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World J Clin Cases. Jul 6, 2021; 9(19): 5007-5018
Published online Jul 6, 2021. doi: 10.12998/wjcc.v9.i19.5007
Insights into the virologic and immunologic features of SARS-COV-2
Ceylan Polat, Koray Ergunay
Ceylan Polat, Koray Ergunay, Department of Medical Microbiology, Hacettepe University Faculty of Medicine, Ankara 06100, Turkey
Author contributions: Polat C and Ergunay K equally contributed to collect data and to write the paper; both authors read and approved the final manuscript.
Conflict-of-interest statement: The authors declare that there is no conflict of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ceylan Polat, PhD, Assistant Professor, Department of Medical Microbiology, Hacettepe University Faculty of Medicine, Sihhiye, Ankara 06100, Turkey. ceylan.polat@hacettepe.edu.tr
Received: March 16, 2021
Peer-review started: March 16, 2021
First decision: May 1, 2021
Revised: May 3, 2021
Accepted: May 24, 2021
Article in press: May 24, 2021
Published online: July 6, 2021
Abstract

The host immunity is crucial in determining the clinical course and prognosis of coronavirus disease 2019, where some systemic and severe manifestations are associated with excessive or suboptimal responses. Several antigenic epitopes in spike, nucleocapsid and membrane proteins of severe acute respiratory syndrome coronavirus 2 are targeted by the immune system, and a robust response with innate and adaptive components develops in infected individuals. High titer neutralizing antibodies and a balanced T cell response appears to constitute the optimal immune response to severe acute respiratory syndrome coronavirus 2, where innate and mucosal defenses also contribute significantly. Following exposure, immunological memory seems to develop and be maintained for substantial periods. Here, we provide an overview of the main aspects in antiviral immunity involving innate and adaptive responses with insights into virus structure, individual variations pertaining to disease severity as well as long-term protective immunity expected to be attained by vaccination.

Keywords: SARS-CoV-2, Immune response, Neutralizing antibodies, Spike protein

Core Tip: Robust cellular and humoral responses are elicited in immunocompetent individuals with severe acute respiratory syndrome coronavirus 2 infection that remain detectable for several months following exposure. A balanced T cell response and neutralizing antibodies in circulation and mucosal surfaces are pivotal in controlling virus infection and for protection. Particular impairments in innate and adaptive immune responses are associated with pathogenesis and severe disease.