Neutralising SARS-CoV-2 RBD-specific antibodies persist for at least six months independently of symptoms in adults

Abstract Background In spring 2020, at the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in Europe, we set up an assay system for large-scale testing of virus-specific and neutralising antibodies including their longevity. Methods We analysed the sera of 1655 adult employees for SARS-CoV-2-specific antibodies using the S1 subunit of the spike protein of SARS-CoV-2. Sera containing S1-reactive antibodies were further evaluated for receptor-binding domain (RBD)- and nucleocapsid protein (NCP)-specific antibodies in relation to the neutralisation test (NT) results at three time points over six months. Results We detect immunoglobulin G (IgG) and/or IgA antibodies reactive to the S1 protein in 10.15% (n = 168) of the participants. In total, 0.97% (n = 16) are positive for S1-IgG, 0.91% (n = 15) were S1-IgG- borderline and 8.28% (n = 137) exhibit only S1-IgA antibodies. Of the 168 S1-reactive sera, 8.33% (n = 14) have detectable RBD-specific antibodies and 6.55% (n = 11) NCP-specific antibodies. The latter correlates with NTs (kappa coefficient = 0.8660) but start to decline after 3 months. RBD-specific antibodies correlate most closely with the NT (kappa = 0.9448) and only these antibodies are stable for up to six months. All participants with virus-neutralising antibodies report symptoms, of which anosmia and/or dysgeusia correlate most closely with the detection of virus-neutralising antibodies. Conclusions RBD-specific antibodies are most reliably detected post-infection, independent of the number/severity of symptoms, and correlate with neutralising antibodies at least for six months. They thus qualify best for large-scale seroepidemiological evaluation of both antibody reactivity and virus neutralisation.

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A longitudinal seroprevalence study in a large cohort of working adults reveals that neutralising SARS-CoV-2 RBD-specific antibodies persist for at least six months independent of the severity of symptoms

10.1101/2020.12.22.20248604 ◽

2020 ◽

Author(s):

Angelika Wagner ◽

Angela Guzek ◽

Johanna Ruff ◽

Joanna Jasinska ◽

Ute Scheikl ◽

...

Keyword(s):

Specific Antibody ◽

Large Scale ◽

Antibody Test ◽

Added Value ◽

Lower Sensitivity ◽

Neutralising Antibodies ◽

Past Infection ◽

Cross Sectional ◽

Specific Antibodies ◽

Iga Antibodies

AbstractBackgroundIn spring 2020, at the beginning of the first pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wave in Europe, we set up an assay system for large-scale testing of virus-specific and protective antibodies including their longevity.MethodsWe analysed the sera of 1655 adult employees for SARS-CoV-2-specific antibodies using the S1 subunit of the spike protein of SARS-CoV-2. Sera containing S1-reactive antibodies were further evaluated for receptor-binding domain (RBD)- and nucleocapsid protein (NCP)-specific antibodies in relation to the neutralisation test (NT) results at 0, three and six months.FindingsWe found immunoglobulin G (IgG) and/or IgA antibodies reactive to the S1 protein in 10.15% (n=168) of the participants. In total, 0.97% (n=16) were positive for S1-IgG, 0.91% (n=15) were S1-IgG-borderline and 8.28% (n=137) exhibited only S1-IgA antibodies. Next, we evaluated the 168 S1-reactive sera for RBD- and NCP specificity: 8.33% (n=14) had detectable RBD-specific and 6.55% (n=11) NCP-specific antibodies. The latter correlated with NTs (kappa coefficient = 0.8660) but started to decline already after 3 months. RBD-specific antibodies correlated best with the NT (kappa = 0.9448) and only these antibodies were stable for up to six months. All participants with virus-neutralising antibodies reported symptoms, of which, anosmia and/or dysgeusia correlated best with the detection of virus-neutralising antibodies.InterpretationRBD-specific antibodies were most reliably detected post infection, independent of the number/severity of symptoms, and correlated best with protective neutralising antibodies at least for six months. They thus qualify best for large-scale seroepidemiological evaluation of both seroprevalence and seroprotection.FundingThis study received funding from the Austrian Ministry of Education, Science and Research within the research framework in relation to the coronavirus disease 2019 pandemic (GZ 2020 0225 104).Key pointsPersistence of SARS-CoV-2 antibodies depends on their specificity. Total RBD-specific antibodies are those that are stable for up to at least six months and correlate best with neutralisation independent of the presence and severity of COVID-19 symptoms.Research in contextEvidence before the studyAt the beginning of the study (early pandemic in April 2020), the SARS-Cov-2 specific seroprevalence was totally unknown. Additionally, S1-specific antibody assays being the first on the market were tested with limited sample size showing a lower sensitivity and specificity at that time. Furthermore, at that time, there were no unambiguous interpretations of antibody test results with regard to immunity/protection against reinfection. It was also not clear whether the detection of different antibody specificities could yield an essential input into the interpretation of the antibody’s qualities. Another open question was how long antibodies of the various specificities as well as antibodies with protective capacities would persist.Added value of this studyWe provide data to confirm the most reliable correlation of RBD-specific antibodies with neutralising antibodies that are stable for at least six months. S1- and NCP-specific antibodies wane more quickly than RBD-specific antibodies, rendering them not as ideal candidates for longitudinal seroprevalence studies. Concerning symptoms, anosmia/dysgeusia was strongly associated with NT-seropositivity and seroprotection in the overall study population.Implications of all the available evidenceOur data suggest that RBD-specific total antibody measurements with assays of high specificity can be used for cross-sectional as well as longitudinal seroepidemiological studies, even in low-prevalence settings. Detection of these antibodies also indicates robust seroprotection for at least six months. Due to the substantial loss of S1- and NCP-specific antibodies within the first months, assays targeting these antigen specificities – in contrast to RBD-specific antibody measurements – are not optimal to assess the duration of seroprotection. Overall, respiratory symptoms alone were not useful in predicting a past infection with SARS-CoV-2. However, anosmia/dysgeusia appeared to be a significant diagnostic marker, in particular for mild COVID-19.

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Rapid seroconversion and persistent functional IgG antibodies in severe COVID-19 patients correlates with an IL-12p70 and IL-33 signature

Scientific Reports ◽

10.1038/s41598-021-83019-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ariel Munitz ◽

L. Edry-Botzer ◽

M. Itan ◽

R. Tur-Kaspa ◽

D. Dicker ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Neutralizing Antibodies ◽

Host Response ◽

Humoral Response ◽

Rapid Onset ◽

Response Analysis ◽

Receptor Binding Domain ◽

Igg Antibodies ◽

Viral Receptor ◽

Iga Antibodies

AbstractDespite ongoing efforts to characterize the host response toward SARS-CoV-2, a major gap in our knowledge still exists regarding the magnitude and duration of the humoral response. Analysis of the antibody response in mild versus moderate/severe patients, using our new developed quantitative electrochemiluminescent assay for detecting IgM/IgA/IgG antibodies toward SARS-CoV-2 antigens, revealed a rapid onset of IgG/IgA antibodies, specifically in moderate/severe patients. IgM antibodies against the viral receptor binding domain, but not against nucleocapsid protein, were detected at early stages of the disease. Furthermore, we observed a marked reduction in IgM/IgA antibodies over-time. Adapting our assay for ACE2 binding-competition, demonstrated that the presence of potentially neutralizing antibodies is corelated with IgG/IgA. Finally, analysis of the cytokine profile in COVID-19 patients revealed unique correlation of an IL-12p70/IL33 and IgG seroconversion, which correlated with disease severity. In summary, our comprehensive analysis has major implications on the understanding and monitoring of SARS-CoV-2 infections.

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Application of Wide-Band Ultrasound for the Detection of Angled Crack Features in Oil and Gas Pipelines

Volume 1: Pipeline and Facilities Integrity ◽

10.1115/ipc2018-78521 ◽

2018 ◽

Author(s):

Willem Vos ◽

Petter Norli ◽

Emilie Vallee

Keyword(s):

Large Scale ◽

Crack Detection ◽

Oil And Gas ◽

Wide Band ◽

Theoretical Background ◽

Proof Of Concept ◽

Offshore Pipelines ◽

Large Scale Testing ◽

Theoretical Predictions ◽

Set Up

This paper describes a novel technique for the detection of cracks in pipelines. The proposed in-line inspection technique has the ability to detect crack features at random angles in the pipeline, such as axial, circumferential, and any angle in between. This ability is novel to the current ILI technology offering and will also add value by detecting cracks in deformed pipes (i.e. in dents), and cracks associated with the girth weld (mid weld cracks, rapid cooling cracks and cracks parallel to the weld). Furthermore, the technology is suitable for detection of cracks in spiral welded pipes, both parallel to the spiral weld as well as perpendicular to the weld. Integrity issues around most features described above are not addressed with ILI tools, often forcing operators to perform hydrostatic tests to ensure pipeline safety. The technology described here is based on the use of wideband ultrasound inline inspection tools that are already in operation. They are designed for the inspection of structures operating in challenging environments such as offshore pipelines. Adjustments to the front-end analog system and data collection from a grid of transducers allow the tools to detect cracks in any orientation in the line. Description of changes to the test set-up are presented as well as the theoretical background behind crack detection. Historical development of the technology will be presented, such as early laboratory testing and proof of concept. The proof of concept data will be compared to the theoretical predictions. A detailed set of results are presented. These are from tests that were performed on samples sourced from North America and Europe which contain SCC features. Results from ongoing testing will be presented, which involved large-scale testing on SCC features in gas-filled pipe spools.

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Reducing the Cost of Rapid Antigen Tests through Swab Pooling and Extraction in a Device

10.1101/2021.03.11.21252969 ◽

2021 ◽

Author(s):

Tim Berking ◽

Sabrina G. Lorenz ◽

Alexander Ulrich ◽

Joachim Greiner ◽

Clemens Richert

Keyword(s):

Large Scale ◽

Signal To Noise Ratio ◽

Point Of Care ◽

Positive Control ◽

Extraction Buffer ◽

Large Scale Testing ◽

Antigen Tests ◽

Set Up ◽

Cost Of Materials ◽

The Cost

AbstractThe COVID-19 pandemic places a significant stress on the viral testing capabilities of many countries. The value of rapid point-of-care (PoC) antigen tests is becoming increasingly clear, but implementing frequent large scale testing is costly. We have developed an inexpensive device for pooling swabs, extracting specimens, and detecting viral antigens with a commercial lateral flow assay detecting the nucleocapsid protein of SARS-CoV-2 as antigen. The holder of the device can be produced locally through 3D printing. The extraction and the elution can be performed with the entire set-up encapsulated in a transparent bag, minimizing the risk of infection for the operator. With 6 swabs holding approx. 0.1 mL specimen each and 0.35 mL extraction buffer, 43±6 % (n= 8) of the signal for an individual extraction of a positive control standard was obtained. Image analysis still showed a signal-to-noise ratio of ≥ 7 upon further eight-fold dilution. Our current total cost of materials is below $ 2 per tested person or 20% of our cost for an individual PoC test. These findings suggest that pooling can make frequent testing more affordable for schools, universities and other institutions, without decreasing sensitivity to an unacceptable level. Further validation of the method is required.

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Detailed Multiplex Analysis of SARS-CoV-2 Specific Antibodies in COVID-19 Disease

Frontiers in Immunology ◽

10.3389/fimmu.2021.695230 ◽

2021 ◽

Vol 12 ◽

Author(s):

Siggeir F. Brynjolfsson ◽

Hildur Sigurgrimsdottir ◽

Elin D. Einarsdottir ◽

Gudrun A. Bjornsdottir ◽

Brynja Armannsdottir ◽

...

Keyword(s):

Antibody Response ◽

Immunological Response ◽

Receptor Binding Domain ◽

Igg Antibody ◽

Nucleocapsid Proteins ◽

The Third ◽

Antibody Isotypes ◽

Iga Antibodies ◽

Set Up ◽

Antibody Levels

A detailed understanding of the antibody response against SARS-CoV-2 is of high importance, especially with the emergence of novel vaccines. A multiplex-based assay, analyzing IgG, IgM, and IgA antibodies against the receptor binding domain (RBD), spike 1 (S1), and nucleocapsid proteins of the SARS-CoV-2 virus was set up. The multiplex-based analysis was calibrated against the Elecsys® Anti-SARS-CoV-2 assay on a Roche Cobas® instrument, using positive and negative samples. The calibration of the multiplex based assay yielded a sensitivity of 100% and a specificity of 97.7%. SARS-CoV-2 specific antibody levels were analyzed by multiplex in 251 samples from 221 patients. A significant increase in all antibody types (IgM, IgG, and IgA) against RBD was observed between the first and the third weeks of disease. Additionally, the S1 IgG antibody response increased significantly between weeks 1, 2, and 3 of disease. Class switching appeared to occur earlier for IgA than for IgG. Patients requiring hospital admission and intensive care had higher levels of SARS-CoV-2 specific IgA levels than outpatients. These findings describe the initial antibody response during the first weeks of disease and demonstrate the importance of analyzing different antibody isotypes against multiple antigens and include IgA when examining the immunological response to COVID-19.

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Lasting antibody and T cell responses to SARS-CoV-2 in COVID-19 patients three months after infection

Nature Communications ◽

10.1038/s41467-021-21155-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Xiao-Lin Jiang ◽

Guo-Lin Wang ◽

Xiang-Na Zhao ◽

Fei-Hu Yan ◽

Lin Yao ◽

...

Keyword(s):

T Cell ◽

Receptor Binding ◽

Symptom Onset ◽

T Cell Responses ◽

Receptor Binding Domain ◽

Neutralising Antibodies ◽

Specific Antibodies ◽

Cell Responses ◽

Protein Receptor ◽

Nucleoprotein N

AbstractThe dynamics, duration, and nature of immunity produced during SARS-CoV-2 infection are still unclear. Here, we longitudinally measured virus-neutralising antibody, specific antibodies against the spike (S) protein, receptor-binding domain (RBD), and the nucleoprotein (N) of SARS-CoV-2, as well as T cell responses, in 25 SARS-CoV-2-infected patients up to 121 days post-symptom onset (PSO). All patients seroconvert for IgG against N, S, or RBD, as well as IgM against RBD, and produce neutralising antibodies (NAb) by 14 days PSO, with the peak levels attained by 15–30 days PSO. Anti-SARS-CoV-2 IgG and NAb remain detectable and relatively stable 3–4 months PSO, whereas IgM antibody rapidly decay. Approximately 65% of patients have detectable SARS-CoV-2-specific CD4+ or CD8+ T cell responses 3–4 months PSO. Our results thus provide critical evidence that IgG, NAb, and T cell responses persist in the majority of patients for at least 3–4 months after infection.

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The Effect of Pooling on the Detection of the Nucleocapsid Protein of SARS-CoV-2 with Rapid Antigen Tests

Diagnostics ◽

10.3390/diagnostics11071290 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1290

Author(s):

Tim Berking ◽

Sabrina Lorenz ◽

Alexander Ulrich ◽

Joachim Greiner ◽

Eric Kervio ◽

...

Keyword(s):

Nucleocapsid Protein ◽

Large Scale ◽

Signal To Noise Ratio ◽

Point Of Care ◽

Pilot Project ◽

Individual Case ◽

Positive Control ◽

Control Line ◽

Antigen Tests ◽

Set Up

The COVID-19 pandemic puts significant stress on the viral testing capabilities of many countries. Rapid point-of-care (PoC) antigen tests are valuable tools but implementing frequent large scale testing is costly. We have developed an inexpensive device for pooling swabs, extracting specimens, and detecting viral antigens with a commercial lateral flow test for the nucleocapsid protein of SARS-CoV-2 as antigen. The holder of the device can be produced locally through 3D printing. The extraction and the elution can be performed with the entire set-up encapsulated in a transparent bag, minimizing the risk of infection for the operator. With 0.35 mL extraction buffer and six swabs, including a positive control swab, 43 ± 6% (n = 8) of the signal for an individual extraction of a positive control standard was obtained. Image analysis still showed a signal-to-noise ratio of approximately 2:1 at 32-fold dilution of the extract from a single positive control swab. The relative signal from the test line versus the control line was found to scale linearly upon dilution (R2 = 0.98), indicating that other pooling regimes are conceivable. A pilot project involving 14 participants and 18 pooled tests in a laboratory course at our university did not give any false positives, and an individual case study confirmed the ability to detect a SARS-CoV-2 infection with five-fold or six-fold pooling, including one swab from a PCR-confirmed COVID patient. These findings suggest that pooling can make frequent testing more affordable for schools, universities, and similar institutions, without decreasing sensitivity to an unacceptable level.

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Molecular clamp stabilised Spike protein for protection against SARS-CoV-2

10.21203/rs.3.rs-68892/v1 ◽

2020 ◽

Author(s):

Daniel Watterson ◽

Danushka Wijesundara ◽

Naphak Modhiran ◽

Francesca Mordant ◽

Zheyi Li ◽

...

Keyword(s):

Clinical Evaluation ◽

Large Scale ◽

Vaccine Candidate ◽

Receptor Binding Domain ◽

Preclinical Development ◽

Neutralising Antibodies ◽

Clinical Safety ◽

Toxicology Study ◽

Efficacy Trials ◽

Large Scale Manufacture

Abstract Efforts to develop and deploy effective vaccines against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) continue at pace with more than 30 candidate vaccines now in clinical evaluation. Here we describe the preclinical development of an adjuvanted, prefusion-stabilised Spike (S) protein “Sclamp” subunit vaccine, from rational antigen design through to assessing manufacturability and vaccine efficacy. In mice, the vaccine candidate elicits high levels of neutralising antibodies to epitopes both within and outside the receptor binding domain (RBD) of S, as well as broadly reactive and polyfunctional S-specific CD4+ and cytotoxic CD8+ T cells. We also show protection in Syrian hamsters, which has emerged as a robust animal model for pulmonary SARS-CoV-2 infection. No evidence of vaccine enhanced disease was observed in animal challenge studies and pre-clinical safety was further demonstrated in a GLP toxicology study in rats. The Sclamp vaccine candidate is currently progressing rapidly through clinical evaluation in parallel with large-scale manufacture for pivotal efficacy trials and potential widespread distribution.

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Efficacy of anti-SARS-CoV-2 mRNA vaccine in systemic autoimmune disorders: induction of high avidity and neutralising anti-RBD antibodies

RMD Open ◽

10.1136/rmdopen-2021-001914 ◽

2021 ◽

Vol 7 (3) ◽

pp. e001914

Author(s):

Chiara Tani ◽

Federico Pratesi ◽

Rosaria Talarico ◽

Chiara Cardelli ◽

Teresita Caruso ◽

...

Keyword(s):

Healthcare Workers ◽

Control Group ◽

High Avidity ◽

Healthy Controls ◽

Receptor Binding Domain ◽

Igg Antibodies ◽

Neutralising Antibodies ◽

Antibody Avidity ◽

Iga Antibodies ◽

Vaccine Testing

ObjectivesIn patients with systemic autoimmune rheumatic disorders (SARDs), vaccination with SARS-CoV-2 mRNA vaccines has been proposed. The aim of this study is to evaluate the immune response elicited by vaccination with mRNA vaccine, testing IgM, IgA and IgG antibodies to SARS-CoV-2 receptor-binding domain (RBD) and measuring neutralising antibodies.MethodsIgG, IgM and IgA anti-RBD antibodies were measured in 101 patients with SARDs. Antibodies inhibiting the interaction between RBD and ACE2 were evaluated. Antibody avidity was tested in a chaotropic ELISA using urea. Twenty-one healthcare workers vaccinated with mRNA vaccine served as control group.ResultsAnti-RBD IgG and IgA were produced after the first dose (69% and 64% of the patients) and after the boost (93% and 83%). Antibodies inhibiting the interaction of RBD with ACE2 were detectable in 40% of the patients after the first dose and 87% after boost, compared with 100% in healthy controls (p<0.01). Abatacept and mycophenolate had an impact on the titre of IgG anti-RBD antibodies (p<0.05 and p<0.005, respectively) and on the amount of neutralising antibodies. No effect of other therapies was observed. Vaccinated patients produce high avidity antibodies, as healthy controls.ConclusionsThese data show that double-dose vaccination induced in patients with SARDs anti-RBD IgG and IgA antibodies in amounts not significantly different from controls, and, most interestingly, characterised by high avidity and endowed with neutralising activity.

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Platelet Anti-Aggregating Activity and Tolerance of Clopidogrel in Atherosclerotic Patients

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650689 ◽

1996 ◽

Vol 76 (06) ◽

pp. 0939-0943 ◽

Cited By ~ 74

Author(s):

B Boneu ◽

G Destelle ◽

Keyword(s):

Platelet Aggregation ◽

Large Scale ◽

Bleeding Time ◽

Antithrombotic Activity ◽

Ambulatory Patients ◽

Patients At Risk ◽

Set Up ◽

Ischemic Events ◽

Large Scale Clinical Trial ◽

Selection Of

SummaryThe anti-aggregating activity of five rising doses of clopidogrel has been compared to that of ticlopidine in atherosclerotic patients. The aim of this study was to determine the dose of clopidogrel which should be tested in a large scale clinical trial of secondary prevention of ischemic events in patients suffering from vascular manifestations of atherosclerosis [CAPRIE (Clopidogrel vs Aspirin in Patients at Risk of Ischemic Events) trial]. A multicenter study involving 9 haematological laboratories and 29 clinical centers was set up. One hundred and fifty ambulatory patients were randomized into one of the seven following groups: clopidogrel at doses of 10, 25, 50,75 or 100 mg OD, ticlopidine 250 mg BID or placebo. ADP and collagen-induced platelet aggregation tests were performed before starting treatment and after 7 and 28 days. Bleeding time was performed on days 0 and 28. Patients were seen on days 0, 7 and 28 to check the clinical and biological tolerability of the treatment. Clopidogrel exerted a dose-related inhibition of ADP-induced platelet aggregation and bleeding time prolongation. In the presence of ADP (5 \lM) this inhibition ranged between 29% and 44% in comparison to pretreatment values. The bleeding times were prolonged by 1.5 to 1.7 times. These effects were non significantly different from those produced by ticlopidine. The clinical tolerability was good or fair in 97.5% of the patients. No haematological adverse events were recorded. These results allowed the selection of 75 mg once a day to evaluate and compare the antithrombotic activity of clopidogrel to that of aspirin in the CAPRIE trial.

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