Exploration of some new secretory proteins to be employed for companion diagnosis of Mycobacterium tuberculosis

• Published in: Immunology letters 2019-05, Vol.209, p.67-74
• Main Authors: Tripathi, Dinesh K., Srivastava, Kanchan, Nagpal, Komal Lata, Shukla, Praveen K., Srivastava, Kishore K.
• Format: Article
• Language: English
• Subjects: Adult; Antigens, Bacterial - immunology; Bacterial Proteins - immunology; Female; Humans; M. tuberculosis; Male; Middle Aged; Mycobacterium tuberculosis - immunology; PE3; PE4; Secretory proteins; Serodiagnostics; Serologic Tests; Tuberculosis - diagnosis; Tuberculosis - immunology; Tuberculosis - metabolism; Tuberculosis - microbiology; Virulence Factors; Young Adult
• ISSN: 0165-2478; 1879-0542
• DOI: 10.1016/j.imlet.2019.03.010

[Display omitted] •The expression of specific antigens is enhanced during active Pulmonary TB (PTB) and extra pulmonary TB (EPTB) infection.•ELISA-based serological tests to detect antibodies to Mtb are simple and inexpensive and are a potentially practical tool for the diagnosis of active PTB and EPTB.•We found that patients with active disease presented high levels of IgG against CFP-10, ESAT-6 and PE3.•PE3 is highly expressed during active human lung infection.•It can further be incorporated with other potent Mtb antigens to improve their accuracy for serodiagnosis. Tuberculosis (TB) is a highly infectious disease and its early and precise diagnosis is essential to reduce morbidity and mortality of patients. Since the routine diagnostic tests (like Monteux, AFB smear microscopy, chest X-Ray) do not give infallible results, additional tests are always recommended. Therefore to address the concerns about non-specificity of the present battery of diagnostic tests, we have attempted to analyze some unique secretory antigens which could be able to identify the stage specific infection of MTB. In this study, we have used recombinant proteins CFP-10, ESAT-6, Ag85 A, Ag85B, Ag85C, PE3, PE4 and Mycp1 to eliminate heterogeneity and cross reactivity in clinical diagnosis. Amplified genes were cloned and over-expressed in Escherichia coli BL21 (DE3). The recombinantly purified proteins were used as antigens against 158 sera samples of TB patients. Secretory proteins showed better response than the PPD control. Among all the used antigens PE3 and PE4 proteins showed better reactivity levels among all the groups of TB patients. The secretions of CFP-10 and ESAT-6 were also higher as compared to other secretory proteins like Ag85 A, Ag85B, Ag85C and MycP1.The clinical use of these newly identified secretory antigens could be of significant value for the confirmatory, rapid, simple and low-cost diagnosis of TB patients.