The Immunogenicity of Replicative Virus Plasmid DNA Containing PrM-E Gene of Chinese D2-43 Virus Strain

To study the immunogenicity of replicative plasmid DNA containing PrM-E gene of Chinese D2-43 virus strain and lay a foundation for new vaccine of dengue, the PrM-E gene was cut from pGEM-T-ME with ApaⅠ and ClaⅠ and inserted into replicative semliki forest virus(SFV) vector. The recombinant plasmid DNA was electroporated into BHK21 cells, then expression products specific to dengue virus type 2 could be detected by IFA (indirect immunofluorescence assay) in transfected cells. Endotoxin-free plasmid DNA was prepared with EndoFree plasmid Maxi kit. Mice were immunized with different doses of the recombinant SFV plasmid DNA intramuscularly at multiple sites. The titres of antibody to dengue virus type 2 was measured by IFA. And sera with recombinant plasmid, could react with antigen of dengue 2 virus on microscope slides.The results showed that recombinant SFV plasmid DNA containing the PrM-E gene of D2-43 virus strain, could produce specific antibody to dengue 2 virus in mice, but the titre was low.