Abstract:Abstract: [Objective] To explore whether polyethylene glycol (PEG) as adjuvant could enhance the humoral and cellular immune responses on hepatitis B virus DNA vaccine. [Methods] C57BL/6J mice were immunized with PEG and pVAX-S2 or alone pVAX-S2. After these mice were finally immunized for 14 days, the anti-HBs IgG, T cell proliferation, the expression of cytokines and CTL in vivo were detected. [Results] Compared to mice immunized with alone pVAX-S2, PEG as adjuvant could increase the production of anti-HBs IgG and HBsAg specific T cell proliferation. In addition, the expression of IL-4, IFN-γ in CD4+ T cells and IFN-γ in CD8+ T cells was higher than control groups. The PEG/pVAX-S2 groups could elicit significantly in vivo HBsAg specific CTL responses. [Conclusions] PEG as adjuvant could enhance humoral and cellular immune responses, as well as in vivo CTL activity.