Inhibition by sugars of opsonization of Staphylococcus aureus in fetal calf serum.

Phagocytosis of Staphylococcus aureus by human peripheral polymorphonuclear leucocytes in vitro in the presence of fetal calf serum was inhibited by D-galactose, N-acetyl-D-glucosamine and asialofetuin but not by fetuin. Absorption of opsonin in the serum with the bacteria, inhibition of the absorption by sugars and the effect of glycosidase treatment of the bacteria on phagocytosis showed that terminal structures of polysaccharides on the surface of bacteria play an important role in binding of opsonin to the target.