Effect of immunization in mice with recombinant DNA encoding the hepatitisC virus structural protein

Objective To explore the possibility and the efficacy of immune responses i n mice inoculated with recombinant plasmid pCD-HCV1 and to lay a foundation for HCV nucleic acid vaccine development in the future. Methods The gene fragment coding C and E regions of HCV-II (type I b) was i nserted into pCD-SR alpha(1) expression vector and formed pCD-HCV1 and then was injected into quadriceps muscles of Balb/c mouse. Serum anti-HCV level of mice was tested by ELISA(A value). Spleen cells proliferation responses to HCV antigens were detected by H-3-TdR incorporation (cpm). Results Balb/c mice immunized with recombinant plasmid pCD-HCV1 three or fo ur times can generate specific antibody responses to HCV antigens and the a ntibody levels gradually ascend to the plateaus and did not have the trend of descending in 18 weeks detected. The serum antibodies in mice immunized by recombinant plasmid pCD-HCV1 were 100 percent positive when the serum we re diluted 40 times and the positive rate of antibody still were 16.6 perce nt positive when the serum were diluted 320 times. Balb/c mice immunized wi th recombinant plasmid pCD-HCV1 (100 mu g, 50 mu g, 10 mu g/mouse three tim es respectively) can elicit antibody responses to HCV antigens and the anti body levels of three groups were 0.70 +/- 0.07, 0.33 +/- 0.04 and 0.11 +/- 0.09 respectively. Spleen cells of Blab/c mice injected with pCD-HCV1 three times were induced to produce proliferation responses to HCVc + e specific antigens. Conclusions These results demonstrated that constructs expressioning HCV co re and envelope proteins can generate anti-HCVc + e specific antibody which suggested it to be possible to elicit immune responses to viral epitopes f rom HCV via DNA Immunization with HCV-DNA recombinant and to warrant furthe r investigation as a potential vaccine against HCV infections.