Biological characteristics of dengue virus type 3 isolated from Yiwu, China / 中国人兽共患病学报

ABSTRACT

This study performed phylogenic analysis on a dengue strain isolated from an outbreak of dengue fever in 2009 at Yiwu City of Zhejiang Province,China,and further to analyze the immunogenicity of E protein of this viral isolate.Firstly,the viral genome was amplified by RT-PCR and phylogenetic trees were constructed by MEGA 4 based on both nucleotide and amino acid sequences of E and NS1 proteins.The phylogenetic analysis showed that the similarity of Yiwu strain with the Guangzhou GZ1D3 strain and the India GWL-25 strain was over 99％.Secondly,the expression plasmid of E protein was constructed and transfected into 293T cells.The secreted E protein were then purified by sucrose density gradient centrifugation and used to inoculate BALB/c mice.The humoral immunity was evaluated by ELISA and neutralizing antibody analysis.Resuits showed that the E protein of Yiwu strain could induce dengue specific IgG antibodies and neutralizing antibodies.Therefore,the study found that the Yiwu strain was classified into the subtype Ⅲ of dengue virus type 3 (DENV-3),and the E protein of this strain had strong immunogenicity