Abstract: The recombinant plasmid was constructed by inserting the HIV-1 clade C gag into a DNA vaccine expression vector-pVAX.Meanwhile the gag gene was inserted into expression vector pGEX-5X-1.The expressed product of gag gene was examined by Western-blot from 293 T cell culture transfected with pVAX-gag and E.coli cell disruption transformed with pGEX-gag.Further,Balb/Cmice were immunized by the recombinant plasmid pVAX-gag,and the cellular immune response of these mice was analyzed by flow cytometry and ELISpot assay.The purified recombinant protein Gag was coated in ELISA plate to evaluate humoral immune response of these mice.As a result,the HIV-1 clade C DNA vaccine pVAX-gag could effectively induce cellular and humoral immune responses in Balb/C mice.These immunological effects showed pos-itive correlation with immunization dose.And the recombinant protein Gag was expressed efficiently in E.coli.It has antigenicity and can be used for diagnosis of HIV as a helpful antigen.