and ligated into XbaI and StuI sites of the replicon-based DNA vaccine vector, pAlpha. The replicon based rabies DNA vaccine (pAlpha-Rab-G) contained CMV promoter at 5′ end, 5′-UTR, nonstructural genes (nSP1-4), 26S subgenomic promoter, rabies G gene, 3′-UTR and polyA signal sequence. (Saxena et al., 2008)
• Immunization Route: Intramuscular injection (i.m.)
• Description: A sindbis virus replicon-based DNA vaccine encoding the rabies virus glycoprotein elicits immune responses and complete protection in mice from lethal challenge. (Saxena et al., 2008)

Mouse Response

• Vaccination Protocol: Groups of Swiss albino mice (3–4 weeks old, each n = 10) were injected intramuscularly each with 50 µg of either replicon-based rabies DNA vaccine (pAplha-Rab-G) or conventional rabies DNA vaccine (pTargeT-Rab-G) or vaccine control (pAlpha) at one site in quadriceps muscle. One group (n = 10) of mice was immunized intramuscularly each with 100 µl (one-tenth dose) of commercial rabies vaccine, Rabipur. One group (n = 10) of mice received PBS (100µl) injection and kept as negative control group. All groups of mice received booster on day 21 post-immunization. (Saxena et al., 2008)
• Immune Response: Rabies-specific seroconversion was observed in all vaccine-immunized mice except vector control and healthy control groups. Significant levels of IgG antibodies to rabies were detected in all of the mice immunized with different vaccines, but not in vector-immunized (pAlpha). Replicon-based DNA vaccine and Rabipur vaccine-immunized mice showed anti- body titres significantly higher (p < 0.05) than conventional DNA vaccine (pTargeT-Rab-G). Replicon-based rabies DNA vaccine and Rabipur vaccine-immunized mice showed VN (virus neutralizing) titres significantly higher (p < 0.05) than conventional DNA vaccine (pTargeT-Rab-G). (Saxena et al., 2008)
• Challenge Protocol: Mice immunized with either pAlpha-Rab-G or pTargeT-Rab-G or Rabipur or pAlpha or PBS were challenged with 20 LD50 dose virulent rabies virus following NIH method and their survival was monitored for 14 days post-challenge. (Saxena et al., 2008)
• Efficacy: Immunization with pAlpha-Rab-G and Rabipur provided significant complete (100%) protection against rabies virus challenge compared with pAlpha and PBS immunization (p < 0.0001 using Log rank test for comparison of survival). The conventional rabies DNA vaccine showed less (80%) protection compared to other vaccines. None of the control mice survived indicating the virulent nature of challenge virus. This experiment conclusively shows that protection by replicon-based rabies DNA vaccine against lethal rabies challenge can be brought about by inoculation with pAlpha-Rab-G plasmid and that the protective ability of this candidate vaccine is comparable with that of Rabipur. (Saxena et al., 2008)