DNA vaccine against tuberculosis by using five Mycobacterium specific genes.

Aim and Objective: In this study, five genes of Mycobacterium tuberculosis were used as DNA vaccine. Each gene was cloned in pcDNA3.1 Topo and later in pND mammalian expression vectors. Methods: All the clones were tested through animal cell lines. In animal trial studies, endotoxin-free DNA were used to inoculate eight week old female Balb/c mice in quadriceps muscles with 50 μg DNA/leg and 25 μg DNA intradermally at the base of tail. No boosters were given. The animals were divided into five groups including positive and negative control groups. Eight animals were used for hspx-pND vaccine, eight for cfp10-pND vaccine, and eight for equally mixed ag85a, b and c pND vaccines. Four animals were used as positive control group injecting Np-pND constructs while four animals were used for negative control group by giving normal saline. The animals were bled after three weeks interval till nine weeks post-vaccination. The antibody titers were confirmed by Western blot analysis and multiplex microbead immunoassay (MMIA). Result: The best humoral response was observed by hspx-pND vaccinated group. Similar but quantitatively less positive response was observed in case of equally mixed ag85a, b and c-pND vaccine group, whereas, cfp10-pND vaccinated animals showed poor immune response. Conclusion: The study concludes that all M. tb gene constructs were good in expression under in vitro and in vivo conditions and produced significant level of antibodies except cfp10-pND construct. The study proved that subunit based DNA vaccines alone or in combination with each or with BCG, can provide breakthrough in vaccines against TB. [ABSTRACT FROM AUTHOR]