To explore the immunogenicity of DNA vaccine expressing IgG2b-­Fc, eukaryotic expression vectors pSV­-Gag and pSV-­Gag-­IgG2b were constructed. The constructed DNA vaccines were validated by restriction enzyme digestion and DNA sequencing. Western blotting results showed both of the two DNA vaccines could be expressed at appreciable levels in vitro. C57BL/6 mice were injected with these two DNA vaccines by intramuscular injection and their antigen­-specific humoral responses and T cell responses were compared after the last immunization. The results showed that human immunodeficiency virus type 1 (HIV­-1) Gag fused with mouse IgG2b-­Fc elicited superior Gag­-specific humoral responses and T cell responses, but there was only significant increase in antigen­-specific humoral responses between the two DNA vaccines.