Evaluation of Cell-Based and Surrogate SARS-CoV-2 Neutralization Assays.

Abstract

Determinants of protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection require the development of well-standardized, reproducible antibody assays. This need has led to the emergence of a variety of neutralization assays. Head-to-head evaluation of different SARS-CoV-2 neutralization platforms could facilitate comparisons across studies and laboratories. Five neutralization assays were compared using 40 plasma samples from convalescent individuals with mild to moderate coronavirus disease 2019 (COVID-19): four cell-based systems using either live recombinant SARS-CoV-2 or pseudotyped viral particles created with lentivirus (LV) or vesicular stomatitis virus (VSV) packaging and one surrogate enzyme-linked immunosorbent assay (ELISA)-based test that measures inhibition of the spike protein receptor binding domain (RBD) binding its receptor human angiotensin converting enzyme 2 (hACE2). Vero cells, Vero E6 cells, HEK293T cells expressing hACE2, and TZM-bl cells expressing hACE2 and transmembrane serine protease 2 were tested. All cell-based assays showed 50% neutralizing dilution (ND50) geometric mean titers (GMTs) that were highly correlated (Pearson r = 0.81 to 0.89) and ranged within 3.4-fold. The live virus assay and LV pseudovirus assays with HEK293T/hACE2 cells showed very similar mean titers, 141 and 178, respectively. ND50 titers positively correlated with plasma IgG targeting SARS-CoV-2 spike protein and RBD (r = 0.63 to 0.89), but moderately correlated with nucleoprotein IgG (r = 0.46 to 0.73). ND80 GMTs mirrored ND50 data and showed similar correlation between assays and with IgG concentrations. The VSV pseudovirus assay and LV pseudovirus assay with HEK293T/hACE2 cells in low- and high-throughput versions were calibrated against the WHO SARS-CoV-2 IgG standard. High concordance between the outcomes of cell-based assays with live and pseudotyped virions enables valid cross-study comparison using these platforms.

• Authors: Anton M Sholukh, Andrew Fiore-Gartland, Emily S Ford, Maurine D Miner, Yixuan J Hou, Longping V Tse, Hannah Kaiser, Haiying Zhu, Joyce Lu, Bhanupriya Madarampalli, Arnold Park, Florian A Lempp, Russell St Germain, Emily L Bossard, Jia Jin Kee, Kurt Diem, Andrew B Stuart, Peter B Rupert, Chance Brock, Matthew Buerger, Margaret K Doll, April Kaur Randhawa, Leonidas Stamatatos, Roland K Strong, Colleen McLaughlin, Meei-Li Huang, Keith R Jerome, Ralph S Baric, David Montefiori, Lawrence Corey
• Journal: Journal of clinical microbiology (J Clin Microbiol) Vol. 59 Issue 10 Pg. e0052721 (09 20 2021) ISSN: 1098-660X [Electronic] United States
• PMID: 34288726 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Antibodies, Neutralizing
• Antibodies, Viral
• Spike Glycoprotein, Coronavirus
• spike protein, SARS-CoV-2

Topics

• Animals
• Antibodies, Neutralizing
• Antibodies, Viral
• COVID-19
• Chlorocebus aethiops
• HEK293 Cells
• Humans
• Neutralization Tests
• SARS-CoV-2
• Spike Glycoprotein, Coronavirus (genetics)
• Vero Cells