[The release of proteinases from neutrophil leukocytes and macrophages]

The main source of proteinases that degrade tissue components in the course of inflammation are neutrophil leukocytes and macrophages. Both cells contain and/or produce a large variety of acid and neutral hydrolases including representatives of all four classes of tissue proteinases. Neutrophils are short-lived end cells with large enzyme stores (i.e. azurophil and specific granules) which they normally discharge in the course of phagocytosis. Macrophages are long-lived cells with a great potential for functional differentiation. In macrophages, proteinases and other lytic enzymes are released both by phagocytosis and by secretion (the latter particularly in activated macrophages) and replaced continuously by de novo synthesis. The acid and neutral proteinases of neutrophils and macrophages, their subcellular localization, their properties in relation to tissue damage and the mechanisms of their release are described.