UNIPROT:P02749 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02749 (beta2-glycoprotein I)
836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

NZW x BXSB F1 (W/B F1) male mice develop systemic lupus-like disease, and several autoantibodies, circulating immune complexes, and lupus nephritis become apparent. The abnormally high incidence of degenerative coronary vascular disease with myocardial infarction and thrombocytopenia due to the presence of both platelet-associated antibodies and circulating antiplatelet antibodies in this animal has been reported. We found that W/B F1 male mice produced autoantibodies against cardiolipin (aCL) and that the titer of aCL increases with age. aCL from W/B F1 male mice were mainly IgG and binding activity to cardiolipin was aCL-cofactor (beta 2-glycoprotein I (beta 2-GPI)) dependent. We developed monoclonal aCL from these animals and examined specificity of the autoantibodies. All the mAb used reacted with the negatively charged phospholipids, cardiolipin, phosphatidylserine, and phosphatidylinositol, and some reacted with platelets and DNA. The addition of human or mouse beta 2-GPI enhanced the titer for monoclonal aCL from the W/B F1 mice. From the results of competitive inhibition enzyme immunoassay with monoclonal aCL and purified beta 2-GPI, aCL from the W/B F1 mice recognized the complex of CL and beta 2-GPI. The W/B F1 male mouse may be an appropriate model for use in studies on the pathologic significance of aCL in patients with antiphospholipid syndrome.
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PMID:Anticardiolipin antibodies in NZW x BXSB F1 mice. A model of antiphospholipid syndrome. 163 62

We developed an ELISA to quantitate complexes of activated protein C (APC) with a major plasma APC inhibitor, alpha 1-antitrypsin (alpha 1AT) in human plasma based on the sandwich principle using two different antibodies directed towards protein C and alpha 1AT, respectively. This ELISA test was specific for APC:alpha 1AT complexes and sensitive to greater than or equal to 150 pg complex. Fifty-one of 56 healthy donors had APC:alpha 1AT complex levels above the detection limit (3 ng/ml) ranging from 4 to 14 ng/ml (mean value +/- SD: 7.6 +/- 2.5 ng/ml). Patients (n = 10) with disseminated intravascular coagulation (DIC) had detectable levels of APC:alpha 1AT complex ranging from 21 to 125 ng/ml (median: 69 ng/ml). Complexes of APC with plasma protein C inhibitor (PCI) were also measured using an ELISA sandwich assay. None of the 30 healthy donors had detectable levels (greater than or equal to 5 ng/ml) of APC:PCI complex, and plasma samples from 9 of 10 DIC patients had detectable concentrations of APC:PCI complex ranging from 10 to 63 ng/ml (median: 22 ng/ml). APC:alpha 1AT complex was detected in 25 of 26 patients with deep venous thrombosis (DVT), with levels ranging from 5 to 136 ng/ml (median: 23 ng/ml), whereas APC:PCI was detected in only 6 DVT patients, with levels between 11 and 105 ng/ml. PCI antigen levels in 70 normals ranged from 56 to 175% (mean +/- SD: 99.1% +/- 24.2%). PCI antigen levels were decreased in DIC patients, in patients with cerebral arterial thrombosis, and in DVT patients undergoing heparin therapy, but not in patients with myocardial infarction. PCI antigen levels were decreased much further in DVT patients receiving heparin compared to those not receiving heparin, showing that heparin therapy is associated with a decrease in PCI levels. The detection in normal subjects and in thrombotic patients of circulating APC:inhibitor complexes supports the view that the protein C pathway is activated during DIC and DVT. Moreover, it emphasizes that both PCI and alpha 1AT are physiologic inhibitors of APC. Thus, measurement of APC complexes may provide sensitive parameters for specific detection of activation of the clotting and protein C pathways.
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PMID:Determination of plasma protein C inhibitor and of two activated protein C-inhibitor complexes in normals and in patients with intravascular coagulation and thrombotic disease. 217 67

Antiphospholipid antibodies in patients with "antiphospholipid syndrome" may be directed at least in part against plasma phospholipid-binding proteins, such as beta 2-glycoprotein I or prothrombin, which are involved in the control of thrombosis and haemostasis. IgG-class antibodies against prothrombin and beta 2-glycoprotein I were measured by enzyme-linked immunoassay in initially healthy middle-aged dyslipidaemic men (non-high-density lipoprotein > 5.2 mml/l). Serum samples had been drawn at entry to a 5-year coronary primary-prevention trial with gemfibrozil from 106 subjects who experienced either a non-fatal myocardial infarction or cardiac death during the follow-up and from 106 subjects without coronary episodes, matched for treatment group (gemfibrozil/placebo) and geographical area. The antiprothrombin antibody level, as expressed in optical density units, was significantly higher in patients than in controls (0.26 +/- 0.17 versus 0.22 +/- 0.09; p < 0.02). A high level of antiprothrombin antibodies (highest tertile of distribution) predicted a 2.5-fold increase in the risk (95% confidence interval 1.2-5.3) of myocardial infarction or cardiac death. The distribution of IgG-class antibodies against beta 2-glycoprotein I did not differ significantly between cases and controls. The joint effect of antiprothrombin antibodies and other factors associated with hypercoagulative state: triglyceride level, lipoprotein(a) and smoking, was multiplicative for the risk. Antiprothrombin antibodies are a new immunological predictor of myocardial infarction and the effect of these antibodies may be mediated by hypercoagulative mechanisms.
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PMID:Antibodies to prothrombin imply a risk of myocardial infarction in middle-aged men. 870 7

NZW x BXSB F1 mice develop a systemic autoimmune syndrome with various lupus-like manifestations. Male animals develop a degenerative coronary disease with myocardial infarction, resulting in death before 6 mo of age. The presence in these mice of anti-phospholipid Abs reacting with beta2-glycoprotein I may contribute to the pathogenesis of the cardiovascular lesions. beta2-glycoprotein I, a plasma protein implicated in various aspects of the coagulation pathway, is also the target of autoantibodies in humans with the anti-phospholipid syndrome. We obtained several mAbs from NZW x BXSB F1 mice that were selected for binding to cardiolipin. Two mAbs are specific for beta2-glycoprotein I and display a species-dependent pattern with preferential reactivity to mouse beta2-glycoprotein I. The other mAbs display charge-mediated interactions with anionic phospholipids in the absence of beta2-glycoprotein I. The analysis of the V region sequences of the mAbs suggests that cationic residues in the H chain complementarity-determining region 3 are important for their phospholipid reactivity. The structural features of the V(H)-D-J(H) junctions of these mAbs further support the view that an increased frequency of unusual V(D)J rearrangements directly contributes to the development of murine autoimmunity.
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PMID:Monoclonal antibodies from NZW x BXSB F1 mice to beta2 glycoprotein I and cardiolipin. Species specificity and charge-dependent binding. 878 29

The family of antiphospholipid antibodies includes antibodies binding to cardiolipin in serological test for syphilis, antibodies prolonging the clotting time in lupus anticoagulant test, antibodies reacting with plasma phospholipid-binding proteins, such as beta 2-glycoprotein I and prothrombin, and antibodies binding to oxidized low-density lipoprotein (LDL). Antiphospholipid antibodies are traditionally associated with arterial and venous thrombosis in patients with primary or secondary antiphospholipid syndrome. The recent studies, especially those on patients with myocardial infarction, extend the concept of antiphospholipid antibodies, and suggest that they play a role also in atherosclerosis. Based on the clinical studies and immunological findings, it seems that the differences in the specificity of antiphospholipid antibodies may reflect to their pathogenetic mechanisms and, finally, to their clinical consequences. The present review suggests that antibodies to oxidized LDL may not interfere directly with blood coagulation, but seem to have importance in the inflammation of the vessel wall in atherosclerosis and in vasculitis. Instead, antibodies to beta 2-glycoprotein I and to prothrombin show a closer association with thrombosis. It is possible that in the atherosclerotic plaque, the plasma proteins, such as beta 2-glycoprotein I or prothrombin, are bound to the endothelial surface and antibodies to cryptic epitopes revealed in these proteins are induced. These antibodies may contribute to the formation of atherosclerotic thrombosis by changing the balance of haemostasis toward hypercoagulative state.
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PMID:Antiphospholipid antibodies and atherosclerosis. 890 78

During late seventies it became apparent that the appearance of antiphospholipid antibodies is associated with thromboembolic manifestations, such as cerebral or myocardial infarction, pulmonary thromboembolism, deep vein thrombosis, intrauterine fetal losses and thrombocytopenia. The term antiphospholipid syndrome has been used to define this set of pathologic features. Recognition of this syndrome has spread worldwide as its clinical implications have become appreciated. Recent studies showed that cofactor, beta 2-glycoprotein I (beta 2-GPI) is required for binding of anticardiolipin antibodies (aCL) raised in the patients with SLE and related other autoimmune disorders. However, this finding has generated considerable controversy. Four different hypotheses have been proposed to explain the specificity of aCL: (1) CL is directly recognized by aCL; (2) the beta 2-GPI-CL complex is the structure recognized by aCL; (3) the beta 2-GPI is the actual target antigen for aCL but is cryptic in the absence of CL; and (4) the actual epitope for aCL appears on the native structure of beta 2-GPI. We showed that aCL bound to beta 2-GPI interacting with poly-oxygenated plates and in the absence of CL, an interaction which depends on introduction of oxygen atoms on the polystyrene surface. We also showed that the beta 2-GPI bound to CL via a particular region on the fifth domain, namely C281KNKEKKC288, and the tertiary structure of the region is involved in binding to phospholipid. Several mechanisms to explain the vascular injury and thrombosis associated with aCL have been proposed, primarily based on their phospholipid reactivity to activated platelets. Whether aCL-through binding to complex of beta 2-GPI and negatively charged phospholipid in the phospholipid-dependent coagulation reactions of hemostasis contribute to the increased risk of thrombosis in patients with aCL is an important question in need of an answer. We have demonstrated the possibility that not only activated platelets but also oxidized lipoproteins, e.g., low-density lipoprotein (LDL), may be thrombogenic targets of aCL which recognize the altered beta 2-GPI structure.
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PMID:[Autoantibodies and thrombosis]. 936 65

Antibodies against phospholipid-binding plasma proteins, such as beta2-glycoprotein I (beta2-GPI) and prothrombin, are associated with thromboembolic events in patients with systemic lupus erythematosus and also in subjects with no evident underlying diseases. We wanted to examine whether increased levels of antibodies to negatively-charged phospholipids (cardiolipin), to phospholipid-binding plasma proteins beta2-GPI and prothrombin and to oxidised low-density lipoprotein (LDL) were associated with risk of deep venous thrombosis or pulmonary embolism in subjects with no previous thrombosis. The antibodies were measured in stored serum samples from 265 cases of deep venous thrombosis of the lower extremity or pulmonary embolism occurring during a median follow-up of about 7 years and from 265 individually matched controls. The study subjects were middle-aged men participating in a cancer prevention trial of alpha-tocopherol and beta-carotene and the cases of thromboembolic events were identified from nationwide Hospital Discharge Register. The risk for thrombotic events was significantly increased only in relation to antiprothrombin antibodies. As adjusted for body mass index, number of daily cigarettes and history of chronic bronchitis, myocardial infarction and heart failure at baseline, the odds ratio per one unit of antibody was 6.56 (95% confidence interval 1.73-25.0). The seven highest individual optical density-unit values of antiprothrombin antibodies were all confined to subjects with thromboembolic episodes. In conclusion, the present nested case-control study showed that high autoantibody levels against prothrombin implied a risk of deep venous thrombosis and pulmonary embolism and could be involved in the development of the thrombotic processes.
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PMID:High antibody levels to prothrombin imply a risk of deep venous thrombosis and pulmonary embolism in middle-aged men--a nested case-control study. 936 81

Ischemic cardiac manifestations have been reported in a various percentage of patients with anti-phospholipid antibodies. As concerns the relationship between anti-beta2 glycoprotein I antibodies (anti-beta2-GPI) and ischemic heart disease (IHD), it was investigated in only one coronary primary prevention study. We investigated the prevalence of anti-beta2-GPI in a well characterized group of patients with different clinical manifestation of IHD. Sera from 37 patients (mean age 62.7 +/- 9.9) with IHD (20 with unstable angina-UA and 17 with effort angina-EA) and from 40 healthy subjects, matched for age and sex, were tested for the presence of IgG and IgM anti-beta2-GPI using an ELISA technique. Eleven/37 patients (29.7%) resulted positive for anti-beta2-GPI. A positivity for IgG anti-beta2-GPI was found in 10 patients, 1 patient was positive for IgM and 1 for both isotypes. The prevalence of anti-beta2-GPI in the control group resulted significantly lower (2.5%; p < 0.005) than in patients with IHD. Positivity for anti-beta2-GPI was found in 9/20 (45%) patients with UA and only in 2/17 patients (11.8%) with EA (p = 0.0365). IgG anti-beta2-GPI levels (median 7.7U/ml, range 2.6-24.1) were significantly higher in patients with UA compared to patients with EA (median 4.6 U/ml, range 2.3-11.5; p = 0.02) and controls (median 3.15 U/ml, range 2.3-9.0; p < 0.0001); also IgM levels resulted higher in patients with unstable angina. A positivity for anti-beta2-GPI was observed in 4/13 patients (30.8%) with a previous myocardial infarction (MI) and in 7/24 (29.2%) patients without a previous MI. Our findings suggest that anti-beta2-GPI could represent an expression of the T-cell activation detectable in patients with unstable angina. The lack of a significant difference in the prevalence of these antibodies in patients with or without a previous MI suggests that anti-beta2-GPI are not induced by tissue necrosis.
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PMID:High prevalence of anti-beta2 glycoprotein I antibodies in patients with ischemic heart disease. 1043 22

Patients with the anti-phospholipid syndrome (APS) have antiphospholipid antibodies (aPA) which are often targeted towards phospholipid binding proteins such as beta2-glycoprotein I and prothrombin. Antibodies to factor XII (FXIIabs) have also been identified in some patients with APS. Factor XII (FXII) is a member of the kringle family of proteins which include plasminogen and prothrombin. Antibodies to prothrombin have been associated with myocardial infarction and have been shown to cross react with plasminogen. Sixteen patients with APS and FXIIabs were investigated for the presence of antibodies to prothrombin, by enzyme linked immunosorbent assay in a calcium (Ca++) independent assay. All sixteen showed different antibody binding patterns than those observed for antibodies to FXII. Eight patients were further investigated using surface plasmon resonance (SPR) for antibody binding to covalently bound FXII and to covalently bound prothrombin in both Ca++ dependent and independent systems. Of three patients demonstrating antibody binding to FXII by SPR, none demonstrated antibody binding to prothrombin in a Ca++ independent system with one demonstrating antibody binding to prothrombin that was Ca++ dependent. Of five patients who did not bind FXII by SPR, one demonstrated antibody binding to prothrombin in a Ca++ independent system while two demonstrated antibody binding to prothrombin in a Ca++ dependent system. Antibodies to FXII in patients with APS appear to be distinct from antibodies to prothrombin.
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PMID:Antibodies to factor XII are distinct from antibodies to prothrombin in patients with the anti-phospholipid syndrome. 1191 74

High-sensitive C-reactive protein (hs-CRP) is a marker of inflammation which has been shown in several prospective studies to independently predict myocardial infarction, stroke and peripheral artery disease. Patients with antiphospholipid antibodies (aPL) are at increased risk of recurrent thromboembolic events, but the possibility of predicting this risk seems rather limited. Similarities were recently found between aPL and CRP in the pathology of thrombosis. The current study investigated the predictive role of hs-CRP in a cohort of patients with neurological manifestations. A follow-up investigation was done in a cohort of 55 aPL-positive patients with acute manifestations of neurological disease. hs-CRP levels were measured in all patients at enrollment and were compared to the patients' condition after a median period of 32 months. Lupus anticoagulants were detected according to the Standardization of Lupus Anticoagulants (SSC) of the ISTH. Anticardiolipin tests were performed by a beta2-glycoprotein I-dependent enzyme-linked immunsorbent assay (Pharmacia ELISA). hs-CRP was measured by latex-enhanced turbidometry (dimension RXL, Dade Behring). Cerebral infarctions and transient ischemic attacks were the most frequent cerebral events. In patients with aPL, elevated levels of hs-CRP were closely associated with an increased rate of recurrent or residual symptoms (OR, 12.5; 95% CI, 3.72-41.94) and were not related to other risk factors, except smoking (p<0.05). The rate at which a given patient's condition deteriorated was also related to the level of hs-CRP. In patients with antiphospholipid syndrome (APS), elevated levels of hs-CRP may identify a group of patients which is at high risk of recurrent or residual neurological symptoms and which may benefit from more careful follow-up and from antithrombotic therapy.
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PMID:Predictive role of hs-C-reactive protein in patients with antiphospholipid syndrome. 1632 94

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