Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 8, 2013
Publication Date: December 2, 2013
Citation: Mcgill, J.L., Sacco, R.E., Baldwin, C., Telfer, J.C., Palmer, M.V., Waters, W.R. 2013. Specific recognition of mycobacterial protein and peptide antigens by gamma-delta T cell subsets following infection with virulent Mycobacterium bovis [abstract]. Australasian Society of Immunology. Abstract No. 24. Technical Abstract: Promoting effective immunity to Mycobacterium tuberculosis complex pathogens is a challenge that is of interest to the fields of human and veterinary medicine alike. We report that gamma delta T cells from virulent Mycobacterium bovis-infected cattle respond specifically and directly to complex, protein, and non-protein mycobacterial antigens. Importantly, bovine gamma delta T cells specifically recognized small peptide antigens derived from the mycobacterial protein complex early secretory antigenic target 6 kDa protein:10 kDa culture filtrate protein (ESAT6:CFP10) and this recognition required direct contact with APCs, but was independent of MHC class II presentation. Furthermore, M. bovis infection of cattle elicited robust IL-17A responses and, in contrast to results from mice, bovine CD4 T cells and not gamma delta T cells were the primary source of this critical pro-inflammatory cytokine. Bovine gamma delta T cells are divided into subsets based upon their expression of Workshop Cluster 1 (WC1). In the present study, M. bovis-specific gamma delta T cells were composed of a heterogeneous mix of WC1-expressing populations, with both WC1.1+ and WC1.2+ subsets responding in vitro to mycobacterial antigens, and both subsets accumulating within the tuberculous lesions. The results described herein enhance our understanding of gamma delta T cell biology and, as virulent M. bovis infection of cattle represents a relevant model of tuberculosis in humans, contribute to our overall understanding of the role of gamma delta T cells in the mycobacterial-specific immune response.