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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Infectious Bacterial Diseases Research » Research » Publications at this Location » Publication #241266

Title: Improved Performance of the Interferon Gamma (IFN-gamma) Assay with Alternative Antigens for Stimulation of Whole Blood

item SCHRODER, B - Prionics Ag
item HARDEGGER, R - Prionics Ag
item MARG-HAUFE, B - Prionics Ag
item SCHILLER, I - Prionics Ag
item MOYEN, J - Department Of Agriculture Analysis Laboratory
item Waters, Wade
item Palmer, Mitchell
item Thacker, Tyler
item STAMM, C - Prionics Ag
item Nonnecke, Brian
item KECK, N - Department Of Veterinary Laboratory Of L'Herault
item EGNUNI, T - Veterinary Laboratories Agency (VLA)
item WHELAN, A - Veterinary Laboratories Agency (VLA)
item SIGAFOOSE, T - Animal And Plant Health Inspection Service (APHIS)
item WELSH, M - Agri-Food And Biosciences Institute
item CAGIOLA, M - Zooprofilattico Institute Of Umbria And March
item GORDON, S - University College - Ireland
item MEIJLIS, J - Lelystad Biologicals
item CARTER, C - Asurequality
item VORDERMEIER, H - Veterinary Laboratories Agency (VLA)
item RAEBER, A - Prionics Ag

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/25/2009
Publication Date: 8/25/2009
Citation: Schroder, B., Hardegger, R., Marg-Haufe, B., Schiller, I., Moyen, J.L., Waters, W.R., Palmer, M.V., Thacker, T.C., Stamm, C., Nonnecke, B.J., Keck, N., Egnuni, T., Whelan, A., Sigafoose, T., Welsh, M., Cagiola, M., Gordon, S., Meijlis, J., Carter, C., Vordermeier, H.M., Raeber, A.J. 2009. Improved Performance of the Interferon Gamma (IFN-gamma) Assay with Alternative Antigens for Stimulation of Whole Blood [abstract].

Interpretive Summary:

Technical Abstract: Bovine tuberculosis caused by infection with Mycobacterium bovis (M. bovis) is a zoonotic disease that affects cattle worldwide and has a significant economic impact on the livestock industry. Although the disease has been effectively eliminated in many countries and regions, it is increasingly reappearing as a result of host reservoirs in wild animal populations. The success of bovine tuberculosis eradication programs in many countries have relied on ante mortem diagnostic tests measuring cell-mediated immune (CMI) responses such as the tuberculin skin test or the interferon gamma test. 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. Diagnosis is based on a comparative measurement with avian and bovine tuberculins. Numerous field trials showed that the IFN-gamma assay was more sensitive than the intradermal skin test for diagnosis of tuberculosis. However, specificity of the IFN-gamma assay was found to be slightly lower than the skin test suggesting limited use of the IFN-gamma assay as a stand-alone screening tool in cattle herds that are either free or have a low prevalence of tuberculosis. In order to increase the specificity of the IFN-gamma test, defined antigens such as ESAT-6 or CFP-10 in combination with other highly specific antigens from the genome of M. bovis have been evaluated in field trials. Here we show, that a combination of antigens including ESAT-6 and CFP-10 showed a specificity of 99.5 % - 100 % in cattle from TB-free regions whereas sensitivities assessed in herds with skin test reactors in France and Ireland showed comparable sensitivities as with tuberculins. These results suggest that IFN-gamma testing comprising stimulation with well characterized antigen cocktails can be used as a stand alone test system for tuberculosis in cattle.