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.