Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/4/2006
Publication Date: 12/4/2006
Citation: Waters, W.R., Palmer, M.V., Thacker, T.C., Harris, N.B., Payeur, J.B., Minion, F.C., Mcnair, J., Pollock, J.M., Lyashchenko, K.P. 2006. Interpretation of tuberculosis diagnostic test results may be confounded in cattle infected with Mycobacterium kansasii [abstract]. Research Workers in Animal Diseases Conference Proceedings. p. 81.
Technical Abstract: Cross-reactive responses elicited by exposure to non-tuberculous mycobacteria often confound interpretation of traditional ante-mortem bovine tuberculosis (TB) tests. Use of specific proteins such as ESAT-6, CFP-10, and MPB83 may improve the specificity of these tests in areas where exposure to environmental non-tuberculous mycobacteria is common. Instillation of M. kansasii (4 x 10**8 cfu) into the tonsilar crypts of calves elicited delayed type hypersensitivity as well as in vitro IFN-gamma and nitrite responses to M. avium and M. bovis purified protein derivative (PPD). While responses by M. kansasii-inoculated calves to M. avium and M. bovis PPD were roughly equivalent, responses by M. bovis-infected calves (4 x 10**4 cfu intratonsilarly) to M. bovis PPD exceeded respective responses to M. avium PPD. IFN-gamma and nitrite responses to rESAT-6:CFP-10 by M. kansasii-inoculated calves exceeded corresponding responses by non-inoculated calves beginning 15 and 50 d after inoculation, respectively. Ranking of mean IFN-gamma and nitrite responses to rESAT-6:CFP-10 by each of the groups generally resulted in M. bovis- > M. kansasii- > non-inoculated cattle. Using a lipoarabinomannan (LAM)-based ELISA, specific serum antibody was detected 50 d after challenge in M. kansasii-inoculated calves but not from animals receiving M. bovis. However, at 124 d after inoculation, antibody responses to LAM by M. bovis-inoculated calves exceeded respective responses by M. kansasii-inoculated calves. By multi-antigen print immunoassay, specific antibody responses to MPB83, but not ESAT-6 or CFP-10, were detected in sera from M. kansasii-inoculated calves; however, MPB83 responses were notably weak as compared to those elicited by M. bovis infection. These findings indicate that M. kansasii infection of calves elicits specific cellular and humoral responses that may confound interpretation of bovine TB tests using antigens generally considered M. tb complex specific.