Macrophages engulf and destroy bacteria in a process known as
phagocytosis. PHAGOCYTOSIS. A three-stage process by which phagocytes (neutrophils, monocytes, and macrophages) engulf and destroy microorganisms, other foreign antigens, and cell debris. three-stage process by which phagocytes (neutrophils, monocytes, and macrophages) engulf and destroy microorganisms, other foreign antigens, and cell debris.