title: A conformation-sensitive monoclonal antibody against the A2 domain of von Willebrand factor reduces its proteolysis by ADAMTS13.
abstract: The size of von Willebrand factor (VWF), controlled by ADAMTS13-dependent proteolysis, is associated with its hemostatic activity. Many factors regulate ADAMTS13-dependent VWF proteolysis through their interaction with VWF. These include coagulation factor VIII, platelet glycoprotein 1bα, and heparin sulfate, which accelerate the cleavage of VWF. Conversely, thrombospondin-1 decreases the rate of VWF proteolysis by ADAMTS13 by competing with ADAMTS13 for the A3 domain of VWF. To investigate whether murine monoclonal antibodies (mAbs) against human VWF affect the susceptibility of VWF to proteolysis by ADAMTS13 in vitro, eight mAbs to different domains of human VWF were used to evaluate the effects on VWF cleavage by ADAMTS13 under fluid shear stress and static/denaturing conditions. Additionally, the epitope of anti-VWF mAb (SZ34) was mapped using recombinant proteins in combination with enzyme-linked immunosorbent assay and Western blot analysis. The results indicate that mAb SZ34 inhibited proteolytic cleavage of VWF by ADAMTS13 in a concentration-dependent manner under fluid shear stress, but not under static/denaturing conditions. The binding epitope of SZ34 mAb is located between A1555 and G1595 in the central A2 domain of VWF. These data show that an anti-VWF mAb against the VWF-A2 domain (A1555-G1595) reduces the proteolytic cleavage of VWF by ADAMTS13 under shear stress, suggesting the role of this region in interaction with ADAMTS13.
authors.affiliation: Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhenni
authors.initials: Z
authors.lastname: Ma
authors.forename: Ningzheng
authors.initials: N
authors.lastname: Dong
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Jian
authors.initials: J
authors.lastname: Su
authors.forename: Yiming
authors.initials: Y
authors.lastname: Zhao
authors.forename: Fei
authors.initials: F
authors.lastname: Shen
authors.forename: Anyou
authors.initials: A
authors.lastname: Wang
authors.forename: Changgeng
authors.initials: C
authors.lastname: Ruan
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000071120:ADAMTS13 Protein; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D006801:Humans; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014841:von Willebrand Factor / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D011994:Recombinant Proteins; D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human