title: Oxidatively altered IgG with increased immunoreactivity to β2-glycoprotein I and its peptide clusters influence human coronary artery endothelial cells.
abstract: Oxidative stress has been shown to play a role in modifying antibodies in favor of higher auto-immunoreactivity. We studied the immunoreactivity of oxidized IgG (oxIgG) to β2-glycoprotein I (β2GPI), six peptide sequences corresponding to amino acid clusters on its different domains, to determine their effects on human coronary artery endothelial cells (HCAEC). Human IgG was purified from seven donors, electro-oxidized and checked for immunoreactivity and avidity to β2GPI and to peptides by ELISA. Conformational stability and antibody-antigen complex formation of oxIgG was analyzed by fluorescence spectroscopy and dynamic light scattering. Resting and activated sub-confluent HCAEC were stimulated with oxIgG or IgG. Secreted cytokines were measured by ELISA. Immunoreactivity of seven oxIgG samples increased to 7.5-fold against β2GPI and to 3.8-fold against six peptides as compared to IgG. oxIgG showed low avidity "properties." Conformational changes and exposure of protein hydrophobic regions were confirmed by an elevation in fluorescence (2.4- to 5.0-fold) on bis-ANS dye binding to oxIgG. oxIgG significantly elevated the release of GROα and IL-8 in resting and activated states of HCAEC. Oxidation alters IgG in favor of autoreactivity toward whole β2GPI and corresponding peptides on different domains of β2GPI and could lead to dysfunction of arterial endothelium by upregulation of chemokines.
authors: Department of Rheumatology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors: A
authors: A
authors: Artenjak
authors: The chair of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
authors: J
authors: J
authors: Omersel
authors: The chair of Pharmaceutical Technology, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
authors: P
authors: P
authors: Ahlin Grabnar
authors: The chair of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
authors: I
authors: I
authors: Mlinarič-Raščan
authors: The Zabludowicz Center for Autoimmune Diseases, Sheba Medical Center, Tel-Hashomer, Israel.
authors: Y
authors: Y
authors: Shoenfeld
authors: Department of Rheumatology, University Medical Centre Ljubljana, Ljubljana, Slovenia Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Koper, Slovenia.
authors: S
authors: S
authors: Sodin-Semrl
authors: Department of Rheumatology, University Medical Centre Ljubljana, Ljubljana, Slovenia The chair of Clinical Biochemistry, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
authors: B
authors: B
authors: Božič
authors: Department of Rheumatology, University Medical Centre Ljubljana, Ljubljana, Slovenia sasa.cucnik@guest.arnes.si.
authors: S
authors: S
authors: Čučnik
mesh_terms: D000937:Antigen-Antibody Reactions; D001323:Autoantibodies / Q000276:immunology; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology; D016207:Cytokines / Q000276:immunology; D000067493:Dynamic Light Scattering; D042783:Endothelial Cells / Q000166:cytology*; D064368:Healthy Volunteers; D006801:Humans; D007074:Immunoglobulin G / Q000302:isolation & purification* / Q000378:metabolism; D018384:Oxidative Stress; D010455:Peptides / Q000276:immunology*; D053482:beta 2-Glycoprotein I / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D016207:Cytokines; D007074:Immunoglobulin G; D010455:Peptides; D053482:beta 2-Glycoprotein I
keywords: Acquired autoreactivity; bis-ANS fluorescence; dynamic light scattering; electro-oxidation; human coronary artery endothelial cells; β2-glycoprotein I