Autoimmune Antiphospholipid Antibodies Are Directed against a Cryptic Epitope Expressed when β2-Glycoprotein I Is Bound to a Suitable Surface

Summary

The antiphospholipid antibodies (aPL) present in autoimmune disorders are associated with thromboembolic episodes, and their binding to phospholipids (PL) is mediated by a plasma cofactor, β2-glycoprotein I (β2GPI). Both PL and β2GPI seem necessary for binding, thus indicating that the two components comprise the epitope against which aPL are directed. Using an anti-β2GPI antibody ELISA with the antigen adsorbed onto polyvinylchloride (PVC) plates, we detected high antibody titres in 12 out of 12 plasmas from patients with the antiphospholipid syndrome. No or very low positivity was obtained when the same ELISA was carried out in polystyrene (PST) plates, while an increasing positivity was found when processed (i.e. more hydrophilic) or COOH-surface PST plates were used. When (β2GPI dependent IgG-aPL were purified using agarose-immobilized cardio- lipin, 4 out of 4 preparations were highly positive in anti-β2GPI antibody ELISA using PVC plates, while β2GPI was not fully recognized by aPL-IgG when adsorbed onto PST plates. These findings demonstrate that aPL are, in fact, anti-β2GPI antibodies directed against a cryptic epitope which is expressed when β2GPI is bound to anionic phospholipid, or another suitable surface.

• References

• 1 Harris EN, Gharavi AE, Hughes GR V. Anti-phospholipid antibodies. Clin Rheum Dis 1985; 11: 591-609
• 2 Gharavi AE, Harris EN, Asherson RA, Hughes GR V. Anticardiolipin anti bodies: isotype distribution and phospholipid specificity. Ann Rheum Dis 1987; 46: 1-6
• 3 Fiumara NJ. Biologic false positive reaction for syphilis. N Engl J Med 1963; 268: 402-405
• 4 Feinstein DI, Rapaport SI. Acquired inhibitors of blood coagulation. Prog Hemostas Thromb 1972; 1: 75-95
• 5 Harris EN, Gharavi AE, Boey ML, Patel BM, Mackworth-Young CB, Loi-zou S, Hughes GR V. Anticardiolipin antibodies: detection by radioimmunoassay and association with thrombosis in systemic lupus erythematosus. Lancet 1983; 2: 1211-1214
• 6 Loizou S, McCrea JD, Rudge AC, Reynolds R, Boyle CC, Harris EN. Measurement of anticardiolipin antibodies by an enzyme-linked immunosorbent assay: standardization and quantitation of results. Clin Exp Immunol 1985; 62: 739-744
• 7 Johansson AE, Lassus A. The occurrence of circulating anticoagulants in patients with syphilitic and biologically false positive antilipoidal antibodies. Ann Clin Res 1974; 6: 105-108
• 8 Levy RA, Gharavi AE, Sammaritano LR, Habina L, Qamar T, Lockshin MD. Characteristics of IgG anitphospholipid antibodies in patients with systemic lupus erythematosus and syphilis. J Rheumatol 1990; 17: 1036-1041
• 9 Costello PB, Green FA. Reactivtiy pattern of human anticardiolipin and other antiphospholipid antibodies in syphilitic sera. Infect Immunol 1986; 51: 771-775
• 10 Santiago MB, Cossermelli W, Tuma MF, Pinto MN, Oliveira RM. Anticardiolipin antibodies in patients with infectious diseases. Clin Rheumatol 1989; 8: 23-28
• 11 McNeil HP, Chesterman CN, Krilis SA. Immunology and clinical importance of antiphospholipid antibodies. Adv Immunol 1991; 49: 193-280
• 12 Brey RL, Coull BM. Antiphospholipid antibodies: origin, specificity, and mechansim of action. Stroke 1992; 23 suppl (Suppl. 01) I-15-I-18
• 13 Roubey RA S, Pratt CW, Buyon JP, Winfield JB. Lupus anticoagulant activity of autoimmune antiphopholipid antibodies is dependent upon β₂-glycoprotein I. J Clin Invest 1992; 90: 1100-1104
• 14 Ordi J, Selva A, Monegal F, Procel JM, Martinez-Costa X, Vilardell M. Anticardiolipin antibodies and dependence of a serum cofactor. A mechanism of thrombosis J Rheumatol 1993; 20: 1321-1324
• 15 McNeil HP, Simpson RJ, Chesterman CN, Krilis SA. Antiphospholipid antibodies are directed against a complex antigen that includes a lipid binding inhibitor of coagulation: β₂-Glycoprotein-I (Apolipoprotein H). Proc Natl Acad Sci USA 1990; 87: 4120-4124
• 16 Galli M, Comfurius P, Maassen C, Hemker HC, De Baets MH, Van Brieda-Vriesman PJ C, Barbui T, Zwaal RF A, Bevers EM. Anticardiolipin antibodies (ACA) directed not to cardiolipin but to a plasma protein cofactor. Lancet 1990; 335: 1544-1547
• 17 Matsuura E, Igarashi Y, Fujimoto M, Ichikava K, Koike T. Anticardiolipin cofactor(s) and differential diagnosis of autoimmune disease. Lancet 1990; 336: 177-178
• 18 Schultze HE, Heide K, Haupt H. Über ein bisher unbekanntes niedermolekulares β₂-globulin des Humanserums. Naturwissenschaften 1961; 48: 719
• 19 Viard JP, Amoura Z, Bach JF. Association of anti-β₂-glycoprotein I antibodies with lupus-type circulating anticoagulant and thrombosis in systemic lupus erythematosus. Am J Med 1992; 93: 181-186
• 20 Wagenknecht DR, McIntyre JA. Changes in β₂-glycoprotein I antigenicity induced by phospholipid binding. Thromb Haemost 1993; 69: 361-365
• 21 Rauch J, Janoff AS. The nature of antiphospholipid antibodies. J Rheumatol 1992; 19: 1782-1785
• 22 Biasiolo A, Pengo V. Antiphospholipid antibodies are not present in the membrane of gel-filtered platelets of patients with IgG anticardiolipin antibodies, lupus anticoagulant and thrombosis. Blood Coag Fibrinol 1993; 4: 425-428
• 23 Harris EN, Gharavi AE, Patel SP, Hughes GV R. Evaluation of the anticardiolipin antibody test: report of an international workshop held 4 April 1986. Clin Exp Immunol 1987; 68: 215-222
• 24 Thiagarajan P, Pengo V, Shapiro SS. The use of dilute Russell Viper Venom Time for the diagnosis of lupus anticoagulants. Blood 1986; 68: 869-873
• 25 Triplett DA, Brandt JT, Kaczor D, Shaeffer J. Laboratory diagnosis of lupus inhibitors: A comparison of the tissue thromboplastin inhibition procedure with a new platelet neutralization procedure. Am J Clin Pathol 1983; 79: 678-682
• 26 Pengo V, Thiagarajan P, Shapiro SS, Heine MJ. Immunologie specificity and mechanism of action of IgG lupus anticoagulants. Blood 1987; 70: 69-76
• 27 Finlayson JS, Mushinki JF. Separation of subfractions of β₂-glycoprotein I. Biochim Biophys Acta 1967; 147: 413-420
• 28 Pengo V, Ruffatti A, Baritussio A, De Marco L, Todesco S, Girolami A. Serum of normal subjects contains IgG with antibody-like specificity for phospholipids. Folia Haematol 1984; 111: 681-685
• 29 Laemmli UK. Cleavage of structural proteins during the assembly of the head of Bacteriphage T4. Nature 1970; 227: 680-685
• 30 Pengo V, Biasiolo A. Purification of anticardiolipin and lupus anticoagulant activities by using cardiolipin immobilized on agarose beads. Thromb Res 1993; 72: 423-430
• 31 Pangborn MC. A new serologically active phospholipid from beef heart. Proc Soc Exp Biol (NY) 1941; 48: 484-486
• 32 Inoue K, Nojima S. Immunochemical studies of phospholipids. IV. The reactivities of antisera against natural cardiolipin and synthetic cardiolipin analogues-containing antigens. Chem Phys Lipids 1969; 3: 70-77
• 33 Moore JE, More CF. Biologically false positive serologic tests for syphilis: type, incidence and cause. J Chronic Dis 1952; 150: 467-473
• 34 Hohmann A, Comacchio R, Boswarva V, Sutjita M, Bradley J. The H3 anti-phospholipid idiotype is found in patients with systemic lupus erythematosus (SLE) but not in patients with syphilis. Clin exp Immunol 1991; 86: 207-211
• 35 Oosting JD, Derksen RH W M, Entjes HT I, Bouma BN, De Groot PG. Lupus anticoagulant activity is frequently dependent on the presence of β₂-Glycoprotein I. Thromb Haemost 1992; 67: 499-502
• 36 Galli M, Comfurius P, Barbui T, Zwaal RF A, Bevers EM. Anticoagulant activity of β₂glycoprotein I is potentiated by a distinct subgroup of anticardiolipin antibodies. Thromb Haemost 1992; 68: 297-300
• 37 Gharavi AE. Antiphospholipid cofactor. Stroke 1992; 23 suppl (Suppl. 01) I-7-I-10
• 38 Verrier Jones J. Antiphospholipid antibodies: new perspective on antigenic specificity. J Rheumatol 1992; 19: 1774-1777
• 39 Gharavi AZ, Sammaritano LR, Wen J, Elkon KB. Induction of antiphospholipid antibodies by immunization with β₂-glycoprotein I (Apolipoprotein H). J Clin Invest 1992; 90: 1105-1109
• 40 Nimpf J, Bevers EM, Bomans PH H, Till U, Wurm H, Kostner GH, Zwaal RF A. Prothrombinase activity of human platelets is inhibited by β₂-glyco-protein I. Biochim Biophys Acta 1986; 844: 142-149
• 41 Rauch J, Meng Q-H, Tannebaum H. Lupus anticoagulant and antiplatelet properties of human hybridoma autoantibodies. J Immunol 1987; 139: 2598-2604
• 42 Rauch J, Tannebaum H, Janoff AS. Distinguishing plasma lupus anticoagulants from anti-factor antibodies using hexagonal (II) phase phospholipids. Thromb Haemost 1989; 66: 453-458
• 43 Canfield WM, Kisiel W. Evidence of normal functional levels of activated protein C inhibitor in combined factor V/VIII deficiency disease. J Clin Invest 1982; 70: 1260-1272
• 44 Arvieux J, Roussel B, Jacob MC, Colomb MG. Measurement of anti-phospholipid antibodies by ELISA using β₂-glycoprotein I as an antigen. J Immunol Meth 1991; 143: 223-229
• 45 Matsuura E, Igarashi Y, Yasuda T, Triplett DA, Koike T. Anticardiolipin antibodies recognize β₂-glycoprotein I structure altered by interacting with an oxygen modified solid phase surface. J Exp Med 1994; 179: 457-462
• 46 Berger A, German JB, Gershwin ME. Implication of modifying cardiolipin acyl composition by diet. 1. Cardiolipin acyl chain is an important determinant in the binding to antiphospholipid antibodies in SLE sera. J Autoimmun 1992; 5: 229-241
• 47 Hasselaar P, Derksen RH W M, Blokzijl L, de Groot PG. Crossreactivity of antibodies directed against cardiolipin, DNA, endothelial cells and blood platelets. Thromb Haemost 1990; 63: 169-173
• 48 Bevers EM, Galli M, Barbui T, Comfurius P, Zwaal RF A. Lupus anticoagulant IgG’s (LA) are not directed to phospholipids only, but to a complex of lipid-bound human prothrombin. Thromb Haemost 1991; 66: 629-632
• 49 Fleck RA, Rapaport SI, Visajia Mohan Rao L. Anti-prothrombin antibodies and the lupus anticoagulant. Blood 1988; 72: 512-519
• 50 Janoff AS, Rauch J. The structural specificity of antiphospholipid antibodies in autoimmune disease. Chem Phys Lipids 1986; 40: 315-332