Evaluation of a Commercial Culture-Free Neutralization Antibody Detection Kit for Severe Acute Respiratory Syndrome-Related Coronavirus-2 and Comparison With an Antireceptor-Binding Domain Enzyme-Linked Immunosorbent Assay
Jesse Papenburg, Matthew P. Cheng, Rachel Corsini, Chelsea Caya, Emelissa J. Mendoza, Kathy Manguiat, L. Robbin Lindsay, Heidi Wood, Michael Drebot, Antonia Dibernardo, Gerasimos J. Zaharatos, Renée Bazin, Romain Gasser, Mehdi Benlarbi, Gabrielle Gendron‐Lepage, Guillaume Beaudoin-Bussières, Jérémie Prévost, Andrés Finzi, Momar Ndao, Cédric P. Yansouni
Abstract
Abstract Background Severe acute respiratory syndrome-related coronavirus 2 (SARS-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 that detects antibodies that block receptor-binding domain (RBD)/angiotensin-converting enzyme (ACE)-2 interaction. We aimed to evaluate cPass to inform its use and assess its added value compared with anti-RBD enzyme-linked immunosorbent assays (ELISAs). Methods Serum 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 immunoglobulin (Ig)G, IgM, and IgA antibodies at a single timepoint and across intervals from onset of symptoms of SARS-CoV-2 infection. Results Compared with PRNT-50, cPass sensitivity ranged from 77% to 100% and specificity was 95% to 100%. Sensitivity was also high compared with the pseudotyped lentiviral neutralization assay (93%; 95% confidence interval [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. Conclusions The added value of cPass compared with an IgG anti-RBD ELISA was modest.