ARS | Publication request: Comparison of peptide cocktails and purified protein derivatives for use in the Bovigam assay

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 20, 2011
Publication Date: October 1, 2011
Citation: Bass, K.E., Nonnecke, B.J., Palmer, M.V., Thacker, T.C., Hardegger, R., Schroeder, B., Raeber, A.J., Waters, W.R. 2011. Comparison of peptide cocktails and purified protein derivatives for use in the Bovigam assay [abstract]. American Society of Veterinary Laboratory Diagnosticians. p. 186.

Technical Abstract: Currently, the Bovigam™ assay is used as an official complementary test within the bovine tuberculosis eradication program. This assay measures Interferon-gamma (IFN-') produced by lymphocytes in response to specific antigens. The objectives of the present study were to compare in vitro antigen preparations and the kinetics of the IFN-' response during experimental infection with Mycobacterium bovis. Purified protein derivatives (PPDs) derived from Mycobacterium avium and M. bovis from two manufacturers, CSL and Lelystad, were also evaluated. Liquid and lyophilized preparations of antigens, along with PPDs, were compared using uninfected (control) and cattle experimentally infected with either M. bovis 95-1315 or M. bovis Ravenel. Prior to infection, responses to PPDs were detected in all cattle with M. avium responses exceeding responses to M. bovis suggesting prior exposure of cattle to M. avium or other non-tuberculosis mycobacteria. Upon M. bovis challenge, responses to Lelystad PPDs exceeded respective responses to CSL PPDs as early as three weeks after infection. It was also noted that responses did not differ between the lyophilized and liquid preparations. M. bovis infections elicited equal responses to both Peptide Cocktail 11 and ESAT-6/CFP-10 peptide cocktail within three weeks after infection. With no difference between responses to liquid and lyophilized preparations, antigens can be stored in a lyophilized state without diminishing effectiveness of stimulation. Variations in response of bovine lymphocytes to PPDs from different manufacturers should be recognized when implementing changes in antigens (e.g., PPDs) for official bovine TB tests.