ARS | Publication request: Bovine Tuberculosis: Analyzing the Parameters of the Interferon Gamma Assay and Improved Diagnosis with New Antigens

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 27, 2007
Publication Date: July 27, 2007
Citation: Schiller, I., Vordermeier, M., Waters, W.R., Marg-Haufe, B., Palmer, M.V., Thacker, T.C., Hardegger, R., Kyburz, A., Raeber, A., Oesch, B. 2007. Bovine Tuberculosis: Analyzing the Parameters of the Interferon Gamma Assay and Improved Diagnosis with New Antigens [abstract].

Technical Abstract: Bovine tuberculosis (TB), a zoonotic disease with a major economic impact, continues to be a significant problem with a global perspective. The BOVIGAM® interferon gamma (IFN-gamma) assay constitutes a laboratory-based tuberculosis test and is widely used complementary to the tuberculin skin test. The assay consists of a first step culturing whole blood with antigens and stimulating leucocytes to produce IFN-gamma which is quantified by ELISA in a second step. The first step measures the cell-mediated immune response (CMI) and critically depends on the sample quality, stimulation reagents and culture conditions. The CMI is known to be impacted negatively by stress. We have stimulated fresh blood from animals with or without stress with mitogens resulting in significantly lower IFN-gamma production in stressed animals and therefore potentially leading to false negative results. These results furthermore emphasize the utility of a positive control for stimulation. Tuberculosis-specific stimulation is currently done with tuberculins. We have analyzed tuberculins at different concentrations from different sources and will report on the optimal standardized tuberculin activity. As an alternative, a cocktail of recombinant antigens for stimulation resulted in improved diagnostic sensitivity and specificity. These recent developments in measuring the CMI therefore represent excellent tools for control and eradication of bovine tuberculosis.