Antibody Response to the SARS-CoV-2 Spike and Nucleocapsid Proteins in Patients with Different COVID-19 Clinical Profiles

Abstract

The first case of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in Brazil was diagnosed on February 26, 2020. Due to the important epidemiological impact of COVID-19, the present study aimed to analyze the specificity of IgG antibody responses to the S1, S2 and N proteins of SARS-CoV-2 in different COVID-19 clinical profiles. This study enrolled 136 individuals who were diagnosed with or without COVID-19 based on clinical findings and laboratory results and classified as asymptomatic or as having mild, moderate or severe disease. Data collection was performed through a semistructured questionnaire to obtain demographic information and main clinical manifestations. IgG antibody responses to the S1 and S2 subunits of the spike (S) protein and the nucleocapsid (N) protein were evaluated using an enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s instructions. The results showed that among the participants, 87.5% (119/136) exhibited IgG responses to the S1 subunit and 88.25% (120/136) to N. Conversely, only 14.44% of the subjects (21/136) displayed S2 subunit responses. When analyzing the IgG antibody response while considering the different proteins of the virus, patients with severe disease had significantly higher antibody responses to N and S1 than asymptomatic individuals (p ≤ 0.0001), whereas most of the participants had low antibody titers against the S2 subunit. In addition, individuals with long COVID-19 showed a greater IgG response profile than those with symptomatology of a short duration. Based on the results of this study, it is concluded that levels of IgG antibodies may be related to the clinical evolution of COVID-19, with high levels of IgG antibodies against S1 and N in severe cases and in individuals with long COVID-19.

Development and Validation of a Highly Sensitive Multiplex Immunoassay for SARS-CoV-2 Humoral Response Monitorization: A Study of the Antibody Response in COVID-19 Patients with Different Clinical Profiles during the First and Second Waves in Cadiz, Spain

“…When comparing the IgG values among patients with different disease severities, we found that symptomatic patients exhibited lower anti-RBD and anti-S1 IgG antibody values than those with mild, moderate or severe symptoms (Figure 7), including critical patients, when the anti-NC antibody values were studied. These results are in line with previous findings, where the correlation between the clinical profiles of individuals and the values of IgG antibodies specific to SARS-CoV-2 was found to be notably stronger in cases of severe illness [37,[43][44][45][46][47].…”

Bridging Computational Predictions and Empirical Data: Insights into SARS-CoV-2 Mutational Impacts and Evolution

“…This mutation has a dual impact: it increases the protein's flexibility (Matsuo 2021) while simultaneously stabilizing its structure 59 . Antibodies targeting the S327 amino acid might exhibit reduced effectiveness in neutralizing the virus carrying the S327L mutation 60 . Consequently, the body's immune response may encounter challenges in effectively combating the infection, potentially leading to more severe disease outcomes 61 .…”