ARS | Publication request: Assessment of Mycobacterium tuberculosis OmpATb as a Novel Antigen for the Diagnosis of Bovine Tuberculosis

Submitted to: Clinical and Vaccine Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 2009
Publication Date: September 1, 2009
Repository URL: http:////cvi.asm.org/cgi/reprint/16/9/1314
Citation: Schiller, I., Vordermeier, M., Waters, W.R., Palmer, M.V., Thacker, T.C., Whelan, A., Hardegger, R., Raeber, A., Oesch, B. 2009. Assessment of Mycobacterium tuberculosis OmpATb as a Novel Antigen for the Diagnosis of Bovine Tuberculosis. Clinical and Vaccine Immunology. 16(9):1314-1321.

Interpretive Summary: Despite highly successful eradication efforts in several countries, tuberculosis of cattle remains a serious health concern worldwide. Outbreaks in Michigan, California, New Mexico, and Minnesota continue and new cases have been detected in North Dakota and Indiana; demonstrating that the disease is far from eliminated from the United States. The Bovigam™ assay is approved for use within the United States as a complimentary test for bovine tuberculosis. This assay relies on a specific response to the tuberculosis agent. In the present study, a new reagent (i.e., an antigen) is described to improve the specificity and sensitivity of this test. Knowledge obtained from this study may lead to an improved test for tuberculosis, thereby, advancing the national tuberculosis eradication program.

Technical Abstract: In search for improved tools to control bovine tuberculosis, the development of diagnostic tests with improved specificity and sensitivity has a high priority. Such tests require the identification of enhanced immunodiagnostic reagents. In this study, we evaluated the potential of Rv0899 (Outer membrane protein A of Mycobacterium tuberculosis, OmpATb) respectively of Mb0923, the Mycobacterium bovis related protein with identical sequence, as a diagnostic target for bovine tuberculosis. OmpATb induced IFN-g responses in cattle experimentally infected with M. bovis as early and as persistently as ESAT-6 and CFP-10, the current lead diagnostic antigens. In naturally infected cattle, OmpATb stimulated IFN-g production in 22 of 26 animals (85%). Importantly, OmpATb detected a portion of M. bovis-infected cattle which did not respond to ESAT-6 and CFP-10. The combined diagnostic sensitivity of OmpATb, ESAT-6 and CFP-10 was 96% (25 of 26 animals) suggesting that the combined use of . OmpATb, ESAT-6 and CFP-10 would improve tuberculosis diagnosis. Specificity of OmpATb in uninfected cattle was 100% (27 cattle tested, 12 of them reacted false positive with tuberculins). In summary, our results suggest that OmpATb has the potential to enhance the sensitivity of previously described diagnostic tests based on ESAT-6 and CFP-10.