Metabolic and Structural Requirements for Concanavalin A Capping in Phagocytic Cells

Colchicine induced Con A capping in polymorphonuclear leukocytes, peritoneal monocytes, and alveolar macrophages, which was prevented in the polymorphonuclear leukocyte and peritoneal monocyte by cytochalasin B. Isoelectrophoresis of whole cell homogenates and purified cytoplasmic actin revealed β- and γ-actin to be present in similar amounts in all three cell types. Alveolar macrophages failed to cap in the presence of 1 mM potassium chloride whereas polymorphonuclear leukocytes and peritoneal monocytes maintained the capping response. In contrast, alveolar macrophages continued to cap during treatment with 5 mM 2-deox-yglucose abeit at lower levels than control; whereas in polymorphonuclear leukocytes and peritoneal monocytes, capping was substantially attenuated. These studies demonstrate the differing metabolic requirements for capping in phagocytic cells and suggest that different topographical relationships of actin-microfilaments to the plasma membrane might exist in the alveolar macro-phages compared to the phagocytic cells dependent on anaerobic metabolism.