Figures & data
Figure 1. In innate immunity, sensors outside and inside a cell detect unusual molecules (e.g. from pathogens like viruses) through pattern recognition receptors (PRR), triggering immediate alarm through the secretion of cytokines and interferons. (Reprinted from ‘Innate Immunity', by BioRender, June 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Figure 2. SARS-CoV-2 genome including ORF1a, ORF1b; spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins. ORF1ab, the largest gene, includes overlapping ORFs that encode polyproteins pp1a and pp1ab. Non-structural proteins (nsp) PLpro, 3CLpro, endoribonuclease, helicase, and RdRp are shown together with the structural proteins and some 3D protein structures. (Reprinted from ‘Genomic Organization of SARS-CoV-2', by BioRender, March 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Figure 3. SARS-CoV-2 life cycle. (Adapted from ‘Life Cycle of Coronavirus', by BioRender, August 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Figure 4. A dendritic cell presents antigens from the virus to a CD8+ T cell, which becomes activated and is able to recognize the same antigen on the surface of an infected cell, releasing perforin and granzymes that destroy the infected cell. (Reprinted from ‘Acute Immune Responses to Coronaviruses', by BioRender, August 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Figure 5. (Left) Once they reach the target tissue, cytotoxic T cells detect antigens of the virus on the surface of infected cells and destroy them, eliminating virus factories. (Right) Antibodies secreted by B cells bind to the surface of the virus and block host entry (neutralizing antibodies). (Reprinted from ‘Recruitment of T and B Cells by Antigen-presenting Cells (APCs)', by BioRender, August 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Figure 6. SARS-CoV-2 PCR and serological tests processes. (Reprinted from ‘COVID-19 Fact Sheet', by BioRender, August 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Figure 7. A healthy alveolus (left) and a damaged alveolus (right) in the acute phase of ARDS. An excess of cytokines increases the permeability of the capillaries leading to pulmonary edema (in light brown) that hinders gas exchange in the alveoli, ending in dyspnea and ARDS. (Reprinted from ‘Acute Respiratory Distress Syndrome (ARDS)', by BioRender, July 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Figure 8. ACE2 receptors facilitating SARS-CoV-2 entry, causing, among others, vascular effects like endothelial dysfunction, vascular inflammation, micro and macrovascular thrombosis and vasospasm. (Reprinted from ‘Expression of ACE2 Receptor in Human Host Tissues', by BioRender, August 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Figure 9. The gut-brain axis bidirectionally relates diseases through the vagus nerve, the interaction with short-chain fatty acids, immunoregulatory elements and tryptophan metabolism, and the secretion of neurotransmitters by certain microbes. (Reprinted from ‘Gut-Brain-Axis', by BioRender, December 2020, retrieved from https://app.biorender.com/biorender-templates/ Copyright 2021 by BioRender.)
Data availability statement
Data sharing is not applicable to this article as no new data were created or analyzed in this study.