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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Different Tuberculin Skin-Testing Regimens on Gamma Interferon and Antibody Responses in Cattle Experimentally Infected with Mycobacterium Bovis

Authors
item PALMER, MITCHELL
item WATERS, WADE
item THACKER, TYLER
item Greenwald, R - CHEMBIO DIAGNOSTIC SYS
item Esfandiari, J - CHEMBIO DIAGNOSTIC SYS
item Lyashchenko, Konstantin - CHEMBIO DIAGNOSTICS, INC

Submitted to: Clinical and Vaccine Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 12, 2006
Publication Date: March 1, 2006
Citation: Palmer, M.V., Waters, W.R., Thacker, T.C., Lyashchenko, K. 2006. Effect of Different Tuberculin Skin-Testing Regimens on Gamma Interferon and Antibody Responses in Cattle Experimentally Infected with Mycobacterium bovis. Clinical and Vaccine Immunology. 13(3):387-394.

Interpretive Summary: Tuberculin skin testing, although a hallmark of bovine tuberculosis eradication campaigns, requires multiple animal handling events and cannot be repeated for at least 60 days. To overcome these difficulties, an effective assay for bovine interferon-gamma (IFN-gamma) has been developed. The IFN-gamma test is commonly used as a confirmatory test following a positive response to skin testing. The present study was conducted to determine the effect of skin testing on IFN-gamma and antibody production using calves experimentally infected with M. bovis. IFN-gamma responses increased 3 days after the CFT, immediately followed by a decrease to pre-skin test levels 7 days after skin testing. Intradermal skin testing also induced antibody responses to various proteins from M. bovis, the causative agent of tuberculosis in cattle. Increases in either IFN-gamma or antibody production were not seen in non-inoculated control cattle. Measurement of both IFN-gamma and antibody responses after skin testing may be useful in identifying M. bovis infected cattle; however the timing of collection of such samples may influence interpretation. This information will be of use to animal health regulatory officials in development of policies for testing strategies to eradicate bovine tuberculosis.

Technical Abstract: Tuberculin skin testing, although a hallmark of bovine tuberculosis eradication campaigns, lacks sensitivity and specificity and cannot be repeated for 60 days due to desensitization. To overcome these difficulties, an effective whole blood cellular immunoassay for bovine interferon-gamma (IFN-gamma) has been developed. The IFN-gamma test is commonly used in conjunction with skin testing as a confirmatory test following a positive response to the caudal fold skin test (CFT). The present study was conducted to determine the effect of different skin testing regimens on IFN-gamma and antibody production using calves experimentally infected with M. bovis. Holstein calves were CFT tested 60 days after inoculation and the comparative cervical test (CCT) conducted 7 (CFT-CCT) or 60 (CFT delayed CCT) days later. In both the CFT-CCT and CFT delayed CCT groups, IFN-gamma responses increased 3 days after the CFT, immediately followed by a decrease to pre-skin test levels 7 days after the CFT. In both groups application of the CCT at 7 or 60 days after the CFT resulted in no significant increase in IFN-gamma production. Administration of the CFT and the CCT to M. bovis-inoculated cattle induced antibody responses to M. bovis PPD, rMPB83, ESAT-6 and the fusion protein Acr1:MPB83. Increases in either IFN-gamma or antibody production were not seen in non-inoculated cattle. Measurement of both IFN-gamma and antibody responses after skin testing may be useful in identifying M. bovis infected cattle; however the timing of collection of such samples may influence interpretation.

Last Modified: 7/28/2014
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