Abstract: 　Objective To detect the in vitro expression of pcDNA3 Eg95 and to observe the immunological effect of the Eg95 DNA vaccine in mice. Methods The eukaryotic recombinant plasmid pcDNA3 Eg95 was transfected into HeLa cells with liposome mediated method. RT PCR, ELISA and Western blotting were used to analyze the expression of Eg95 mRNA and Eg95 protein, respectively. The BALB/c mice were immunized by pcDNA3 Eg95. Anti Eg95 IgG and IgG2a in murine serum were determined by ELISA. The proliferation activity of spleen T lymphocytes was tested using MTT assay. Results Using RT |PCR method, the expression of Eg95 mRNA was confirmed in vitro. The results of ELISA and Western blotting showed that there was a specific Eg95 protein, which can be specifically recognized by anti sera of Eg95 prokaryotic expressing protein in pcDNA3 Eg95 transfected HeLa cell lysis. The specific IgG was induced during the 3rd week and continued to increase until week 10. IgG2a was detected after 2 weeks and maintained a higher level till week 10. There was a significant difference of IgG2a level between pcDNA3 Eg95 immunized group and pcDNA3 control(P<0.01). In spleen T cell proliferation response, the stimulation index(SI) in pcDNA3 Eg95 group was higher than that of vector control(P<0.01). Conclusion Eg95 DNA vaccine can induce significant cellular and humoral immune response in mice.

Key words: Echinococcus granulosus, Antigens, DNA vaccine, Gene expression, Immune response