Expression of recombinant Treponema pallidum membrane protein A (TmpA) and development of an Enzyme-linked Immunoassay for diagnosing syphilis / 中华传染病杂志

ABSTRACT

Objective To express TmpA recombinant antigen of Treponema pallidum in E.coli and to develop an Enzyme linked Immunoassay (EIA) based on the recombinant antigen for diagnosing syphilis. Methods The target TmpA gene was amplified by polymerase chain reaction (PCR). The PCR products of the gene were inserted into pBluescript T vector, and then expressed in E.coli, using pQE 30 system. Then the recombinant antigen was purified by an affinity chromatography and used for the development of EIA. Results The antigenicity of the recombinant antigen was identified by western blotting (WB) and EIA. The sensitivity and specificity of EIA were 100%(10/10) and 100% (20/20), respectively. The positive rates of anti TmpA antibodies were 91.67% (11/12) for the patients with Ⅰ phase of syphilis and 100% for the patients of Ⅱ and late stage of the disease. Conclusions The TmpA recombinant protein can be used to diagnose syphilis since 97.2% (35/36) of patients with syphilis were positive for the anti TmpA antibody by EIA.