Submitted to: Clinical and Diagnostic Laboratory Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2003
Publication Date: 9/1/2003
Citation: Waters, W.R., Palmer, M.V., Whipple, D.L., Carlson, M.P., Nonnecke, B.J. 2003. Antigen-induced ifn-gamma, nitric oxide, and tnf-alpha production by blood mononuclear cells from mycobacterium bovis-infected cattle: diagnostic implications. Clinical and Diagnostic Laboratory Immunology.
Interpretive Summary: Despite highly successful eradication efforts in several countries, tuberculosis of cattle remains a serious health concern worldwide. In addition, recent outbreaks of tuberculosis in Michigan, California, Texas, and New Mexico demonstrate that the disease is far from eliminated from the United States. Improved techniques are needed for detection of infected cattle. To develop improved tests, it is beneficial to first understand the immune response to infection. In this study, specific host responses of cattle to tuberculosis infection were determined. Specifically, two readouts of the response were compared to a known response (i.e., one used in a commercially available test). The three responses were similar in magnitude and kinetics. Knowledge obtained from this study will assist in the development of new reagents and methods for the detection of tuberculosis of cattle.
Technical Abstract: Bovine tuberculosis in the United States has proven costly to cattle producers as well as government regulatory agencies. While in vivo responsiveness to mycobacterial antigens is the current standard for the diagnosis of tuberculosis, in vitro assays are gaining acceptance, especially as ancillary or complimentary tests. To evaluate in vitro indices of cellular sensitization, antigen induced interferon (IFN)-g, nitric oxide (NO), and tumor necrosis factor (TNF)-a responses by blood mononuclear cells from Mycobacterium bovis-infected cattle were quantified and compared. Using an aerosol model of infection, two doses each of two strains of M. bovis (95-1315 and HC-2045T) were used to induce a range of IFN-g, NO, and TNF-a responses. Infection specific increases in NO, but not IFN-g or TNF-a, were detected in nonstimulated cultures at 48h, indicative of nonspecific activation and spontaneous release of NO. The infective dose of M. bovis also influenced responses. At 34d postinfection, IFN-g, NO, and TNF-a responses in antigen-stimulated cells from cattle receiving 105 cfu M. bovis were greater than responses of cells from cattle infected with 103 cfu M. bovis. The NO response, but not IFN-g and TNF-a responses, was influenced by infective strain of M. bovis. TNF-a, NO, and IFN-g responses followed similar kinetics with strong positive associations between the three readouts. Overall, these findings indicate that NO and TNF-a, like IFN-g, may prove useful as indices for the diagnosis of bovine tuberculosis.