结核分枝杆菌特异性抗原ESXO的重组制备及其免疫原性评估

Recombination,preparation and immunological evaluation of Mycobacterium tuberculosis specific antigen ESXO

目的评估结核分枝杆菌(MTB)重组特异性抗原ESXO在大肠埃希菌中的高效表达,并评价其免疫原性。方法采用常规分子克隆方法获得MTB重组蛋白ESXO。酶联免疫吸附试验(ELISA)方法检测84份确诊结核病(TB)患者血清和48份健康人血清中相应的抗结核ESXO抗体水平,评价血清学抗原活性,并与结核早期分泌蛋白ESAT-6和CFP-10的检测结果进行比较。结果重组特异性抗原ESXO在大肠杆菌中获得成功表达,其在E.coli BL 21 plysS(DE3)中以可溶性和包涵体两种形式存在,相对分子质量(27 300)与预期相符,血清学抗原活性评估结果显示其特异度和敏感度分别为94.0%(45/48)和32.1%(27/84),特异度与ESAT-6和CFP-10相当,敏感度高于ESAT-6。结论结核特异性抗原ESXO有望成为新的TB诊断与疫苗设计的候选抗原。

Objective To determine the expression of recombinant Mycobacterium tuberculosis （MTB） specific antigen ESXO in E. coli, and evaluate its immunogenicity. Methods Recombinant ESXO protein of MTB was obtained with conventional molecular cloning method. The serum antibody against ESXO was detected by enzyme linked immunosorbent assay （ELISA） in 84 patients with tuberculosis （TB） and 48 healthy controls, the serum immunogenicity was evaluated, and the results were compared with findings in detection of ESAT-6 and CFP-10 protein for sei＇odiagnosis of TB. Results The recombinant specific antigen ESXO was expressed as soluble and inclusion body protein in E. coli BL21 plysS （DE3）, with the relative molecular weight of 27 300, which was in line with expectations. The immunogenic evaluation of recombinant ESXO protein indicated that its specificity and sensitivity reached 94.0% （45/48） and 32.1% （27/84） respectively, which was equal to ESAT-6 and CFP-10 in specificity and higher than ESAT-6 in sensitivity. Conclusion The specific antigen ESXO is expected to be a novel candidate antigen for the diagnosis and vaccine design in TB.