A study on the enhancement of immunogenicity of tuberculosis DNA vaccines by electroporation and prime-boost strategy
Objective A study for the enhancement of immunogenicity of tuberculosis DNA vaccines by electroporation (EP) prime and boost strategy. Methods DNA vaccines HG85 and HG6 were constructed by inserting the gene encoding Ag85A or ESAT-6 into pVAX1 vector respectively. BALB/c mice were intramuscularly injected with 10 μg HG85 or HG6 DNA vaccine followed by electroporation. Electroporation of plasmid DNA in vivo was improved by square wave applied at the site of DNA injection. Mice were DNA/EP primed for three times and boosted with corresponding recombinant protein or BCG. Results A humoral immunity induced by injecting mice with 10 μg DNA followed by EP was equal to or better than that obtained by using 100 μg DNA without EP. Boosting the DNA/EP primed animals with corresponding recombinant protein induced T_H2 immune response and evoked more than a 5-76 fold increase in the antibody titer. However, boosting the DNA/EP primed animals with BCG induced T_H1 immune response. Conclusion The immunogenicity of tuberculosis DNA vaccines in animals could be significantaly increased by DNA/EP prime and protein or BCG boost strategy.