Improved cellular immune response elicited by a ubiquitin-fused ESAT-6 DNA vaccine against Mycobacterium tuberculosis.

The present study evaluated the immune response elicited by a ubiquitin-fused ESAT-6 DNA vaccine against Mycobacterium tuberculosis. BALB/c mice were vaccinated with plasmid DNA encoding ESAT-6 protein, ubiquitin-fused ESAT-6 DNA vaccine (UbGR-ESAT-6), pcDNA3-ubiquitin and blank vector, respectively. ESAT-6 DNA vaccine immunization induced a Thl-polarized immune response. The production of Thl-type cytokine (IFN-gamma) and proliferative T-cell responses was enhanced significantly in mice immunized with UbGR-ESAT-6 fusion DNA vaccine, compared to non-fusion DNA vaccine. This fusion DNA vaccine also resulted in an increased relative ratio of IgG(2a) to IgG(l) and the cytotoxicity of T cells. Thus, the present study demonstrated that the UbGR-ESAT-6 fusion DNA vaccine inoculation improved antigen-specific cellular immune responses, which is helpful for protection against tuberculosis infection.