T. Szuwart et al., Oxidized low-density lipoprotein inhibits the binding of monoclonal antibody to platelet glycoprotein IIb-IIIa, THROMB RES, 96(2), 1999, pp. 85-90
Previous studies have shown that oxidized low-density lipoprotein (LDL) ind
uces platelet activation more effectively than native LDL. To achieve a bet
ter understanding of the mechanism underlying the activation of human plate
lets by oxidized LDL, the present study relates the effect of oxidized LDL
to changes of binding characteristics for glycoprotein (GP) IIb-IIIa. Washe
d human platelets were treated by monoclonal antibody against GP IIb-IIIa,
and the ligand-receptor complexes were revealed by immunocytochemical techn
iques on the ultrastructural level. The localization of the antiglycoprotei
n IIb-IIIa was time-dependent. After binding to the platelet surface membra
ne and open canalicular system, the surface-membrane labeling decreased dur
ing longer incubation periods. Preincubation with oxidized LDL inhibited th
e binding of antiglycoprotein IIb-IIIa. Our findings suggest that GP IIb-II
Ia acts as a receptor for oxidized LDL. The binding of oxidized LDL to the
GP IIb-IIIa might be the first step in platelet activation by plasma lipopr
oteins. (C) 1999 Elsevier Science Ltd. All rights reserved.