ACTIVATED MACROPHAGES DIGEST THE EXTRACELLULAR MATRIX PROTEINS PRODUCED BY CULTURED-CELLS

Activated mouse peritoneal macrophages were cultured directly on the extracellular matrix proteins produced by smooth muscle cells in vitro. The breakdown of the connective tissue proteins to the level of amino acids was followed by observing the release of radioactivity from matrices labelled with [3H]proline. These studies showed that macrophages produce enzymes capable of digesting the matrix and indicated a major role for the macrophage plasminogen activator in this digestion. © 1979.