Release of mediators from purified rat mast cells during phagocytosis

Purified mature rat peritoneal mast cells, on exposure to zymosan or latex beads, phagocytize these particles, although less efficiently than macrophages. During phagocytosis, histamine, beta-glucuronidase, and eosinophil chemotactic factor are released from mast cells in a time-, temperature- and dose-dependent fashion. Complement components, cytochalasin B (5 microgram/ml), and indomethacin (10-6M), enhanced mediator release, whereas compound BW 755C (20 microgram/ml), a cyclooxygenase and lipoxygenase inhibitor of arachidonate metabolism, totally abolished this process. Phagocytosis of mast cell thus activates intracellular mechanisms that closely resemble those observed with other phagocytic cells. These observations add a new perspective to the role of mast cells in inflammatory events.