Veterinary and Biomedical Sciences, Department of


Date of this Version



Published in Comparative Immunology, Microbiology and Infectious Diseases 32:5 (September 2009), pp. 365-377; doi 10.1016/j.cimid.2007.11.003 Copyright © 2008 Elsevier Ltd Used by permission.


Mycobacterium avium subsp. paratuberculosis is the etiologic agent of Johne’s disease, a chronic intestinal infection in ruminants. Adenosine 5′-Triphosphate (ATP) has been reported to induce killing of several Mycobacterium species in human and murine macrophages. We investigated whether ATP secreted from M. avium subsp. paratuberculosis-infected bovine monocytes affects intracellular survival of the bacilli. Bovine monocytes constitutively secreted ATP during an 8-day incubation period in vitro; however, M. avium subsp. paratuberculosis infection did not enhance ATP release. Removal of extracellular ATP by the addition of apyrase increased the viability of infected monocytes, but surprisingly decreased the number of viable intracellular bacilli. In contrast to previous reports, addition of extracellular ATP (1 mM) increased intracellular survival of M. avium subsp. paratuberculosis in bovine monocytes. Neither apyrase nor ATP altered production of reactive oxygen intermediates (ROI) or reactive nitrogen intermediates (RNI) by bovine monocytes. These results suggest that ATP release from infected bovine monocytes improves, rather than decreases, the intracellular survival of M. avium subsp. paratuberculosis.