title: Epitope mapping of monoclonal antibodies directed to PAI-1 using PAI-1/PAI-2 chimera and PAI-1-derived synthetic peptides.
abstract: Plasminogen activator inhibitor type-1 is a key regulatory protein of the fibrinolytic system that is involved in a variety of physiological and pathophysiological processes. A panel of 14 monoclonal antibodies directed against plasminogen activator inhibitor type-1 was analyzed regarding epitope specificity on plasminogen activator inhibitor type-1. For this purpose, chimera consisting of plasminogen activator inhibitor type-1 and another plasminogen activator inhibitor, plasminogen activator inhibitor type-2, with different portions of the respective wild-type proteins, were generated and plasminogen activator inhibitor type-1-derived 20-mer and 10-mer linear peptides were synthesized. Nine of the 14 monoclonal antibodies recognized an epitope located in the region between amino acid 76-188 of plasminogen activator inhibitor type-1, which encompasses the binding sites for vitronectin, heparin, and part of the fibrin binding region. Of these nine monoclonal antibodies, six reacted with a quadruple plasminogen activator inhibitor type-1 mutant (N152H, K156T, Q321L, M356I), and seven detected a plasminogen activator inhibitor type-1 deletion mutant (DeltaF111-H114). Two of the remaining five monoclonal antibodies recognized epitopes located between amino acid 209-227 and amino acid 352-371, respectively, while the other three antibodies reacted with wild-type plasminogen activator inhibitor type-1, only. Additional experiments revealed that two of the 14 mAbs neutralized and one monoclonal antibodies increased plasminogen activator inhibitor type-1 activity toward urokinase-type plasminogen activator, one of its target proteases.
authors.affiliation: Frauenklinik, München, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Muehlenweg
authors.forename: E
authors.initials: E
authors.lastname: Guthaus
authors.forename: N A
authors.initials: NA
authors.lastname: de Prada
authors.forename: M
authors.initials: M
authors.lastname: Schmitt
authors.forename: N
authors.initials: N
authors.lastname: Schmiedeberg
authors.forename: M
authors.initials: M
authors.lastname: Kotzsch
authors.forename: S
authors.initials: S
authors.lastname: Creutzburg
authors.forename: M D
authors.initials: MD
authors.lastname: Kramer
authors.forename: H
authors.initials: H
authors.lastname: Kessler
authors.forename: O G
authors.initials: OG
authors.lastname: Wilhelm
authors.forename: V
authors.initials: V
authors.lastname: Magdolen
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D018604:Epitope Mapping; D006801:Humans; D016056:Immunodominant Epitopes; D010446:Peptide Fragments / Q000276:immunology; D017395:Plasminogen Activator Inhibitor 1 / Q000276:immunology*; D017396:Plasminogen Activator Inhibitor 2 / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D016056:Immunodominant Epitopes; D010446:Peptide Fragments; D017395:Plasminogen Activator Inhibitor 1; D017396:Plasminogen Activator Inhibitor 2; D011993:Recombinant Fusion Proteins