Platelets have more than one binding site for von Willebrand factor. J Clin Invest 1983 Jul;72(1):1-12
Date
07/01/1983Pubmed ID
6223940Pubmed Central ID
PMC1129155DOI
10.1172/jci110946Abstract
The binding of 125I-von Willebrand factor (125I-vWF) to platelets stimulated by thrombin, ADP, and a combination of ADP + epinephrine (EPI) is specific, saturable, and reversible. Active platelet metabolism and divalent cations are required for binding induced by these stimuli, but not by ristocetin, suggesting the existence of different mechanisms involved in the vWF-platelet interaction. A monoclonal antibody directed against an epitope of membrane glycoprotein (GP) Ib had no effect on the binding of 125I-vWF to normal platelets stimulated by thrombin or a combination of ADP + EPI, but completely blocked ristocetin-induced binding. Binding induced by thrombin to GPIb-blocked platelets was specific. Moreover, thrombin-induced binding of 125I-vWF was increased, rather than decreased, in two patients with the Bernard-Soulier syndrome whose platelets lacked GPIb. Conversely, monoclonal antibodies directed against the GPIIb/IIIa complex had no effect on ristocetin-induced binding of 125I-v-WF to normal platelets, but blocked thrombin- and ADP + EPI-induced binding. To exclude effects mediated by the platelet Fc receptor, a monoclonal IgG directed against an epitope present on human B cells and monocytes, but not expressed on resting or stimulated platelets, was used. It did not affect 125I-vWF binding induced by any of the stimuli. These studies show that platelets have more than one binding site for vWF, and that they may be exposed by different stimuli.
Author List
Ruggeri ZM, De Marco L, Gatti L, Bader R, Montgomery RRAuthor
Robert R. Montgomery MD Adjunct Professor in the Pediatrics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Adenosine DiphosphateBinding Sites
Blood Coagulation Factors
Blood Platelets
Dose-Response Relationship, Drug
Epinephrine
Glycoproteins
Humans
Platelet Membrane Glycoproteins
Ristocetin
Thrombin
von Willebrand Factor
