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Updated: Jul 18, 2026

Platelet Adhesion and Aggregation Under Flow using Microfluidic Flow Cells
Published on: October 27, 2009
Dynamic redistribution of glycoprotein Ib/IX on surface-activated platelets. A second look
J G White1, M D Krumwiede, D J Cocking-Johnson
1Department of Laboratory Medicine, University of Minnesota Medical School, Minneapolis 55455, USA.
Glycoprotein Ib/IX (GPIb/IX) receptors move to platelet centers due to antibody binding, not surface activation or thrombin. This study clarifies GPIb/IX mobility in platelets.
Area of Science:
- Platelet biology
- Immunology
- Cellular membrane dynamics
Background:
- Glycoprotein Ib/IX (GPIb/IX) is the von Willebrand factor receptor on platelets.
- Previous studies suggested GPIb/IX is stabilized on activated platelets.
- Conflicting data exists regarding GPIb/IX mobility upon platelet activation and spreading.
Purpose of the Study:
- To re-evaluate the mobility of GPIb/IX on surface-activated platelets.
- To investigate the role of antibodies and fixation in GPIb/IX receptor distribution.
- To clarify the mechanisms driving GPIb/IX translocation.
Main Methods:
- Surface-activated platelets were fixed with varying glutaraldehyde concentrations.
- Immunogold cytochemistry using anti-GPIb/IX and anti-glycocalicin antibodies was employed.
- Protein A gold (PAG) was used as a secondary marker.
- Platelets were treated with thrombin before or after antibody/PAG exposure.
Main Results:
- Even fixation before antibody/PAG showed even GPIb/IX distribution, unaffected by thrombin.
- Antiglycocalicin antibody induced GPIb/IX movement from platelet edges, independent of thrombin.
- Fixation after antibody/PAG exposure caused GPIb/IX to cap centrally, irrespective of activation or thrombin.
- Central GPIb/IX capping was attributed to antibody and PAG interactions.
Conclusions:
- Central movement of GPIb/IX receptors is an artifact induced by antibody and PAG.
- Surface activation, spreading, and thrombin do not cause central GPIb/IX translocation.
- Revises understanding of GPIb/IX mobility and experimental artifacts in platelet studies.
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