Comprehensive assessment of SARS-CoV-2 antibodies against various antigenic epitopes after naive COVID-19 infection and vaccination (BNT162b2 or ChAdOx1 nCoV-19)

Abstract

Comprehensive assessment of SARS-CoV-2 antibodies against antigenic epitopes and cross-neutralization on variants is essential to monitor after infection or vaccination. From 32 COVID-19 patients and 40 vaccinated individuals [20 Oxford–AstraZeneca (AZ) and 20 Pfizer–BioNTech (BNT)], 348 serial sera are collected until 40 days after infection and 3 months after homologous booster vaccination. Antibody levels were monitored using a multiplex-bead assay including variant spike antigens, Roche (S1/RBD total) and a surrogate virus neutralization test (GenScript). Anti-S/S1/RBD levels were higher than anti-S2/N levels from 2 weeks after infection and were higher in severe infection (P < 0.05). Vaccination showed highest antibody levels after 1-month booster and had consistently high levels in the order of anti-full S, anti-RBD, anti-S1 and anti-S2. Infection induced higher anti-S2/N levels than prime vaccination (P < 0.05). Three months after BNT/BNT vaccination, antibody levels against S1/RBD and 23 variant antigens were higher than post-infection or AZ groups (P < 0.05). Regarding intraindividual changes from post-prime to post-boost vaccination, boost induced a 1.1- to 3.9-fold increase on multiplex-bead assay, 22.8- to 24.2-fold on Roche assay and 22.8- to 24.2-fold on GenScript assay. Post-prime levels by multiplex-bead assay predicted post-boost levels, but Roche and GenScript results were not predictive in the AZ group. The kinetics of SARS-CoV-2 antibody levels vary depending on the antigenic epitopes, assay kit, disease severity or vaccine type. Assessing seroconversion using multiplex-bead assays may contribute to monitoring the disease course, adjusting vaccination strategies, and accelerating vaccination efficacy.

Longitudinal Analysis of SARS-CoV-2-Specific Cellular and Humoral Immune Responses and Breakthrough Infection following BNT162b2/BNT162b2/BNT162b2 and ChAdOx1/ChAdOx1/BNT162b2 Vaccination: A Prospective Cohort in Naive Healthcare Workers

“…When we compared cellular responses via ELISPOT against different S-antigens, a strong correlation was observed. Similarly, the humoral responses assessed through total binding antibody assays exhibited a strong correlation with neutralizing activities in both groups, consistent with findings in previous studies [34][35][36][37]. However, we found no correlation between quantitative ELISPOT results and total binding antibody levels or sVNT results, which is in line with previous study [38].…”

Comparison of humoral and cellular immune responses between ChAd-BNT heterologous vaccination and BNT-BNT homologous vaccination following the third BNT dose: A prospective cohort study

“…Additionally, we analyzed correlations between eight commercial kits used in this study. Three antibody assays (Roche assay for total binding antibody, Abbott assay for IgG binding antibody, and sVNT for neutralizing antibody) were highly correlated with each other, as described in previous studies (13,32,33). When we compared cellular responses by different assays, weak correlation was observed between Covi-FERON and QuantiFERON assays.…”

Non-neutralizing functions in anti-SARS-CoV-2 IgG antibodies

“…This is also supported by the lack of efficacy in the therapy of convalescent plasma from recovered patients [ 69 ]⁠. It may be possible that during the course of severe disease, significant anti-SARS-CoV-2 concentrations are reached, similar to mRNA vaccination [ 70 ]⁠ up to 100–5000 μg/ml [ 60 ]⁠, thus have the potential eliciting Fc-mediated functions. It is important to note that in in vitro neutralization assays, the maximum inhibition of infection is reached at 1 ug/ml [ 49 , 57 ]⁠, indicating that in vitro measurements are too sensitive and do not reflect the necessary concentration needed for in vivo conditions.…”