Characterization of a ligand-attenuated binding site on glycoprotein IIb/IIIa

M.J. Quinn, J. Fullard, S. Kerrigan, Patrick Harriott, D. Cox, D.J. Fitzgerald

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


We describe an epitope on the platelet integrin, GPIIb/IIIa, identified by the monoclonal antibody, 4F8, which is attenuated by small-molecule GPIIb/IIIa ligands. 4F8 did not bind to the ligand binding pocket as it did not compete with a radiolabelled antagonist, H-3-SC-52012. This indicates that the 4F8 epitope behaves as a ligand-attenuated binding site (LABS). Ligand-induced attenuation of 4178 was an active process as it was prevented by pretreating platelets with cytochalasin D and reduced by prostaglandin E-1 or inhibition of protein kinase C. Disappearance of the epitope was required for full platelet activation as 4F8 prevented platelet aggregation without inhibiting fibrinogen binding. These results suggest a model where disappearance of the 4F8 epitope is a secondary event required for full
Original languageEnglish
Pages (from-to)811-816
Number of pages6
Issue number5
Publication statusPublished - 01 Nov 2002

ASJC Scopus subject areas

  • Hematology

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