scholarly journals A comparison of four serological assays for detecting anti–SARS-CoV-2 antibodies in human serum samples from different populations

2020 ◽  
Vol 12 (559) ◽  
pp. eabc3103 ◽  
Author(s):  
Ludivine Grzelak ◽  
Sarah Temmam ◽  
Cyril Planchais ◽  
Caroline Demeret ◽  
Laura Tondeur ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Blood Donors ◽  
Serum Samples ◽  
Neutralization Activity ◽  
S Protein ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Different Populations ◽  
Carboxyl Terminal ◽  
Nucleoprotein N

It is of paramount importance to evaluate the prevalence of both asymptomatic and symptomatic cases of SARS-CoV-2 infection and their differing antibody response profiles. Here, we performed a pilot study of four serological assays to assess the amounts of anti–SARS-CoV-2 antibodies in serum samples obtained from 491 healthy individuals before the SARS-CoV-2 pandemic, 51 individuals hospitalized with COVID-19, 209 suspected cases of COVID-19 with mild symptoms, and 200 healthy blood donors. We used two ELISA assays that recognized the full-length nucleoprotein (N) or trimeric spike (S) protein ectodomain of SARS-CoV-2. In addition, we developed the S-Flow assay that recognized the S protein expressed at the cell surface using flow cytometry, and the luciferase immunoprecipitation system (LIPS) assay that recognized diverse SARS-CoV-2 antigens including the S1 domain and the carboxyl-terminal domain of N by immunoprecipitation. We obtained similar results with the four serological assays. Differences in sensitivity were attributed to the technique and the antigen used. High anti–SARS-CoV-2 antibody titers were associated with neutralization activity, which was assessed using infectious SARS-CoV-2 or lentiviral-S pseudotype virus. In hospitalized patients with COVID-19, seroconversion and virus neutralization occurred between 5 and 14 days after symptom onset, confirming previous studies. Seropositivity was detected in 32% of mildly symptomatic individuals within 15 days of symptom onset and in 3% of healthy blood donors. The four antibody assays that we used enabled a broad evaluation of SARS-CoV-2 seroprevalence and antibody profiling in different subpopulations within one region.

scholarly journals Longitudinal Study of SARS-CoV-2 Antibody Characteristics Using Label-Free Immunoassays

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S32-S32
Author(s):  
Y R Luo ◽  
C Yun ◽  
A H Wu ◽  
K L Lynch ◽  
I Chakraborty
Keyword(s):  
Symptom Onset ◽  
Neutralizing Antibody ◽  
Label Free ◽  
Serum Samples ◽  
Neutralization Activity ◽  
Antibody Avidity ◽  
Avidity Assay ◽  
Initial Rise ◽  
Igg Avidity ◽  
Antibody Titers

Abstract Introduction/Objective Since the start of the COVID-19 pandemic, much research has focused on the kinetics and magnitude of humoral immune response. With the advantages of monitoring real-time immunoreactions, label-free immunoassay (LFIA) is becoming a powerful tool in serology studies. We have developed LFIAs to measure SARS- CoV-2 antibody avidity and neutralization activity in a cohort of COVID-19 patients and determine if they correlate with antibody concentration. Serial serum samples collected from mild to severe COVID-19 patients were measured out to 8 months post-symptom onset to determine the durability of the neutralizing antibody response. Methods/Case Report Based on thin-film interferometry technology, we established a label-free IgG avidity assay and a label-free surrogate virus neutralization test (LF-sVNT). For measurement, sensing probes pre-coated with receptor-binding domain (RBD) of SARS-CoV-2 spike protein are applied to serum samples containing SARS-CoV-2 antibodies. The label-free IgG avidity assay measures the binding strength between RBD and IgG under urea dissociation. The LF-sVNT analyzes the binding ability of RBD to ACE2 after neutralizing RBD with antibodies. Results (if a Case Study enter NA) IgG avidity indices and neutralizing antibody titers (IC50) were determined from serum samples (n=246) from COVID-19 patients (n=113). IgG concentrations were measured using a fluorescent immunoassay. The neutralizing antibody titers showed a weak correlation with IgG concentrations and no correlation with IgG avidity indices. Over the time course up to 8 months post-symptom onset, IgG concentrations and neutralizing antibody titers presented similar trends: an initial rise, plateau and then in some cases a gradual decline after 40 days. The IgG avidity indices, in the same cases, plateaued after the initial rise. Conclusion The results demonstrated that LFIA could be used an excellent solution in the determination of SARS- CoV-2 antibody characteristics. The study found that IgG concentration and neutralizing antibody titer declined over time, while IgG avidity index remained constant after reaching a plateau. The decline of antibody neutralization activity can be attributed to the reduction in antibody quantity rather than the deterioration of antibody quality, as measured by antibody avidity.

scholarly journals SARS-CoV-2 serological analysis of COVID-19 hospitalized patients, pauci-symptomatic individuals and blood donors

2020 ◽  
Author(s):  
Ludivine Grzelak ◽  
Sarah Temmam ◽  
Cyril Planchais ◽  
Caroline Demeret ◽  
Christèle Huon ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Blood Donors ◽  
Hospitalized Patients ◽  
High Antibody ◽  
Serological Analysis ◽  
Healthy Donors ◽  
Response Profile ◽  
Antibody Titers ◽  
Antibody Profiling ◽  
Nucleoprotein N

AbstractIt is of paramount importance to evaluate the prevalence of both asymptomatic and symptomatic cases of SARS-CoV-2 infection and their antibody response profile. Here, we performed a pilot study to assess the levels of anti-SARS-CoV-2 antibodies in samples taken from 491 pre-epidemic individuals, 51 patients from Hôpital Bichat (Paris), 209 pauci-symptomatic individuals in the French Oise region and 200 contemporary Oise blood donors. Two in-house ELISA assays, that recognize the full-length nucleoprotein (N) or trimeric Spike (S) ectodomain were implemented. We also developed two novel assays: the S-Flow assay, which is based on the recognition of S at the cell surface by flow-cytometry, and the LIPS assay that recognizes diverse antigens (including S1 or N C-terminal domain) by immunoprecipitation. Overall, the results obtained with the four assays were similar, with differences in sensitivity that can be attributed to the technique and the antigen in use. High antibody titers were associated with neutralisation activity, assessed using infectious SARS-CoV-2 or lentiviral-S pseudotypes. In hospitalized patients, seroconversion and neutralisation occurred on 5-14 days post symptom onset, confirming previous studies. Seropositivity was detected in 29% of pauci-symptomatic individuals within 15 days post-symptoms and 3 % of blood of healthy donors collected in the area of a cluster of COVID cases. Altogether, our assays allow for a broad evaluation of SARS-CoV2 seroprevalence and antibody profiling in different population subsets.

scholarly journals Predicting the Efficacy of COVID-19 Convalescent Plasma Donor Units with the Lumit Dx anti-Receptor Binding Domain Assay

2021 ◽  
Author(s):  
Sanath Kumar Janaka ◽  
Natasha M Clark ◽  
David T Evans ◽  
Joseph P Connor
Keyword(s):  
Receptor Binding ◽  
Therapeutic Option ◽  
Passive Immunization ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
S Protein ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Novel Coronavirus ◽  
Design And Methods

AbstractBackgroundThe novel coronavirus SARS-CoV2 that causes COVID-19 has resulted in the death of more than 2.5 million people, but no cure exists. Although passive immunization with COVID-19 convalescent plasma (CCP) provides a safe and viable therapeutic option, the selection of optimal units for therapy in a timely fashion remains a barrier.Study design and methodsSince virus neutralization is a necessary characteristic of plasma that can benefit recipients, the neutralizing titers of plasma samples were measured using a retroviral-pseudotype assay. Binding antibody titers to the spike (S) protein were also determined by a clinically available serological assay (Ortho-Vitros total IG), and an in-house ELISA. The results of these assays were compared to a measurement of antibodies directed to the receptor binding domain (RBD) of the SARS-CoV2 S protein (Promega Lumit Dx).ResultsAll measures of antibodies were highly variable, but correlated, to different degrees, with each other. However, the anti-RBD antibodies correlated with viral neutralizing titers to a greater extent than the other antibody assays.DiscussionOur observations support the use of an anti-RBD assay such as the Lumit Dx assay, as an optimal predictor of the neutralization capability of CCP.

scholarly journals A SARS-CoV-2 Label-Free Surrogate Virus Neutralization Test and a Longitudinal Study of Antibody Characteristics in COVID-19 Patients

2021 ◽  
Author(s):  
Yiqi Ruben Luo ◽  
Cassandra Yun ◽  
Indrani Chakraborty ◽  
Alan H.B. Wu ◽  
Kara L. Lynch
Keyword(s):  
Symptom Onset ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Label Free ◽  
Serum Samples ◽  
Initial Rise ◽  
Igg Avidity ◽  
Antibody Titers

AbstractBackgroundThe laboratory-based methods to measure the SARS-CoV-2 humoral response include virus neutralization tests (VNTs) to determine antibody neutralization potency. For ease of use and universal applicability, surrogate virus neutralization tests (sVNTs) based on antibody-mediated blockage of molecular interactions have been proposed.MethodsA surrogate virus neutralization test established on a label-free immunoassay platform (LF-sVNT). The LF-sVNT analyzes the binding ability of RBD to ACE2 after neutralizing RBD with antibodies in serum.ResultsThe LF-sVNT neutralizing antibody titers (IC50) were determined from serum samples (n=246) from COVID-19 patients (n=113), as well as the IgG concentrations and the IgG avidity indices. Although there is variability in the kinetics of the IgG concentrations and neutralizing antibody titers between individuals, there is an initial rise, plateau and then in some cases a gradual decline at later timepoints after 40 days post-symptom onset. The IgG avidity indices, in the same cases, plateau after the initial rise and did not show a decline.ConclusionsThe LF-sVNT can be a valuable tool in clinical laboratories for the assessment of the presence of neutralizing antibodies to COVID-19. This study is the first to provide longitudinal neutralizing antibody titers beyond 200 days post-symptom onset. Despite the decline of IgG concentration and neutralizing antibody titer, IgG avidity index increases, reaches a plateau and then remains constant up to 8 months post-infection. The decline of antibody neutralization potency can be attributed to the reduction in antibody quantity rather than the deterioration of antibody avidity, a measure of antibody quality.SummaryA surrogate virus neutralization test established on a label-free immunoassay platform (LF-sVNT). Using the LF-sVNT and other assays, 246 serum samples from 113 COVID-19 patients were measured. We observed the time course of antibody characteristics beyond 200 days post-symptom onset.

scholarly journals Seven-Month Analysis of Five SARS-CoV-2 Antibody Assay Results after ChAdOx1 nCoV-19 Vaccination: Significant Decrease in SARS-CoV-2 Antibody Titer

Diagnostics ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 85
Author(s):  
Seri Jeong ◽  
Nuri Lee ◽  
Su-Kyung Lee ◽  
Eun-Jung Cho ◽  
Jungwon Hyun ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Antibody Titer ◽  
Healthcare Workers ◽  
Vaccination Strategy ◽  
Antibody Assay ◽  
Serum Samples ◽  
Vaccination Strategies ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Dose Scheme

We investigated the longevity rates of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after a complete ChAdOx1 nCoV-19 vaccination, which are rare and important to estimate their efficacy and establish a vaccination strategy. We assessed the positivity rates and changes of titers before (T0) and at one month (T1), four months (T2), and seven months (T3) after a ChAdOx1 nCoV-19 vaccination using five SARS-CoV-2 antibody assays. A total of 874 serum samples were obtained from 228 (T0 and T1), 218 (T2), and 200 (T3) healthcare workers. The positive rates for all five assays were 0.0–0.9% at T0, 66.2–92.5% at T1, 98.2–100.0% at T2, and 66.0–100.0% at T3. The positive rates at T3 were decreased compared to those at T2. The median antibody titers of all the assays at T3 were significantly decreased compared to those at T2 (860.5 to 232.0 U/mL for Roche total, 1041.5 to 325.5 AU/mL for Abbott IgG, 10.9 to 2.3 index for Siemens IgG, 99.5% to 94.7% for SD Biosensor V1, and 88.5% to 38.2% for GenScript). A third-dose scheme can be considered based on our data generated from five representative assays. Our findings contribute insights into SARS-CoV-2 antibody assays and appropriate vaccination strategies.

scholarly journals Differences in Performance Characteristics Among Four High-Throughput Assays for the Detection of Antibodies Against SARS-CoV-2 Using a Common Set of Patient Samples

2020 ◽  
Author(s):  
David M Manthei ◽  
Jason F Whalen ◽  
Lee F Schroeder ◽  
Anthony M Sinay ◽  
Shih-Hon Li ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Performance Characteristics ◽  
Clinical Test ◽  
Test Results ◽  
Rt Pcr ◽  
Serum Samples ◽  
Specificity And Sensitivity ◽  
Antibody Assays ◽  
Polymerase Chain ◽  
Serology Testing

Abstract Objectives Serologic testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has experienced a changing landscape of available assays coupled with uncertainty surrounding performance characteristics. Studies are needed to directly compare multiple commercially available assays. Methods Residual serum samples were identified based on SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) testing, clinical test results, and collection dates. Serum samples were analyzed using assays from four different manufacturers: DiaSorin anti–SARS-CoV-2 S1/S2 IgG, EUROIMMUN anti–SARS-CoV-2 IgG ELISA, Roche Elecsys anti–SARS-CoV-2, and Siemens SARS-CoV-2 Total antibody assays. Results Samples from SARS-CoV-2 RT-PCR–positive patients became increasingly positive as time from symptom onset increased. For patients with latest sample 14 or more days after symptom onset, sensitivities reached 93.1% to 96.6%, 98.3%, and 96.6% for EUROIMMUN, Roche, and Siemens assays, respectively, which were superior to the DiaSorin assay at 87.7%. The specificity of Roche and Siemens assays was 100% and superior to DiaSorin and EUROIMMUN assays, which ranged from 96.1% to 97.0% and 86.3% to 96.4%, respectively. Conclusions Laboratories should be aware of the advantages and limitations of serology testing options for SARS-CoV-2. The specificity and sensitivity achieved by the Roche and Siemens assays would be acceptable for testing in lower-prevalence regions and have the potential of orthogonal testing advantages if used in combination.

scholarly journals Neutralization Activity of Patient Sera Collected during the 2008-2009 Chikungunya Outbreak in Thailand

2014 ◽  
Vol 53 (1) ◽  
pp. 184-190 ◽  
Author(s):  
Natsuko Kishishita ◽  
Mikiko Sasayama ◽  
Naokazu Takeda ◽  
Areerat Sa-ngasang ◽  
Atchareeya Anuegoonpipat ◽  
...  
Keyword(s):  
Joint Pain ◽  
Clinical Symptoms ◽  
Neutralizing Antibody ◽  
Serum Samples ◽  
Chikv Infection ◽  
Neutralization Activity ◽  
Proinflammatory Mediators ◽  
Adaptive Immune Cells ◽  
Number Of Patients ◽  
Antibody Titers

Chikungunya virus (CHIKV) infection typically causes fever, rash, myalgia, and arthralgia and sometimes results in recurrent joint pain or, in severe cases, neurological disorders or death. How CHIKV infection leads to prolonged or severe symptoms is still not well understood. In this study, we examined the neutralization (NT) titer of 98 serum samples collected from patients during the 2008-2009 chikungunya outbreak in Thailand. While all serum samples showed neutralizing activity, virus was detected in 58% of the serum samples. When we analyzed a possible association between virus and antibody titers and the presence of typical symptoms of CHIKV infection, fever and joint pain, there was no significant association except that the number of patients with fever was over three times more than the number of those without fever when CHIKV was detectable in serum. This study indicates that although neutralizing antibody is critical to eliminate CHIKV, it appears not to be the main factor associated with clinical symptoms in some cases, so that other aspects of immune responses, such as those involving proinflammatory mediators and adaptive immune cells, should be considered altogether.

scholarly journals A SARS-CoV-2 Label-Free Surrogate Virus Neutralization Test and a Longitudinal Study of Antibody Characteristics in COVID-19 Patients

2021 ◽  
Author(s):  
Yiqi Ruben Luo ◽  
Cassandra Yun ◽  
Indrani Chakraborty ◽  
Alan H.B. Wu ◽  
Kara L. Lynch
Keyword(s):  
Symptom Onset ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Label Free ◽  
Neutralization Activity ◽  
Initial Rise ◽  
Igg Avidity ◽  
Antibody Titers

Methods designed to measure SARS-CoV-2 humoral response include virus neutralization tests to determine antibody neutralization activity. For ease of use and universal applicability, surrogate virus neutralization tests (sVNTs) based on antibody-mediated blockage of molecular interactions have been proposed. A surrogate virus neutralization test was established on a label-free immunoassay platform (LF-sVNT). The LF-sVNT analyzes the binding ability of SARS-CoV-2 spike protein receptor-binding domain (RBD) to ACE2 after neutralizing RBD with antibodies in serum. The LF-sVNT neutralizing antibody titers (IC50) were determined from serum samples (n=246) from COVID-19 patients (n=113), as well as the IgG concentrations and the IgG avidity indices. Although there was variability in the kinetics of the IgG concentrations and neutralizing antibody titers between individuals, there was an initial rise, plateau and then in some cases a gradual decline at later timepoints after 40 days post-symptom onset. The IgG avidity indices, in the same cases, plateaued after an initial rise and did not show a decline. The LF-sVNT can be a valuable tool in research and clinical laboratories for the assessment of the presence of neutralizing antibodies to COVID-19. This study is the first to provide longitudinal neutralizing antibody titers beyond 200 days post-symptom onset. Despite the decline of IgG concentration and neutralizing antibody titer, IgG avidity index increases, reaches a plateau and then remains constant up to 8 months post-infection. The decline of antibody neutralization activity can be attributed to the reduction in antibody quantity rather than the deterioration of antibody quality, as measured by antibody avidity.

scholarly journals Comparing Five SARS-CoV-2 Antibody Assay Results Before and After the First and Second ChAdOx1 nCoV-19 Vaccination Among Health Care Workers: A Prospective Multicenter Study

2021 ◽  
Author(s):  
Seri Jeong ◽  
Nuri Lee ◽  
Su Kyung Lee ◽  
Eun-Jung Cho ◽  
Jungwon Hyun ◽  
...  
Keyword(s):  
Health Care Workers ◽  
Adverse Reactions ◽  
Neutralizing Antibody ◽  
Fold Increase ◽  
Serum Samples ◽  
Prospective Multicenter Study ◽  
Care Workers ◽  
Before And After ◽  
Antibody Assays ◽  
Antibody Titers

Reliable results for serologic positivity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody after the second dose of AstraZeneca (AZ) vaccination are important to estimate the real efficacy of vaccination. We evaluated the positivity rates and the changes of semi-quantitative antibody titers before and after the first and second ChAdOx1 nCoV-19 Vaccinations using five SARS-CoV-2 antibody assays, including two surrogate virus neutralization tests. A total of 674 serum samples were obtained from 228 participants during three blood sampling periods. A questionnaire on symptoms, severity and adverse reactions duration was completed after the second vaccination. The overall positive rates for all assays were 0.0-0.9% before vaccination, 66.2-92.5% after the first vaccination, and 98.2-100.0% after the second vaccination. Median antibody titers in five assays after the second dose of vaccination were increased compared to those after the first dose (106.4-fold increase for Roche total antibody, 3.6-fold for Abbott IgG, 3.6-fold for Siemens, 1.2-fold for SD Biosensor V1 neutralizing antibody, and 2.2-fold for GenScript neutralizing antibody). Adverse reactions reduced after the second dose in 89.9% of participants compared to after the first dose. Overall, the second vaccination led to almost 100% positivity rates based on these SARS-CoV-2 antibody assays. The results should be interpreted with caution, considering the characteristics of applied assays. Our findings could inform decisions regarding vaccination and the use of immunoassays, thus, contributing to the SARS-CoV-2 pandemic control.

scholarly journals Comparison of sixteen serological SARS-CoV-2 immunoassays in sixteen clinical laboratories

2020 ◽  
Author(s):  
Lene Holm Harritshoej ◽  
Mikkel Gybel-Brask ◽  
Shoaib Afzal ◽  
Pia R. Kamstrup ◽  
Charlotte Svaerke Joergensen ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Blood Donors ◽  
High Sensitivity ◽  
Cross Reactivity ◽  
Nucleic Acid Amplification ◽  
Limited Data ◽  
Serum Samples ◽  
Diagnostic Use ◽  
Ig G ◽  
Abbott Architect

Serological SARS-CoV-2 assays are needed to support clinical diagnosis and epidemiological investigations. Recently, assays for the large-volume detection of total antibodies (Ab) and immunoglobulin (Ig) G and M against SARS-CoV-2 antigens have been developed, but there are limited data on the diagnostic accuracy of these assays. This study was organized as a Danish national collaboration and included fifteen commercial and one in-house anti-SARS-CoV-2 assays in sixteen laboratories. Sensitivity was evaluated using 150 serum samples from individuals diagnosed with asymptomatic, mild or moderate nonhospitalized (n=129) or hospitalized (n=31) COVID-19, confirmed by nucleic acid amplification tests, collected 13-73 days from symptom onset. Specificity and cross-reactivity were evaluated in samples collected prior to the SARS-CoV-2 epidemic from > 586 blood donors and patients with autoimmune diseases or CMV or EBV infections. Predefined specificity criteria of ≥99% were met by all total-Ab and IgG assays except one (Diasorin/LiaisonXL-IgG 97.2%). The sensitivities in descending order were: Wantai/ELISA total-Ab (96.7%), CUH/NOVO in-house ELISA total-Ab (96.0%), Ortho/Vitros total-Ab (95.3%), YHLO/iFlash-IgG (94.0%), Ortho/Vitros-IgG (93.3%), Siemens/Atellica total-Ab (93.2%), Roche-Elecsys total-Ab (92.7%), Abbott-Architect-IgG (90.0%), Abbott/Alinity-IgG (median 88.0%), Diasorin/LiaisonXL-IgG (84.6%), Siemens/Vista total-Ab (81.0%), Euroimmun/ELISA-IgG (78.0%), and Snibe/Maglumi-IgG (median 78.0%). The IgM results were variable, but one assay (Wantai/ELISA-IgM) had both high sensitivity (82.7%) and specificity (99%). The rate of seropositivity increased with time from symptom onset and symptom severity. In conclusion, predefined sensitivity and specificity acceptance criteria of 90%/99%, respectively, for diagnostic use were met in five of six total-Ab and three of seven IgG assays.

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