Plaque Reduction Neutralization Test (PRNT) Accuracy in Evaluating Humoral Immune Response to SARS-CoV-2.

Plaque Reduction Neutralization Test (PRNT) Accuracy in Evaluating Humoral Immune Response to SARS-CoV-2.

Publication date: Jan 18, 2024

Massive vaccination positively impacted the SARS-CoV-2 pandemic, being a strategy to increase the titers of neutralizing antibodies (NAbs) in the population. Assessing NAb levels and understanding the kinetics of NAb responses is critical for evaluating immune protection. In this study, we optimized and validated a PRNT assay to assess 50% virus neutralization and evaluated its accuracy to measure NAbs to the original strain or variant of SARS-CoV-2. The optimal settings were selected, such as the cell (2 cD7 10 cells/well) and CMC (1. 5%) concentrations and the viral input (~60 PFU/well) for PRNT-SARS-CoV-2 with cut-off point = 1. 64 log based on the ROC curve (AUC = 0. 999). The validated PRNT-SARS-CoV-2 assay presented high accuracy with an intraassay precision of 100% for testing samples with different NAb levels (low, medium, and high titers). The method displays high selectivity without cross-reactivity with dengue (DENV), measles (MV), zika (ZIKV), and yellow fever (YFV) viruses. In addition, the standardized PRNT-SARS-CoV-2 assay presented robustness when submitted to controlled variations. The validated PRNT assay was employed to test over 1000 specimens from subjects with positive or negative diagnoses for SARS-CoV-2 infection. Patients with severe COVID-19 exhibited higher levels of NAbs than those presenting mild symptoms for both the Wuhan strain and Omicron. In conclusion, this study provides a detailed description of an optimized and validated PRNT assay to monitor immune protection and to subsidize surveillance policies applied to epidemiologic studies of COVID-19.

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Concepts Keywords
Antibodies COVID-19
Pandemic neutralizing antibodies
Viral Omicron


Type Source Name
disease IDO humoral immune response
disease VO vaccination
disease VO population
disease IDO assay
disease IDO cell
drug DRUGBANK Saquinavir
disease MESH dengue
disease MESH measles
pathway KEGG Measles
disease MESH yellow fever
disease VO Viruses
disease MESH SARS-CoV-2 infection
pathway REACTOME SARS-CoV-2 Infection
drug DRUGBANK Ribostamycin
drug DRUGBANK Coenzyme M
disease MESH severe acute respiratory syndrome
disease MESH morbidities
disease IDO host
disease VO effective
disease MESH infection
disease MESH viral infection
disease MESH reinfection
disease MESH mumps
disease MESH Japanese encephalitis
drug DRUGBANK Gold
disease VO vaccine effectiveness
disease VO report
disease VO immunized
drug DRUGBANK Ademetionine
disease IDO blood
disease VO time
disease VO protocol
disease MESH Emergencies
disease VO USA
drug DRUGBANK Sodium bicarbonate
drug DRUGBANK Cefaclor
drug DRUGBANK Carboxymethylcellulose
drug DRUGBANK Formaldehyde
drug DRUGBANK Gentian violet cation
disease IDO facility
disease VO titer
disease IDO quality
disease VO Dengue virus
disease VO Yellow fever virus
drug DRUGBANK Methylergometrine
disease VO URE
drug DRUGBANK Esomeprazole

Original Article

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