The activities of elastase and other lysosomal enzymes in professional phagocytes and mechanism of their release.

Differences in specific activities of elastase, myeloperoxidase, and lysozyme were found between polymorphonuclear leukocytes (PMNs) and macrophages of various species, between PMNs derived from different anatomic sites and between macrophages isolated in different ways. The percentage of extracellular release of lysosomal enzymes during immunological phagocytosis depends on the receptors in the phagocyte membrane which were stimulated by binding of a ligand. These differences may reflect various functional activities of separate populations of phagocytes.