Protein array identification of protein markers for serodiagnosis of Mycobacterium tuberculosis infection

The lack of effective and accurate diagnostic tools contributes to the high prevalence of tuberculosis (TB) worldwide. The current serodiagnostics for TB are inadequate mainly due to lack of TB-specific antigens with highly accurate diagnosis. In the current study, we aimed to identify novel diagnostic antigens using glutathione S-transferase (GST)-fusion protein technique. We determined the reactivity of these recombinant proteins arrayed in solution and on GSH-immobilized microplates with TB patient sera. Of 409 TB proteins produced, ninety-two yielded seropositive reactions, fourteen including eight novel proteins showed strong immunoreactivity. Further, six were selected and constructed as a multiple-antigen combination set through analysis of various combinations. A comparative study of the multiple-antigen combination set and a commercially available kit revealed that the combination set showed 66.3% (95% CI 60.5-71.8) sensitivity, which was significantly higher than that of the commercial kit [31.6% (95% CI 26.3-37.3)]. The specificity of both methods was similar at 89.6% (95% CI 83.3-95.4) and 90.6% (95% CI 83.0-95.6), respectively. This study provides a set of novel diagnostic protein markers with great potential for the development of novel diagnostic tools for active TB.