Objective:To investigate Th1 and Th2 cytokines production in the C57BL/6 mice vaccinated by recombinant ESAT-6 (6KD early secretory antigenic target) and FL (fms-like tyrosine kinase 3 ligand) plasmid DNA vaccine encapsulated with nano-chitosan. Methods:The chitosan nanoparticles were prepared,and recombinant plasmid DNA vaccines,namely pIRES-ESAT-6-FL,pIRES-ESAT-6,pIRES-FL and pIRES plasmids,were encapsulated by the nano-chitosan. Then,the size and morphology of nano-ESAT-6-FL plasmid were examined by transmission electron microscope and the expressions of corresponding protein were detected using Western blot. C57BL/6 mice were immunized with nano-ESAT-6-FL,nano-ESAT-6,nano-FL,and nano-pIRES, respectively. At the same time,the corresponding plasmids without nano-chitosan encapsultion,and PBS,nano-chitosan and BCG were also immunized with C57BL/6 mice. Nine weeks after vaccination,the splenocytes separated from the immunized mice were stimulated with PPD for 72 h in vitro,and the Th1 cytokines (IFN-γ and IL-12) and Th2 cytokines (IL-4 and IL-10) in splenocyte supernatant were measured using ELISA kit. Results:Nano-ESAT-6-FL and other chitosan-encapsulated plasmids were well prepared,and nano-ESAT-6-FL plasmid expressed the corresponding protein in glomerular mesangial cells (GMC). The mice immunized with nano-ESAT-6-FL plasmid group(nano-ESAT-6-FL) had significantly higher levels of Th1 cytokines (IFN-γ and IL-12) in splenocyte supernatants than those of the mice treated with control plasmids,but as for IL-4 and IL-10,the changes of the two cytokines in mice with mentioned-above plasmids did not show obvious differences. Conclusion:Recombinant ESAT-6-FL plasmid DNA vaccination encapsulated by nano-chitosan could markedly improve production of Th1 cytokines,suggesting that the mice vaccinated with nano-ESAT-6-FL plasmid DNA vaccine can enhance the cell immune responses.