Abstract: Objective To construct prokaryotic expression vector of Egene partial sequence of Bstra in dengue virus type 2 for proka ryotic expression for further study of dengue virus.Methods Egene partial sequence of B strain dengue virus type 2 was amplified by RT-PCR,and then in serted into prokaryotic vector pET28a(+)and transformed to E.coli BL21 cells.The Egene partial sequence was expressed with IPTG induction.Results The expressed products was identified by SDS-PAGE and Western B lot and purified.Mean while,the cyto to xicity of the purified protein on C6/36 was detected.The exper miental results showed that prokaryotic expression recom binant vectors pET28a(+)-Eb was successfully constructed.SDS-PAGE assay suggested that the recom binant proteins with a relative molecular weight of 23KD a could be highly expressed in BL21 and the yields were 29% of total bacterial proteins.there sult of Western B lot indicated that the expression products could specifically react with monoantibody aga inst dengue virus type.Vitrocy to toxic expermients suggested that target proteins had relatively cyto toxic function for C6/36.Conclusion pET28a(+)-Eb with Egene partial sequence can be highly expressed in BL21.The antigenicity of target prote in provide a potential source for fur ther developing dengue virus diagnosis reagent.Cyto toxic expermients suggest that target proteins had relatively cyto toxic function for C6/36.