Five Commercial Immunoassays for SARS-CoV-2 Antibody Determination and Their Comparison and Correlation with the Virus Neutralization Test

There is an ongoing debate as to whether SARS-CoV-2 antibodies can be found in patients who have recovered from COVID-19 disease. Currently, there is no consensus on whether the antibodies, if present, are protective. Our regular measurements of SARS-CoV-2 antibodies, starting in July 2020, have provided us with the opportunity of becoming acquainted with the five different immunoassays. A total of 149 patients were enrolled in our study. We measured the samples using each immunoassay, then performing a virus neutralization test and comparing the results of SARS-CoV-2 antibodies with this test. We observed that the production of neutralizing antibodies is age-dependent. Elderly patients have a higher proportion of high neutralizing titers than young patients. Based on our results, and in combination with the literature findings, we can conclude that the serological SARS-CoV-2 antibody measurement is a helpful tool in the fight against COVID-19. The assays can provide information about the patient’s previous contact with the virus. Anti-spike protein assays correlate well with the virus neutralization test and can be used in the screening of potential convalescent plasma donors.

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Evaluation of a Novel Reporter Virus Neutralization Test for Serological Diagnosis of Zika and Dengue Virus Infection

Journal of Clinical Microbiology ◽

10.1128/jcm.00975-17 ◽

2017 ◽

Vol 55 (10) ◽

pp. 3028-3036 ◽

Cited By ~ 21

Author(s):

Chao Shan ◽

Daniel A. Ortiz ◽

Yujiao Yang ◽

Susan J. Wong ◽

Laura D. Kramer ◽

...

Keyword(s):

Dengue Virus ◽

Neutralizing Antibodies ◽

Neutralization Test ◽

Reference Method ◽

Laboratory Diagnosis ◽

Virus Neutralization Test ◽

Virus Neutralization ◽

Enzyme Linked Immunosorbent Assay ◽

Reporter Virus ◽

Screening Assay

ABSTRACT Currently, the laboratory diagnosis of Zika virus (ZIKV) infection is primarily through the detection of ZIKV RNA or antibodies against ZIKV proteins. The detection of viral RNA is highly sensitive and specific, but periods of viremia and viruria are brief, limiting the utility of ZIKV RNA assays. Instead, most ZIKV infections are diagnosed serologically, using an IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) for screening, followed by a confirmatory plaque reduction neutralization test (PRNT). Typical turnaround times vary, due to assay incubation periods and a lack of clinical laboratories performing these tests. Recently, a novel luciferase-ZIKV- and -dengue virus (DENV)-based serological assay, which considerably improves the turnaround times and throughput for ZIKV diagnosis, was described. Using the traditional PRNT as a reference method, we evaluated the performance characteristics of the reporter virus neutralization test (RVNT) with 258 clinical serum specimens. The ZIKV RVNT produced primary ZIKV screening and secondary confirmation results in 4 days, with 100% reproducibility. As a screening assay, the ZIKV RVNT displayed excellent diagnostic accuracy, sensitivity, and specificity of 98.2%, 100%, and 98.1%, respectively. As a confirmatory assay, the ZIKV RVNT titers displayed 93.1% agreement with the traditional ZIKV PRNT titers. Overall, the RVNT accurately and reliably detects neutralizing antibodies in patient serum specimens, with improved turnaround times, and can be used for the serological detection of ZIKV infections. Due to the homogeneous 96-well format, the RVNT has also significantly improved the assay throughput to allow testing of a large number of specimens in a single run.

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Evaluation of high-throughput SARS-CoV-2 serological assays in a longitudinal cohort of mild COVID-19 patients: sensitivity, specificity and association with virus neutralization test

10.1101/2020.09.30.20194290 ◽

2020 ◽

Author(s):

Antonin Bal ◽

Bruno Pozzetto ◽

Mary-Anne Trabaud ◽

Vanessa Escuret ◽

Muriel Rabilloud ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Healthcare Workers ◽

Neutralization Test ◽

Neutralizing Antibody ◽

Virus Neutralization Test ◽

Virus Neutralization ◽

Serological Tests ◽

Course Of Disease ◽

Antibody Titers ◽

Sensitivity Specificity

BackgroundThe association between SARS-CoV-2 commercial serological assays and virus neutralization test (VNT) has been poorly explored in mild COVID-19 patients.MethodsA total of 439 serum specimens were longitudinally collected from 76 healthcare workers with RT-PCR-confirmed COVID-19. The sensitivity (determined weekly) of nine commercial serological assays were evaluated. Specificity was assessed using 69 pre-pandemic sera. Correlation, agreement and concordance with the VNT were also assessed on a subset of 170 samples. Area under the ROC curve (AUC) was estimated at several neutralizing antibody titers.ResultsThe Wantai Total Ab assay targeting the receptor binding domain (RBD) within the S protein presented the best sensitivity at different times during the course of disease. The specificity was greater than 95% for all tests except for the Euroimmun IgA assay. The overall agreement with the presence of neutralizing antibodies ranged from 62.2% (95%CI; 56.0-68.1) for bioMérieux IgM to 91.2% (87.0-94.2) for Siemens. The lowest negative percent agreement (NPA) was found with the Wantai Total Ab assay (NPA 33% (21.1-48.3)). The NPA for other total Ab or IgG assays targeting the S or the RBD was 80.7% (66.7-89.7), 90.3 (78.1-96.1) and 96.8% (86.8-99.3) for Siemens, bioMérieux IgG and DiaSorin, respectively. None of commercial assays have sufficient performance to detect a neutralizing titer of 80 (AUC<0.76).ConclusionsAlthough some assays presented a better agreement with VNT than others, the present findings emphasize that commercialized serological tests including those targeting the RBD cannot substitute a VNT for the assessment of functional antibody response.

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Evaluation of a multi-species SARS-CoV-2 surrogate virus neutralization test

10.1101/2021.05.07.21252267 ◽

2021 ◽

Author(s):

Carmen W.E. Embregts ◽

Babs Verstrepen ◽

Jan A.M. Langermans ◽

Kinga P Boszormenyi ◽

Reina S. Sikkema ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Respiratory Infections ◽

Neutralization Test ◽

Rhesus Macaques ◽

High Sensitivity ◽

High Specificity ◽

Virus Neutralization Test ◽

Virus Neutralization ◽

Antibody Detection ◽

Intermediate Hosts

Assays to measure SARS-CoV-2-specific neutralizing antibodies are important to monitor seroprevalence, to study asymptomatic infections and to reveal (intermediate) hosts. A recently developed assay, the surrogate virus-neutralization test (sVNT) is a quick and commercially available alternative to the 'gold standard' virus neutralization assay using authentic virus, and does not require processing at BSL-3 level. The assay relies on the inhibition of binding of the receptor binding domain (RBD) on the spike (S) protein to human angiotensin-converting enzyme 2 (hACE2) by antibodies present in sera. As the sVNT does not require species- or isotype-specific conjugates, it can be similarly used for antibody detection in human and animal sera. In this study, we used 298 sera from PCR-confirmed COVID-19 patients and 151 sera from patients confirmed with other coronavirus or other (respiratory) infections, to evaluate the performance of the sVNT. To analyze the use of the assay in a One Health setting, we studied the presence of RBD-binding antibodies in 154 sera from nine animal species (cynomolgus and rhesus macaques, ferrets, rabbits, hamsters, cats, cattle, mink and dromedary camels). The sVNT showed a moderate to high sensitivity and a high specificity using sera from confirmed COVID-19 patients (91.3% and 100%, respectively) and animal sera (93.9% and 100%), however it lacked sensitivity to detect low titers. Significant correlations were found between the sVNT outcomes and PRNT50 and the Wantai total Ig and IgM ELISAs. While species-specific validation will be essential, our results show that the sVNT holds promise in detecting RBD-binding antibodies in multiple species.

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Evaluation of high-throughput SARS-CoV-2 serological assays in a longitudinal cohort of patients with mild COVID-19: clinical sensitivity, specificity and association with virus neutralization test

Clinical Chemistry ◽

10.1093/clinchem/hvaa336 ◽

2021 ◽

Author(s):

Antonin Bal ◽

Bruno Pozzetto ◽

Mary-Anne Trabaud ◽

Vanessa Escuret ◽

Muriel Rabilloud ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Neutralization Test ◽

Neutralizing Antibody ◽

Virus Neutralization Test ◽

Virus Neutralization ◽

Serological Tests ◽

Course Of Disease ◽

Clinical Sensitivity ◽

Antibody Titers ◽

Sensitivity Specificity

Abstract Background The association between SARS-CoV-2 commercial serological assays and virus neutralization test (VNT) has been poorly explored in mild patients with COVID-19. Methods 439 serum specimens were longitudinally collected from 76 healthcare workers with RT-PCR-confirmed COVID-19. The clinical sensitivity (determined weekly) of nine commercial serological assays were evaluated. Clinical specificity was assessed using 69 pre-pandemic sera. Correlation, agreement and concordance with the VNT were also assessed on a subset of 170 samples. Area under the ROC curve (AUC) was estimated at 2 neutralizing antibody titers. Results The Wantai Total Ab assay targeting the receptor binding domain (RBD) within the S protein presented the best sensitivity at different times during the course of disease. The clinical specificity was greater than 95% for all tests except for the Euroimmun IgA assay. The overall agreement with the presence of neutralizing antibodies ranged from 62.2% (95%CI; 56.0-68.1) for bioMérieux IgM to 91.2% (87.0-94.2) for Siemens. The lowest negative percent agreement (NPA) was found with the Wantai Total Ab assay (NPA 33% (21.1-48.3)). The NPA for other total Ab or IgG assays targeting the S or the RBD was 80.7% (66.7-89.7), 90.3 (78.1-96.1) and 96.8% (86.8-99.3) for Siemens, bioMérieux IgG and DiaSorin, respectively. None of commercial assays have sufficient performance to detect a neutralizing titer of 80 (AUC<0.76). Conclusions Although some assays show a better agreement with VNT than others, the present findings emphasize that commercialized serological tests including those targeting the RBD cannot substitute a VNT for the assessment of functional antibody response.

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Evaluation of Serological Tests for Detection of Antibodies against Lumpy Skin Disease Virus

Journal of Clinical Microbiology ◽

10.1128/jcm.00348-20 ◽

2020 ◽

Vol 58 (9) ◽

Author(s):

Nina Krešić ◽

Ivana Šimić ◽

Tomislav Bedeković ◽

Žaklin Acinger-Rogić ◽

Ivana Lojkić

Keyword(s):

Skin Disease ◽

Neutralizing Antibodies ◽

Large Scale ◽

Neutralization Test ◽

Virus Neutralization Test ◽

Virus Neutralization ◽

Enzyme Linked Immunosorbent Assay ◽

Surveillance Program ◽

Kappa Index ◽

Lumpy Skin Disease

ABSTRACT Lumpy skin disease (LSD) is an emerging, transboundary viral pox disease affecting cattle of all ages and breeds. The serological assay for monitoring immunity following vaccination is a virus neutralization test (VNT/OIE) that determines the neutralization index (NI). The first validated enzyme-linked immunosorbent assay (ELISA; IDVet) has become commercially available, facilitating large-scale serosurveillance for LSD. Although the VNT is labor intensive and time consuming, it is still the recommended test by the OIE. Thus, in this study, we modified the virus neutralization test by employing Madin-Darby bovine kidney (MDBK) cells. The qualitative results obtained with the modified method were compared to the qualitative results obtained by VNT/OIE and ELISA. We used blood sera received within a surveillance program for LSD in 2018. In total, 291 serum samples were tested using VNT/MDBK and ELISA. Of 291 samples, 80 samples were tested by VNT/OIE and used for comparison of the performances between VNT/MDBK and VNT/OIE. The compatibility of results obtained by VNT/MDBK and VNT/OIE resulted in a kappa index of 0.9 with overall proportion agreement of 0.96. Agreement between VNT/MDBK and VNT/OIE was achieved in 56 positive and 21 negative samples. The compatibility of results obtained by ELISA and VNT/MDBK were compared on 291 samples in total and resulted in a kappa index 0.834 with overall proportion agreement of 0.955. Agreement between ELISA and VNT/MDBK was achieved in 238 positive and 40 negative samples. The results obtained demonstrated a strong correlation between VNT/MDBK and the other two methods, indicating the suitability of VNT/MDBK for the detection of the LSD virus-specific neutralizing antibodies.

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Evaluation of a surrogate virus neutralization test for high-throughput serosurveillance of SARS-CoV-2

10.1101/2021.02.24.21252047 ◽

2021 ◽

Author(s):

Joachim Mariën ◽

Johan Michiels ◽

Leo Heyndrickx ◽

Antoine Nkuba-Ndaye ◽

Ann Ceulemans ◽

...

Keyword(s):

High Throughput ◽

Neutralizing Antibodies ◽

Neutralization Test ◽

Evaluation Studies ◽

Sub Saharan Africa ◽

Virus Neutralization Test ◽

Virus Neutralization ◽

Serological Tests ◽

Live Virus ◽

Screening Programs

AbstractHigh-throughput serological tests that can detect neutralizing antibodies against SARS-CoV-2 are desirable for serosurveillance and vaccine efficacy evaluation. Although the conventional neutralization test (cVNT) remains the gold standard to confirm the presence of neutralizing antibodies in sera, the test is too labour-intensive for massive screening programs and less reproducible as live virus and cell culture is involved. Here, we performed an independent evaluation of a commercially available surrogate virus neutralization test (sVNT, GenScript cPass™) that can be done without biosafety level 3 containment in less than 2 hours. When using the cVNT and a Luminex multiplex immunoassay (MIA) as reference, the sVNT obtained a sensitivity of 94% (CI 90-96%) on a panel of 317 immune sera that were obtained from hospitalized and mild COVID-19 cases from Belgium and a sensitivity of 89% (CI 81-93%) on a panel of 184 healthcare workers from the Democratic Republic of Congo. We also found strong antibody titer correlations (rs>0.8) among the different techniques used. In conclusion, our evaluation suggests that the sVNT could be a powerful tool to monitor/detect neutralising antibodies in cohort and population studies. The technique could be especially useful for vaccine evaluation studies in sub-Saharan Africa where the basic infrastructure to perform cVNTs is lacking.

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A SARS-CoV-2 surrogate virus neutralization test (sVNT) based on antibody-mediated blockage of ACE2-spike (RBD) protein-protein interaction

10.21203/rs.3.rs-24574/v1 ◽

2020 ◽

Cited By ~ 13

Author(s):

Chee Wah Tan ◽

Wan Ni Chia ◽

Mark I-C Chen ◽

Zhiliang Hu ◽

Barnaby E. Young ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Neutralization Test ◽

Serological Test ◽

Rapid Test ◽

Virus Neutralization Test ◽

Virus Neutralization ◽

Contact Tracing ◽

Receptor Protein ◽

Independent Manner ◽

Live Virus

Abstract At this critical moment of the international response to the COVID-19 outbreak, there is an urgent need for a robust serological test to detect neutralizing antibodies to SARS-CoV-2. Such a test is not only important for contact tracing, but for determining infection rate, herd immunity and predicted humoral protection. The current gold standard is a virus neuralization test (VNT) requiring live virus and a biosafety level 3 (BSL3) laboratory. On the other hand, the ELISA- or lateral flow-based assays are for the detection of binding antibodies, which does not directly correlate with their neutralizing ability. Here we report a SARS-CoV-2 surrogate virus neutralization test (sVNT) that is designed to detect total neutralizing antibodies in an isotype- and species-independent manner. Our simple and rapid test is based on antibody-mediated blockage of virus-host interaction between the ACE2 receptor protein and the receptor binding domain (RBD) of the viral spike protein. The test has been validated with two COVID-19 patient cohorts in two different countries, achieving 100% specificity and 95-100% sensitivity and is capable of differentiating antibody responses from other known human coronaviruses. Importantly, the sVNT does not require BSL3 containment, thereby making the test immediately accessible to the global community.

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Evaluation of six commercial SARS-CoV-2 serology assays detecting different antibodies for clinical testing and serosurveillance

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab239 ◽

2021 ◽

Author(s):

Suellen Nicholson ◽

Theo Karapanagiotidis ◽

Arseniy Khvorov ◽

Celia Douros ◽

Francesca Mordant ◽

...

Keyword(s):

Cell Culture ◽

Neutralization Test ◽

Serological Test ◽

Neutralizing Antibody ◽

Neutralization Assay ◽

Virus Neutralization Test ◽

Virus Neutralization ◽

Binding Assays ◽

Humoral Immune ◽

A Cell

Abstract Background Serological testing for SARS-CoV-2 complements nucleic acid tests for patient diagnosis and enables monitoring of population susceptibility to inform the COVID-19 pandemic response. It is important to understand the reliability of assays with different antigen or antibody targets to detect humoral immunity after SARS-CoV-2 infection and to understand how antibody (Ab) binding assays compare to those detecting neutralizing antibody (nAb), particularly as we move into the era of vaccines. Methods We evaluated the performance of six commercially available Enzyme-linked Immunosorbent Assays (ELISAs), including a surrogate virus neutralization test (sVNT), for detection of SARS-CoV-2 immunoglobulins (IgA, IgM, IgG), total or nAb. A result subset was compared to a cell culture-based microneutralisation (MN) assay. We tested sera from patients with prior RT-PCR confirmed SARS-CoV-2 infection, pre-pandemic sera and potential cross-reactive sera from patients with other non-COVID-19 acute infections. Results For sera collected > 14 days post-symptom onset, the assay achieving the highest sensitivity was the Wantai total Ab at 100% (95% confidence interval: 94.6-100) followed by 93.1% for Euroimmun NCP-IgG, 93.1% for GenScript sVNT, 90.3% for Euroimmun S1-IgG, 88.9% for Euroimmun S1-IgA and 83.3% for Wantai IgM. Specificity for the best performing assay was 99.5% for the Wantai total Ab and for the lowest performing assay was 97.1% for sVNT (as per IFU). The Wantai Total Ab had the best agreement with MN at 98% followed by Euroimmun S1-IgA, Euro NCP-IgG and sVNT (as per IFU) with (97%, 97% and 95% respectively) and Wantai IgM having the poorest agreement at 93%. Conclusion Performance characteristics of the SARS-CoV-2 serology assays detecting different antibody types are consistent with those found in previously published reports. Evaluation of the surrogate virus neutralization test in comparison to the Ab binding assays and a cell culture-based neutralization assay showed good result correlation between all assays. However correlation between the cell-based neutralization test and some assays detecting Ab’s not specifically involved in neutralization was higher than with the sVNT. This study demonstrates the reliability of different assays to detect the humoral immune response following SARS-CoV-2 infection, which can be used to optimise serological test algorithms for assessing antibody responses post SARS-CoV-2 infection or vaccination.

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