生物素化HCV多抗原表位融合基因的克隆及可溶性表达

为了建立丙型肝炎病毒抗体(HCV-Ab)的双抗原夹心ELISA检测方法．克隆表达带有生物素标签的Hcv多种抗原优势表位融合蛋白，选取HCV各抗原如Core，NS3，NS4，NS5和E的优势抗原表位片段编码序列．克隆重组为融合基因，插入Pinpoint^TM Xa-1 T载体中诱导表达，并用Western blot进行抗原性及标签生物素活性鉴定；表达抗原经Promega SoftLink Soft Release Avidin Resin系统亲和层析纯化后包被酶联板，用抗HCV单片段抗体阳性血清对表达融合蛋白各区的抗原性作间接ELISA法鉴定。结果显示：成功构建了带有生物素标签的HCV多抗原表位融合基因表达载体，该载体可在JM109(DE3)中可溶性表达目的蛋白，表达产物携带生物素标签，融合的各片段区均具有良好的抗原性。结论：所构建融合抗原可可溶性表达，可以用作双抗原夹心ELISA的酶标抗原．所含生物素标签也可用作酶联检测的生物素一亲和素信号放大系统。

Cloning and Expression of a Biotinylated Multiple-epitope HCV Fusion Antigen Gene

The aim was to develop a single multiple-epitope fusion antigen which incorporates all of the major immunodominant epitopes from the six functional regions of the HCV genome. A nucleic acid sequence consisting of viral core,E1,E2,NS3,NS4,and NS5 regions was constructed and inserted into the Promega Pinpoint Xa-1 T vector for inducing expression. The protein was expressed in JM109 (DE3) as a fusion protein with a 13 kD biotinlated tag to be used for detection and affinity purification. Immunogenicity and biotinylated tag of the fusion protein were detected by Western blot analysis with positive anti-HCV serum and streptavidin alkaline phosphatase. After purified by Promega SoftLink Soft Release Avidin Resin,the protein was pre-coated on microwell and detected with anti-core,anti-NS3,anti-NS4 and anti-NS5 positive sera by EIA,respectively. The results indicated that the recombinant soluble protein was expressed and labelled with biotin successfully,it reacted with anti-HCV positive serum,and exposed all of the major immunogenic epitopes chosen. In conclusion,this recombinant antigen may be used to design an double antigen sandwich anti-HCV immunoassay.