Biosensor Analysis of β2-Glycoprotein I–Reactive Autoantibodies: Evidence for Isotype-Specific Binding and Differentiation of Pathogenic from Infection-Induced Antibodies

Metzger, Jochen; Landenberg, Philipp von; Kehrel, Marcus; Buhl, Alexander; Lackner, Karl J.; Luppa, Peter B.

doi:10.1373/clinchem.2006.079632

Cited by 48 publications

(37 citation statements)

References 27 publications

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“…66 Anti-␤ 2 GPI antibodies may be divided into high and low avidity, and it is the former that tend to associate with thrombosis. [67][68][69][70][71] The 2 types may be distinguished by their ability to dissociate from immobilized ␤ 2 GPI in the presence of increasing concentrations of urea 67 or ionic buffer. 70 Both types have been detected in patients with systemic lupus erythematosus (SLE).…”

Section: Characteristics Of Anti-␤ 2 Gpi Antibodies That Associate Wimentioning

confidence: 99%

How we diagnose the antiphospholipid syndrome

Giannakopoulos

Passam

Ioannou

et al. 2009

Blood

163

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IntroductionThe antiphospholipid syndrome (APS) is an important cause of acquired thrombophilia and recurrent miscarriages. This narrativestyle review discusses the key laboratory and clinical aspects of APS. Particular focus is given to antibodies against beta 2-glycoprotein I (␤ 2 GPI), in view of their recent inclusion in the APS laboratory classification criteria 1 (Figure 1). The evidence for assessing antiprothrombin and antiphosphatidylethanolamine antibodies to diagnose APS is also examined.The utility of the ␤ 2 GPI enzyme-linked immunosorbent assay (ELISA), when used in conjunction with the cardiolipin (CL) ELISA and the lupus anticoagulant (LA) assays, in risk-stratifying APS patients is explored. Work undertaken by many groups over the years, ours included, in delineating the key characteristics of anti-␤ 2 GPI antibodies that associate with APS is presented.Miscarriages are a major feature of APS. The relative importance of the LA assays, the CL-ELISA, and the ␤ 2 GPI-ELISA in diagnosing APS in the context of early and late gestation miscarriages is assessed. The value of recent epidemiologic and basic science insights in refining our understanding of obstetric APS pathophysiology is examined, particularly with regards to considering the possibility that distinct mechanisms may be responsible for early and late miscarriages. The clinical implications arising from these observations are discussed. Clarification of the nomenclatureAntiphospholipid antibodies is a term applied to antibodies detected traditionally by 2 types of assays, the CL-ELISA, which stems from the earlier work of Harris et al, 2 and the LA assays. 3 The first report of a cofactor requirement for antibodies to bind cardiolipin (an anionic phospholipid) from patients with APS was by McNeil et al in 1989. 4 This was subsequently confirmed by Galli et al 5 and Matsuura et al 6 in 1990. Purification and sequencing of the cofactor as ␤ 2 GPI was reported by McNeil et al in 1990. 7 It was noted that anionic phospholipid is not an absolute requirement for antibodies to bind ␤ 2 GPI, 8 negating the notion that ␤ 2 GPI is a "cofactor" for antibody binding. Antibodies from these patients can bind to ␤ 2 GPI immobilized on an irradiated plate in the absence of anionic phospholipids. 9 A negatively charged surface serves a 2-fold role. It enables ␤ 2 GPI clustering, allowing divalent binding by the low affinity antibodies. 10,11 It also enables the ␤ 2 GPI molecule to undergo a conformational change, 9 exposing a cryptic epitope on the first domain. 12 Positivity on the CL-ELISA is not directed against ␤ 2 GPI in the context of a number of infections. 13 However, this is not true for all types of infections, as elevated anti-␤ 2 GPI antibodies in patients with leishmaniasis, leptospirosis, 14 and leprosy 15 have been noted. A key distinguishing feature between anti-␤ 2 GPI antibodies occurring in the context of leprosy and those that strongly associate with thrombosis is that in the former instance they are directed against an epitope on dom...

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Section: Characteristics Of Anti-␤ 2 Gpi Antibodies That Associate Wimentioning

confidence: 99%

How we diagnose the antiphospholipid syndrome

Giannakopoulos

Passam

Ioannou

et al. 2009

Blood

163

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“…After a period of silence, several SPR papers appeared on the topic of conformation-dependent sensing despite many considering the reports to be simply anomalous behavior (43)(44)(45)(46)(47), attributed to the following: (i) buffer mismatch, (ii) volume exclusion due to ligand density differences (43)(44)(45), (iii) nonspecific matrix interaction (46), and (iv) nonspecific reference interactions (47). Regardless, a recent paper reported that the RI sensing figures of merit were dependent on shape and the size of the Au nanoparticles (48) with sensitivities generally increasing as the nanoparticles became elongated and their apexes become sharper.…”

Section: Introductionmentioning

confidence: 99%

Origin and prediction of free-solution interaction studies performed label-free

Bornhop

Kammer

Kussrow

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Interaction/reaction assays have led to significant scientific discoveries in the biochemical, medical, and chemical disciplines. Several fundamental driving forces form the basis of intermolecular and intramolecular interactions in chemical and biochemical systems (London dispersion, hydrogen bonding, hydrophobic, and electrostatic), and in the past three decades the sophistication and power of techniques to interrogate these processes has developed at an unprecedented rate. In particular, label-free methods have flourished, such as NMR, mass spectrometry (MS), surface plasmon resonance (SPR), biolayer interferometry (BLI), and backscattering interferometry (BSI), which can facilitate assays without altering the participating components. The shortcoming of most refractive index (RI)-based label-free methods such as BLI and SPR is the requirement to tether one of the interaction entities to a sensor surface. This is not the case for BSI. Here, our hypothesis is that the signal origin for freesolution, label-free determinations can be attributed to conformation and hydration-induced changes in the solution RI. We propose a model for the free-solution response function (FreeSRF) and show that, when quality bound and unbound structural data are available, FreeSRF correlates well with the experiment (R 2 > 0.99, Spearman rank correlation coefficients >0.9) and the model is predictive within ∼15% of the experimental binding signal. It is also demonstrated that a simple mass-weighted dη/dC response function is the incorrect equation to determine that the change in RI is produced by binding or folding event in free solution.backscattering interferometry | assay methodology | molecular interactions | conformation change | hydration change C ontemporary assays enabling single-molecule detection (1,2) have accelerated the sequencing of the human genome (3) and facilitated imaging with extraordinary resolution without labels (4). To most closely approximate the natural state, an interaction assay methodology would interrogate the processes (reaction, molecular interaction, protein folding event, etc.) without perturbation. Label-free chemical and biochemical investigations (5, 6) transduce the desired signal without an exogenous label (fluorescent, radioactive, or otherwise) representing an essential step toward this goal. Many label-free methods require one of the interacting species to be either tethered or immobilized to the sensor surface, introducing a potential perturbation to the natural state of the species (7,8). However, back-scattering interferometry (BSI) is a free-solution label-free technique with the added benefit of sensitivity that rivals fluorescence (9). There are other techniques performed in free solution, such as MS (10, 11) and NMR (12,13) and the widely used isothermal titration calorimetry (ITC) (14, 15). As with NMR, ITC has many advantages, but exhibits modest sensitivity and often requires large sample quantities. Another increasingly popular free-solution approach is microscale thermophoresis (...

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“…Another study with domains I-V of b2GPI-specific peptides (including elongated peptides A-C) was conducted by Muller et al [39] on a surface plasmon resonance (SPR) biosensor system. No differences between 21 serum samples from APS patients and age-/sex-matched controls were detected in SPR signals for all peptides [39], in contrast to higher SPR responses for patient serum samples compared with controls when immobilized b2GPI was used [40], indicating a problem in detection of antibody binding to short amino acid sequences. Zager et al [26] used SPR chips with immobilized b2GPI and noted that antibodyantigen interactions between polyclonal HAv IgG antib2GPI and b2GPI are presumably more stable, monovalent and less dependent on antigen density as compared to polyclonal LAv IgG anti-b2GPI, which form less stable complexes, are more dependent on antigen density and require bivalent interactions.…”

Section: Discussionmentioning

confidence: 75%

Immunoreactivity and avidity of IgG anti-β2-glycoprotein I antibodies from patients with autoimmune diseases to different peptide clusters of β2-glycoprotein I

Artenjak¹,

Locatelli

Brelih

et al. 2014

Immunol Res

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The pathogenicity of antibodies against β2-glycoprotein I (anti-β2GPI) depends on multiple factors such as subclass type, epitope binding and avidity. Due to their large heterogeneity, their impact on antiphospholipid syndrome (APS) onset is still not fully clarified. We studied the binding characteristics of IgG anti-β2GPI with known avidity from sera of 201 autoimmune patients (87 with APS, 67 with APS associated with systemic lupus erythematosus (SLE), 47 with only SLE) to six β2GPI peptides corresponding to amino acid clusters on domains I-II, II, III and III-IV by indirect ELISA and evaluated their association with clinical features of APS. Peptides A (LKTPRV; domain I-II), B (KDKATF; domain IV) and C (TLRVYK; domain III) were derived from a hexapeptide phage display library previously shown to react with pathogenic monoclonal anti-β2GPI. Peptides D (NGPANSK; domain III), E (YNPLWFV; domain II) and F (KMDGNHP; domain III-IV) represent surface amino acid clusters on β2GPI. The percentage of patients positive for peptides were observed as follows: 30.3% for peptide D, 28.90% for B, 25.9% for C, 24.9% for E, 24.4% for F and 10.0% for A. The anti-peptide antibodies in studied serum samples were predominantly of heterogeneous avidity, followed by law avidity anti-peptide antibodies, whereas only a few were of high avidity. Positive and negative correlations were found between several anti-peptide antibodies and the rate of thrombosis. Our results indicated diverse reactivity of IgG anti-β2GPI to different epitopes on β2GPI. Classification of IgG anti-β2GPI into subgroups regarding epitope specificity and avidity could represent an additional tool in understanding their pathogenicity in APS.

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Biosensor Analysis of β2-Glycoprotein I–Reactive Autoantibodies: Evidence for Isotype-Specific Binding and Differentiation of Pathogenic from Infection-Induced Antibodies

Cited by 48 publications

References 27 publications

How we diagnose the antiphospholipid syndrome

How we diagnose the antiphospholipid syndrome

Origin and prediction of free-solution interaction studies performed label-free

Immunoreactivity and avidity of IgG anti-β2-glycoprotein I antibodies from patients with autoimmune diseases to different peptide clusters of β2-glycoprotein I

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