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An A1-A1 mutant with improved binding and inhibition of β2GPI/antibody complexes in antiphospholipid syndrome.

ABSTRACT: β2 glycoprotein I (β2GPI) is the most common antigen for autoimmune antibodies in antiphospholipid syndrome (APS). Thrombosis is a clinical feature of APS. We created a molecule (A1-A1) that consists of two identical β2GPI-binding modules from ApoE receptor 2 (ApoER2). A1-A1 binds to β2GPI/antibody complexes, preventing their association with ApoER2 and anionic phospholipids, and reducing thrombus size in the mouse model of APS. Here, we describe a mutant of A1-A1 (mA1-A1ND) with improved affinity for β2GPI. mA1-A1ND inhibits the binding of β2GPI to cardiolipin in the presence of anti-β2GPI antibodies, and inhibits the binding to phospholipids in plasma samples of APS patients, affecting the clotting time. Reduction of the clotting time demonstrates the presence of soluble β2GPI/antibody complexes in patients' plasma. These complexes either already exist in patients' plasma or form rapidly in the proximity to phospholipids. All members of the low-density lipoprotein receptor family bind β2GPI. Modeling studies of A1 in a complex with domain V of β2GPI (β2GPI-DV) revealed two possible modes of interaction of a ligand-binding module from lipoprotein receptors with β2GPI-DV. In both orientations, the ligand-binding module interferes with binding of β2GPI to anionic phospholipids; however, it interacts with two different but overlapping sets of lysine residues in β2GPI-DV, depending on the orientation.

SUBMITTER: Kolyada A

PROVIDER: S-EPMC4351136 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

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An A1-A1 mutant with improved binding and inhibition of β2GPI/antibody complexes in antiphospholipid syndrome.

Kolyada Alexey A Karageorgos Ioannis I Mahlawat Pardeep P Beglova Natalia N

The FEBS journal 20150127 5

β2 glycoprotein I (β2GPI) is the most common antigen for autoimmune antibodies in antiphospholipid syndrome (APS). Thrombosis is a clinical feature of APS. We created a molecule (A1-A1) that consists of two identical β2GPI-binding modules from ApoE receptor 2 (ApoER2). A1-A1 binds to β2GPI/antibody complexes, preventing their association with ApoER2 and anionic phospholipids, and reducing thrombus size in the mouse model of APS. Here, we describe a mutant of A1-A1 (mA1-A1ND) with improved affini ...[more]

PMID: 25546421

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Project description:ObjectivesThe objectives of this study were to determine the prevalence of anti-β2glycoprotein-1 antibodies (anti-β2GPI) in Pakistani patients clinically suspected to have antiphospholipid syndrome (APS) and assess their association with clinical manifestations.IntroductionThe antiphospholipid syndrome (APS) is a complex disorder characterized by recurrent thrombotic and obstetric complications.MethodsAn analytical cross-sectional study was conducted at Aga Khan University Hospital from January to June 2022, after obtaining ethical approval (ERC ID: 2021-6404-19580). A total of 133 patients aged 18-60 years, clinically suspected of having APS based on the updated international consensus (Sydney) classification criteria, were recruited. Anti-β2GPI antibodies were tested using the same blood samples provided for aCL testing, with verbal consent. Demographic, clinical, and biochemical data were collected via a structured questionnaire, while information on lupus anticoagulant testing was retrospectively obtained from prior records.ResultsThe study included 120 females (90.2%) and 13 males (9.8%) with a mean age of 31.3 ± 8.8 years. Predominant clinical manifestations included unexplained miscarriages at >10 weeks of gestation (n = 77/120 female, 64.2%), while deep venous thrombosis (DVT) was a common non-obstetric clinical feature (n = 18/133, 13.5%). The median level of anti-β2GPI was 2.12 U/ml (1.34-7.04) and 7.5% (n = 10) were positive. Of the 10 positive patients, 2 displayed positive anti-β2GPI while concurrently testing negative for other aPL antibodies. A significant association was identified between the presence of anti-β2GPI and the occurrence of DVT and other venous thromboembolic events (VTE).ConclusionThis study highlights the prevalence and diagnostic utility of anti-β2GPI in Pakistani patients suspected of APS, identifying cases missed by other aPL tests and showing significant associations with thrombotic manifestations like DVT and VTE. However, the cross-sectional design, lack of confirmatory testing, and absence of locally derived cut-offs limit causal inferences.

Dataset Information

An A1-A1 mutant with improved binding and inhibition of β2GPI/antibody complexes in antiphospholipid syndrome.

Publications

An A1-A1 mutant with improved binding and inhibition of β2GPI/antibody complexes in antiphospholipid syndrome.

Similar Datasets

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