Submitted to: International Workshop on Tuberculosis in Animals
Publication Type: Abstract Only
Publication Acceptance Date: 9/15/1999
Publication Date: N/A
Technical Abstract: Whitetail deer are significant wildlife reservoirs of Mycobacterium bovis infection of cattle. Recall CD4+ and CD8+ T cell responses are elicited by M. bovis infection of cattle with both CD4+ and CD8+ cells implicated in protective immunity. Few studies, however, have examined lymphocyte subset responses to experimental M. bovis infection of deer. In this study, a flow cytometric proliferation assay was used to examine the relative contribution of individual peripheral blood mononuclear cell (PBMC) subsets to the recall response to M. bovis infection of deer. Naive deer were challenged with M. bovis by cohabitation with known infected deer. These deer developed significant in vivo (delayed type hypersensitivity) and in vitro (proliferative responses) to M. bovis purified protein derivative (PPD). Selected deer were necropsied and typical tuberculous lesions containing M. bovis were detected within lungs and lung-associated lymph nodes of challenged deer. The predominant subset of lymphocytes proliferating in response to in vitro stimulation with PPD were CD4+ cells. Proliferative responses were also detected from CD8+, ë TCR+, and IgM+ cells with the magnitude of this response correlating with the percentage of each subset within the PBMC culture. Additional studies utilizing monoclonal antibodies to block subset proliferation or antigen presentation via MHC I, MHC II, and/or CD1 are underway to further characterize this response.