(Department of Epidemiology，Faculty of Preventive Medicine，Fourth Military Medical University，Xi'an710033，China)

    Keywords:hepatitis C virus;HCV C protein;humoral im-mune response;nucleic acids

    Abstract:AIM To study the protective and therapeutic val-ue of DNA vaccine in HCV infection.METHODS The re-combinant plasmid pEF-HCV was constructed by inserting the highly conserved HCV-core gene fragment into the eu-karyotic expression vector pEF under the control of an EF-1αpromoter，and then was injected into the quadriceps muscles or inoculated subcutaneously into right and left flank of BALB/c mice.Antibody to the HCV core protein in serum was detected by ELISA.RESULTS Antibody to HCV core protein was detected in serum of all the mice receiving injec-tion of recombinant pEF-HCV-C，but the titers were low.The serum antibody level rose significantly after the booster injection，the antibody levels of mice with four times inocula-tion were the highest.CONCLUSION The results suggest-ed that HCV core DNA-based immunization can induce HCV specific antibody，but the humoral immune response was weak at early stage ......