结核分枝杆菌38 ku蛋白的制备及其抗原性研究

目的基因克隆、表达、纯化结核分枝杆菌38ku蛋白,研究其抗原性,评价其在血清学诊断中的价值。方法2003年2月至2004年3月在中国药品生物制品检定所菌苗室以结核分枝杆菌H37Rv基因组DNA为模板,通过聚合酶链反应(PCR)方法对38ku蛋白基因进行扩增,以PET-30a( )为载体构建重组质粒,在大肠埃希菌中表达38ku蛋白,通过金属离子螯合亲和层析方法纯化重组蛋白,免疫印迹和酶联免疫吸附试验(ELISA)方法分析该重组蛋白的抗原性。结果构建了具有正确基因序列的38ku蛋白重组质粒,在大肠埃希菌BL21(DE3)中以包涵体形式表达,经过一步金属离子螯合亲和层析后得到纯度为92.7%的目的蛋白。免疫印迹试验结果表明该蛋白能与羊抗结核血清发生特异免疫结合反应。应用ELISA方法对结核血清参考品进行检测,敏感度和特异度分别为80.5%(33/41)和96.0%(25/26)。结论大肠埃希菌工程菌以包涵体的形式表达38ku蛋白,该蛋白具有良好的免疫原性,可望成为结核血清学的诊断抗原之一。

Preparation and antigenicity analysis of 38 ku protein of mycobacterium tuberculosis

Objective To Clone,express,purify 38 ku protein of mycobacterium tuberculosis,to study its immunological characteristics,and to evaluate its potenial value for serodiagnosis of tuberculosis.Methods Extract DNA from standard strain of H37Rv as the template,amplify gene of 38 ku protein by PCR,insert to PET-30a( )and construct the recombinant plasmid,express 38 ku protein in E.coli BL21(DE3),purify by Nickel affinity chromatography,at last get target proteins of higher purity,analyze its immol/Lunological characteristics by Western blotting and ELISA technology from Feb.2003 to Mar.2004. Results The clone was analyzed at the nucleotide lever and showed the same DNA sequence coding for natural 38 ku protein. The recombinant protein expressed in inclusion body in E.coli BL21(DE3). The purity of terget protein was 92.7% by Nickel affinity chromatography,Western blotting assays showed that the recombinant protein had satisfactory antigenicity . 38 ku protein detected TB postive and negative refference serum based on the mechanism of indirect ELISA,results showed that the sensitivity was 80.5%(33/41)and the specificity reached to 96%(25/26).Conclusion The recombinant protein expressed in inclusion body in E.coli BL21(DE3)and had satisfactory antigenicity,and might be selected as one of serodiagnostic antigen of tuberculosis.