title: Effect of cardiolipin oxidation on solid-phase immunoassay for antiphospholipid antibodies.
abstract: Diagnostic assays for antiphospholipid antibodies are routinely performed on microtitre plates coated with cardiolipin. Here we show that contact between cardiolipin and NUNC-Immuno plates leads to extensive oxidation, generating a series of peroxy-cardiolipins which were identified by electrospray ionization mass spectrometry. To investigate the impact of oxidation on the antibody assay. cardiolipin was resolved into 12 molecular species, including oxidized species and non-oxidized species with different degrees of unsaturation. All 12 species reacted under anaerobic conditions with serum from patients with primary antiphospholipid syndrome. Immune reactivity was similar for tetralinoleoyl-cardiolipin, trilinoleoyl-oleoyl-cardiolipin, and peroxycardiolipins, but somewhat lower for tristearoyl-oleoyl-cardiolipin. Oxidative treatment of cardiolipin with air, cytochrome c, or Cu2+/tert-butylhydroperoxide, either before or during the assay, did not enhance immune reactivity. Similar results were obtained with a monoclonal IgM from lupus-prone mice, that binds cardiolipin in the absence of protein cofactors. We conclude that the solid-phase assay for antiphospholipid antibodies can be supported by various oxidized and non-oxididized molecular species of cardiolipin.
authors.affiliation: Department of Anesthesiology, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, USA. schlame@hotmail.com
authors.forename: M
authors.initials: M
authors.lastname: Schlame
authors.forename: I
authors.initials: I
authors.lastname: Haller
authors.forename: L R
authors.initials: LR
authors.lastname: Sammaritano
authors.forename: T J
authors.initials: TJ
authors.lastname: Blanck
mesh_terms: D000328:Adult; D000388:Air; D000818:Animals; D017153:Antibodies, Anticardiolipin / Q000032:analysis* / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions; D016736:Antiphospholipid Syndrome / Q000276:immunology*; D001324:Autoantigens / Q000737:chemistry / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology*; D002308:Cardiolipins / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D002417:Cattle; D003574:Cytochrome c Group / Q000494:pharmacology; D004195:Disease Models, Animal; D005260:Female; D006023:Glycoproteins / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D007075:Immunoglobulin M / Q000276:immunology; D015227:Lipid Peroxidation; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D051379:Mice; D008875:Middle Aged; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization; D053482:beta 2-Glycoprotein I; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
chemical_list: D017153:Antibodies, Anticardiolipin; D000911:Antibodies, Monoclonal; D001324:Autoantigens; D002308:Cardiolipins; D003574:Cytochrome c Group; D006023:Glycoproteins; D007075:Immunoglobulin M; D016877:Oxidants; D053482:beta 2-Glycoprotein I; D020122:tert-Butylhydroperoxide