Regulation by Fc fragments of the secretion of collagenase, PGE2, and lysozyme by mouse peritoneal macrophages

Fc fragments of human IgG can stimulate resident mouse macrophages in culture to secret collagenase, to increase PGE2 secretion, and to decrease the secretion of lysozyme. Active synthesis and secretion were shown by the progressive accumulation of these products in the extracellular medium and inhibition of secretion by cycloheximide. A dose-dependent effect of Fc fragments was demonstrable. Brief exposure of cells to Fc fragments was sufficient to cause the macrophages to secrete collagenase and large amounts of PGE2 for prolonged periods of time, suggesting that a sustained activation rather than temporary modulation of the cells had occurred. Con A had similar effects on macrophage secretory activity. These findings indicate that proteins that bind to specific macrophage plasma membrane receptors may stimulate the secretion of products that promote the inflammatory response.