scholarly journals Correlation of sample‐to‐cut‐off ratio of anti‐SARS‐CoV‐2 IgG antibody chemiluminescent assay with neutralization activity: a prospective multi‐centric study in India

2021 ◽  
Author(s):  
Aseem K. Tiwari ◽  
Gita Negi ◽  
Ram Mohan Jaiswal ◽  
Geet Aggarwal ◽  
Neeti Yadav ◽  
...  
Keyword(s):  
Igg Antibody ◽  
Neutralization Activity

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 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.

Partial Inhibition of Platelet Aggregation and Fibrinogen Binding by a Murine Monoclonal Antibody to GPIIIa: Requirement for Antibody Bivalency

1994 ◽  
Vol 72 (06) ◽  
pp. 964-972 ◽  
Author(s):  
Jeffery L Kutok ◽  
Barry S Coller
Keyword(s):  
Monoclonal Antibody ◽  
Platelet Aggregation ◽  
Murine Monoclonal Antibody ◽  
Platelet Glycoprotein ◽  
Igg Antibody ◽  
Surface Receptors ◽  
Partial Inhibition ◽  
Fibrinogen Binding ◽  
Igg Binding ◽  
Agonist Concentration

SummaryWe produced a murine monoclonal antibody, 7H2, and localized its epitope to one or more small regions on platelet glycoprotein (GP) Ilia. 7H2-IgG and 7H2-F(ab’)2 completely inhibit platelet aggregation and fibrinogen binding at low agonist concentrations, but only partially inhibit aggregation and fibrinogen binding at high agonist concentrations; 7H2-Fab has no effect on aggregation or fibrinogen binding at any agonist concentration. 7H2-IgG binds to the entire platelet population as judged by flow cytometry. At near saturating concentrations, ∼40,000 7H2-IgG antibody molecules bind per platelet. In contrast, ∼80,000 7H2 Fab molecules bind per platelet, suggesting that 7H2-IgG binding is bivalent. 7H2 was unable to inhibit fibrinogen binding to purified, immobilized GPIIb/IIIa. These data indicate that the bivalent binding of 7H2 to GPIIIa is required for its partial inhibition of fibrinogen binding to platelets, perhaps through dimerization of GPIIb/IIIa surface receptors (or more complex GPIIb/IIIa redistribution triggered by 7H2 binding) resulting in limited accessibility of fibrinogen to its binding site(s).

Physiological Effects of Nonimmune Platelet Associated Immunoglobulin G

1981 ◽  
Vol 45 (01) ◽  
pp. 027-033 ◽  
Author(s):  
K Sugiura ◽  
M Steiner ◽  
M Baldini
Keyword(s):  
Shape Change ◽  
Fluorescein Isothiocyanate ◽  
Recovery Phase ◽  
Human Platelets ◽  
Serotonin Release ◽  
Platelet Volume ◽  
Igg Antibody ◽  
Heterologous Antiserum ◽  
Igg Binding ◽  
Series Of Experiments

SummaryThe function of nonimmune IgG associated with platelets is unknown. In a series of experiments we have investigated this problem, relating amount of platelet-associated IgG (PAIgG) to platelet volume, serotonin release, adherence of platelets to monocytes and platelet senescence. Most of these studies were performed with human platelets. Platelets freed of preexisting PAIgG by incubation at 22° C were incubated with IgG in a series of concentrations ranging from 0.4 — 27.0 X10-6 M. The IgG preparations used were demonstrably free of aggregated forms of the protein. The amount of PAIgG bound to platelets was determined by the use of fluorescein isothiocyanate-conjugated anti-IgG antibody (F-anti-IgG antibody) which was quantified in a fluorospectrophotometer. Newly bound IgG was assayed similarly by the use of F-IgG. A dose-dependent increase in platelet volume was associated with the binding of nonimmune IgG by platelets. The process which leveled off at an IgG concentration of 1.2 —1.5 X10-5 M was almost fully reversible and was not due to platelet shape change or aggregation. Release of serotonin from IgG-treated platelets was relatively small but to the extent that it occurred was positively related to the IgG concentration to which platelets were exposed. Adherence to autologous monocytes studied quantitatively by the use of formaldehyde-fixed cells was also positively related to the amount of IgG on the platelets. Normal or IgG-defident serum had a potent inhibitory (noncompetitive) action on the binding of F-IgG and F-anti-human IgG antibody to human platelets. Cohorts of platelets prepared in rabbits during the recovery phase of immunological thrombocytopenia induced by injection of heterologous antiserum, showed an age-dependent increase of PAIgG and of IgG binding. These results suggest that PAIgG plays a role in the clearance of senescent platelets.

Prevalence of Health Care and Hospital Worker SARS-CoV-2 IgG Antibody in a Pediatric Hospital

2020 ◽  
pp. hpeds.2020-003517
Author(s):  
Yekaterina Tokareva ◽  
Janet A. Englund ◽  
Jane A. Dickerson ◽  
Julie C. Brown ◽  
Danielle M. Zerr ◽  
...  
Keyword(s):  
Health Care ◽  
Pediatric Hospital ◽  
Igg Antibody ◽  
Hospital Worker

The Inducing Roles of the New Isolated Bursal Hexapeptide and Pentapeptide on the Immune Response of AIV Vaccine in Mice

2019 ◽  
Vol 26 (7) ◽  
pp. 542-549 ◽  
Author(s):  
Shan Shan Hao ◽  
Man Man Zong ◽  
Ze Zhang ◽  
Jia Xi Cai ◽  
Yang Zheng ◽  
...  
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Amino Acid ◽  
T Cell ◽  
Antigen Presentation ◽  
Amino Acid Sequences ◽  
Cell Subpopulation ◽  
Igg Antibody ◽  
Antibody Titers ◽  
Specific Igg

Background: Bursa of Fabricius is the acknowledged central humoral immune organ. The bursal-derived peptides play the important roles on the immature B cell development and antibody production. Objective: Here we explored the functions of the new isolated bursal hexapeptide and pentapeptide on the humoral, cellular immune response and antigen presentation to Avian Influenza Virus (AIV) vaccine in mice immunization. Methods: The bursa extract samples were purified following RP HPLC method, and were analyzed with MS/MS to identify the amino acid sequences. Mice were twice subcutaneously injected with AIV inactivated vaccine plus with two new isolated bursal peptides at three dosages, respectively. On two weeks after the second immunization, sera samples were collected from the immunized mice to measure AIV-specific IgG antibody levels and HI antibody titers. Also, on 7th day after the second immunization, lymphocytes were isolated from the immunized mice to detect T cell subtype and lymphocyte viabilities, and the expressions of co-stimulatory molecule on dendritic cells in the immunized mice. Results: Two new bursal hexapeptide and pentapeptide with amino acid sequences KGNRVY and MPPTH were isolated, respectively. Our investigation proved the strong regulatory roles of bursal hexapeptide on AIV-specific IgG levels and HI antibody titers, and lymphocyte viabilities, and the significant increased T cells subpopulation and expressions of MHCII molecule on dendritic cells in the immunized mice. Moreover, our findings verified the significantly enhanced AIV-specific IgG antibody and HI titers, and the strong increased T cell subpopulation and expressions of CD40 molecule on dendritic cells in the mice immunized with AIV vaccine and bursal pentapeptide. Conclusion: We isolated and identified two new hexapeptide and pentapeptide from bursa, and proved that these two bursal peptides effectively induced the AIV-specific antibody, T cell and antigen presentation immune responses, which provided an experimental basis for the further clinical application of the bursal derived active peptide on the vaccine improvement.

Seroprevalence of anti-SARS-CoV-2 IgG antibodies in hospitalized patients at a tertiary referral center in North India (Preprint)

2020 ◽  
Author(s):  
Dr. Animesh Ray ◽  
Dr. Komal Singh ◽  
Souvick Chattopadhyay ◽  
Farha Mehdi ◽  
Dr. Gaurav Batra ◽  
...  
Keyword(s):  
Tertiary Care ◽  
Age Groups ◽  
Hospitalized Patients ◽  
North India ◽  
P Value ◽  
Care Hospital ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Increased Risk ◽  
Significant Difference

BACKGROUND Seroprevalence of IgG antibodies against SARS-CoV-2 is an important tool to estimate the true extent of infection in a population. However, seroprevalence studies have been scarce in South East Asia including India, which, as of now, carries the third largest burden of confirmed cases in the world. The present study aimed to estimate the seroprevalence of anti-SARS-CoV-2 IgG antibody among hospitalized patients at one of the largest government hospital in India OBJECTIVE The primary objective of this study is to estimate the seroprevalence of SARS-CoV-2 antibody among patients admitted to the Medicine ward and ICU METHODS This cross-sectional study, conducted at a tertiary care hospital in North India, recruited consecutive patients who were negative for SARS-CoV-2 by RT-PCR or CB-NAAT. Anti-SARS-CoV-2 IgG antibody levels targeting recombinant spike receptor-binding domain (RBD) protein of SARS CoV-2 were estimated in serum sample by the ELISA method RESULTS A total of 212 hospitalized patients were recruited in the study with mean age (±SD) of 41.2 (±15.4) years and 55% male population. Positive serology against SARS CoV-2 was detected in 19.8%patients(95% CI 14.7-25.8). Residency in Delhi conferred a higher frequency of seropositivity 26.5% (95% CI 19.3-34.7) as compared to that of other states 8% (95% CI 3.0-16.4) with p-value 0.001. No particular age groups or socio-economic strata showed a higher proportion of seropositivity CONCLUSIONS Around, one-fifth of hospitalized patients, who were not diagnosed with COVID-19 before, demonstrated seropositivity against SARS-CoV-2. While there was no significant difference in the different age groups and socio-economic classes; residence in Delhi was associated with increased risk (relative risk of 3.62, 95% CI 1.59-8.21)

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