目的 :构建人CD81分子胞外大环 (EC2 )的原核表达质粒 ,并研究胞外大环同HCVE2蛋白的结合性能。方法 :从人外周血淋巴细胞中经RT PCR克隆出CD81胞外大环序列 ,插入原核表达载体pBVIL1中 ,构建表达质粒pBVIL1 EC2并在大肠杆菌中表达。表达产物经纯化后用间接ELISA法测定同E2蛋白的结合能力。结果 :经序列测定证明 ,CD81分子胞外大环正确插入载体。融合蛋白得到高效表达 ,以包涵体形式存在 ,经Q SepharoseFF阴离子交换柱得到有效纯化。初步结果表明 ,重组CD81胞外大环能同原核表达的截短的HCVE2 (384 661)蛋白结合。结论 :本研究为进一步研究CD81同E2及HCV的相互作用和制备抗EC2单克隆抗体奠定了基础 OBJECTIVE: To construct a prokaryotic expression plasmid of human extracellular macrocycle (EC2) of human CD81 and study its binding ability with HCVE2 protein. Methods: CD81 extracellular domain was cloned from human peripheral blood lymphocytes by RT-PCR and inserted into prokaryotic expression vector pBVIL1. The expression plasmid pBVIL1 EC2 was constructed and expressed in E. coli. The expressed product was purified and its binding ability to E2 protein was determined by indirect ELISA. Results: Sequencing proved that the extracellular macrocycle of CD81 was correctly inserted into the vector. The fusion protein was highly expressed in the form of inclusion bodies and was effectively purified by Q Sepharose FF anion exchange column. Preliminary results show that the recombinant CD81 extracellular macrocycle can bind to the truncated HCVE2 (384 661) protein expressed in prokaryotes. Conclusion: This study laid the foundation for further study on the interaction of CD81 with E2 and HCV and preparation of anti-EC2 monoclonal antibody