ATP receptors and giant cell formation

We have investigated the role of the purinergic P2X(7) receptor in the form ation of multinucleated giant cells in human monocyte/macrophage cultures s timulated with either concanavalin A or phytohemagglutinin. Macrophage fusi on can be blocked by a P2X(7)-selective pharmacological antagonist or by a mAb directed against the extracellular P2X(7) domain, Furthermore, macropha ge cell, clones expressing high P2X(7) levels spontaneously fuse in culture , whereas macrophage clones lacking P2X(7) are unable to fuse, Our findings suggest that the newly identified purinergic P2X(7) receptor plays a centr al role in the complex chain of events leading to generation of macrophage- derived giant cells.