Recombinant phosphoenolpyruvate carboxykinase from Mycobacteriumtu-berculosis for sero diagnosis

Abstract:

[Objective] To express phosphoenolpyruvate carboxykinase (PEPCK) of tuberculosis and evaluate its immune diagnostic ability. [Methods] PEPCK was cloned and expressed in prokaryotic expression system. We analyzed immune response of recombinant PEPCK with Western blot and studied the immunity of it through mice immunization. We also investigated the sensitivity and specificity of immunodiagnosis of PEPCK via detecting the sera from tubercular patients by using ELISA. The results were evaluated by comparing with a Mycobacterium tuberculosis antibody Colloidal Gold Diagnostic Kit. [Results] The recombinant protein was 72 kDa and specifically reacted with anti-BCG antibody. Specific humoral immune response was elicited after mouse immunization with PEPCK protein and the high titer specific antibody was generated (1:1280). Antibodies were detected against M. tuberculosis 17.3% in all tuberculosis patients, 32.5% in patients harboring Mycobacterium currently and 12.9% in patients without M. tuberculosis. The sensitivity and specificity of ELISA were 51.0% and 96.7%. [Conclusion] These results indicated that the recombinant PEPCK might be one of the suitable antigens for serodiagnosis of tuberculosis.

Key words:Mycobacterium tuberculosis; phosphoenolpyruvate carboxykinase (PEPCK); serodiagnosis; enzyme-linked immunosorbent assay (ELISA)