scholarly journals Evaluation of Commercial Anti-SARS-CoV-2 Neutralizing Antibody Assays in seropositive subjects

2022 ◽  
Author(s):  
Kahina Saker ◽  
Bruno Pozzetto ◽  
Vanessa ESCURET ◽  
Virginie Pitiot ◽  
Amélie Massardier-Pilonchéry ◽  
...  
Keyword(s):  
Functional Ability ◽  
Neutralizing Antibodies ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Added Value ◽  
P Value ◽  
Antibody Assays ◽  
Qualitative Test ◽  
User Friendly ◽  
Commercial User

The virus neutralization test (VNT) is the reference for the assessment of the functional ability of neutralizing antibodies (NAb) to block SARS-CoV-2 entry into cells. New competitive immunoassays measuring antibodies preventing interaction between the spike protein and its cellular receptor are proposed as surrogate VNT (sVNT). We tested three commercial sVNT (a qualitative immunochromatographic test and two quantitative immunoassays named YHLO and TECO) together with a conventional anti-spike IgG assay (bioMerieux) in comparison with an in-house plaque reduction neutralization test (PRNT50) using the original 19A strain and different variants of concern (VOC), on a panel of 306 sera from naturally-infected or vaccinated patients. The qualitative test was rapidly discarded because of poor sensitivity and specificity. Areas under the curve of YHLO and TECO assays were, respectively, 85.83 and 84.07 (p-value >0.05) using a positivity threshold of 20 for PRNT50, and 95.63 and 90.35 (p-value =0.02) using a threshold of 80. However, the performances of YHLO and bioMerieux were very close for both thresholds, demonstrating the absence of added value of sVNT compared to a conventional assay for the evaluation of the presence of NAb in seropositive subjects. In addition, the PRNT50 assay showed a reduction of NAb titers towards different VOC in comparison to the 19A strain that could not be appreciated by the commercial tests. Despite the good correlation between the anti-spike antibody titer and the titer of NAb by PRNT50, our results highlight the difficulty to distinguish true NAb among the anti-RBD antibodies with commercial user-friendly immunoassays.

scholarly journals Effect of a booster-dose of rabies vaccine on the duration of virus neutralizing antibody titers in bovines

1998 ◽  
Vol 31 (4) ◽  
pp. 367-371 ◽  
Author(s):  
Avelino Albas ◽  
Paulo Eduardo Pardo ◽  
Albério Antonio Barros Gomes ◽  
Fernanda Bernardi ◽  
Fumio Honma Ito
Keyword(s):  
Immune Response ◽  
Neutralizing Antibodies ◽  
Booster Dose ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Rabies Vaccine ◽  
Western Region ◽  
Humoral Immune ◽  
Paulo State ◽  
Antibody Titers

Humoral immune response using inactivated rabies vaccine was studied in 35 nelore cross-bred bovines of western region of São Paulo state. Ninety days after vaccination, 13 (92.8%) animals presented titers 30.5IU/ml, through mouse neutralization test. After 180 days, 9 (64.3%) sera showed titers 30.5IU/ml, after 270 days, only one (7.1%) showed a titer of 0.51IU/ml, and after 360 days, all animals showed titers < 0.5IU/ml. Group of animals receiving booster dose 30 days after vaccination presented, two months after, all with titers > 0.5IU/ml. At 180 days, 17 (80.9%) sera presented titers > 0.5IU/ml; at 270 days, 15 (71.4%), with titers 30.5IU/ml and at 360 days, 4 (19.0%), with titers 30.5IU/ml. Booster-dose ensured high levels of neutralizing antibodies for at least three months, and 240 days after revaccination, 71.4% of animals were found with titers 30.5IU/ml.

scholarly journals Performance Evaluation of the BZ COVID-19 Neutralizing Antibody Test for the Culture-Free and Rapid Detection of SARS-CoV-2 Neutralizing Antibodies

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2193
Author(s):  
Bo Kyeung Jung ◽  
Jung Yoon ◽  
Joon-Yong Bae ◽  
Jeonghun Kim ◽  
Man-Seong Park ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Diagnostic Performance ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Antibody Test ◽  
Lower Sensitivity ◽  
Control Line ◽  
Perfect Agreement ◽  
Strong Negative Correlation ◽  
Percent Inhibition

Rapid and accurate measurement of SARS-CoV-2 neutralizing antibodies (nAbs) can aid in understanding the development of immunity against COVID-19. This study evaluated the diagnostic performance of a rapid SARS-CoV-2 nAb detection test called the BZ COVID-19 nAb test BZ-nAb (BZ-nAb; BioZentech). Using the 90% plaque-reduction neutralization test (PRNT-90) as a reference, 104 serum specimens collected from COVID-19-positive and -negative patients were grouped into 40 PRNT-90-positive and 64 PRNT-90-negative specimens. The performance of the BZ-nAb was compared with that of the cPass surrogate virus neutralization test (cPass sVNT; Genscript). The BZ-nAb showed a sensitivity ranging from 92.5%–95.0% and specificity ranging from 96.9%–100%, whereas cPass sVNT showed a sensitivity of 100% (95% confidence interval (CI) 90.5%–100%) and specificity of 98.4% (95% CI, 91.6%–100%). The dilution factor obtained with PRNT-90 showed a stronger correlation with the percent inhibition of cPass sVNT (r = 0.8660, p < 0.001) compared with the test and control line ratio (T/C ratio) of the BZ-nAb (r = −0.7089, p < 0.001). An almost perfect agreement was seen between the BZ-nAb and cPass sVNT results, with a strong negative correlation between the BZ-nAb T/C ratio and cPass sVNT percent inhibition (r = −0.8022, p < 0.001). In conclusion, the diagnostic performance of the BZ-nAb was comparable to that of the cPass sVNT, although the BZ-nAb had a slightly lower sensitivity.

scholarly journals Evaluation of high-throughput SARS-CoV-2 serological assays in a longitudinal cohort of mild COVID-19 patients: sensitivity, specificity and association with virus neutralization test

2020 ◽  
Author(s):  
Antonin Bal ◽  
Bruno Pozzetto ◽  
Mary-Anne Trabaud ◽  
Vanessa Escuret ◽  
Muriel Rabilloud ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Healthcare Workers ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Serological Tests ◽  
Course Of Disease ◽  
Antibody Titers ◽  
Sensitivity Specificity

BackgroundThe association between SARS-CoV-2 commercial serological assays and virus neutralization test (VNT) has been poorly explored in mild COVID-19 patients.MethodsA total of 439 serum specimens were longitudinally collected from 76 healthcare workers with RT-PCR-confirmed COVID-19. The sensitivity (determined weekly) of nine commercial serological assays were evaluated. Specificity was assessed using 69 pre-pandemic sera. Correlation, agreement and concordance with the VNT were also assessed on a subset of 170 samples. Area under the ROC curve (AUC) was estimated at several neutralizing antibody titers.ResultsThe Wantai Total Ab assay targeting the receptor binding domain (RBD) within the S protein presented the best sensitivity at different times during the course of disease. The specificity was greater than 95% for all tests except for the Euroimmun IgA assay. The overall agreement with the presence of neutralizing antibodies ranged from 62.2% (95%CI; 56.0-68.1) for bioMérieux IgM to 91.2% (87.0-94.2) for Siemens. The lowest negative percent agreement (NPA) was found with the Wantai Total Ab assay (NPA 33% (21.1-48.3)). The NPA for other total Ab or IgG assays targeting the S or the RBD was 80.7% (66.7-89.7), 90.3 (78.1-96.1) and 96.8% (86.8-99.3) for Siemens, bioMérieux IgG and DiaSorin, respectively. None of commercial assays have sufficient performance to detect a neutralizing titer of 80 (AUC<0.76).ConclusionsAlthough some assays presented a better agreement with VNT than others, the present findings emphasize that commercialized serological tests including those targeting the RBD cannot substitute a VNT for the assessment of functional antibody response.

scholarly journals IMMUNOLOGICAL REACTIONS OF THE COXSACKIE VIRUSES

1950 ◽  
Vol 92 (5) ◽  
pp. 463-482 ◽  
Author(s):  
Joseph L. Melnick ◽  
Nada Ledinko
Keyword(s):  
North Carolina ◽  
Neutralizing Antibodies ◽  
Neutralization Test ◽  
Normal Population ◽  
Standard Procedure ◽  
Neutralizing Antibody ◽  
The United States ◽  
Immune Serum ◽  
Newborn Mice ◽  
Immunological Reactions

The neutralization test is a reliable and useful procedure for following immunological reactions of the Coxsackie viruses (C virus). The standard procedure has been an incubation period of 1 hour at room temperature followed by subcutaneous inoculation into newborn mice. However, this time and temperature are not critical, for the virus in neutralized within 10 minutes of mixing with immune serum and remains neutralized for long periods. During the variable incubation periods used, the control virus remained active, even in dilute suspensions. The neutralization test is not affected by the presence or absence of complement. Neutralizing antibody is stable at 65°C. for 30 minutes, and immune serum has to be heated to 80°C. for 30 minutes before the antibody is no longer detectable. As the quantity of virus is increased, the quantity of serum required for neutralization likewise increases, but not in a regular or predictable fashion. Neutralized mixtures of the virus can be made infective again by simple dilution before inoculation. The neutralization test is a satisfactory means for typing Coxsackie viruses. At least seven antigenic types have been identified. Similar antigenic types have been found to be scattered over wide areas. Thus the Conn.-5 type was present in 1948 in Massachusetts, Connecticut, New York, and North Carolina. The Texas-1 type was present in 1943 in Connecticut and in 1948 in North Carolina and Texas. Further information on the specificity of the neutralizing antibody response has been obtained from a study of the occurrence and development of antibodies in 6 patients who contracted infections with one or another of the C viruses while working with them in the laboratory. From each patient a virus was isolated during the illness. No patient had detectable antibodies to his strain before his illness, but each soon thereafter developed antibodies to his own strain and to the prototype strain to which it was related. By means of the neutralization test, it has been shown that a family epidemic may include two different immunological types of virus. Neutralizing antibodies appear at the time of or soon after onset of illness, increase rapidly to titers of about 1:1000 which are maintained during the period of 1 to 3 months following infection, and are still present 2 years later, although at lower levels. Neutralizing antibodies are present in the normal population. In North Carolina, over 80 per cent of the children have antibodies at birth. The level falls rapidly to a minimum of 14 per cent at the age of 1, and then it quickly rises to reach the adult level at the age of 7. Gamma globulin collected in various parts of the United States between 1944 and 1949 and in Denmark in 1949 neutralizes at least four antigenically different Coxsackie viruses.

scholarly journals Seroprevalence of SARS-CoV-2 IgG antibodies, in Corsica (France), April and June 2020.

2020 ◽  
Author(s):  
Lisandru Capai ◽  
Nazli Ayhan ◽  
Shirley Masse ◽  
Jean Canarelli ◽  
Stephane Priet ◽  
...  
Keyword(s):  
Neutralization Test ◽  
Age Groups ◽  
Neutralizing Antibody ◽  
Blood Analysis ◽  
Spike Protein ◽  
P Value ◽  
Igg Antibodies ◽  
Antibody Titers ◽  
The Impact ◽  
Sera Samples

Our aim was to assess the seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection after the lockdown in a sample of the Corsican population. Between 16th April and 15th June 2020, 2,312 residual sera were collected from patients having carried out a blood analysis in one of the participating laboratories. Residual sera obtained from persons of all ages were tested for the presence of anti-SARS-CoV-2 IgG using the EUROIMMUN enzyme immunoassay kit for semiquantitative detection of IgG antibodies against S1 domain of viral spike protein (ELISA-S). Borderline and positive samples in ELISA-S were also tested with an in-house virus neutralization test (VNT). Prevalence values were adjusted for sex and age. A total of 1,973 residual sera samples were included in the study. The overall seroprevalence based on ELISA-S was 5.27% [95% confidence interval (CI) 4.33-6.35] and 5.46% [4.51-6.57] after adjustment. Gender was not associated with IgG detection. However, significant differences were observed between age groups (p-value = 1 E-5) and particularly for people being younger than 50 years of age (Odd ratio (OR) = 2.86 95% CI [1.80- 4.53]; p-value <0.000001*). The prevalence of neutralizing antibody titers ≥40 was of 3% [2.28-3.84]. In conclusion the present study showed that a low seroprevalence for COVID-19 in Corsica in accordance with values reported for other French regions in which the impact of the pandemic was low.

scholarly journals Predicting COVID-19 Vaccine Efficacy from Neutralizing Antibody Levels

2021 ◽  
Author(s):  
Majid R. Abedi ◽  
Samuel Dixon ◽  
Timothy Guyon ◽  
Serene Hsu ◽  
Aviva R. Jacobs ◽  
...  
Keyword(s):  
High Throughput ◽  
Vaccine Efficacy ◽  
Neutralizing Antibodies ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Published Data ◽  
Real World Data ◽  
Symptomatic Infection ◽  
Viral Neutralization ◽  
Antibody Levels

Recent studies using data accrued from global SARS-CoV-2 vaccination efforts have demonstrated that breakthrough infections are correlated with levels of neutralizing antibodies. The decrease in neutralizing antibody titers of vaccinated individuals over time, combined with the emergence of more infectious variants of concern has resulted in waning vaccine efficacy against infection and a rise in breakthrough infections. Here we use a combination of neutralizing antibody measurements determined by a high throughput surrogate viral neutralization test (sVNT) together with published data from vaccine clinical trials and comparative plaque reduction neutralization test (PRNT) between SARS-CoV-2 variants to develop a model for vaccine efficacy (VE) against symptomatic infection. Vaccine efficacy estimates using this model show good concordance with real world data from the US and Israel. Our work demonstrates that appropriately calibrated neutralizing antibody measurements determined by high throughput sVNT can be used to provide a semi-quantitative estimate of protection against infection. Given the highly variable antibody levels among the vaccinated population, this model may be of use in identification of individuals with an elevated risk of breakthrough infections.

scholarly journals Evaluation of a Commercial Culture-free Neutralization Antibody Detection Kit for Severe Acute Respiratory Syndrome-Related Coronavirus-2 and Comparison with an Anti-RBD ELISA Assay

2021 ◽  
Author(s):  
Jesse Papenburg ◽  
Matthew P. Cheng ◽  
Rachel Corsini ◽  
Chelsea Caya ◽  
Emelissa Mendoza ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Neutralization Test ◽  
Neutralization Assay ◽  
Added Value ◽  
Antibody Detection ◽  
Elisa Assay ◽  
Commercial Culture ◽  
Viral Culture ◽  
Iga Antibodies

ABSTRACTBackgroundSARS-CoV-2 surrogate neutralization assays that obviate the need for viral culture offer substantial advantages regarding throughput and cost. The cPass SARS-CoV-2 Neutralization Antibody Detection Kit (Genscript) is the first such commercially available assay, detecting antibodies that block RBD/ACE-2 interaction. We aimed to evaluate cPass to inform its use and assess its added value compared to anti-RBD ELISA assays.MethodsSerum reference panels comprising 205 specimens were used to compare cPass to plaque-reduction neutralization test (PRNT) and a pseudotyped lentiviral neutralization (PLV) assay for detection of neutralizing antibodies. We assessed the correlation of cPass with an ELISA detecting anti-RBD IgG, IgM, and IgA antibodies at a single timepoint and across intervals from onset of symptoms of SARS-CoV-2 infection.ResultsCompared to PRNT-50, cPass sensitivity ranged from 77% - 100% and specificity was 95% - 100%. Sensitivity was also high compared to the pseudotyped lentiviral neutralization assay (93% [95%CI 85-97]), but specificity was lower (58% [95%CI 48-67]). Highest agreement between cPass and ELISA was for anti-RBD IgG (r=0.823). Against the pseudotyped lentiviral neutralization assay, anti-RBD IgG sensitivity (99% [95%CI 94-100]) was very similar to that of cPass, but overall specificity was lower (37% [95%CI 28-47]). Against PRNT-50, results of cPass and anti-RBD IgG were nearly identical.ConclusionsThe added value of cPass compared to an IgG anti-RBD ELISA was modest.

West Nile virus neutralizing antibody prevalence in donkeys from northern Nigeria

2020 ◽  
Author(s):  
Idoko Sunday Idoko ◽  
Gili Schvartz ◽  
Sharon Tirosh-Levy ◽  
Oran Erster ◽  
Jibril Yakubu Jibril ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Neutralizing Antibodies ◽  
Healthy Adult ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Virus Neutralization Test ◽  
Northern Nigeria ◽  
Antibody Prevalence ◽  
West Nile ◽  
Zoonotic Pathogen

Abstract Background This study aimed to evaluate the prevalence of anti-West Nile virus (WNV) neutralizing antibodies in donkeys from two areas in northern Nigeria. Methods Serology was determined by a virus neutralization test in samples collected from 205 healthy adult donkeys. Results Fifty-seven donkeys (27.8%) tested seropositive for WNV. Donkeys from Zaria were 2.6 times more likely to have been exposed to WNV (p&lt;0.001). Conclusion The results of this study demonstrate that this zoonotic pathogen is prevalent in these areas and that measures should be implemented to reduce the risk for both humans and equids.

scholarly journals Evaluation of Three SARS CoV-2 IgG Antibody Assays and Correlation with Neutralizing Antibodies

2020 ◽  
Author(s):  
Jenna Rychert ◽  
Marc Roger Couturier ◽  
Marc Elgort ◽  
Bucky Ken Lozier ◽  
Sonia La’ulu ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Quantitative Result ◽  
Neutralizing Antibody ◽  
Performance Characteristics ◽  
Igg Antibody ◽  
Assay Sensitivity ◽  
Clinical Sensitivity ◽  
Antibody Assays ◽  
Comparable Performance ◽  
Sensitivity Specificity

Abstract Background As serologic assays for SARS-CoV-2 become more widely utilized, it is important to understand their performance characteristics and correlation with neutralizing antibodies. We evaluated three commonly used SARS-CoV-2 IgG assays (Abbott, DiaSorin and EUROIMMUN) for clinical sensitivity, specificity, and correlation with neutralizing antibodies and then compared antibody kinetics during the acute phase of infection. Methods Three panels of samples were tested on every assay. Sensitivity was assessed using a panel of 35 specimens serially collected from 7 RT-PCR-confirmed COVID-19 patients. Specificity was determined using 100 sera samples collected in 2018 from healthy individuals prior to the outbreak. Analytical specificity was determined using a panel of 37 samples from individuals with respiratory illnesses other than COVID-19. Results Clinical sensitivity was 91.43% (95% CI 76.94%-98.20%) for Abbott, and 88.57% (95% CI 73.26%-96.80%) for both DiaSorin and EUROIMMUN. Clinical specificity was 99.00% (95% CI 94.55%-99.97%) for Abbott and DiaSorin and 94.00% (95% CI 87.40%-97.77%) for EUROIMMUN. The IgG assays demonstrated good qualitative agreement (minimum of 94%) and good correlation between the quantitative result for each combination of assays (r2≥0.90). The neutralizing antibody response did not necessarily follow the same temporal kinetics as the IgG response and did not necessarily correlate with IgG values. Conclusion The three IgG antibody assays demonstrated comparable performance characteristics. Importantly, a qualitative positive IgG result obtained with any of the assays was associated with the presence of neutralizing antibodies; however, neutralizing antibody concentrations did not correlate well with signal to cutoff ratios.

scholarly journals Evaluation of high-throughput SARS-CoV-2 serological assays in a longitudinal cohort of patients with mild COVID-19: clinical sensitivity, specificity and association with virus neutralization test

2021 ◽  
Author(s):  
Antonin Bal ◽  
Bruno Pozzetto ◽  
Mary-Anne Trabaud ◽  
Vanessa Escuret ◽  
Muriel Rabilloud ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Virus Neutralization Test ◽  
Virus Neutralization ◽  
Serological Tests ◽  
Course Of Disease ◽  
Clinical Sensitivity ◽  
Antibody Titers ◽  
Sensitivity Specificity

Abstract Background The association between SARS-CoV-2 commercial serological assays and virus neutralization test (VNT) has been poorly explored in mild patients with COVID-19. Methods 439 serum specimens were longitudinally collected from 76 healthcare workers with RT-PCR-confirmed COVID-19. The clinical sensitivity (determined weekly) of nine commercial serological assays were evaluated. Clinical specificity was assessed using 69 pre-pandemic sera. Correlation, agreement and concordance with the VNT were also assessed on a subset of 170 samples. Area under the ROC curve (AUC) was estimated at 2 neutralizing antibody titers. Results The Wantai Total Ab assay targeting the receptor binding domain (RBD) within the S protein presented the best sensitivity at different times during the course of disease. The clinical specificity was greater than 95% for all tests except for the Euroimmun IgA assay. The overall agreement with the presence of neutralizing antibodies ranged from 62.2% (95%CI; 56.0-68.1) for bioMérieux IgM to 91.2% (87.0-94.2) for Siemens. The lowest negative percent agreement (NPA) was found with the Wantai Total Ab assay (NPA 33% (21.1-48.3)). The NPA for other total Ab or IgG assays targeting the S or the RBD was 80.7% (66.7-89.7), 90.3 (78.1-96.1) and 96.8% (86.8-99.3) for Siemens, bioMérieux IgG and DiaSorin, respectively. None of commercial assays have sufficient performance to detect a neutralizing titer of 80 (AUC&lt;0.76). Conclusions Although some assays show a better agreement with VNT than others, the present findings emphasize that commercialized serological tests including those targeting the RBD cannot substitute a VNT for the assessment of functional antibody response.

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