Anti-glycoprotein VI monoclonal antibodies directly aggregate platelets independently of FcγRIIa and induce GPVI ectodomain shedding

Autor:	Michael C. Berndt, Yang Shen, Jane Frances Arthur, Fi-Tjen Mu, Elizabeth E. Gardiner, Robert K. Andrews, Mohammad Al-Tamimi, Masaaki Moroi
Rok vydání:	2009
Předmět:	Blood Platelets Platelet Aggregation medicine.drug_class Fc receptor Platelet Membrane Glycoproteins Immunoglobulin domain Monoclonal antibody Immunoglobulin Fab Fragments Mice medicine Animals Humans Platelet chemistry.chemical_classification biology Chemistry Receptors IgG Antibodies Monoclonal Hematology General Medicine Molecular biology Ectodomain biology.protein GPVI Antibody Glycoprotein
Zdroj:	Platelets. 20:75-82
ISSN:	1369-1635 0953-7104
DOI:	10.1080/09537100802645029
Popis:	Adhesion of circulating platelets to the blood vessel wall initiates thrombus formation in haemostasis and thrombotic disease. The platelet collagen receptor, glycoprotein (GP) VI, is critical for thrombus formation at arterial shear rates and is a potential therapeutic target for anti-thrombotic drugs. In this study, we evaluate eight newly-derived, purified murine anti-human GPVI monoclonal antibodies (mAbs) for their effect on GPVI-dependent platelet aggregation and GPVI ectodomain shedding. All mAbs were raised against the ligand-binding GPVI ectodomain encompassing two immunoglobulin domains (residues 21-234, excluding the signal sequence) and recognized full-length GPVI in human platelet lysates by western blotting. The majority of antibodies induced aggregation in both human platelet-rich plasma (PRP) and washed platelets independently of the Fc receptor, FcgammaRIIa (not inhibited by the blocking anti-FcgammaRIIa mAb, IV.3), whereas one mAb (11A7) neither induced aggregation nor inhibited aggregation in response to GPVI ligands, collagen, and collagen-related peptide (CRP). In contrast, Fab fragments of mAb 12A5 strongly blocked collagen- and CRP-, but not convulxin-induced aggregation. In addition, it is shown for the first time in vitro that anti-GPVI mAbs can induce metalloproteinase-dependent ectodomain shedding of human GPVI, generating an approximately 10-kDa remnant that remained platelet-associated and an approximately 55-kDa soluble fragment. In conclusion, this analysis of anti-GPVI mAbs provides useful tools for studying the functional role of platelet GPVI.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d9be4f3c58b7c6cba6994f588cf76914 https://doi.org/10.1080/09537100802645029 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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