scholarly journals SARS-CoV-2 Serum Neutralization Assay: A Traditional Tool for a Brand-New Virus

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 655
Author(s):  
Giulia Matusali ◽  
Francesca Colavita ◽  
Daniele Lapa ◽  
Silvia Meschi ◽  
Licia Bordi ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Serum Samples ◽  
Roc Curve Analysis ◽  
Routine Testing ◽  
Serum Neutralization ◽  
Testing Algorithms ◽  
Set Up ◽  
Testing Algorithm ◽  
Microneutralization Test

SARS-CoV-2 serum neutralization assay represents the gold standard for assessing antibody-mediated protection in naturally infected and vaccinated individuals. In the present study, 662 serum samples collected from February 2020 to January 2021 from acute and convalescent COVID-19 patients were tested to determine neutralizing antibody (NAb) titers using a microneutralization test (MNT) for live SARS-CoV-2. Moreover, anti-SARS-CoV-2 IgG, IgA, and IgM directed against different viral antigens were measured by high-throughput automated platforms. We observed higher levels of NAbs in elderly (>60 years old) individuals and in patients presenting acute respiratory distress syndrome. SARS-CoV-2 NAbs develop as soon as five days from symptom onset and, despite a decline after the second month, persist for over 11 months, showing variable dynamics. Through correlation and receiver operating characteristic (ROC) curve analysis, we set up a testing algorithm, suitable for the laboratory workload, by establishing an optimal cutoff value of anti-SARS-CoV-2 IgG for convalescent plasma donors to exclude from MNT samples foreseen to have low/negative NAb titers and ineligible for plasma donation. Overall, MNT, although cumbersome and not suitable for routine testing of large sample sizes, remains the reference tool for the assessment of antibody-mediated immunity after SARS-CoV-2 infection. Smart testing algorithms may optimize the laboratory workflow to monitor antibody-mediated protection in COVID-19 patients, plasma donors, and vaccinated individuals.

scholarly journals Evaluation of Modified Two-Tiered Testing Algorithms for Lyme Disease Laboratory Diagnosis Using Well-Characterized Serum Samples

2018 ◽  
Vol 56 (8) ◽  
Author(s):  
Adoracion Pegalajar-Jurado ◽  
Martin E. Schriefer ◽  
Ryan J. Welch ◽  
Marc R. Couturier ◽  
Tiffany MacKenzie ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Laboratory Testing ◽  
Laboratory Diagnosis ◽  
Serum Samples ◽  
Chemiluminescence Immunoassay ◽  
Testing Algorithms ◽  
Second Tier ◽  
Testing Algorithm ◽  
Low Sensitivity ◽  
Recommended Algorithm

ABSTRACTStandard two-tiered testing (STTT) is the recommended algorithm for laboratory diagnosis of Lyme disease (LD). Several limitations are associated with STTT that include low sensitivity in the early stages of disease, as well as technical complexity and subjectivity associated with second-tier immunoblotting; therefore, modified two-tiered testing (MTTT) algorithms that utilize two sequential first-tier tests and eliminate immunoblotting have been evaluated. Recently, a novel MTTT that uses a VlsE chemiluminescence immunoassay followed by a C6 enzyme immunoassay has been proposed. The purpose of this study was to evaluate the performance of the VlsE/C6 MTTT using well-characterized serum samples. Serum samples from the CDC Lyme Serum Repository were tested using three MTTTs, VlsE/C6, whole-cell sonicate (WCS)/C6, and WCS/VlsE, and three STTTs (immunoblotting preceded by three different first-tier assays: VlsE, C6, and WCS). Significant differences were not observed between the results of the MTTTs assessed; however, the VlsE/C6 MTTT resulted in the highest specificity (100%) when other diseases were tested and the lowest sensitivity (75%) for LD samples. Significant differences were present between the results for various MTTTs and STTTs evaluated. Specifically, all MTTTs resulted in higher sensitivities than the STTTs for all LD groups combined and were significantly more accurate (i.e., higher proportion of correct classifications) for this group, with the exception of the WCS/ViraStripe STTT. Additionally, when other diseases were tested, only the results of the VlsE/C6 MTTT differed significantly from those of the WCS/ViraStripe STTT, with the VlsE/C6 MTTT resulting in a 6.2% higher accuracy. Overall, the VlsE/C6 MTTT offers an additional laboratory testing algorithm for LD with equivalent or enhanced performance compared to that of the other MTTTs and STTTs evaluated in this study.

scholarly journals Serum Neutralization Assay Can Efficiently Replace Plaque Reduction Neutralization Test for Detection and Quantitation of West Nile Virus Antibodies in Human and Animal Serum Samples

2014 ◽  
Vol 21 (10) ◽  
pp. 1460-1462 ◽  
Author(s):  
Annapia Di Gennaro ◽  
Alessio Lorusso ◽  
Claudia Casaccia ◽  
Annamaria Conte ◽  
Federica Monaco ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Neutralization Test ◽  
Neutralization Assay ◽  
Serum Samples ◽  
West Nile ◽  
Plaque Reduction Neutralization Test ◽  
Serum Neutralization ◽  
Human Sera

ABSTRACTA serum neutralization assay (SN) was compared with the official plaque reduction neutralization test for the quantitation of West Nile virus antibodies. A total of 1,348 samples from equid sera and 38 from human sera were tested by these two methods. Statistically significant differences were not observed, thus supporting the use of SN for routine purposes.

scholarly journals Rabies neutralizing antibody detection by indirect immunperoxidase serum neutralization assay performed on chicken embryo related cell line

2004 ◽  
Vol 99 (5) ◽  
pp. 531-534 ◽  
Author(s):  
Tereza Cristina Cardoso ◽  
Luzia Helena Queiroz da Silva ◽  
Avelino Albas ◽  
Helena Lage Ferreira ◽  
Silvia Helena Venturoli Perri
Keyword(s):  
Cell Line ◽  
Chicken Embryo ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Antibody Detection ◽  
Serum Neutralization ◽  
Related Cell

scholarly journals Quantification of SARS-CoV-2 neutralizing antibody by a pseudotyped virus based assay

2020 ◽  
Author(s):  
Jianhui Nie ◽  
Qianqian Li ◽  
Jiajing Wu ◽  
Chenyan Zhao ◽  
Huan Hao ◽  
...  
Keyword(s):  
Small Molecules ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Pseudotyped Virus ◽  
Serum Samples ◽  
Virus Stock ◽  
Virus Attachment ◽  
Fusion Inhibitors ◽  
Level 2 ◽  
Biosafety Level

Abstract Jianhui Nie, Qianqian Li, and Jiajing Wu contributed equally to this work.Pseudotyped viruses are useful virological tools due to their safety and versatility. Based on a VSV pseudotyped virus production system, we developed a pseudotyped virus-based neutralization assay against SARS-CoV-2 in biosafety level 2 facilities. This protocol includes production, titration of the SARS-CoV-2 S pseudotyped virus and neutralization assay based on it. Various types of samples targeting virus attachment and entry could be evaluated for their potency, including serum samples derived from animals and humans, monoclonal antibodies, fusion inhibitors (peptides or small molecules). If the pseudotyped virus stock has been prepared in advance, it will take 2 days to get the potency data for the candidate samples. Experience of handling cells is needed before implementing this protocol.

scholarly journals DISAPPEARANCE OF ANTIBODIES IN COVID-19 MYTHS ORREALITY

2021 ◽  
Vol 71 (Suppl-3) ◽  
pp. S530-33
Author(s):  
Maqbool Raza ◽  
Muhammed Ali Raza ◽  
De Emmal Asjad Cheema ◽  
Maham Asjad Cheema ◽  
Atif Rafique ◽  
...  
Keyword(s):  
Antibody Level ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Cross Sectional Study ◽  
Assay Method ◽  
Military Hospital ◽  
Serum Samples ◽  
Cross Sectional ◽  
Severity Of The Disease

Objective: To explore the disappearance of neutralizing antibodies from patients, their myths, and facts. Study Design: Cross-sectional study. Place and Duration of Study: Combined Military Hospital Multan Pakistan, from Jul 2021 to Aug 2021. Methodology: A total of 100 blood samples were collected from 100 COVID-19 patients. These 100 patients were followed up for a period of 3 months. Antibodies were determined with the modified neutralization assay method and enzyme-linked immuno-sorbent assay (ELISA). Results: The antibody level by NA and ELISA peaked on days 30-35 then decreased slightly. In multivariate analysis, patients aged 25-35, 36-56, and 57-84 years had a higher neutralizing antibody level than those aged 10-21 years. The patient with the worst clinical manifestation had a higher neutralizing antibody titer. In serum samples, IgG was undetectable at 18.3% and 11% and the geographical mean reciprocal titers dropped from 244 at 3-month period and neutralizing antibodies, the geographical mean reciprocal titers dropped from 874 at 3 months. Conclusion: All COVID-19 patients were seropositive and significantly neutralizing antibody response. Neutralizing antibody levels depend on the time after the onset of symptoms, age, and severity of the disease.

scholarly journals Kinetics of Neutralizing Antibody Response Underscores Clinical COVID-19 Progression

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Qing Lei ◽  
Hongyan Hou ◽  
Caizheng Yu ◽  
Yandi Zhang ◽  
Jo-Lewis Banga Ndzouboukou ◽  
...  
Keyword(s):  
Viral Infections ◽  
Onset Time ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Multiple Organ ◽  
Pseudotyped Virus ◽  
Serum Samples ◽  
Virus Neutralization Assay ◽  
Effective Interventions

Background. Neutralizing antibody (nAb) response is generated following infection or immunization and plays an important role in the protection against a broad of viral infections. The role of nAb during clinical progression of coronavirus disease 2019 (COVID-19) remains little known. Methods. 123 COVID-19 patients during hospitalization in Tongji Hospital were involved in this retrospective study. The patients were grouped based on the severity and outcome. The nAb responses of 194 serum samples were collected from these patients within an investigation period of 60 days after the onset of symptoms and detected by a pseudotyped virus neutralization assay. The detail data about onset time, disease severity and laboratory biomarkers, treatment, and clinical outcome of these participants were obtained from electronic medical records. The relationship of longitudinal nAb changes with each clinical data was further assessed. Results. The nAb response in COVID-19 patients evidently experienced three consecutive stages, namely, rising, stationary, and declining periods. Patients with different severity and outcome showed differential dynamics of the nAb response over the course of disease. During the stationary phase (from 20 to 40 days after symptoms onset), all patients evolved nAb responses. In particular, high levels of nAb were elicited in severe and critical patients and older patients (≥60 years old). More importantly, critical but deceased COVID-19 patients showed high levels of several proinflammation cytokines, such as IL-2R, IL-8, and IL-6, and anti-inflammatory cytokine IL-10 in vivo, which resulted in lymphopenia, multiple organ failure, and the rapidly decreased nAb response. Conclusion. Our results indicate that nAb plays a crucial role in preventing the progression and deterioration of COVID-19, which has important implications for improving clinical management and developing effective interventions.

scholarly journals A multiplexed high-throughput neutralization assay reveals a lack of activity against multiple variants after SARS-CoV-2 infection

2021 ◽  
Author(s):  
Craig Fenwick ◽  
Priscilla Turelli ◽  
Celine Pellaton ◽  
Alex Farina ◽  
Jeremy Campos ◽  
...  
Keyword(s):  
High Throughput ◽  
Neutralizing Antibodies ◽  
Large Scale ◽  
Competitive Inhibition ◽  
Natural Infection ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Antibody Responses ◽  
Serum Samples ◽  
Live Virus

The detection of SARS-CoV-2-specific antibodies in the serum of an individual indicates prior infection or vaccination. However, it provides limited insight into the protective nature of this immune response. Neutralizing antibodies recognizing the viral Spike are far more revealing, yet their measurement traditionally requires virus- and cell-based systems that are costly, time-consuming, poorly flexible and potentially biohazardous. Here we present a cell-free quantitative neutralization assay based on the competitive inhibition of trimeric SARS-CoV-2 Spike protein binding to the angiotensin converting enzyme 2 (ACE2) viral receptor. This high-throughput method matches the performance of the gold standard live virus infectious assay, as verified with a panel of 206 seropositive donors with varying degrees of infection severity and virus-specific IgG titers, achieving 96.7% sensitivity and 100% specificity. Furthermore, it allows for the parallel assessment of neutralizing activities against multiple SARS-CoV-2 Spike variants of concern (VOC), which is otherwise unpredictable even in individuals displaying robust neutralizing antibody responses. Profiling serum samples from 59 hospitalized COVID-19 patients, we found that although most had high activity against the 2019-nCoV Spike and to a lesser extent the B.1.1.7 variant, only 58% could efficiently neutralize a Spike derivative containing mutations present in the B.1.351 variant. In conclusion, we have developed an assay that has proven its clinical relevance in the large-scale evaluation of effective neutralizing antibody responses to VOC after natural infection and that can be applied to the characterization of vaccine-induced antibody responses and of the potency of human monoclonal antibodies.

TO DETERMINE THE ROLE OF CA125 IN THE DIAGNOSIS OF ACUTE APPENDICITIS

2020 ◽  
Vol 4 (7) ◽  
Author(s):  
Vinod Kumar ◽  
Bhupen Songra ◽  
Richa Jain ◽  
Deeksha Mehta
Keyword(s):  
Acute Appendicitis ◽  
Clinical Diagnosis ◽  
Tertiary Care Hospital ◽  
Tertiary Care ◽  
Ca 125 ◽  
Care Hospital ◽  
Serum Samples ◽  
Roc Curve Analysis ◽  
Surgery Department

Background: the present study was under taken to determine the role of CA-125 in the diagnosis of acute appendicitis (AA), to prevent its complications and also in preventing negative appendicectomies in tertiary care hospital. Methods: The study was conducted at a tertiary care and research center between 01/03/2018 to 30/06/2019. Patients admitted to the surgery department with diagnosis of AA were considered for the study. After informed consent, a, standardized history was obtained as a case Performa. Serum samples from all the cases with clinical diagnosis of AA were obtained and stored. Only the cases with histopathologically approved AA were included in the study. Cases operated for clinical diagnosis of AA, but not histopathologically proven AA was not included in the study. CA125 levels in cases with definitive diagnosis of AA were measured. Results: In present study, ROC curve analysis revealed the sensitivity of 87.27 % and specificity of 90.91 % when the CA 125 cut-off value of > 16.8 was taken to diagnose acute appendicitis. AUC was 0.911 with a standard error of 0.0292. Conclusion: In this study we have observed that CA125 showed a positive correlation with acute appendicitis, that was statistically not significant (P>0.05). We didn’t evaluate the correlation with the disease severity. We consider that CA125 can be used as a marker in acute appendicitis cases although further research is still needed. Keywords: CA125, Acute Appendicitis, Surgery.

scholarly journals Detection of Nipah virus in Pteropus medius in 2019 outbreak from Ernakulam district, Kerala, India

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
A. B. Sudeep ◽  
Pragya D. Yadav ◽  
Mangesh D. Gokhale ◽  
R. Balasubramanian ◽  
Nivedita Gupta ◽  
...  
Keyword(s):  
Index Case ◽  
Nipah Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Genotype I ◽  
Visceral Organs ◽  
Distinct Cluster ◽  
New Genotype ◽  
Kerala State ◽  
Set Up

Abstract Background In June 2019, Nipah virus (NiV) infection was detected in a 21-year-old male (index case) of Ernakulum, Kerala, India. This study was undertaken to determine if NiV was in circulation in Pteropus species (spp) in those areas where the index case had visit history in 1 month. Methods Specialized techniques were used to trap the Pteropus medius bats (random sampling) in the vicinity of the index case area. Throat and rectal swabs samples of 141 bats along with visceral organs of 92 bats were collected to detect the presence of NiV by real-time reverse transcriptase-polymerase chain reaction (qRTPCR). Serum samples of 52 bats were tested for anti-NiV Immunoglobulin (Ig) G antibodies by Enzyme-Linked Immunosorbent Assay (ELISA). The complete genome of NiV was sequenced by next-generation sequencing (NGS) from the tissues and swab samples of bats. Results One rectal swab sample and three bats visceral organs were found positive for the NiV. Interestingly, 20.68% (12/58) of Pteropus were positive for anti-NiV IgG antibodies. NiV sequences of 18,172; 17,200 and 15,100 nucleotide bps could be retrieved from three Pteropus bats. Conclusion A distinct cluster of NiV sequences, with significant net-evolutionary nucleotide divergence, was obtained, suggesting the circulation of new genotype (I-India) in South India. NiV Positivity in Pteropus spp. of bats revealed that NiV is circulating in many districts of Kerala state, and active surveillance of NiV should be immediately set up to know the hotspot area for NiV infection.

scholarly journals Evaluation of a Pseudovirus Neutralization Assay for SARS-CoV-2 and Correlation with Live Virus-Based Micro Neutralization Assay

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 994
Author(s):  
Ahmed Majdi K. Tolah ◽  
Sayed S. Sohrab ◽  
Khaled Majdi K. Tolah ◽  
Ahmed M. Hassan ◽  
Sherif A. El-Kafrawy ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Epidemiological Studies ◽  
Neutralization Assay ◽  
Serum Samples ◽  
Live Virus ◽  
Spike Gene ◽  
Microneutralization Assay ◽  
Viral Particles ◽  
Reliable Performance ◽  
Prior Infection

The unusual cases of pneumonia outbreak were reported from Wuhan city in late December 2019. Serological testing provides a powerful tool for the identification of prior infection and for epidemiological studies. Pseudotype virus neutralization assays are widely used for many viruses and applications in the fields of serology. The accuracy of pseudotype neutralizing assay allows for its use in low biosafety lab and provides a safe and effective alternative to the use of wild-type viruses. In this study, we evaluated the performance of this assay compared to the standard microneutralization assay as a reference. The lentiviral pseudotype particles were generated harboring the Spike gene of SARS-CoV-2. The generated pseudotype particles assay was used to evaluate the activity of neutralizing antibodies in 300 human serum samples from a COVID-19 sero-epidemiological study. Testing of these samples resulted in 55 positive samples and 245 negative samples by pseudotype viral particles assay while microneutralization assay resulted in 64 positive and 236 negative by MN assay. Compared to the MN, the pseudotyped viral particles assay showed a sensitivity of 85.94% and a specificity of 100%. Based on the data generated from this study, the pseudotype-based neutralization assay showed a reliable performance for the detection of neutralizing antibodies against SARS-CoV-2 and can be used safely and efficiently as a diagnostic tool in a biosafety level 2 laboratory.

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