scholarly journals Predictive Analysis of the Neutralization Activity in Convalescent Plasmas From COVID-19 Recovered Patients in Zhejiang Province, China, January-March, 2020

2021 ◽  
Vol 11 ◽  
Author(s):  
Yajie Yuan ◽  
Liang Yu ◽  
Zi Jin ◽  
Yongjun Wang ◽  
Meng Gao ◽  
...  
Keyword(s):  
Indirect Elisa ◽  
Therapeutic Option ◽  
Neutralizing Antibody ◽  
High Sensitivity ◽  
High Specificity ◽  
Neutralization Assay ◽  
Infusion Therapy ◽  
Emerging Infections ◽  
Igg Antibody ◽  
Neutralization Activity

BackgroundConvalescent plasma (CP) transfusion is considered to be the priority therapeutic option for COVID-19 inpatients when no specific drugs are available for emerging infections. An alternative, simple, and sensitive method is urgently needed for clinical use to detect neutralization activity of the CP to avoid the use of inconvenient micro-neutralization assay.MethodThis study aims to explore optimal index in predicting the COVID-19 CP neutralization activity (neutralizing antibody titers, NAb titers) in an indirect ELISA format. Fifty-seven COVID-19-recovered patients plasma samples were subjected to anti-SARS-CoV-2 RBD, S1, and N protein IgG antibody by indirect ELISA.ResultsELISA-RBD exhibited high specificity (96.2%) and ELISA-N had high sensitivity (100%); while ELISA-S1 had low sensitivity (86.0%) and specificity (73.1%). Furthermore, ELISA-RBD IgG titers and pseudovirus-based NAb titers correlated significantly, with R2 of 0.2564 (P < 0.0001).ConclusionELISA-RBD could be a substitute for the neutralization assay in resource-limited situations to screen potential plasma donors for further plasma infusion therapy.

scholarly journals INDIRECT ELISA FOR DETECTION OF ANTIBODIES TO FMDV NON-STRUCTURAL PROTEINS IN PORCINE SERA

2018 ◽  
pp. 13-20
Author(s):  
A. S. Yakovleva ◽  
A. V. Kanshina ◽  
A. V. Scherbakov
Keyword(s):  
Indirect Elisa ◽  
High Sensitivity ◽  
High Specificity ◽  
Structural Proteins ◽  
Post Inoculation ◽  
Nonstructural Proteins ◽  
Diagnostic Specificity ◽  
Fmd Virus ◽  
Specificity And Sensitivity ◽  
Sensitivity Specificity

An indirect variant of ELISA used for detection of antibodies to nonstructural proteins of the FMD virus in porcine blood sera was developed. The results of the validation showed that the developed method is characterized by high sensitivity, specificity and reproducibility. When testing the blood serum panel obtained from experimentally infected animals, the method allowed to detect antibodies to FMD virus in 7 of 18 sera collected on day 6 post inoculation, in 13 of 19 sera – on day 7 post inoculation, in 16 of 19 sera – on day 8 post inoculation and in all 76 sera obtained on days 9–12 post inoculation. The diagnostic specificity of 3AB-ELISA was 100% when testing 100 knowingly negative blood sera from pigs imported to Russia from Norway. High specificity and sensitivity of the method, established during the development of the method, are confirmed in the course of routine diagnostic tests.

scholarly journals Commercial Serology Assays Predict Neutralization Activity Against SARS-CoV-2

2020 ◽  
Author(s):  
Raymond T Suhandynata ◽  
Melissa A Hoffman ◽  
Deli Huang ◽  
Jenny T Tran ◽  
Michael J Kelner ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Positive Serology ◽  
Neutralization Activity ◽  
Antibody Titers ◽  
Negative Controls ◽  
First Time ◽  
The Relationship ◽  
Positive Results

Background. Currently it is unknown whether a positive serology results correlates with protective immunity against SARS-CoV-2. There are also concerns regarding the low positive predictive value of SARS-CoV-2 serology tests, especially when testing populations with low disease prevalence. Methods. A neutralization assay was validated in a set of PCR confirmed positive specimens and in a negative cohort. 9,530 specimens were screened using the Diazyme SARS-CoV-2 IgG serology assay and all positive results (N=164) were reanalyzed using the neutralization assay, the Roche total immunoglobin assay, and the Abbott IgG assay. The relationship between the magnitude of a positive SARS-CoV-2 serology result and the levels of neutralizing antibodies detected was correlated. Neutralizing antibody titers (ID50) were also longitudinally monitored in SARS-CoV-2 PCR confirmed patients. Results. The SARS-CoV-2 neutralization assay had a PPA of 96.6% with a SARS-CoV-2 PCR test and a NPA of 98.0% across 100 negative controls. ID50 neutralization titers positively correlated with all three clinical serology platforms. Longitudinal monitoring of hospitalized PCR confirmed COVID-19 patients demonstrates they made high neutralization titers against SARS-CoV-2. PPA between the Diazyme IgG assay alone and the neutralization assay was 50.6%, while combining the Diazyme IgG assay with either the Roche or Abbott platforms increased the PPA to 79.2% and 78.4%, respectively. Conclusions. For the first time, we demonstrate that three widely available clinical serology assays positively correlate with SARS-CoV-2 neutralization activity observed in COVID-19 patients. When a two-platform screen and confirm approach was used for SARS-CoV-2 serology, nearly 80% of two-platform positive specimens had neutralization titers (ID50 >50).

scholarly journals Commercial Serology Assays Predict Neutralization Activity against SARS-CoV-2

2020 ◽  
Author(s):  
Raymond T Suhandynata ◽  
Melissa A Hoffman ◽  
Deli Huang ◽  
Jenny T Tran ◽  
Michael J Kelner ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Negative Control ◽  
Percentage Agreement ◽  
Positive Serology ◽  
Neutralization Activity ◽  
Antibody Titers ◽  
The Relationship ◽  
Positive Results

Abstract Background It is unknown whether a positive serology result correlates with protective immunity against SARS-CoV-2. There are also concerns regarding the low positive predictive value of SARS-CoV-2 serology tests, especially when testing populations with low disease prevalence. Methods A neutralization assay was validated in a set of PCR-confirmed positive specimens and in a negative cohort. In addition, 9530 specimens were screened using the Diazyme SARS-CoV-2 IgG serology assay and all positive results (N = 164 individuals) were reanalyzed using the neutralization assay, the Roche total immunoglobin assay, and the Abbott IgG assay. The relationship between the magnitude of a positive SARS-CoV-2 serology result and neutralizing activity was determined. Neutralizing antibody titers (50% inhibitory dilution, ID50) were also longitudinally monitored in patients confirmed to have SARS-CoV-2 by PCR. Results The SARS-CoV-2 neutralization assay had a positive percentage agreement (PPA) of 96.6% with a SARS-CoV-2 PCR test and a negative percentage agreement (NPA) of 98.0% across 100 negative control individuals. ID50 neutralization titers positively correlated with all 3 clinical serology platforms. Longitudinal monitoring of hospitalized PCR-confirmed patients with COVID-19 demonstrated they made high neutralization titers against SARS-CoV-2. PPA between the Diazyme IgG assay alone and the neutralization assay was 50.6%, while combining the Diazyme IgG assay with either the Roche or Abbott platforms increased the PPA to 79.2 and 78.4%, respectively. Conclusions These 3 clinical serology assays positively correlate with SARS-CoV-2 neutralization activity observed in patients with COVID-19. All patients confirmed SARS-CoV-2 positive by PCR develop neutralizing antibodies.

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 The Antigenicity of Epidemic SARS-CoV-2 Variants in the United Kingdom

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiajing Wu ◽  
Li Zhang ◽  
Yue Zhang ◽  
Haixin Wang ◽  
Ruxia Ding ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Virus Vaccine ◽  
Immune Escape ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Antibody Responses ◽  
Neutralization Activity ◽  
The United Kingdom ◽  
Different Types ◽  
The Uk

To determine whether the neutralization activity of monoclonal antibodies, convalescent sera and vaccine-elicited sera was affected by the top five epidemic SARS-CoV-2 variants in the UK, including D614G+L18F+A222V, D614G+A222V, D614G+S477N, VOC-202012/01(B.1.1.7) and D614G+69-70del+N439K, a pseudovirus-neutralization assay was performed to evaluate the relative neutralization titers against the five SARS-CoV-2 variants and 12 single deconvolution mutants based on the variants. In this study, 18 monoclonal antibodies, 10 sera from convalescent COVID-19 patients, 10 inactivated-virus vaccine-elicited sera, 14 mRNA vaccine-elicited sera, nine RBD-immunized mouse sera, four RBD-immunized horse sera, and four spike-encoding DNA-immunized guinea pig sera were tested and analyzed. The N501Y, N439K, and S477N mutations caused immune escape from nine of 18 mAbs. However, the convalescent sera, inactivated virus vaccine-elicited sera, mRNA vaccine-elicited sera, spike DNA-elicited sera, and recombinant RBD protein-elicited sera could still neutralize these variants (within three-fold changes compared to the reference D614G variant). The neutralizing antibody responses to different types of vaccines were different, whereby the response to inactivated-virus vaccine was similar to the convalescent sera.

scholarly journals Measles immunity and response to revaccination among secondary school children in Cumbria

1996 ◽  
Vol 116 (1) ◽  
pp. 65-70 ◽  
Author(s):  
N. Calvert ◽  
F. Cutts ◽  
R. Irving ◽  
D. Brown ◽  
J. Marsh ◽  
...  
Keyword(s):  
Secondary School ◽  
School Children ◽  
Measles Virus ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Antibody Testing ◽  
Igg Antibody ◽  
Populations At Risk ◽  
Antibody Levels ◽  
Selective Vaccination

SummaryThe prevalence of antibody to measles virus in 759 children aged 11–18 years attending a secondary school in Cumbria was measured using a salivary IgG antibody capture assay. Serum IgG antibody levels were measured using a plaque reduction neutralization assay in subjects whose saliva was antibody negative. Vaccination histories were obtained from the child health computer and general practice records. A total of 662 pupils (87 % of those tested) had detectable measles-specific IgG in saliva. Of the remaining 97, 82 provided blood samples and 29 had serum neutralizing antibody levels above 200 mlU/ml. After adjusting for non-participation rates, the proportion considered non-immune (no IgG in saliva and ≤ 200 mlU/ml in serum) was 9 % overall, ranging from 6 % in vaccinated children to 20 % in unvaccinated children. Measles-mumps-rubella vaccine was given to 50 children of whom 38 provided post-vaccination serum and 32 saliva samples. Thirty (79 %) had a fourfold or greater rise in serum neutralizing antibody and 28 (88 %) developed IgG antibody in saliva. Half of the children considered non-immune by antibody testing would have been overlooked in a selective vaccination programme targeted at those without a history of prior vaccination. A programme targeted at all school children should substantially reduce the proportion non-immune since a primary or booster response was achieved in three quarters of previously vaccinated children with low antibody levels and in all unvaccinated children. While it is feasible to screen a school-sized population for immunity to measles relatively quickly using a salivary IgG assay, a simple inexpensive field assay would need to be developed before salivary screening and selective vaccination could substitute for universal vaccination of populations at risk of measles outbreaks. The salivary IgG assay provided a sensitive measure of a booster response to vaccination.

scholarly journals Early detection of neutralizing antibodies against SARS-CoV-2 in COVID-19 patients in Thailand

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246864
Author(s):  
Opass Putcharoen ◽  
Supaporn Wacharapluesadee ◽  
Wan Ni Chia ◽  
Leilani Paitoonpong ◽  
Chee Wah Tan ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Viral Infections ◽  
Serological Test ◽  
Neutralization Assay ◽  
Igg Antibody ◽  
Independent Manner ◽  
Neutralization Activity ◽  
Viral Neutralization ◽  
Before And After ◽  
Antibody Levels

Background The presence of neutralizing antibodies (NAbs) is an indicator of protective immunity for most viral infections. A newly developed surrogate viral neutralization assay (sVNT) offers the ability to detect total receptor binding domain-targeting NAbs in an isotype-independent manner, increasing the test sensitivity. Thus, specimens with low IgM/ IgG antibody levels showed strong neutralization activity in sVNT. Methods This study aimed to measure the %inhibition of NAbs measured by sVNT in PCR-confirmed COVID-19 patients. The sensitivity of sVNT for the diagnosis of SARS-CoV-2 infection and its kinetics were determined. Results Ninety-seven patients with PCR-confirmed SARS-CoV-2 infection were included in this study. Majority of the patients were 21–40 years old (67%) and 63% had mild symptoms. The sensitivity of sVNT for the diagnosis of SARS-CoV-2 infection was 99% (95% confidence interval (CI) 94.4–100%) and the specificity was 100% (95% CI 98.3–100%). The negative predictive value of sVNT from the samples collected before and after 7 days of symptom onset was 99.5% (95% CI 97.4–100%) and 100% (95% CI 93.8–100%), respectively. The level of inhibition at days 8–14 were significantly higher than days 0–7 (p<0.001). The median %inhibition values by severity of COVID-19 symptoms were 79.9% (interquartile range (IQR) 49.7–91.8%); 89.0% (IQR 71.2–92.4%); and 86.6% (IQR 69.5–92.8%), for mild, moderate and severe/critical symptoms respectively. The median level of sVNT %inhibition of severe was significantly higher than the mild group (p = 0.05). Conclusion The sVNT is a practical and robust serological test for SARS-CoV-2 infection and does not require specialized biosafety containment. It can be used clinically to aid diagnosis in both early and late infection especially in cases when the real-time RT-PCR results in weakly negative or weakly positive, and to determine the protective immune response from SARS-CoV-2 infection in patients.

scholarly journals Radiochemistry, Production Processes, Labeling Methods, and ImmunoPET Imaging Pharmaceuticals of Iodine-124

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 414
Author(s):  
Krishan Kumar ◽  
Arijit Ghosh
Keyword(s):  
Physical Properties ◽  
Imaging Modality ◽  
Target Selection ◽  
Positron Emission Tomography Imaging ◽  
High Sensitivity ◽  
High Specificity ◽  
Production Processes ◽  
Positron Emission ◽  
Significant Research ◽  
Clinical Environments

Target-specific biomolecules, monoclonal antibodies (mAb), proteins, and protein fragments are known to have high specificity and affinity for receptors associated with tumors and other pathological conditions. However, the large biomolecules have relatively intermediate to long circulation half-lives (>day) and tumor localization times. Combining superior target specificity of mAbs and high sensitivity and resolution of the PET (Positron Emission Tomography) imaging technique has created a paradigm-shifting imaging modality, ImmunoPET. In addition to metallic PET radionuclides, 124I is an attractive radionuclide for radiolabeling of mAbs as potential immunoPET imaging pharmaceuticals due to its physical properties (decay characteristics and half-life), easy and routine production by cyclotrons, and well-established methodologies for radioiodination. The objective of this report is to provide a comprehensive review of the physical properties of iodine and iodine radionuclides, production processes of 124I, various 124I-labeling methodologies for large biomolecules, mAbs, and the development of 124I-labeled immunoPET imaging pharmaceuticals for various cancer targets in preclinical and clinical environments. A summary of several production processes, including 123Te(d,n)124I, 124Te(d,2n)124I, 121Sb(α,n)124I, 123Sb(α,3n)124I, 123Sb(3He,2n)124I, natSb(α, xn)124I, natSb(3He,n)124I reactions, a detailed overview of the 124Te(p,n)124I reaction (including target selection, preparation, processing, and recovery of 124I), and a fully automated process that can be scaled up for GMP (Good Manufacturing Practices) production of large quantities of 124I is provided. Direct, using inorganic and organic oxidizing agents and enzyme catalysis, and indirect, using prosthetic groups, 124I-labeling techniques have been discussed. Significant research has been conducted, in more than the last two decades, in the development of 124I-labeled immunoPET imaging pharmaceuticals for target-specific cancer detection. Details of preclinical and clinical evaluations of the potential 124I-labeled immunoPET imaging pharmaceuticals are described here.

scholarly journals Immunogenicity of HIV-1-Based Virus-Like Particles with Increased Incorporation and Stability of Membrane-Bound Env

Vaccines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 239
Author(s):  
Christopher A. Gonelli ◽  
Hannah A. D. King ◽  
Charlene Mackenzie ◽  
Secondo Sonza ◽  
Rob J. Center ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Neutralization Activity ◽  
Virus Like Particles ◽  
Antibody Isotypes ◽  
Immunodeficiency Virus ◽  
Proline Substitution ◽  
Membrane Bound ◽  
Antibody Epitopes ◽  
Hiv 1

An optimal prophylactic vaccine to prevent human immunodeficiency virus (HIV-1) transmission should elicit protective antibody responses against the HIV-1 envelope glycoprotein (Env). Replication-incompetent HIV-1 virus-like particles (VLPs) offer the opportunity to present virion-associated Env with a native-like structure during vaccination that closely resembles that encountered on infectious virus. Here, we optimized the incorporation of Env into previously designed mature-form VLPs (mVLPs) and assessed their immunogenicity in mice. The incorporation of Env into mVLPs was increased by replacing the Env transmembrane and cytoplasmic tail domains with those of influenza haemagglutinin (HA-TMCT). Furthermore, Env was stabilized on the VLP surface by introducing an interchain disulfide and proline substitution (SOSIP) mutations typically employed to stabilize soluble Env trimers. The resulting mVLPs efficiently presented neutralizing antibody epitopes while minimizing exposure of non-neutralizing antibody sites. Vaccination of mice with mVLPs elicited a broader range of Env-specific antibody isotypes than Env presented on immature VLPs or extracellular vesicles. The mVLPs bearing HA-TMCT-modified Env consistently induced anti-Env antibody responses that mediated modest neutralization activity. These mVLPs are potentially useful immunogens for eliciting neutralizing antibody responses that target native Env epitopes on infectious HIV-1 virions.

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