Immunity in SARS-CoV-2 Infection: Clarity or Mystery? A Broader Perspective in the Third Year of a Worldwide Pandemic

Abstract

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its mechanisms have been thoroughly studied by researchers all over the world with the hope of finding answers that may aid the discovery of new treatment options or effective means of prevention. Still, over 2 years into the pandemic that is an immense burden on health care and economic systems, there seem to be more questions than answers. The character and multitude of immune responses elicited in coronavirus disease 2019 (COVID-19) vary from uncontrollable activation of the inflammatory system, causing extensive tissue damage and consequently leading to severe or even fatal disease, to mild or asymptomatic infections in the majority of patients, resulting in the unpredictability of the current pandemic. The aim of the study was to systematize the available data regarding the immune response to SARS-CoV-2, to provide some clarification among the abundance of the knowledge available. The review contains concise and current information on the most significant immune reactions to COVID-19, including components of both innate and adaptive immunity, with an additional focus on utilizing humoral and cellular responses as effective diagnostic tools. Moreover, the authors discussed the present state of knowledge on SARS-CoV-2 vaccines and their efficacy in cases of immunodeficiency.

Interferon-γ Release Assay in the Assessment of Cellular Immunity—A Single-Centre Experience with mRNA SARS-CoV-2 Vaccine in Patients with Juvenile Idiopathic Arthritis

“…It has already been proven in a few sources that the assessment of cellular responses after SARS-CoV-2 infection or vaccination provides a more comprehensive evaluation of individual immunity than the sole use of serological testing [28][29][30]. While different branches of adaptive immunity coordinate to maintain optimal protection against pathogens, T-cells play a key role in controlling the developing infection by modulating disease severity and in creating long-term memory pools that are believed to decline at a slower rate than antibody titers [30,31].…”

COVID‐19 and cancer: Dichotomy of the menacing dilemma

“…SARS-CoV-2 is an enveloped, positive-sense single-stranded RNA virus. 32 Its mode of transmission is through aerosols and direct/indirect contact. It belongs to the CoV family.…”

“…They help in mediating binding with cellular receptors, viral replication, and eliciting the characteristic pathogenicity. 32 Communication of the virus with the host cell is facilitated by interaction between angiotensin-converting enzyme 2 (ACE2) receptors and the S protein of the virus. ACE2 receptors are found to be highly expressed along the cell surface of the respiratory tract mucosa, the myocardial surface, and the digestive system mucosa.…”

“…SARS‐CoV‐2 shares characteristic homology with other members of the CoV family through major structural and molecular characteristics like the presence of four structural proteins: S (spike), E (envelope), M (membrane), and N (nucleocapsid). They help in mediating binding with cellular receptors, viral replication, and eliciting the characteristic pathogenicity 32 . Communication of the virus with the host cell is facilitated by interaction between angiotensin‐converting enzyme 2 (ACE2) receptors and the S protein of the virus.…”

Acute Pulmonary Embolism and Immunity in Animal Models

“…Recently, SARS-CoV-2 virus pandemic demonstrated a close link between inflammation and thrombotic events in clinical setting. COVID-19 patients have a higher risk of VTE events, which increases among females and with aging (Brauninger et al, 2022;Nishijima et al, 2022;Kapten et al, 2023). Moreover, it seems that complications associated with clotting contributed to up to 70% of deaths related to COVID-19 (Task Force for the management of COVID-19 of the European Society of Cardiology et al, 2022).…”