Longitudinal clinico-serological analysis of anti-nucleocapsid and anti-receptor binding domain of spike protein antibodies against SARS-CoV-2.

Objectives: Monitoring the antibody responses to SARS-CoV-2 infection and its correlation to clinical spectrum of disease is critical in understanding the disease progression and protection against re-infection. We assessed the nucleocapsid (N) and receptor-binding-domain of spike (SRBD) protein specific IgG and neutralizing antibody (NAb) responses in COVID-19 patients up to 8 months and its correlation with diverse disease spectrum.
Methods: During the first wave of the SARS-CoV-2 pandemic, from 284 COVID-19 patients, 608 samples were collected up to 8 months post infection. The patients were categorized as asymptomatic, symptomatic and severe. The N and SRBD IgG and NAb titers were evaluated and correlated with clinical data.
Results: A steep increase in antigen specific antibody titers was observed till 40 days post onset of the disease (POD), followed by a partial decline till 240 days. Severe disease was associated with a stronger SRBD IgG response and higher NAb titers. The persistence of antibody response was observed in 76% against N, 80% against SRBD and 80% for NAbs of cases up to 8 months POD.
Conclusion: RBD and N protein specific IgG persisted till 240 days POD which correlated with NAb response, irrespective of individual`s symptomatic status indicating overall robust protection against re-infection.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)