Laminarin, a soluble beta-glucan, inhibits macrophage phagocytosis of zymosan but has no effect on lipopolysaccharide mediated augmentation of phagocytosis

► We examine the effect of the beta-glucan laminarin on phagocytosis of zymosan. ► We also compare the effects of laminarin with lipopolysaccharide and dexamethasone. ► Laminarin and dexamethasone inhibited phagocytosis, but LPS enhanced it. ► Dexamethasone, but not laminarin, ameliorated the effect of LPS on phagocytosis. ► Macrophages have laminarin sensitive and insensitive mechanisms of zymosan ingestion.