Evaluation of Human Serological Response to Recombinant TB10.4 Antigen of Mycobacterium tuberculosis

Development of effective immunodiagnostic methods for detection of Mycobacterium tuberculosis infection is crucial. Serodiagnostic methods, based on antibody response to specific antigens could provide promising approaches for rapid, economical and easy to perform diagnostic tests which are crucial for tuberculosis (TB) control. In this study, the level of IgG antibody responses against recombinant TB10.4 and BacilleCalmette-Guerin (BCG) in sera from TB patients and vaccinated healthy controls were evaluated. Indirect ELISA was used to assess the anti-TB10.4 IgG levels. Serum samples were obtained from vaccinated healthy controls (65), confirmed TB positive patients (77), TB cases under antibiotic treatment (14), and cases with atypical mycobacteria infection (5). The ratio of test sera optical density to the optical density of pooled negative control was taken as cut off value. Using indirect ELISA method, anti-TB10.4 was detected in 64.5%, 93.5%, 85.7% and 100% of the sera from vaccinated healthy controls, confirmed TB positive cases, TB cases under antibiotic treatment and cases with atypical mycobacteria infection, respectively. The relative sensitivity for TB10.4 was calculated as 84.32%. In this study, the use of TB10.4 protein showed high sensitivity, but low specificity in detection of anti-M. tb antibodies in TB patients. These results suggest that further studies should be undertaken to identify the optimal combinations of antigens for the sensitive and specific serodiagnosis of TB.