ATP receptors and giant cell formation

Abstract: We have investigated the role of the purinergic P2X7 receptor in the formation of multi-nucleated giant cells in human monocyte/macro-phage cultures stimulated with either concanavalin A or phytohemagglutinin. Macrophage fusion can be blocked by a P2X7-selective pharmacological antagonist or by a mAb directed against the extra-cellular P2X7 domain. Furthermore, macrophage cell clones expressing high P2X7 levels spontane-ously fuse in culture, whereas macrophage clones lacking P2X7 are unable to fuse. Our findings suggest that the newly identified purinergic P2X7 receptor plays a central role in the complex chain of events leading to generation of macrophage-derived giant cells. J. Leukoc. Biol. 66: 723–726; 1999. Key Words: P2 purinergic receptor · chronic inflammation · granulom