Quantification of Lupus Anticoagulants in Clinical Samples Using Anti- β2GP1 and Anti-Prothrombin Monoclonal Antibodies

2001 ◽  
Vol 86 (08) ◽  
pp. 584-589 ◽  
Author(s):  
A. Le Querrec ◽  
J. Arnout ◽  
D. Arnoux ◽  
J. Y. Borg ◽  
C. Caron ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Lupus Anticoagulant ◽  
Solid Phase ◽  
Clinical Samples ◽  
Lupus Anticoagulants ◽  
Asymptomatic Patients ◽  
Solid Phase Immunoassay ◽  
Dependent Activity ◽  
Variable Contribution ◽  
Suitable Standard

SummaryQuantification of lupus anticoagulant (LA) in clinical samples is hampered by the lack of a suitable standard of activity. We evaluated the use of mAbs displaying LA activity for this purpose. As most patient samples contain both β2Glycoprotein I (β2GP1) and prothrombin dependent LA, a combination of two mAbs, one of each specificity, was added to normal plasma in a concentration from 0 to 60 g/ml. Eight assay systems using different reagents and instruments were used. The calibration curves were linear for all but one, with marked differences between the responsiveness to each mAb. A panel of plasmas from 69 patients with persistent LA diagnosed using the SSCISTH criteria was tested. An antiphospholipid syndrome (APS) was present in 40, whereas 29 were asymptomatic. LA activities of individual plasmas varied between assays (p <10–4), but homogeneous subgroups were identified. In a majority of samples, LA activity displayed a prothrombin-dependent profile, with a variable contribution of β2GP1-dependent activity. The latter was associated to β2GP1 antibodies detected by solid-phase immunoassay. By using 3 dilute Russell viper venom time assays, higher LA titers were found in APS, compared to asymptomatic patients (p <0.05).

scholarly journals Detection of Bovine Herpesvirus-1-Specific IgM Using a Capture Enzyme Immune Assay with Isotype-Specific Monoclonal Antibodies

1989 ◽  
Vol 1 (2) ◽  
pp. 139-145 ◽  
Author(s):  
Fernando Osorio ◽  
Subramaniam Srikumaran ◽  
Marvin Rhodes ◽  
David Christensen ◽  
Pushpa Srikumaran
Keyword(s):  
Monoclonal Antibodies ◽  
Solid Phase ◽  
Bovine Herpesvirus ◽  
Immunoglobulin M ◽  
Viral Reactivation ◽  
Clinical Samples ◽  
Serum Samples ◽  
Bovine Herpesvirus 1 ◽  
Igm Antibody ◽  
Herpesvirus 1

The detection of virus-specific immunoglobulin M (IgM) antibodies in acute-phase serum samples offers the possibility of making an accurate and rapid serologic diagnosis. We have developed a solid-phase capture assay that uses murine monoclonal antibodies specific for bovine IgM to separate the whole IgM fraction of a bovine serum sample. The IgM specific for bovine herpesvirus-1 (BHV-1) is then detected by the addition of viral antigen, which in turn is detected by BHV-1-specific monoclonal antibodies conjugated to horseradish peroxidase. A BHV-1 IgM antibody response was detected during the early postinfection period (7–40 days PI). Bovine herpesvirus-1 IgM antibody was not detected in sera taken from 3 animals following dexamethasone-induced viral reactivation. This method compares favorably with viral isolation, antigen detection in the clinical samples, and paired serology in the diagnosis of BHV-1 infection at a herd level.

A solid-phase immunoassay to screen anti-HLA monoclonal antibodies

1988 ◽  
Vol 107 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Hiroshi Okada ◽  
Ryosaku Ono ◽  
Joseph C. Addonizio ◽  
George R. Nagamatsu ◽  
Soldano Ferrone
Keyword(s):  
Monoclonal Antibodies ◽  
Solid Phase ◽  
Solid Phase Immunoassay

scholarly journals ELISA for thyroglobulin in serum: recovery studies to evaluate autoantibody interference and reliability of thyroglobulin values

1996 ◽  
Vol 42 (5) ◽  
pp. 766-770 ◽  
Author(s):  
M Erali ◽  
R B Bigelow ◽  
A W Meikle
Keyword(s):  
Monoclonal Antibodies ◽  
Solid Phase ◽  
Polyclonal Antibodies ◽  
Clinical Samples ◽  
Reference Laboratory ◽  
Good Recovery ◽  
Additional Information ◽  
Percent Recovery ◽  
The Mean ◽  
Expected Values

Abstract An ELISA for measuring thyroglobulin (Tg) in serum was developed with polyclonal antibodies to Tg on the solid phase and two monoclonal antibodies to Tg as the second antibodies. The assay has a detection limit of 1 microgram/L, a within-run imprecision (CV) of &lt;7%, and a between-run CV of &lt; 10%. Parallelism of the assay was shown in dilution studies, in which the percent observed/expected values for n = 5 autoantibody-containing samples gave a mean of 99% (SD 13.1 %); for n = 5 samples with undetectable autoantibody concentrations, the mean was 103% (SD 11.8%). The correlation of the ELISA with an RIA for Tg in 46 normal samples was ELISA = 1.11(RIA) + 0.52, S y/x = 2.23, SD intercept = 0.54, SD slope = 0.03, range = 0 to 53 micrograms/L, r = 0.980. Comparison of the ELISA with a reference laboratory RIA for 29 clinical samples gave a correlation of: ELISA = 1.53(RIA) - 0.48, S y/x = 9.00, SD intercept = 2.19, SD slope = 0.10, range = 0 to 98 micrograms/L, r = 0.950. To provide additional information concerning the reliability of the Tg measurement in samples containing autoantibodies to Tg, we developed a procedure for determining the percent recovery. A percent recovery greater than or equal to 80% indicates minimal interference by autoantibodies in this assay. The assay is straightforward to perform, results can be posted within 8 h, and the routinely good recovery of Tg in the presence of Tg autoantibodies indicates minimal autoantibody interference in this assay.

Characterization of Monoclonal Anti-human Factor VII Antibody (B101/B1) that Recognized Three-dimensional Structures near Arg at Position 79 in the First EGF-like Domain

1998 ◽  
Vol 79 (01) ◽  
pp. 104-109 ◽  
Author(s):  
Osamu Takamiya
Keyword(s):  
Monoclonal Antibodies ◽  
Tissue Factor ◽  
Human Factor ◽  
Solid Phase ◽  
Three Dimensional ◽  
Coagulation Factors ◽  
Factor Vii ◽  
Dimensional Structure ◽  
Epidermal Growth

SummaryMurine monoclonal antibodies (designated hVII-B101/B1, hVIIDC2/D4 and hVII-DC6/3D8) directed against human factor VII (FVII) were prepared and characterized, with more extensive characterization of hVII-B101/B1 that did not bind reduced FVIIa. The immunoglobulin of the three monoclonal antibodies consisted of IgG1. These antibodies did not inhibit procoagulant activities of other vitamin K-dependent coagulation factors except FVII and did not cross-react with proteins in the immunoblotting test. hVII-DC2/D4 recognized the light chain after reduction of FVIIa with 2-mercaptoethanol, and hVIIDC6/3D8 the heavy chain. hVII-B101/B1 bound FVII without Ca2+, and possessed stronger affinity for FVII in the presence of Ca2+. The Kd for hVII-B101/B1 to FVII was 1.75 x 10–10 M in the presence of 5 mM CaCl2. The antibody inhibited the binding of FVII to tissue factor in the presence of Ca2+. hVII-B101/B1 also inhibited the activation of FX by the complex of FVIIa and tissue factor in the presence of Ca2+. Furthermore, immunoblotting revealed that hVII-B101/B1 reacted with non-reduced γ-carboxyglutaminic acid (Gla)-domainless-FVII and/or FVIIa. hVII-B101/B1 showed a similar pattern to that of non-reduced proteolytic fragments of FVII by trypsin with hVII-DC2/D4 on immunoblotting test. hVII-B101/B1 reacted differently with the FVII from the dysfunctional FVII variant, FVII Shinjo, which has a substitution of Gln for Arg at residue 79 in the first epidermal growth factor (1st EGF)-like domain (Takamiya O, et al. Haemosta 25, 89-97,1995) compared with normal FVII, when used as a solid phase-antibody for ELISA by the sandwich method. hVII-B101/B1 did not react with a series of short peptide sequences near position 79 in the first EGF-like domain on the solid-phase support for epitope scanning. These results suggested that the specific epitope of the antibody, hVII-B101/B1, was located in the three-dimensional structure near position 79 in the first EGF-like domain of human FVII.

Synchronized Inhibition of the Phospholipid Mediated Autoactivation of Factor XII in Plasma by β2-glycoprotein I and Anti-β2-glycoprotein I

1995 ◽  
Vol 73 (05) ◽  
pp. 798-804 ◽  
Author(s):  
Inger Schousboe ◽  
Margit Søe Rasmussen
Keyword(s):  
Lupus Erythematosus ◽  
Lupus Anticoagulant ◽  
Response Curve ◽  
Inhibitory Effect ◽  
Factor Xii ◽  
High Antibody ◽  
Contact Activation ◽  
Maximal Inhibition ◽  
Lupus Anticoagulants ◽  
Glycoprotein I

SummaryLupus anticoagulants are a group of antibodies commonly found in patients with autoimmune diseases such as systemic lupus erythematosus. Lupus anticoagulants inhibit phospholipid dependent coagulation and may bind to negatively charged phospholipids. Recent studies have suggested an association between anti-β2-glycoprotein I and a lupus anticoagulant, whose activity is frequently dependent on the presence of β2-glycoprotein I. Based on these observations, the effect of anti-β2-glycoprotein I on the autoactivation of factor XII in plasma was investigated. Autoactivation initiated by the presence of negatively charged phospholipids, but not by sulfatide, was strongly inhibited by immunoaffinity purified anti-β2-glycoprotein I. The dose-response curve of anti-β2-gly coprotein I was identical with that of a precipitating antibody, showing no inhibition at low and high antibody dilutions and maximal inhibition at an intermediate dilution. At high antibody concentrations, an increased rate of factor Xlla activation was observed. This increase was of the same magnitude as the decreased rate observed in plasma supplemented with the same amount of β2-glycoprotein I as in the plasma itself. This confirms the inhibitory effect of β2-GP-I on the contact activation and shows that inhibition is effective on the autoactivation of factor XII in plasma. The inhibitory action of β2-glycoprotein I was independent of the inhibition caused by the anti- β2-glycoprotein I/β2-glycoprotein I complex suggesting a synchronized inhibition of factor XII autoactivation by β2-glycoprotein I and anti-β2-gly coprotein I. The inhibition caused by the antibody is suggested to be caused by a reduced availability of negatively charged phospholipids due to the binding of the anti-β2- GP-I/β2-GP-I complex. This complex may be a lupus anticoagulant.

The clinical relevance of isolated lupus anticoagulant positivity in patients with thrombotic antiphospholipid syndrome

2020 ◽  
Author(s):  
Dong-mei Yin ◽  
Philip de Groot ◽  
Marisa Ninivaggi ◽  
Katrien M.J. Devreese ◽  
Bas de Laat
Keyword(s):  
Antiphospholipid Syndrome ◽  
Clinical Relevance ◽  
Antiphospholipid Antibodies ◽  
Odds Ratio ◽  
Lupus Anticoagulant ◽  
Solid Phase ◽  
Control Group ◽  
Domain I ◽  
Normal Controls ◽  
Better Than

Background: Patients positive for three types of antiphospholipid antibodies (aPLs) (triple positivity) have been identified at a high risk for thrombotic events. However, the clinical significance of isolated lupus anticoagulant (LAC) positivity is debated. Objectives: To investigate the clinical relevance of isolated LAC. Patients/Methods 456 patients were enrolled in this study; 66 antiphospholipid syndrome patients and 390 control patients. The control group existed of autoimmune patients (n=91), patients with thrombosis but without aPLs (n=127) and normal controls (n=172). The criteria LAC, anti-cardiolipin (anti-CL) and anti-beta2glycoprotein I (anti-β2GPI) IgG and IgM and the non-criteria IgA anti-CL and anti-β2GPI, anti-domain I (anti-DI) of β2GPI IgG and anti-phosphatidylserine/prothrombin (anti-PS/PT) IgG and IgM were detected according to the ISTH guidelines for solid phase assays. Results: 70 patients were positive for LAC, of which 44 were negative for both anti-β2GPI and anti-CL. We found that isolated LAC proved to be strongly associated with vascular thrombosis (Odds ratio (OR) (95% CI) 7.3 (3.3-16.1)), even better than triple positive samples (OR 4.3 (1.6-12.2)). The titers of the anti-PS/PT IgG and IgM were significantly higher in triple positivity samples compared to samples with isolated LAC positivity. The majority of single LAC positives were anti-PS/PT negative. We observed that LAC positivity was weaker in isolated LAC positive patients compared to LAC activity in triple positive patients. Conclusions: Isolated LAC was highly associated with thrombosis. The presence of anti-PS/PT could not explain LAC positivity in isolated LAC. Isolated LAC showed a weaker LAC activity compared to triple positive patients.

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