scholarly journals Kinetics of SARS-CoV-2 Antibody Avidity Maturation and Association with Disease Severity

2020 ◽  
Author(s):  
Yiqi Ruben Luo ◽  
Indrani Chakraborty ◽  
Cassandra Yun ◽  
Alan H.B. Wu ◽  
Kara Lake Lynch
Keyword(s):  
Disease Severity ◽  
Symptom Onset ◽  
Strong Correlation ◽  
Label Free ◽  
Antibody Avidity ◽  
Mild Disease ◽  
Avidity Assay ◽  
Igg Avidity ◽  
Kinetics Of ◽  
Avidity Maturation

The kinetics of IgG avidity maturation during SARS-CoV-2 infection was studied. The IgG avidity assay used a novel label-free immunoassay technology. It was found that there was a strong correlation between IgG avidity and days since symptom onset, and peak readings were significantly higher in severe than mild disease cases.

scholarly journals Kinetics of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Antibody Avidity Maturation and Association with Disease Severity

2020 ◽  
Author(s):  
Yiqi Ruben Luo ◽  
Indrani Chakraborty ◽  
Cassandra Yun ◽  
Alan H B Wu ◽  
Kara L Lynch
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Disease Severity ◽  
Symptom Onset ◽  
Strong Correlation ◽  
Label Free ◽  
Antibody Avidity ◽  
Mild Disease ◽  
Igg Avidity ◽  
Kinetics Of ◽  
Avidity Maturation

Abstract The kinetics of IgG avidity maturation during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was studied. The IgG avidity assay, using a novel label-free immunoassay technology, revealed a strong correlation between IgG avidity and days since symptom onset. Peak readings were significantly higher in severe than mild disease cases.

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 Time to negative PCR from symptom onset in COVID-19 patients on Hydroxychloroquine and Azithromycin - A real world experience

2020 ◽  
Author(s):  
Sarfraz A Saleemi ◽  
Abdulrahman Alrajhi ◽  
Mohammed Alhajji ◽  
Areej Alfattani ◽  
Faisal Albaiz
Keyword(s):  
Disease Severity ◽  
Median Time ◽  
Symptom Onset ◽  
Viral Clearance ◽  
P Value ◽  
Nasopharyngeal Swab ◽  
Multivariate Regression Model ◽  
Mild Disease ◽  
Virus Clearance

Background: The role of hydroxychloroquine (HCQ) and azithromycin in the treatment of COVID-19 and its effect on SARS-CoV-2 viral clearance is not known. Methods: This is a retrospective observational study to assess the effect of HCQ and Azithromycin on duration from symptom onset to negative SARS-CoV-2 PCR using nasopharyngeal swab in hospitalized patient with COVID-19. Eighty-five patients were included in the study, 65 in HCQ (Hydroxychloroquine + Azithromycin) and 20 in non-HCQ group. Measurement of duration from symptom onset to negative PCR and effect of gender, age and disease severity on time to viral clearance was measured. Results: Median time to negative PCR in HCQ group was 23 days (IQR: 9, Mean 24+8, N=65) compared with non-HCQ group, 19 days (IQR: 8, Mean 18+6, N=20), (p <0.05). Forty-one (63%) patients in HCQ group and all patients (100%) in non-HCQ group had mild disease. Multivariate regression model (F=6.8, P<0.002, R2=0.20) shows that being in HCQ group would delay the time to negative PCR by 7 days (95%CI: 2-12) and with every year increase in the age, the time to negative PCR would be delayed by 0.12 days (95%CI: 0.017-0.22). Among HCQ sub-groups, gender and disease severity had no effect on duration (p 0.142 and 0.156 respectively) but older patients >60 year had longer duration compared to patients <60 year of age although p value did not reach significance (p 0.073). Median time to negative PCR in mild-HCQ group (23 days, IQR: 9, Mean 23+8, N=41) was longer when compared with non-HCQ group (p <0.05). On day 28, all patients in non-HCQ group had negative PCR while only 50/65 (77%) were negative in HCQ group. Conclusion: Hydroxychloroquine (HCQ) and azithromycin delay SARS-CoV-2 virus clearance in hospitalized patients with COVID-19 and it is correlated with older age. Larger studies are needed to confirm this finding.

scholarly journals Development and Use of an Endpoint Titration Assay To Characterize Mumps IgG Avidity following Measles, Mumps, and Rubella Vaccination and Wild-Type Mumps Infection

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Sara Mercader ◽  
Marcia McGrew ◽  
Sun B. Sowers ◽  
Nobia J. Williams ◽  
William J. Bellini ◽  
...  
Keyword(s):  
Virus Infection ◽  
Characteristic Curve ◽  
Vaccine Dose ◽  
The United States ◽  
Mumps Virus ◽  
Igg Antibody ◽  
Avidity Assay ◽  
Igg Avidity ◽  
Specific Igg ◽  
Avidity Maturation

ABSTRACTWaning mumps IgG antibody and incomplete IgG avidity maturation may increase susceptibility to mumps virus infection in some vaccinees. To measure mumps IgG avidity, serum specimens serially diluted to the endpoint were incubated on a commercial mumps-specific IgG enzyme immunoassay and treated with the protein denaturant diethylamine (60 mM, pH 10). End titer avidity indices (etAIs [percent ratio of detected diethylamine-resistant IgG at endpoint]) were calculated. Unpaired serum specimens (n= 108) from 15-month-old children living in a low-incidence setting were collected 1 month and 2 years after the first measles, mumps, and rubella vaccine dose (MMR1) and tested for mumps avidity. Per the receiver operating characteristic curve, the avidity assay is accurate (area under the curve, 0.994; 95% confidence interval [CI], 0.956 to 1.000), 96.5% sensitive (95% CI, 87.9 to 99.6%), and 92.2% specific (95% CI, 81.1 to 97.8%) at an etAI of 30%. When 9 sets of paired serum specimens collected 1 to 60 months post-MMR1 were tested for mumps and measles IgG avidity using comparable methods, the mumps etAI increased from 11% to 40 to 60% in 6 months. From 6 to 60 months, avidity was sustained at a mean etAI of 50% (95% CI, 46 to 54%), significantly lower (P  < 0.0001) than the mean measles etAI of 80% (95% CI, 74 to 86%). Mean etAIs in children 2 years post-MMR1 (n= 51), unvaccinated adults with distant mumps disease (n= 29), and confirmed mumps cases (n= 23) were 54, 62, and 57%, respectively. A mumps-specific endpoint avidity assay was developed and validated, and mumps avidity was determined to be generally sustained at etAIs of 40 to 60%, reaching etAIs of >80% in some individuals.IMPORTANCENumerous outbreaks of mumps have occurred in the United States among two-dose measles-mumps-rubella (MMR)-vaccinated populations since 2006. The avidity of mumps-specific IgG antibodies may affect susceptibility to mumps virus infection in some vaccinated individuals. To accurately measure mumps avidity, we developed and validated a mumps-specific IgG avidity assay that determines avidity at the endpoint titer of serially diluted serum specimens, providing results that are independent of IgG concentration. At low antibody titers, endpoint methods are considered more accurate than methods that determine avidity at a single dilution. We determined that 6 months after the first MMR dose, mumps IgG avidity is high and generally sustained at avidity indices of 40 to 60%, reaching values of >80% in some individuals. Additionally, 4% (4/103) of individuals had avidity indices of ≤30% (low avidity) 2 years after vaccination. Inadequate mumps avidity maturation may be one factor influencing susceptibility to mumps virus infection among previously vaccinated or naturally infected individuals.

Re-evaluation of the VIDAS® cytomegalovirus (CMV) IgG avidity assay: Determination of new cut-off values based on the study of kinetics of CMV–IgG maturation

2013 ◽  
Vol 56 (2) ◽  
pp. 118-123 ◽  
Author(s):  
Christelle Vauloup-Fellous ◽  
Mario Berth ◽  
Fabienne Heskia ◽  
Jean-Marc Dugua ◽  
Liliane Grangeot-Keros
Keyword(s):  
Avidity Assay ◽  
Igg Avidity ◽  
Kinetics Of

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 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 Measles Virus IgG Avidity Assay for Use in Classification of Measles Vaccine Failure in Measles Elimination Settings

2012 ◽  
Vol 19 (11) ◽  
pp. 1810-1817 ◽  
Author(s):  
Sara Mercader ◽  
Philip Garcia ◽  
William J. Bellini
Keyword(s):  
Measles Virus ◽  
Area Under The Curve ◽  
Epidemiological Data ◽  
Diagnostic Tools ◽  
High Avidity ◽  
Characteristic Analysis ◽  
Vaccine Failure ◽  
Avidity Assay ◽  
Igg Avidity

ABSTRACTIn regions where endemic measles virus has been eliminated, diagnostic assays are needed to assist in correctly classifying measles cases irrespective of vaccination status. A measles IgG avidity assay was configured using a commercially available measles-specific IgG enzyme immunoassay by modifying the protocol to include three 5-min washes with diethylamine (60 mM; pH 10.25) following serum incubation; serum was serially diluted, and the results were expressed as the end titer avidity index. Receiver operating characteristic analysis was used for evaluation and validation and to establish low (≤30%) and high (≥70%) end titer avidity thresholds. Analysis of 319 serum specimens expected to contain either high- or low-avidity antibodies according to clinical and epidemiological data indicated that the assay is highly accurate, with an area under the curve of 0.998 (95% confidence interval [CI], 0.978 to 1.000), sensitivity of 91.9% (95% CI, 83.2% to 97.0%), and specificity of 98.4% (95% CI, 91.6% to 100%). The assay is rapid (<2 h) and precise (standard deviation [SD], 4% to 7%). In 18 samples from an elimination setting outbreak, the assay identified 2 acute measles cases with low-avidity results; both were IgM-positive samples. Additionally, 11 patients (15 samples) with modified measles who were found to have high-avidity IgG results were classified as secondary vaccine failures; one sample with an intermediate-avidity result was not interpretable. In elimination settings, measles IgG avidity assays can complement existing diagnostic tools in confirming unvaccinated acute cases and, in conjunction with adequate clinical and epidemiologic investigation, aid in the classification of vaccine failure cases.

Assessment of IgM enzyme immunoassay and IgG avidity assay for distinguishing between primary and secondary immune response to rubella vaccine

2005 ◽  
Vol 130 (1-2) ◽  
pp. 59-65 ◽  
Author(s):  
Rasool Hamkar ◽  
Somayeh Jalilvand ◽  
Talat Mokhtari-Azad ◽  
Keramat Nouri Jelyani ◽  
Hosein Dahi-Far ◽  
...  
Keyword(s):  
Immune Response ◽  
Enzyme Immunoassay ◽  
Secondary Immune Response ◽  
Rubella Vaccine ◽  
Avidity Assay ◽  
Igg Avidity

scholarly journals Declining Levels of Neutralizing Antibodies Against SARS-CoV-2 in Convalescent COVID-19 Patients One Year Post Symptom Onset

2021 ◽  
Vol 12 ◽  
Author(s):  
Tiandan Xiang ◽  
Boyun Liang ◽  
Yaohui Fang ◽  
Sihong Lu ◽  
Sumeng Li ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Protein S ◽  
Igg Antibodies ◽  
Neutralizing Activity ◽  
Specific Igg ◽  
One Year ◽  
Kinetics Of

Major advances have been made in understanding the dynamics of humoral immunity briefly after the acute coronavirus disease 2019 (COVID-19). However, knowledge concerning long-term kinetics of antibody responses in convalescent patients is limited. During a one-year period post symptom onset, we longitudinally collected 162 samples from 76 patients and quantified IgM and IgG antibodies recognizing the nucleocapsid (N) protein or the receptor binding domain (RBD) of the spike protein (S). After one year, approximately 90% of recovered patients still had detectable SARS-CoV-2-specific IgG antibodies recognizing N and RBD-S. Intriguingly, neutralizing activity was only detectable in ~43% of patients. When neutralization tests against the E484K-mutated variant of concern (VOC) B.1.351 (initially identified in South Africa) were performed among patients who neutralize the original virus, the capacity to neutralize was even further diminished to 22.6% of donors. Despite declining N- and S-specific IgG titers, a considerable fraction of recovered patients had detectable neutralizing activity one year after infection. However, neutralizing capacities, in particular against an E484K-mutated VOC were only detectable in a minority of patients one year after symptomatic COVID-19. Our findings shed light on the kinetics of long-term immune responses after natural SARS-CoV-2 infection and argue for vaccinations of individuals who experienced a natural infection to protect against emerging VOC.

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