• Vaccine Ontology ID: VO_0000567
• Type: DNA vaccine
• Antigen: Rv1806 and Rv1807 (Vipond et al., 2006).
• PE20 gene engineering:
  • Type: DNA vaccine construction
  • Detailed Gene Information: Click Here.
• PPE31 gene engineering:
  • Type: DNA vaccine construction
  • Detailed Gene Information: Click Here.
• Adjuvant:
  • VO ID: VO_0001261
  • Description: Dioctadecylammonium (DDA), trehalose dibehenate (TDB), and stable liposomes (SSI) (Vipond et al., 2006)
• Vector: pET11d, modified to form pET3a (Vipond et al., 2006)
• Preparation: Two bacterial strains, E. coli DH5α and Rosetta™ 2(DE3)pLysS, were propagated in Luria Bertani (LB) broth and solid medium at 37°C. An expression vector pET3a was created from pET11d expression vector (Novagen) by replacing an ampicillin cassette with kanamycin cassette, followed by restriction digestion of a HindIII site and linker insertion containing cloning sites and an N- and C-terminal 6* histidine tag. The vaccine candidate gene was amplified from M. tuberculosis using PCR and cloned into pVAX1tPA. Recombinant plasmids were generated from four encoding gene sequences and sub-cloned into pET3a prior to transformation, induction, and harvesting in E. coli Rosetta™ 2(DE3)pLysS (Vipond et al., 2006).
• Virulence: Not virulent.
• Description: Rv1806-1807 was one of three potential vaccines compared against gold-standard BCG vaccine and saline control. Rv1806-1807 induced protection in the guinea pig aerosol infection model 30 days post-challenge on the basis of reducing the bacterial burden of M tuberculosis in the lungs ( a reduction in log10 cfu of 0 . 52 and 0 . 83 in lungs and spleen , respectively , following DNA vaccination , compared with reductions of 0 . 3 and 0 . 57 , respectively , with a protein formulation) (Vipond et al., 2006).

Guinea pig Response

• Host Strain: Dunkin-Hartley guinea pig
• Vaccination Protocol: Female Dunkin-Hartley guinea pigs were vaccinated by injecting 100 μg of protein intramuscularly into both hind quadriceps muscles per guinea pig in 100 μl of dioctadecylammonium (DDA) and trehalose dibehenate (TDB) (500 μg DDA plus 100 μg TDB) stable liposomes (SSI). Sub-cutaneous inoculation with 5×10^4 CFU BCG Pasteur was used as positive control. Saline was used as negative control. Ten guinea pigs were used for each group. Vaccinated animals were booster vaccinated with 200 μg protein in adjuvant after 3 and 6 weeks (Vipond et al., 2006).
• Challenge Protocol: Six weeks after the final vaccination, six animals per group were aerosol challenged with approximately 50 CFU of M. tuberculosis H37Rv (NCTC 7416) each in a contained Henderson apparatus. Protection was assessed by CFU in the lungs and spleen at 30 days post-challenge (Vipond et al., 2006).
• Efficacy: Level of protection by Rv1806-1807 at week 15 post challenge was significantly better than saline (p=.018) and comparable to related DNA vaccinations. However, the protection was significantly less than gold-standard BCG. An antigen dose of 10 μg/ml of Rv1806-1807 vaccine stimulated the better protection than for 1 μg/ml (Vipond et al., 2006).