scholarly journals Evaluation of a Pseudovirus Neutralization Assay for SARS-CoV-2 and Correlation with Live Virus-Based Micro Neutralization Assay

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 994
Author(s):  
Ahmed Majdi K. Tolah ◽  
Sayed S. Sohrab ◽  
Khaled Majdi K. Tolah ◽  
Ahmed M. Hassan ◽  
Sherif A. El-Kafrawy ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Epidemiological Studies ◽  
Neutralization Assay ◽  
Serum Samples ◽  
Live Virus ◽  
Spike Gene ◽  
Microneutralization Assay ◽  
Viral Particles ◽  
Reliable Performance ◽  
Prior Infection

The unusual cases of pneumonia outbreak were reported from Wuhan city in late December 2019. Serological testing provides a powerful tool for the identification of prior infection and for epidemiological studies. Pseudotype virus neutralization assays are widely used for many viruses and applications in the fields of serology. The accuracy of pseudotype neutralizing assay allows for its use in low biosafety lab and provides a safe and effective alternative to the use of wild-type viruses. In this study, we evaluated the performance of this assay compared to the standard microneutralization assay as a reference. The lentiviral pseudotype particles were generated harboring the Spike gene of SARS-CoV-2. The generated pseudotype particles assay was used to evaluate the activity of neutralizing antibodies in 300 human serum samples from a COVID-19 sero-epidemiological study. Testing of these samples resulted in 55 positive samples and 245 negative samples by pseudotype viral particles assay while microneutralization assay resulted in 64 positive and 236 negative by MN assay. Compared to the MN, the pseudotyped viral particles assay showed a sensitivity of 85.94% and a specificity of 100%. Based on the data generated from this study, the pseudotype-based neutralization assay showed a reliable performance for the detection of neutralizing antibodies against SARS-CoV-2 and can be used safely and efficiently as a diagnostic tool in a biosafety level 2 laboratory.

scholarly journals A rapid real-time polymerase chain reaction-based live virus microneutralization assay for detection of neutralizing antibodies against SARS-CoV-2 in blood/serum

2021 ◽  
Author(s):  
Syed Hani Abidi ◽  
Kehkeshan Imtiaz ◽  
Akbar Kanji ◽  
Shama Qaiser ◽  
Erum Khan ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Vero Cells ◽  
Neutralization Assay ◽  
Dilution Method ◽  
Rt Pcr ◽  
Serum Samples ◽  
Live Virus ◽  
Viral Neutralization ◽  
Microneutralization Assay ◽  
Infected Cells

Abstract Background Individuals recovering from COVID-19 are shown to have antibodies against the Spike and other structural proteins. Antibodies against Spike have been shown to display viral neutralization. However, not all antibodies against Spike have neutralizing ability and some may be cross-reactive. There is a need for easy-to-use SARS-CoV-2 neutralizing assays that allow the determination of virus neutralizing activity in sera of individuals. Here we describe a PCR-based micro-neutralization assay that can be used to evaluate the viral neutralization titers of serum from SARS-CoV-2 infected individuals. Methods The SARS-CoV-2 strain used was isolated from a nasopharyngeal specimen of a COVID-19 case. The limiting dilution method was used to obtain a 50% tissue culture infective dose (TCID50) of Vero cells. For the micro‐neutralization assay, 19 serum samples, with positive IgG titers against Spike receptor binding domain (RBD) were tested. After 24 hours, infected cells were inspected for the presence of the cytopathic effect, then lysed and RNA RT-PCR of SARS-CoV-2. The Ct values were used to calculate percent neutralization/inhibition of SARS-CoV-2. Results Out of 19 samples, 13 samples gave 100% neutralization at all dilutions, while 4 samples gave neutralization at lower dilution, while one sample did not give any neutralization. The correlation between RBD OD and neutralization potential was found to be statistically correlated. Conclusion We describe a rapid RT-PCR based SARS-CoV-2 microneutralization assay for detection of neutralizing antibodies. This can effectively be used to test anti-viral activity of serum antibodies for investigation of both disease-driven and vaccine-induced responses.

scholarly journals A rapid real-time polymerase chain reaction-based live virus microneutralization assay for detection of neutralizing antibodies against SARS-CoV-2 in blood/serum

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259551
Author(s):  
Syed Hani Abidi ◽  
Kehkashan Imtiaz ◽  
Akbar Kanji ◽  
Shama Qaiser ◽  
Erum Khan ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Vero Cells ◽  
Neutralization Assay ◽  
Dilution Method ◽  
Rt Pcr ◽  
Serum Samples ◽  
Live Virus ◽  
Viral Neutralization ◽  
Microneutralization Assay ◽  
Infected Cells

Background Individuals recovering from COVID-19 are known to have antibodies against the Spike and other structural proteins. Antibodies against Spike have been shown to display viral neutralization. However, not all antibodies against Spike have neutralizing ability although they may be cross-reactive. There is a need for easy-to-use SARS-CoV-2 neutralizing assays for the determination of virus-neutralizing activity in sera of individuals. Here we describe a PCR-based micro‐neutralization assay that can be used to evaluate the viral neutralization titers of serum from SARS-CoV-2 infected individuals. Methods The SARS-CoV-2 strain used was isolated from a nasopharyngeal specimen of a COVID-19 case. The limiting dilution method was used to obtain a 50% tissue culture infective dose (TCID50) of Vero cells. For the micro‐neutralization assay, 19 serum samples, with positive IgG titers against Spike Receptor-Binding Domain (RBD) were tested. After 24 hours, infected cells were inspected for the presence of a cytopathic effect, lysed and RNA RT-PCR conducted for SARS-CoV-2. PCR target Ct values were used to calculate percent neutralization/inhibition of SARS-CoV-2. Results Out of 19 samples, 13 samples gave 100% neutralization at all dilutions, 1 sample showed neutralization at the first dilution, 4 samples showed neutralization at lower dilutions, while one sample did not demonstrate any neutralization. The RBD ODs and neutralization potential percentages were found to be positively correlated. Conclusion We describe a rapid RT-PCR-based SARS-CoV-2 microneutralization assay for the detection of neutralizing antibodies. This can effectively be used to test the antiviral activity of serum antibodies for the investigation of both disease-driven and vaccine-induced responses.

scholarly journals Evaluation of SARS‐CoV‐2 neutralizing antibodies using a CPE‐based colorimetric live virus micro‐neutralization assay in human serum samples

2020 ◽  
Vol 92 (10) ◽  
pp. 2096-2104 ◽  
Author(s):  
Alessandro Manenti ◽  
Marta Maggetti ◽  
Elisa Casa ◽  
Donata Martinuzzi ◽  
Alessandro Torelli ◽  
...  
Keyword(s):  
Human Serum ◽  
Neutralizing Antibodies ◽  
Neutralization Assay ◽  
Serum Samples ◽  
Live Virus ◽  
Human Serum Samples

scholarly journals A multiplexed high-throughput neutralization assay reveals a lack of activity against multiple variants after SARS-CoV-2 infection

2021 ◽  
Author(s):  
Craig Fenwick ◽  
Priscilla Turelli ◽  
Celine Pellaton ◽  
Alex Farina ◽  
Jeremy Campos ◽  
...  
Keyword(s):  
High Throughput ◽  
Neutralizing Antibodies ◽  
Large Scale ◽  
Competitive Inhibition ◽  
Natural Infection ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Antibody Responses ◽  
Serum Samples ◽  
Live Virus

The detection of SARS-CoV-2-specific antibodies in the serum of an individual indicates prior infection or vaccination. However, it provides limited insight into the protective nature of this immune response. Neutralizing antibodies recognizing the viral Spike are far more revealing, yet their measurement traditionally requires virus- and cell-based systems that are costly, time-consuming, poorly flexible and potentially biohazardous. Here we present a cell-free quantitative neutralization assay based on the competitive inhibition of trimeric SARS-CoV-2 Spike protein binding to the angiotensin converting enzyme 2 (ACE2) viral receptor. This high-throughput method matches the performance of the gold standard live virus infectious assay, as verified with a panel of 206 seropositive donors with varying degrees of infection severity and virus-specific IgG titers, achieving 96.7% sensitivity and 100% specificity. Furthermore, it allows for the parallel assessment of neutralizing activities against multiple SARS-CoV-2 Spike variants of concern (VOC), which is otherwise unpredictable even in individuals displaying robust neutralizing antibody responses. Profiling serum samples from 59 hospitalized COVID-19 patients, we found that although most had high activity against the 2019-nCoV Spike and to a lesser extent the B.1.1.7 variant, only 58% could efficiently neutralize a Spike derivative containing mutations present in the B.1.351 variant. In conclusion, we have developed an assay that has proven its clinical relevance in the large-scale evaluation of effective neutralizing antibody responses to VOC after natural infection and that can be applied to the characterization of vaccine-induced antibody responses and of the potency of human monoclonal antibodies.

scholarly journals Scalable, Micro-Neutralization Assay for Qualitative Assessment of SARS-CoV-2 (COVID-19) Virus-Neutralizing Antibodies in Human Clinical Samples

2021 ◽  
Author(s):  
Richard S. Bennett ◽  
Elena N. Postnikova ◽  
Janie Liang ◽  
Robin Gross ◽  
Steven Mazur ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Imaging System ◽  
Neutralization Assay ◽  
Qualitative Assessment ◽  
Clinical Samples ◽  
Therapeutic Approaches ◽  
Serum Samples ◽  
Specific Test ◽  
Multiple Virus ◽  
Infected Cells

AbstractAs the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic was expanding, it was clear that effective testing for the presence of neutralizing antibodies in the blood of convalescent patients would be critical for development of plasma-based therapeutic approaches. To address the need for a high-quality neutralization assay against SARS-CoV-2, a previously established fluorescence reduction neutralization assay (FRNA) against Middle East respiratory syndrome coronavirus (MERS-CoV) was modified and optimized. The SARS-CoV-2 FRNA provides a quantitative assessment of a large number of infected cells through use of a high-content imaging system. Because of this approach, and the fact that it does not involve subjective interpretation, this assay is more efficient and more accurate than other neutralization assays. In addition, the ability to set robust acceptance criteria for individual plates and specific test wells provided further rigor to this assay. Such agile adaptability avails use with multiple virus variants. By February 2021, the SARS-CoV-2 FRNA had been used to screen over 5,000 samples, including acute and convalescent plasma or serum samples and therapeutic antibody treatments, for SARS-CoV-2 neutralizing titers.

scholarly journals Serology in Children with Multisystem Inflammatory Syndrome (MIS-C) associated with COVID-19

2020 ◽  
Author(s):  
Christina A. Rostad ◽  
Ann Chahroudi ◽  
Grace Mantus ◽  
Stacey A. Lapp ◽  
Mehgan Teherani ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Limit Of Detection ◽  
Geometric Mean ◽  
Neutralization Assay ◽  
Adverse Outcomes ◽  
Igg Antibody ◽  
Live Virus ◽  
Lengths Of Stay ◽  
Antibody Titers ◽  
Inflammatory Syndrome

Objectives: We aimed to measure SARS-CoV-2 serologic responses in children hospitalized with multisystem inflammatory syndrome (MIS-C) compared to COVID-19, Kawasaki Disease (KD) and other hospitalized pediatric controls. Methods: From March 17, 2020 - May 26, 2020, we prospectively identified hospitalized children at Children's Healthcare of Atlanta with MIS-C (n=10), symptomatic PCR-confirmed COVID-19 (n=10), KD (n=5), and hospitalized controls (n=4). With IRB approval, we obtained prospective and residual blood samples from these children and measured SARS-CoV-2 spike (S) receptor binding domain (RBD) IgM and IgG binding antibodies by quantitative ELISA and SARS-CoV-2 neutralizing antibodies by live-virus focus reduction neutralization assay. We statistically compared the log-transformed antibody titers among groups and performed correlation analyses using linear regression. Results: All children with MIS-C had high titers of SARS-CoV-2 RBD IgG antibodies, which correlated strongly with neutralizing antibodies (R2=0.667, P<0.001). Children with MIS-C had significantly higher SARS-CoV-2 RBD IgG antibody titers (geometric mean titer [GMT] 6800, 95%CI 3495-13231) than children with COVID-19 (GMT 626, 95%CI 251-1563, P<0.001), children with KD (GMT 124, 95%CI 91-170, P<0.001) and other hospitalized pediatric controls (GMT 85 [all below assay limit of detection], P<0.001). All children with MIS-C also had detectable RBD IgM antibodies, indicating recent SARS-CoV-2 infection. RBD IgG titers correlated with erythrocyte sedimentation rate (ESR) (R2=0.512, P<0.046) and with hospital and ICU lengths of stay (R2=0.590, P=0.010). Conclusion: Quantitative SARS-CoV-2 RBD antibody titers may have a role in establishing the diagnosis of MIS-C, distinguishing it from other similar clinical entities, and stratifying risk for adverse outcomes.

scholarly journals Evaluation of SARS-CoV-2 Neutralizing Antibodies Using a Vesicular Stomatitis Virus Possessing SARS-CoV-2 Spike Protein

2020 ◽  
Author(s):  
Hideki Tani ◽  
Long Tan ◽  
Miyuki Kimura ◽  
Yoshihiro Yoshida ◽  
Hiroshi Yamada ◽  
...  
Keyword(s):  
Virus Infection ◽  
Whole Blood ◽  
Neutralizing Antibodies ◽  
High Specificity ◽  
Immunofluorescence Assay ◽  
Hospitalized Patients ◽  
Pseudotyped Virus ◽  
Serum Samples ◽  
Live Virus ◽  
Specificity And Sensitivity

Abstract Background:SARS-CoV-2 is a novel coronavirus that emerged in 2019 and is now classified in the genus Coronavirus with closely related SARS-CoV. SARS-CoV-2 is highly pathogenic in humans and is classified as a biosafety level (BSL)-3 pathogen, which makes manipulating it relatively difficult due to its infectious nature. Methods:To circumvent the need for BSL-3 laboratories, an alternative assay was developed that avoids live virus and instead uses a recombinant VSV expressing luciferase and possesses the full length or truncated spike proteins of SARS-CoV-2. Furthermore, to measure SARS-CoV-2 neutralizing antibodies under BSL2 conditions, a chemiluminescence reduction neutralization test (CRNT) for SARS-CoV-2 was developed. The neutralization values of the serum samples collected from hospitalized patients with COVID-19 or SARS-CoV-2 PCR-negative donors against the pseudotyped virus infection evaluated by the CRNT were compared with antibody titers determined from an immunofluorescence assay (IFA). Results:The CRNT, which used whole blood collected from hospitalized patients with COVID-19, was also examined. As a result, the inhibition of pseudotyped virus infection was specifically observed in both serum and whole blood and was also correlated with the results of the IFA. Conclusions:In conclusion, the CRNT for COVID-19 is a convenient assay system that can be performed in a BSL-2 laboratory with high specificity and sensitivity for evaluating the occurrence of neutralizing antibodies against SARS-CoV-2.

scholarly journals Prevalence of Neutralizing Antibodies to Adenoviral Serotypes 5 and 35 in the Adult Populations of The Gambia, South Africa, and the United States

2004 ◽  
Vol 11 (2) ◽  
pp. 351-357 ◽  
Author(s):  
Edward Nwanegbo ◽  
Eftyhia Vardas ◽  
Wentao Gao ◽  
Hilton Whittle ◽  
Huijie Sun ◽  
...  
Keyword(s):  
United States ◽  
South Africa ◽  
Gene Therapy ◽  
Neutralizing Antibodies ◽  
Fluorescent Proteins ◽  
The United States ◽  
Neutralization Assay ◽  
The Gambia ◽  
Serum Samples ◽  
Lung Carcinoma Cells

ABSTRACT One of the major limitations of the use of adenoviruses as gene therapy vectors is the existence of preformed immunity in various populations. Recent studies have linked failure of adenoviral gene therapy trials to the presence of antiadenoviral neutralizing antibodies (NAb). Understanding the distribution and specificity of such antibodies will assist in the design of successful recombinant adenoviral gene therapies and vaccines. To assess the prevalence of NAb to adenovirus serotypes 5 and 35 (Ad5 and Ad35), we analyzed serum samples from adult immunocompetent individuals living in The Gambia, South Africa, and the United States by using a neutralization assay. Serum samples were incubated with A549 lung carcinoma cells and adenoviruses encoding enhanced green or yellow fluorescent proteins; results were analyzed by fluorescence microscopy and flow cytometry. Using this technique, we found a high prevalence of NAb against Ad5 in Gambian, South African, and U.S. subjects at both low and high titers. Conversely, all subjects displayed a low prevalence of NAb to Ad35; when present, anti-Ad35 NAb were seen at low titers. Because of the ability of adenoviruses to elicit systemic and mucosal immune responses, Ad35 with its low NAb prevalence appears to be an attractive candidate vector for gene therapy applications.

scholarly journals Antigenicity, stability, and reproducibility of Zika reporter virus particles for long-term applications

2020 ◽  
Vol 14 (11) ◽  
pp. e0008730
Author(s):  
J. Charles Whitbeck ◽  
Anu Thomas ◽  
Kathryn Kadash-Edmondson ◽  
Ariadna Grinyo-Escuer ◽  
Lewis J. Stafford ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Large Scale ◽  
Vaccine Development ◽  
Epidemiological Studies ◽  
Reporter Virus ◽  
Neutralization Titer ◽  
Safe Alternative ◽  
Live Virus ◽  
Time Frames

The development of vaccines against flaviviruses, including Zika virus (ZIKV) and dengue virus (DENV), continues to be a major challenge, hindered by the lack of efficient and reliable methods for screening neutralizing activity of sera or antibodies. To address this need, we previously developed a plasmid-based, replication-incompetent DENV reporter virus particle (RVP) production system as an efficient and safe alternative to the Plaque Reduction Neutralization Test (PRNT). As part of the response to the 2015–2016 ZIKV outbreak, we developed pseudo-infectious ZIKV RVPs by modifying our DENV RVP system. The use of ZIKV RVPs as critical reagents in human clinical trials requires their further validation using stability and reproducibility metrics for large-scale applications. In the current study, we validated ZIKV RVPs using infectivity, neutralization, and enhancement assays with monoclonal antibodies (MAbs) and human ZIKV-positive patient serum. ZIKV RVPs are antigenically equivalent to live virus based on binding ELISA and neutralization results and are nonreplicating based on the results of live virus replication assays. We demonstrate reproducible neutralization titer data (NT50 values) across different RVP production lots, volumes, time frames, and laboratories. We also show RVP stability across experimentally relevant time intervals and temperatures. Our results demonstrate that ZIKV RVPs provide a safe, high-throughput, and reproducible reagent for large-scale, long-term studies of neutralizing antibodies and sera, which can facilitate large-scale screening and epidemiological studies to help expedite ZIKV vaccine development.

scholarly journals Evidence of Chikungunya virus seroprevalence in Myanmar among dengue-suspected patients and healthy volunteers in 2013, 2015, and 2018

2021 ◽  
Vol 15 (12) ◽  
pp. e0009961
Author(s):  
Elizabeth Ajema Chebichi Luvai ◽  
Aung Kyaw Kyaw ◽  
Nundu Sabiti Sabin ◽  
Fuxun Yu ◽  
Saw Wut Hmone ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Neutralizing Antibodies ◽  
Chikungunya Virus ◽  
Clinical Symptoms ◽  
Febrile Illness ◽  
Neutralization Assay ◽  
Confirmatory Test ◽  
Serum Samples ◽  
Igm Elisa ◽  
Focus Reduction

Introduction Chikungunya virus (CHIKV) is a mosquito-borne virus known to cause acute febrile illness associated with debilitating polyarthritis. In 2019, several institutions in Myanmar reported a CHIKV outbreak. There are no official reports of CHIKV cases between 2011 and 2018. Therefore, this study sought to determine the seroprevalence of CHIKV infection before the 2019 outbreak. Methods A total of 1,544 serum samples were collected from healthy volunteers and patients with febrile illnesses in Yangon, Mandalay, and the Myeik district in 2013, 2015, and 2018. Participants ranged from one month to 65 years of age. Antibody screening was performed with in-house anti-CHIKV IgG and IgM ELISA. A neutralization assay was used as a confirmatory test. Results The seroprevalence of anti-CHIKV IgM and anti-CHIKV IgG was 8.9% and 28.6%, respectively, with an overall seropositivity rate of 34.5%. A focus reduction neutralization assay confirmed 32.5% seroprevalence of CHIKV in the study population. Age, health status, and region were significantly associated with neutralizing antibodies (NAbs) and CHIKV seropositivity (p < 0.05), while gender was not (p = 0.9). Seroprevalence in 2013, 2015, and 2018 was 32.1%, 28.8%, and 37.3%, respectively. Of the clinical symptoms observed in participants with fevers, arthralgia was mainly noted in CHIKV-seropositive patients. Conclusion The findings in this study reveal the circulation of CHIKV in Myanmar’s Mandalay, Yangon, and Myeik regions before the 2019 CHIKV outbreak. As no treatment or vaccine for CHIKV exists, the virus must be monitored through systematic surveillance in Myanmar.

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