Phosphatidylinositol liposomes opsonized by concanavalin A stimulate phosphatidylinositol turnover in macrophages.
We have previously found that concanavalin A binds specifically to inositol and phosphatidylinositol. In the present study we demonstrate that binding of concanavalin A to liposomes containing phosphatidylinositol influences the uptake of such liposomes by macrophages. Although resident mouse peritoneal macrophages normally ingest liposomes only to a slight extent, attachment of concanavalin A to the liposomes caused a marked enhancement of phagocytosis. Furthermore induction of phagocytosis of concanavalin A-opsonized liposomes was associated with increased phosphatidylinositol turnover. We conclude that (a) concanavalin A can serve as an opsonizing agent for liposomes; (b) opsonization results from binding of concanavalin A to phosphatidylinositol on the liposomal surface; and (c) concanavalin A-induced phagocytosis is associated with increased phosphatidylinositol turnover in the macrophages.
D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D002478:Cells, Cultured; D002784:Cholesterol; D003208:Concanavalin A / Q000378:metabolism; D004134:Dimyristoylphosphatidylcholine; D066298:In Vitro Techniques; D007294:Inositol / Q000378:metabolism; D008081:Liposomes; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D051379:Mice; D009895:Opsonin Proteins / Q000378:metabolism*; D010587:Phagocytosis; D010716:Phosphatidylinositols / Q000378:metabolism*; D012969:Sodium Fluoride / Q000494:pharmacology
D008081:Liposomes; D009895:Opsonin Proteins; D010716:Phosphatidylinositols; D003208:Concanavalin A; D007294:Inositol; D000968:Antimycin A; D012969:Sodium Fluoride; D002784:Cholesterol; D004134:Dimyristoylphosphatidylcholine