Correlation Between Sars-Cov-2 Antibody Screening by Immunoassay and Neutralizing Antibody Testing

Abstract

Background: Passive antibody therapy with convalescent plasma (CP) represents a promising alternative for the treatment of SARS CoV 2 infection. The efficacy of CP therapy has been associated with high titers of neutralizing antibodies (nAbs) in the plasma of recovered patients, but the assays for quantifying nAbs are not widely available. Our goal was to develop a strategy to predict high titers of nAbs based on the results of anti-SARS CoV 2 immunoassays and the clinical characteristics of the CP potential donors. Methods: Two hundred and fourteen CP donors were enrolled and tested for the presence of anti-SARS CoV 2 antibodies using two commercial immunoassays (IA): Anti SARS CoV 2 ELISA IgG EUROIMMUN and Anti SARS CoV 2 Chemiluminescence IgG Abbott. In parallel, quantification of neutralizing antibodies (nAbs) was performed using the Cytopathic effect-based virus neutralization test (CPE VNT). Three criteria for identifying donors with high titers of nAbs (more than 160) were tested: Criterion1: Curve ROC Method; Criterion 2: Conditional decision tree considering only the results from the IA and Criterion 3: Conditional decision tree including both the IA results and the clinical variables. Results: The performance of Abbott and EUROIMMUN immunoassays was similar referring to both S/CO and predictive value for identifying nAbs titers more than 1:160. Regarding the three studied criteria for identifying CP donors with high nAbs titers (more than 1:160): 1) Criterion 1 showed 76.1% accuracy when the S/CO cut-off of 4.65 was used, 2) Criterion 2 presented 76.1% accuracy if the S/CO more than 4.57 was applied and 3) Criterion 3 had 71.6% accuracy if either S/CO more than 4.57 or S/CO between 2.68 and 4.57 and the last COVID-19-related symptoms occurred less than 19 days from donor recruiting were used. Conclusion: The results of SARS-CoV-2 immunoassays (S/CO) can be used to predict high nAbs titers of potential CP donors. This study has proposed three different criteria for identifying donors with more than 160 nAbs titer based on either solely S/CO results or S/CO together with clinical variables, all with high efficacy and accuracy.

Humoral immune response to COVID-19 mRNA vaccine in patients with multiple sclerosis treated with high-efficacy disease-modifying therapies

“…12,13 In the current study we used the Euroimmune ELISA assay to quantify SARS-CoV-2 antibody level as it was reported to highly correlate with the neutralizing antibody assay. 14 Our findings demonstrated that untreated COVID-19-vaccinated MS patients developed protective SARS-CoV-2 humoral responses similarly to healthy vaccinees, and similarly to the findings recently reported in the literature for non-MS vaccinees. 15 However, for MS patients treated with high-efficacy DMTs, the immune response to COVID-19 vaccination varied.…”

“…12,13 In the current study we used the Euroimmune ELISA assay to quantify SARS-CoV-2 antibody level as it was reported to highly correlate with the neutralizing antibody assay. 14…”

SARS-CoV-2 antibody dynamics and B-cell memory response over time in COVID-19 convalescent subjects

“…We used the Euroimmune ELISA assay to quantify SARS-COV-2 antibody level as it was reported to highly correlate with the neutralizing antibody assay [ 6 , 7 ]. It is well known that high neutralizing titers are particularly important for protection against the COVID-19 pandemic [ 8 ].…”

Individuals who were mildly symptomatic following infection with SARS-CoV-2 B.1.1.28 have neutralizing antibodies to the P.1 variant

“…The cytopathic effect (CPE)-based virus neutralization test (VNT) was adapted from Nurtop et al 10 and was previously described by Wendel et al 11 and Mendrone-Junior et al 12 . VNT was performed with SARS-CoV-2 (EPI_ISL_1557222 and EPI_ISL_804814 ) in 96-well microtiter plates containing 5 × 10 4 Vero cells/mL.…”