Submitted to: International Conference on Mycobacterium bovis
Publication Type: Abstract Only
Publication Acceptance Date: August 22, 2005
Publication Date: August 22, 2005
Citation: Thacker, T.C., Palmer, M.V., Waters, W.R. 2005. White-tailed deer (odocoileus virginianus) Cytokine Expression in Response to Infection with Mycobacterium Bovis [abstract]. International Conference on Mycobacterium bovis. Paper No. 3085. Technical Abstract: Mycobacterium bovis infected white-tailed deer were detected in Michigan in 1994. Subsequent survey's revealed a focus of infection. This represents the first known reservoir of M. bovis in a population of free ranging wildlife in North America posing a threat to domestic livestock and humans. Relatively little work has been done to characterize the immune response of white-tailed deer, however, understanding immune responses to infection may be critical in developing effective vaccine and diagnostic strategies. Cytokine expression in response to infection was characterized by stimulating isolated PBMC with M.bovis-PPD (PPDb), or recombinant protein ESAT-6 fused with CFP10 (rE:C). The relative levels of IFN-gamma, IL-12p40, GM-CSF, and iNOS mRNA were measured to evaluate TH1 type responses. In addition, the TH2 cytokine mRNA’s; IL-4, IL-10 and TGF-beta were measured. IFN-gamma production in whole blood assays were measured using a commercially available ELISA. IFN-gamma expression was induced in response to both PPDb and rE:C at each time point assayed. IL-12p40 expression increased over time until 112 days post infection at which time it dropped to levels equivalent to those in uninfected animals. Expression of the TH2 cytokine, IL-4 was detected when the PBMC were stimulated with rE:C, but not with PPDb. No significant expression of GM-CSF, iNOS, IL-10, and TGF-beta were detected. IFN-gamma production in response to both PPDb and rE:C was detected as early as 14 days post infection peaked at 58 days then declined. Interestingly, IFN-gamma protein production did not correlate with pathology; however, increased IFN-gamma and IL-12p40 mRNA expression did correlate with increased pathology.