PARTIAL CHARACTERIZATION OF LEUKOCYTE BINDING-MOLECULES ON ENDOTHELIAL-CELLS INDUCED BY MINIMALLY OXIDIZED LDL

Treatment of rabbit aortic endothelial cells, human umbilical vein endothelial cells, and human aortic endothelial cells for 4 hours with minimally oxidized low-density lipoprotein (MM-LDL) induced the adhesion of monocytes but not neutrophils or lymphocytes to these cells. This induction was blocked by inhibitors of glycoprotein synthesis (cyclo-heximide and tunicamycin), and binding was abolished by treatment of cells with low levels of trypsin, suggesting that the binding molecule(s) is a protein. There was no increase in binding of antibodies to E-selectin, vascular cell adhesion molecule-1 (VCAM-1), or intercellular adhesion molecule-1 (ICAM-1) after treatment of cells with MM-LDL. Treatment of endothelial cells with Fab fragments of antibody to monocyte chemotactic protein-1 or to fibronectin did not block monocyte binding. Several sugars (lactose-1-phosphate, maltose-1-phosphate, and N-acetylglucosamine) inhibited monocyte binding to cells treated with MM-LDL, but binding was not blocked by mannose-6-phosphate, fructose-6-phosphate, glucose-1-phosphate, or glucose-6-phosphate. EDTA or EGTA treatment inhibited binding, which was restored by adding either calcium or magnesium. We conclude that the binding of monocytes to endothelial cells induced by a 4-hour treatment with MM-LDL is caused by a binding molecule(s) other than E-selectin, VCAM-1, or ICAM-1 and that carbohydrate chains on the monocytes or the endothelium play a role in binding. (Arterioscler Thromb. 1994;14:427-433.)