The P2X7 purinergic receptor on bovine macrophages mediates mycobacterial death

P2X7 is an ATP gated purinoceptor that has been linked to various immune re sponses. P2X7 appears to be expressed ubiquitously in the immune system and thus may be important as an effector pathway or play significant roles in cell activation/death. 2',3'-(4-Benzoyl)benzoyl ATP is the most potent agon ist of this receptor and ATP in its fully dissociated form (ATP(4-)) also a ctivates the receptor. High concentrations of ATP can cause the P2X7 recept or to induce pore formation on the surface of the cell that allows molecule s of considerable size to pass and can lead to cell death. The P2X7 recepto r has also been linked to various immune activities when the concentration of ATP is lower, including the release of IL-1 beta. The role P2X7 receptor s have on immune cell activities is just beginning to be understood. We sou ght to determine the role of P2X7 on bovine macrophages in eliminating the causative agent of bovine-type tuberculosis, Mycobacterium bovis. Because h igh concentrations of ATP are linked to macrophage death, we determined if this method of cell destruction also leads to reduced bacterial viability. We find that P2X7 is present on bovine macrophages from different sources, including both peripheral blood-derived as well as alveolar macrophages. In addition, P2X7 mRNA is present in B and T lymphocytes. The treatment of M. bovis-infected macrophages with ATP results in reduced macrophage viabilit y as well as reduced M. bovis viability, (C) 2001 Elsevier Science B.V. All rights reserved.