The seven constitutive respiratory defense barriers against SARS-CoV-2 infection
Abstract Before eliciting an adaptive immune response, SARS-CoV-2 must overcome seven constitutive respiratory defense barriers. The first is the mucus covering the respiratory tract’s luminal surface, which entraps inhaled particles, including infectious agents, and eliminates them by mucociliary c...
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ftdoajarticles:oai:doaj.org/article:be770274284c46bfb301e6fee2b656f3 2023-05-15T15:12:58+02:00 The seven constitutive respiratory defense barriers against SARS-CoV-2 infection Eduardo Tosta 2021-12-01T00:00:00Z https://doi.org/10.1590/0037-8682-0461-2021 https://doaj.org/article/be770274284c46bfb301e6fee2b656f3 EN eng Sociedade Brasileira de Medicina Tropical (SBMT) http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0037-86822021000100202&tlng=en https://doaj.org/toc/1678-9849 1678-9849 doi:10.1590/0037-8682-0461-2021 https://doaj.org/article/be770274284c46bfb301e6fee2b656f3 Revista da Sociedade Brasileira de Medicina Tropical, Vol 54 (2021) Respiratory tract microbiota Defensins and lactoferrin Surfactant proteins Epithelial cell interferons Innate immunity Arctic medicine. Tropical medicine RC955-962 article 2021 ftdoajarticles https://doi.org/10.1590/0037-8682-0461-2021 2022-12-30T23:23:24Z Abstract Before eliciting an adaptive immune response, SARS-CoV-2 must overcome seven constitutive respiratory defense barriers. The first is the mucus covering the respiratory tract’s luminal surface, which entraps inhaled particles, including infectious agents, and eliminates them by mucociliary clearance. The second barrier comprises various components present in the airway lining fluid, the surfactants. Besides providing low surface tension that allows efficient gas exchange at the alveoli, surfactants inhibit the invasion of epithelial cells by respiratory viruses, enhance pathogen uptake by phagocytes, and regulate immune cells’ functions. The respiratory tract microbiota constitutes the third defense barrier against SARS-CoV-2. It activates the innate and adaptive immune cells and elicits anti-infectious molecules such as secretory IgA antibodies, defensins, and interferons. The fourth defense barrier comprises the antimicrobial peptides defensins, and lactoferrin. They show direct antiviral activity, inhibit viral fusion, and modulate the innate and adaptive immune responses. Secretory IgA antibodies, the fifth defense barrier, besides protecting the local microbiota against noxious agents, also inhibit SARS-CoV-2 cell invasion. If the virus overcomes this barrier, it reaches its target, the respiratory epithelial cells. However, these cells also act as a defense barrier, the sixth one, since they hinder the virus’ access to receptors and produce antiviral and immunomodulatory molecules such as interferons, lactoferrin, and defensins. Finally, the sensing of the virus by the cells of innate immunity, the last constitutive defense barrier, elicits a cascade of signals that activate adaptive immune cells and may inhibit the development of productive infection. The subject of the present essay is discussing these mechanisms. Article in Journal/Newspaper Arctic Directory of Open Access Journals: DOAJ Articles Arctic Revista da Sociedade Brasileira de Medicina Tropical 54 |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Respiratory tract microbiota Defensins and lactoferrin Surfactant proteins Epithelial cell interferons Innate immunity Arctic medicine. Tropical medicine RC955-962 |
spellingShingle |
Respiratory tract microbiota Defensins and lactoferrin Surfactant proteins Epithelial cell interferons Innate immunity Arctic medicine. Tropical medicine RC955-962 Eduardo Tosta The seven constitutive respiratory defense barriers against SARS-CoV-2 infection |
topic_facet |
Respiratory tract microbiota Defensins and lactoferrin Surfactant proteins Epithelial cell interferons Innate immunity Arctic medicine. Tropical medicine RC955-962 |
description |
Abstract Before eliciting an adaptive immune response, SARS-CoV-2 must overcome seven constitutive respiratory defense barriers. The first is the mucus covering the respiratory tract’s luminal surface, which entraps inhaled particles, including infectious agents, and eliminates them by mucociliary clearance. The second barrier comprises various components present in the airway lining fluid, the surfactants. Besides providing low surface tension that allows efficient gas exchange at the alveoli, surfactants inhibit the invasion of epithelial cells by respiratory viruses, enhance pathogen uptake by phagocytes, and regulate immune cells’ functions. The respiratory tract microbiota constitutes the third defense barrier against SARS-CoV-2. It activates the innate and adaptive immune cells and elicits anti-infectious molecules such as secretory IgA antibodies, defensins, and interferons. The fourth defense barrier comprises the antimicrobial peptides defensins, and lactoferrin. They show direct antiviral activity, inhibit viral fusion, and modulate the innate and adaptive immune responses. Secretory IgA antibodies, the fifth defense barrier, besides protecting the local microbiota against noxious agents, also inhibit SARS-CoV-2 cell invasion. If the virus overcomes this barrier, it reaches its target, the respiratory epithelial cells. However, these cells also act as a defense barrier, the sixth one, since they hinder the virus’ access to receptors and produce antiviral and immunomodulatory molecules such as interferons, lactoferrin, and defensins. Finally, the sensing of the virus by the cells of innate immunity, the last constitutive defense barrier, elicits a cascade of signals that activate adaptive immune cells and may inhibit the development of productive infection. The subject of the present essay is discussing these mechanisms. |
format |
Article in Journal/Newspaper |
author |
Eduardo Tosta |
author_facet |
Eduardo Tosta |
author_sort |
Eduardo Tosta |
title |
The seven constitutive respiratory defense barriers against SARS-CoV-2 infection |
title_short |
The seven constitutive respiratory defense barriers against SARS-CoV-2 infection |
title_full |
The seven constitutive respiratory defense barriers against SARS-CoV-2 infection |
title_fullStr |
The seven constitutive respiratory defense barriers against SARS-CoV-2 infection |
title_full_unstemmed |
The seven constitutive respiratory defense barriers against SARS-CoV-2 infection |
title_sort |
seven constitutive respiratory defense barriers against sars-cov-2 infection |
publisher |
Sociedade Brasileira de Medicina Tropical (SBMT) |
publishDate |
2021 |
url |
https://doi.org/10.1590/0037-8682-0461-2021 https://doaj.org/article/be770274284c46bfb301e6fee2b656f3 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Revista da Sociedade Brasileira de Medicina Tropical, Vol 54 (2021) |
op_relation |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0037-86822021000100202&tlng=en https://doaj.org/toc/1678-9849 1678-9849 doi:10.1590/0037-8682-0461-2021 https://doaj.org/article/be770274284c46bfb301e6fee2b656f3 |
op_doi |
https://doi.org/10.1590/0037-8682-0461-2021 |
container_title |
Revista da Sociedade Brasileira de Medicina Tropical |
container_volume |
54 |
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