ABSTRACT
Objective To express and purify Japanese encephalitis virus ( JEV) EDⅢprotein and evaluate the possibility of using it as a candidate antigen in JEV diagnostic kit .Methods PCR primers spe-cific for the gene encoding JEV EDⅢprotein were designed and used to amplify the gene fragment by RT-PCR.The cloned gene fragment was then inserted into pET-30a (+) to construct the recombinant expression plasmid.The transformed E.coli BL21 carrying expression plasmid were induced by IPTG to express JEV EDⅢ protein.The expressed JEV EDⅢprotein and a control antigen of tick-borne encephalitis virus protein were deposited in small spots to set up ELISA microarray .The serum samples from patients with Japanese encephalitis and healthy people were detected by Array-ELISA.The results obtained by Array-ELISA were compared with those by using indirect immunofluorescence assay .Results The gene fragment encoding JEV EDⅢprotein was successfully cloned and expressed in E.coli BL21.The recombinant protein could be used in Array-ELISA assay for the detection of serum samples from patients with Japanese encephalitis and healthy subjects .The results were consistent with those by using indirect immunofluorescence assay.Conclusion The recombinant JEV EDⅢprotein can be used as a candidate antigen for the diagnosis of JEV infection .
ABSTRACT
Objective To express and purify the recombinant nucleoprotein fragments of hemor-rhagic fever with renal syndrome ( HFRS) virus and to evaluate their diagnostic efficacy by using array-ELISA technology .Methods The target genes encoding nucleoprotein fragments of HFRS virus were amplified by PCR, and then inserted into prokaryotic expression vectors to construct the recombinant plasmids of pET -32a (+)/Pn and pET-32a(+)/Pc.The plasmids were transformed into E.coli BL21 ( DE3) to induce the ex-pression of nucleoprotein fragments by IPTG and the expressed products were purified by affinity chromatog -raphy using Ni-NTA agarose.The specificity and sensitivity of the recombinant antigens were evaluated by the assay of array-ELISA using commercial colloidal gold assay kit as a comparison .Results The recombi-nant nucleoprotein fragments of HFRS virus were correctly expressed in E.coli and highly purified by affinity chromatography .Array-ELISA showed that 13 of 16 suspected serum samples were positive by using the His-Pn protein as diagnostic antigen , consistency with the commercial colloidal gold assay kit reaching 94%. Conclusion The recombinant His-Pn protein expressed in E.coli cells could be used for specific serodiag-nosis of HFRS virus as its high antigenicity and sensitivity .The array-ELISA is an effective assay for the de-tection of virus at protein level .