Lectin-Induced Phagocytosis of Erythrocytes by Guinea Pig and Mouse Macrophages

Abstract

Various lectins were examined for their ability to induce phagocytosis of sheep erythrocytes by peritoneal macrophages of the guinea pig and mouse. Phaseorous vulgaris lectin-L (PHA(L)) induced the phago-cytosis of erythrocytes by guinea pig macrophages and wheat germ agglutinin (WGA) that of erythrocytes by mouse macrophages. Concanavalin A (Con A) induced little ingestion by either macrophage, although it induced much attachment of the erythrocytes to both. The PHA(L)-induced phagocytosis of erythrocytes by guinea pig macrophages was inhibited specifically by N-acetyl-D-galactosamine. PHA(L) linked the guinea pig macrophages and sheep erythrocytes. Con A did not suppress the PHA(L)-induced phagocytosis of erythrocytes by guinea pig macrophages. These results suggest that the attach-ment of erythrocytes to macrophages is not sufficient for phagocytosis and that certain sites on the surface of the macrophages must be stimulated for phago-cytosis to occur. Soluble antigen-antibody complexes, which block the Fc receptors of macrophage and other cell types, inhibited both the antibody-induced and the PHA(L)-induced ingestion of erythrocytes by guinea pig macrophages. A prior incubation of guinea pig macrophages with high con-centrations of PHA(L) suppressed the ingestion of erythrocytes which was induced by PHA(L), but not that induced by antibody. This is evidence that some relation exists between the Fc receptors and the PHA(L) binding site that is responsible for the induction of phagocytosis.