运用聚合酶链反应( PCR) 技术从结核分枝杆菌标准株H37Rv 中扩增获得19kD 脂蛋白和esat-6 基因片段, 将目的片段分别克隆到pMD18-T 载体, 再亚克隆目的片段到同一表达载体pET-21a, 构建重组表达载体pET21a-19kD-ESAT6, 转化至大肠埃希菌BL21( DE3) , 表达纯化后用蛋白质印迹法( Western blot) 分析其抗原反应性。结果成功构建了重组质粒pET21a-19kD-ESAT6, 并在大肠埃希菌中获得高效表达。SDS-PAGE 结果显示, 在相对分子质量( Mr) 约29 ×103 处有表达条带。estern blot 结果表明, 重组蛋白19kD-ESAT6 与确诊的结核病患者血清发生特异性免疫反应, 具有特异的抗原性。本研究构建的结核分枝杆菌19kD-ESAT6 融合蛋白为结核病血清学诊断试剂的开发提供了依据。

The genes encoding 19kD lipoprotein and early secreting antigenic target-6( ESAT-6) were amplified from genome of the standard Mycobacterium tuberculosis H37Rv using polymerase chain reaction, and then cloned into the vector pMD18-T followed by subcloning into the expression vector pET-21a, respectively. Recombinant 19kD-ESAT6 was expressed in E. coli, and then purified by Ni-NTA. The antigenicity of the fusion protein was analyzed by Western blot analysis. The recombinant 19kD-ESAT6 plasmid was constructed successfully, and could be expressed efficiently in E. coli BL21 ( DE3) . The relative molecular mass of the fusion protein was approximately 29 ×10³ by SDS-PAGE. The recombinant 19kD-ESAT6 protein showed specific antigenicity as determined by Western blot, and can be used for the development of serodiagnostic reagents.