A phagocytosis-stimulating peptide; binds human PMN, human monocytes, and mouse macrophages (Kds = 130, 125, and 53 nM, respectively); increases phagocytosis of IgG-coated ovine red blood cells by 61% in isolated mouse peritoneal macrophages at 200 nM; increases phagocytosis of S. aureus, L. monocytogenes, and S. oviformis by isolated human, mouse, rabbit, dog, or guinea pig phagocytes from 0.01-0.15 UG/ml; increases survival in a syngeneic mouse model of 2-methylcholanthrene-induced fibrosarcoma at 0.1, 0.5, and 25 mg/kg