Enhanced Cellular Immune Response Elicited by a DNA Vaccine Fused with Ub Against Mycobacterium tuberculosis

This study evaluated the immune response elicited by a Ub‐fused Ag85A DNA vaccine against Mycobacterium tuberculosis. BALB/c mice were vaccinated with plasmid DNA encoding Ag85A protein, Ub‐fused Ag85A DNA vaccine (UbGR‐Ag85A) and negative DNA vaccines, respectively. Ag85A DNA vaccine immunization induced a Thl‐polarized immune response. The production of Thl‐type cytokine (IFN‐γ) and proliferative T cell responses was enhanced significantly in mice immunized with UbGR‐Ag85A fusion DNA vaccine, compared with non‐fusion DNA vaccine. Moreover, this fusion DNA vaccine also resulted in an increased relative ratio of IgG2a to IgGl and the cytotoxicity of T cells. IFN‐γ intracellular staining of splenocytes indicated that UbGR‐Ag85A fusion DNA vaccine activated CD4+ and CD8+ T cells, particularly CD8+ T cells. Thus, this study demonstrated that the UbGR‐Ag85A fusion DNA vaccine inoculation could improve antigen‐specific cellular immune responses, which is helpful for protection against TB infection.