scholarly journals SARS-CoV-2 Spike Pseudoviruses: A Useful Tool to Study Virus Entry and Address Emerging Neutralization Escape Phenotypes

2021 ◽  
Vol 9 (8) ◽  
pp. 1744
Author(s):  
Raj Kalkeri ◽  
Zhaohui Cai ◽  
Shuling Lin ◽  
John Farmer ◽  
Yury V. Kuzmichev ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Unmet Need ◽  
Neutralizing Antibody ◽  
High Sensitivity ◽  
Cost Effective ◽  
Neutralization Assay ◽  
Post Vaccination ◽  
Angiotensin Converting Enzyme 2 ◽  
Antibody Levels ◽  
Neutralization Ability

SARS-CoV-2 genetic variants are emerging around the globe. Unfortunately, several SARS-CoV-2 variants, especially variants of concern (VOCs), are less susceptible to neutralization by the convalescent and post-vaccination sera, raising concerns of increased disease transmissibility and severity. Recent data suggests that SARS-CoV-2 neutralizing antibody levels are a reliable correlate of vaccine-mediated protection. However, currently used BSL3-based virus micro-neutralization (MN) assays are more laborious, time-consuming, and expensive, underscoring the need for BSL2-based, cost-effective neutralization assays against SARS-CoV-2 variants. In light of this unmet need, we have developed a BSL-2 pseudovirus-based neutralization assay (PBNA) in cells expressing the human angiotensin-converting enzyme-2 (hACE2) receptor for SARS-CoV-2. The assay is reproducible (R2 = 0.96), demonstrates a good dynamic range and high sensitivity. Our data suggest that the biological Anti-SARS-CoV-2 research reagents such as NIBSC 20/130 show lower neutralization against B.1.351 SA (South Africa) and B.1.1.7 UK (United Kingdom) VOC, whereas a commercially available monoclonal antibody MM43 retains activity against both these variants. SARS-CoV-2 spike PBNAs for VOCs would be useful tools to measure the neutralization ability of candidate vaccines in both preclinical models and clinical trials and would further help develop effective prophylactic countermeasures against emerging neutralization escape phenotypes.

scholarly journals SARS-CoV-2 Spike Pseudoviruses: A Useful tool to study virus entry and address emerging neutralization escape phenotypes

2021 ◽  
Author(s):  
Raj Kalkeri ◽  
Zhaohui Cai ◽  
Shuling Lin ◽  
John Farmer ◽  
Yury V Kuzmichev ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Virus Entry ◽  
Unmet Need ◽  
High Sensitivity ◽  
Cost Effective ◽  
Neutralization Assay ◽  
Preclinical Models ◽  
Post Vaccination ◽  
Angiotensin Converting Enzyme 2 ◽  
Neutralization Ability

SARS-CoV-2 genetic variants are emerging around the globe. Unfortunately, several SARS-CoV-2 variants, especially, variants of concern (VOC) are less susceptible to neutralization by the convalescent and post-vaccination sera, raising concerns of increased disease transmissibility and severity. Recent data suggests the SARS-CoV-2 neutralizing anti-body levels as a good correlate of vaccine mediated protection. However, currently used BSL3 based virus micro-neutralization (MN) assays are more laborious, time consuming and expensive, underscoring the need for BSL2 based, cost effective neutralization assays against SARS-CoV-2 variants. In light of this unmet need, we have developed a BSL2 pseudovirus based neutralization assay (PBNA) in cells expressing Angiotensin Converting Enzyme-2 (ACE2) receptor for SARS-CoV-2. The assay is reproducible (R2=0.96), demonstrates a good dynamic range and high sensitivity. Our data suggests that the biological Anti-SARS-CoV-2 research reagents such as NIBSC 20/130 show lower neutralization against B.1.351 RSA and B1.1.7 UK VOC, whereas a commercially available monoclonal antibody MM43 retains activity against both these variants. SARS-CoV-2 Spike Pseudovirus based neutralization assays for VOC would be useful tools to measure the neutralization ability of candidate vaccines in both preclinical models and clinical trials and further help develop effective prophylactic countermeasures against emerging neutralization escape phenotypes.

Rapid, targeted and culture-free viral infectivity assay in drop-based microfluidics

Lab on a Chip ◽  
2015 ◽  
Vol 15 (19) ◽  
pp. 3934-3940 ◽  
Author(s):  
Ye Tao ◽  
Assaf Rotem ◽  
Huidan Zhang ◽  
Connie B. Chang ◽  
Anindita Basu ◽  
...  
Keyword(s):  
High Throughput ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Cost Effective ◽  
Serial Dilution ◽  
Viral Infectivity ◽  
Large Dynamic Range ◽  
Infectivity Assay ◽  
Dilution Experiments

We developed a rapid, targeted and culture-free infectivity assay using high-throughput drop-based microfluidics. The high sensitivity and large dynamic range of our cost effective assay alleviates the need for serial dilution experiments.

scholarly journals Significant reduction in humoral immunity among healthcare workers and nursing home residents 6 months after COVID-19 BNT162b2 mRNA vaccination

2021 ◽  
Author(s):  
David H. Canaday ◽  
Oladayo A. Oyebanji ◽  
Debbie Keresztesy ◽  
Michael Payne ◽  
Dennis Wilk ◽  
...  
Keyword(s):  
Nursing Home ◽  
Humoral Immunity ◽  
Healthcare Workers ◽  
Limit Of Detection ◽  
Nursing Home Residents ◽  
Good Health ◽  
Neutralization Assay ◽  
Vaccine Response ◽  
Post Vaccination ◽  
Antibody Levels

AbstractHigh COVID-19 mortality among nursing home (NH) residents led to their prioritization for SARS-CoV-2 vaccination; most NH residents received BNT162b2 mRNA vaccination under the Emergency Use Authorization due to first to market and its availability. With NH residents’ poor initial vaccine response, the rise of NH breakthrough infections and outbreaks, characterization of the durability of immunity to inform public health policy on the need for boosting is needed. We report on humoral immunity from 2 weeks to 6-months post-vaccination in 120 NH residents and 92 ambulatory healthcare worker controls with and without pre-vaccination SARS-CoV-2 infection. Anti-spike and anti-receptor binding domain (RBD) IgG, and serum neutralization titers, were assessed using a bead-based ELISA method and pseudovirus neutralization assay. Anti-spike, anti-RBD and neutralization levels dropped more than 84% over 6 months’ time in all groups irrespective of prior SARS-CoV-2 infection. At 6 months post-vaccine, 70% of the infection-naive NH residents had neutralization titers at or below the lower limit of detection compared to 16% at 2 weeks after full vaccination. These data demonstrate a significant reduction in levels of antibody in all groups. In particular, those infection-naive NH residents had lower initial post-vaccination humoral immunity immediately and exhibited the greatest declines 6 months later. Healthcare workers, given their younger age and relative good-health, achieved higher initial antibody levels and better maintained them, yet also experienced significant declines in humoral immunity. Based on the rapid spread of the delta variant and reports of vaccine breakthrough in NH and among younger community populations, boosting NH residents may be warranted.

scholarly journals Durability of antibody response to vaccination and surrogate neutralization of emerging variants based on SARS-CoV-2 exposure history

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thomas W. McDade ◽  
Alexis R. Demonbreun ◽  
Amelia Sancilio ◽  
Brian Mustanski ◽  
Richard T. D’Aquila ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Messenger Rna ◽  
Booster Vaccination ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Post Vaccination ◽  
Vaccine Responses ◽  
Clinical Protection ◽  
Exposure History ◽  
Antibody Levels

AbstractTwo-dose messenger RNA vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are highly effective in preventing symptomatic COVID-19 infection. However, the durability of protection is not known, nor is the effectiveness against emerging viral variants. Additionally, vaccine responses may differ based on prior SARS-CoV-2 exposure history. To investigate protection against SARS-CoV-2 variants we measured binding and neutralizing antibody responses following both vaccine doses. We document significant declines in antibody levels three months post-vaccination, and reduced neutralization of emerging variants, highlighting the need to identify correlates of clinical protection to inform the timing of and indications for booster vaccination.

scholarly journals Seasonal Betacoronavirus Antibodies’ Expansion Post-BNT161b2 Vaccination Associates with Reduced SARS-CoV-2 VoC Neutralization

2022 ◽  
Author(s):  
Stefania Dispinseri ◽  
Ilaria Marzinotto ◽  
Cristina Brigatti ◽  
Maria Franca Pirillo ◽  
Monica Tolazzi ◽  
...  
Keyword(s):  
Health Care ◽  
Health Care Workers ◽  
Neutralizing Antibodies ◽  
Spike Protein ◽  
Post Vaccination ◽  
Care Workers ◽  
Sequential Samples ◽  
Alpha Beta ◽  
Antibody Levels ◽  
Neutralization Ability

AbstractSARS-CoV-2 vaccination is known to induce antibodies that recognize also variants of concerns (VoCs) of the virus. However, epidemiological and laboratory evidences indicate that these antibodies have a reduced neutralization ability against VoCs. We studied binding and neutralizing antibodies against the Spike protein domains and subunits of the Wuhan-Hu-1 virus and its alpha, beta, delta VoCs and of seasonal betacoronaviruses (HKU1 and OC43) in a cohort of 31 health care workers prospectively followed post-vaccination with BNT162b2-Comirnaty. The study of sequential samples collected up to 64 days post-vaccination showed that serological assays measuring IgG against Wuhan-Hu-1 antigens were a poor proxy for VoC neutralization. In addition, in subjects who had asymptomatic or mild COVID-19 prior to vaccination, the loss of nAbs following disease could be rapid and accompanied by post-vaccination antibody levels similar to those of naïve vaccinees. Interestingly, in health care workers naïve for SARS-CoV-2 infection, vaccination induced a rapid and transient reactivation of pre-existing seasonal coronaviruses IgG responses that was associated with a subsequent reduced ability to neutralize alpha and beta VoCs.

scholarly journals Neutralizing antibody titres to SARS-CoV-2 Omicron variant and wild-type virus in those with past infection or vaccinated or boosted with mRNA BNT162b2 or inactivated CoronaVac vaccines

2022 ◽  
Author(s):  
Malik Peiris ◽  
Samuel Cheng ◽  
Chris Ka Pun Mok ◽  
Yonna Leung ◽  
Susanna Ng ◽  
...  
Keyword(s):  
Protective Immunity ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Wild Type Virus ◽  
Wild Type ◽  
Past Infection ◽  
Post Vaccination ◽  
Antibody Titres ◽  
Duration Of Protection ◽  
Antibody Levels

Abstract Omicron, a novel SARS-CoV-2 variant has emerged and is rapidly becoming the dominant SARS-CoV-2 virus circulating globally. It is important to define reductions in virus neutralizing activity in serum of convalescent or vaccinated individuals to understand potential loss of protection from infection or re-infection. Two doses of BNT162b2 or CoronaVac vaccines provided little 50% plaque reduction neutralization test (PRNT50) antibody immunity against the Omicron variant, even at one-month post vaccination. Booster doses with BNT162b2 in those with two doses of either BNT162b2 or CoronaVac provided acceptable neutralizing immunity against Omicron variant at 1-month post-booster dose. However, three doses of BNT162b2 elicited higher levels of PRNT50 antibody to Omicron variant suggesting longer duration of protection. Convalescent from SARS-CoV-2 infection did not have protective PRNT50 antibody levels to Omicron, but a single dose of BNT162b2 vaccine provided protective immunity. Field vaccine-efficacy studies against Omicron variant against different vaccines are urgently needed.

A novel approach to design electrochemical aptamer-based biosensor for ultrasensitive detecting of zearalenone as a prevalent estrogenic mycotoxin

2021 ◽  
Vol 28 ◽  
Author(s):  
Shokoufeh Hassani ◽  
Armin Salek Maghsoudi ◽  
Milad Rezaei Akmal ◽  
Shahram Shoeibi ◽  
Fatemeh Ghadipasha ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Electrochemical Impedance ◽  
Fusarium Species ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Differential Pulse ◽  
Electrode Position ◽  
Novel Approach ◽  
Modified Surface

Background: Zearalenone is a well-known estrogenic mycotoxin produced by Fusarium species, a serious threat to the agricultural and food industries worldwide. Zearalenone, with its known metabolites, are biomarkers of exposure to certain fungi, primarily through food. It has considerable toxic effects on biological systems due to its carcinogenicity, mutagenicity, renal toxicity, teratogenicity, and immunotoxicity. Introduction: This study aims to design a simple, quick, precise, and cost-effective method on a biosensor platform to evaluate the low levels of this toxin in foodstuffs and agricultural products. Methods: An aptamer-based electrochemical biosensor was introduced that utilizes screen-printed gold electrodes instead of conventional electrodes. The electrode position process was employed to develop a gold nanoparticle-modified surface to enhance the electroactive surface area. Thiolated aptamers were immobilized on the surface of gold nanoparticles, and subsequently, the blocker and analyte were added to the modified surface. In the presence of a redox probe, electrochemical characterization of differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy were used to investigate the various stages of aptasensor fabrication. Results: The proposed aptasensor for zearalenone concentration had a wide linear dynamic range covering the 0.5 pg/mL to 100 ng/mL with a 0.14 pg/mL detection limit. Moreover, this aptasensor had high specificity so that a non-specific analyte cannot negatively affect the selectivity of the aptasensor. Conclusion: Overall, due to its simple design, high sensitivity, and fast performance, this aptasensor showed a high potential for assessing zearalenone in real samples, providing a clear perspective for designing a portable and cost-effective device.

scholarly journals Low serum neutralizing anti-SARS-CoV-2 S antibody levels in mildly affected COVID-19 convalescent patients revealed by two different detection methods

2020 ◽  
Author(s):  
Berislav Bošnjak ◽  
Saskia Catherina Stein ◽  
Stefanie Willenzon ◽  
Anne Katrin Cordes ◽  
Wolfram Puppe ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Clinical Symptoms ◽  
Neutralization Test ◽  
Antibody Therapy ◽  
Neutralization Assay ◽  
Detection Methods ◽  
Angiotensin Converting Enzyme 2 ◽  
Iga Antibodies ◽  
Vesicular Stomatitis ◽  
Antibody Levels

Abstract Neutralizing antibodies targeting the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into cells via surface-expressed angiotensin-converting enzyme 2 (ACE2). We used a surrogate virus neutralization test (sVNT) and SARS-CoV-2 S protein-pseudotyped vesicular stomatitis virus (VSV) vector-based neutralization assay (pVNT) to assess the degree to which serum antibodies from coronavirus disease 2019 (COVID-19) convalescent patients interfere with the binding of SARS-CoV-2 S to ACE2. Both tests revealed neutralizing anti-SARS-CoV-2 S antibodies in the sera of ~90% of mildly and 100% of severely affected COVID-19 convalescent patients. Importantly, sVNT and pVNT results correlated strongly with each other and to the levels of anti-SARS-CoV-2 S1 IgG and IgA antibodies. Moreover, levels of neutralizing antibodies correlated with the duration and severity of clinical symptoms but not with patient age. Compared to pVNT, sVNT is less sophisticated and does not require any biosafety labs. Since this assay is also much faster and cheaper, sVNT will not only be important for evaluating the prevalence of neutralizing antibodies in a population but also for identifying promising plasma donors for successful passive antibody therapy.

scholarly journals Robust Neutralizing Antibody Levels Detected after Either SARS-CoV-2 Vaccination or One Year after Infection

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2003
Author(s):  
Stefan Glöckner ◽  
Franziska Hornung ◽  
Michael Baier ◽  
Sebastian Weis ◽  
Mathias W. Pletz ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Booster Vaccination ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Neutralization Titer ◽  
Neutralization Capacity ◽  
A Cell ◽  
One Year ◽  
Study Participants ◽  
Antibody Levels

Humoral immunity after infection or after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been attributed a key part in mitigating the further transmission of the virus. In this study, we used a commercial anti-Spike immunoglobulin G (S-IgG) assay and developed a cell culture-based neutralization assay to understand the longitudinal course of neutralizing antibodies in both SARS-CoV2 infected or vaccinated individuals. We show that even more than one year after infection, about 78% of observed study participants remained seropositive concerning S-IgG antibodies. In addition, the serum of the individuals had stable neutralization capacity in a neutralization assay against a SARS-CoV-2 patient isolate from March 2020. We also examined volunteers after either homologous BNT162b2 prime-boost vaccination or heterologous AZD1222 prime/mRNA-based booster vaccination. Both the heterologous and the homologous vaccination regimens induced higher levels of neutralizing antibodies in healthy subjects when compared to subjects after a mild infection, showing the high effectiveness of available vaccines. In addition, we could demonstrate the reliability of S-IgG levels in predicting neutralization capacity, with 94.8% of seropositive samples showing a neutralization titer of ≥10, making it a viable yet cheap and easy-to-determine surrogate parameter for neutralization capacity.

scholarly journals Evaluating SARS-CoV-2 spike and nucleocapsid proteins as targets for IgG antibody detection in severe and mild COVID-19 cases using a Luminex bead-based assay

2020 ◽  
Author(s):  
Joachim Marien ◽  
Johan Michiels ◽  
Leo Heyndrickx ◽  
Karen Kerkhof ◽  
Nikki Foque ◽  
...  
Keyword(s):  
Large Scale ◽  
Detection Threshold ◽  
Neutralizing Antibody ◽  
Cost Effective ◽  
Antibody Detection ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Serological Tests ◽  
Specific Igg ◽  
Antibody Levels

Large-scale serosurveillance of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) will only be possible if serological tests are sufficiently reliable, rapid and inexpensive. Current assays are either labour-intensive and require specialised facilities (e.g. virus neutralization assays), or expensive with suboptimal specificity (e.g. commercial ELISAs). Bead-based assays offer a cost-effective alternative and allow for multiplexing to test for antibodies of other pathogens. Here, we compare the performance of four antigens for the detection of SARS-CoV-2 specific IgG antibodies in a panel of sera that includes both severe (n=40) and mild (n=52) cases, using a neutralization and a Luminex bead-based assay. While we show that neutralising antibody levels are significantly lower in mild than in severe cases, we demonstrate that a combination of recombinant nucleocapsid protein (NP), receptor-binding domain (RBD) and the whole spike protein (S1S2) results in a highly sensitive (96%) and specific (99%) bead-based assay that can detect IgG antibodies in both groups. Although S1-specific IgG levels correlate most strongly with neutralizing antibody levels, they fall below the detection threshold in 10% of the cases in our Luminex assay. In conclusion, our data supports the use of RBD, NP and S1S2 for the development of SARS-CoV-2 serological bead-based assays. Finally, we argue that low antibody levels in mild/asymptomatic cases might complicate the epidemiological assessment of large-scale surveillance studies.

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