OBJECTIVETo diagnose imported dengue fever case from Henan province, and to sequence and analyze the characteristics of whole genome sequence, and to explore the possible viral origin source.

METHODSA suspected dengue fever case was reported in Yuzhou city, Henan province. The patient returned from foshan, Guangdong province on September 19, 2014, after the epidemiological investigation and serum specimen collected, which dengue fever case was diagnosed in the laboratory, then it was inoculated on Vero cells. Whole genome sequence was amplified by several pairs primers and characterized using biologic software.

RESULTSThe imported case was diagnosed as dengue virus 1 serotype infection. Dengue 1 strain was isolated using Vero cells successfully. Whole genome was 10,670 nt, which belonged to dengue virus 1 serotype V genotype and didn't found any recombination event. The phylogenetic analysis demonstrated that the strain was closed to Indian starins isolated in 2008-2011, and the homology of nucleotide sequence was between 98.2%-99.4%.

CONCLUSIONIt was the first time to discover imported dengue 1 serotype case in Henan province. However, according to the patient has been to Guangdong province before onset, it inferred that the Indian strain had been imported to Guangdong province before this case in Henan province.

Animals ; Cercopithecus aethiops ; China ; Dengue ; Dengue Virus ; Genes, Viral ; Genotype ; Humans ; India ; Molecular Epidemiology ; Serogroup ; Vero Cells

OBJECTIVETo clone and express the recombinant capsid protein VP2 of enterovirus type 71 (EV71) and to identify the immune activity of expressed protein in order to build a basis for the investigation work of vaccine and diagnostic antigen.

METHODSVP2 gene of EV71 was amplified by PCR, and then was cut by restriction enzyme and inserted into expression vector pMAL-c2X. The positive recombinants were transferred into E.coli TB1, the genetically engineered bacteria including pMAL-c2X-VP2 plasmids were induced by isopropyl thiogalactoside ( IPTG) , and the expression products were analyzed by SDS-PAGE and western blotting method. EV71 IgM antibody detection method by ELISA was set up, and the sensitivity and specificity of this method was assessed; 60 neutralizing antibody positive serum samples from hand foot and mouth disease (HFMD) patients were determined, of which 52 samples were positive and 8 samples were negative; a total of 88 acute phase serum samples of HFMD patients diagnosed in clinical were also detected.

RESULTSVP2 gene of 762 bp was obtained by PCR, the gene segment inserted into the recombinant vector was identified using restriction enzyme digestion. The recombinant vector could express a specific about 71 500 fusion protein in E.coli by SDS-PAGE. The purified recombinant protein of EV71-VP2 can react with the serum of HFMD patients to produce a specific band by western blotting. The sensitivity and specificity of ELISA was 87% and 83%, respectively. Of the 88 acute phase serum samples from children with HFMD, 48 samples (55%) were positive by the ELISA assay.

CONCLUSIONSVP2 gene of EV71 has been cloned and a prokaryotic high expression system for VP2 gene was successfully constructed in the present study. The recombination EV71-VP2 has well antigenicity, which could be useful for developing diagnose reagent or vaccine of EV71.

Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; Capsid Proteins ; genetics ; immunology ; Enterovirus A, Human ; genetics ; immunology ; isolation & purification ; Enzyme-Linked Immunosorbent Assay ; Genetic Vectors ; Hand, Foot and Mouth Disease ; immunology ; Humans ; Immunoglobulin M ; blood ; Recombinant Proteins ; genetics ; immunology