Cell mediated and humoral immune responses of white-tailed deer experimentally infected with Mycobacterium bovis

The objective of this study was to improve the understanding of immune resp onses of whitetailed deer (Odocoileus virginianus) infected with Mycobacter ium bovis. Ten mature, female, white-tailed deer were inoculated by intrato nsilar instillation of 2 x 10(3) or 2 x 10(5) colony-forming units of M. bo vis. Lymphocyte proliferation and humoral response to M. bovis PPD and the M. bovis protein, MPB70 were measured. Deer were tested for exposure to M. bovis by the comparative cervical skin test. Biopsy specimens of skin test sites were examined microscopically and immunohistochemically. The comparat ive cervical skin test correctly identified all M. bovis-inoculated deer as exposed to M. bovis. Lymphocyte proliferative responses to MPB70 were more consistent than responses to M. bovis PPD in M. bovis inoculated deer. Ant ibody responses were more prominent in deer with disseminated disease than in deer with localised disease. The cellular components of delayed type hyp ersensitivity reactions at skin test sites were similar to tuberculin react ions in other species. T lymphocytes of the gamma/delta phenotype were seen in increased numbers in M. bovis PPD injection sites.