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1.
Fac Rev ; 11: 15, 2022.
Article in English | MEDLINE | ID: covidwho-1934629

ABSTRACT

COVID-19 ranges from asymptomatic through to respiratory failure and death. Although specific pre-existing conditions such as age and male sex have been associated with poor outcomes, we remain largely ignorant of the mechanisms predisposing to severe disease. In this study, the authors discovered that approximately 10% of 987 patients with life-threatening COVID-19 harbored neutralizing antibodies to Type I interferons (IFNs)1. They demonstrated that these antibodies could neutralize high concentrations of the corresponding IFN and could rescue SARS-CoV-2 infection from inhibition by IFN in vitro. Importantly, anti-IFN antibodies were associated with low levels of serum IFN. These observations suggest that disease severity in these individuals results from a failure to control SARS-CoV-2 replication because of antibody-mediated IFN inhibition. The study suggests specific treatments and diagnostics for this class of severe COVID-19.

2.
Cell ; 185(4): 614-629.e21, 2022 02 17.
Article in English | MEDLINE | ID: covidwho-1676664

ABSTRACT

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.


Subject(s)
Adjuvants, Immunologic/pharmacology , Antigens, Viral/immunology , Candida albicans/chemistry , Mannans/immunology , Aluminum Hydroxide/chemistry , Animals , Antibodies, Neutralizing/immunology , Antibody Specificity/immunology , B-Lymphocytes/immunology , COVID-19/immunology , COVID-19/prevention & control , COVID-19/virology , Chlorocebus aethiops , Epitopes/immunology , Immunity, Innate , Immunization , Inflammation/pathology , Interferons/metabolism , Lectins, C-Type/metabolism , Ligands , Lung/immunology , Lung/pathology , Lung/virology , Lymph Nodes/immunology , Lymph Nodes/metabolism , Macrophages/metabolism , Mice, Inbred C57BL , Paranasal Sinuses/metabolism , Protein Subunits/metabolism , Sialic Acid Binding Ig-like Lectin 1/metabolism , Solubility , Spike Glycoprotein, Coronavirus/metabolism , T-Lymphocytes/immunology , Transcription Factor RelB/metabolism , Vero Cells , beta-Glucans/metabolism
3.
iScience ; 24(11): 103256, 2021 Nov 19.
Article in English | MEDLINE | ID: covidwho-1464739

ABSTRACT

Neutrophil extracellular traps (NETs) have been implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) driven by viruses or bacteria, as well as in numerous immune-mediated disorders. Histone citrullination by the enzyme peptidylarginine deiminase 4 (PAD4) and the consequent decondensation of chromatin are hallmarks in the induction of NETs. Nevertheless, additional histone modifications that may govern NETosis are largely overlooked. Herein, we show that histone deacetylases (HDACs) play critical roles in driving NET formation in human and mouse neutrophils. HDACs belonging to the zinc-dependent lysine deacetylases family are necessary to deacetylate histone H3, thus allowing the activity of PAD4 and NETosis. Of note, HDAC inhibition in mice protects against microbial-induced pneumonia and septic shock, decreasing NETosis and inflammation. Collectively, our findings illustrate a new fundamental step that governs the release of NETs and points to HDAC inhibitors as therapeutic agents that may be used to protect against ARDS and sepsis.

4.
Curr Opin Virol ; 50: 119-127, 2021 10.
Article in English | MEDLINE | ID: covidwho-1375918

ABSTRACT

Type I and type III interferons are among the most potent anti-viral cytokines produced by the immune system. The recent outbreak of SARS-CoV-2, which causes COVID-19, underscores the vital role of these cytokines in controlling the virus and dictating disease severity. Here we delineate the pathways that lead to interferon production in response to SARS-CoV-2 encounter, and elucidate how this virus hinders the production and action of these cytokines; we also highlight that these interferon families serve protective as well as detrimental roles in patients with COVID-19, and conclude that a better understanding of the time, dose, localization, and activity of specific members of the interferon families is imperative for designing more efficient therapeutic interventions against this disease.


Subject(s)
COVID-19/immunology , Interferons/physiology , SARS-CoV-2 , COVID-19/drug therapy , Humans
5.
Cell ; 184(19): 4953-4968.e16, 2021 09 16.
Article in English | MEDLINE | ID: covidwho-1363913

ABSTRACT

Severe coronavirus disease 2019 (COVID-19) is characterized by overproduction of immune mediators, but the role of interferons (IFNs) of the type I (IFN-I) or type III (IFN-III) families remains debated. We scrutinized the production of IFNs along the respiratory tract of COVID-19 patients and found that high levels of IFN-III, and to a lesser extent IFN-I, characterize the upper airways of patients with high viral burden but reduced disease risk or severity. Production of specific IFN-III, but not IFN-I, members denotes patients with a mild pathology and efficiently drives the transcription of genes that protect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In contrast, compared to subjects with other infectious or noninfectious lung pathologies, IFNs are overrepresented in the lower airways of patients with severe COVID-19 that exhibit gene pathways associated with increased apoptosis and decreased proliferation. Our data demonstrate a dynamic production of IFNs in SARS-CoV-2-infected patients and show IFNs play opposing roles at distinct anatomical sites.


Subject(s)
COVID-19/pathology , Interferons/metabolism , Respiratory System/virology , Severity of Illness Index , Age Factors , Aging/pathology , COVID-19/genetics , COVID-19/immunology , Epithelial Cells/pathology , Epithelial Cells/virology , Gene Expression Regulation , Humans , Interferons/genetics , Leukocytes/pathology , Leukocytes/virology , Lung/pathology , Lung/virology , Respiratory Distress Syndrome/pathology , Respiratory Distress Syndrome/virology , Viral Load
6.
iScience ; 24(7): 102738, 2021 Jul 23.
Article in English | MEDLINE | ID: covidwho-1272496

ABSTRACT

Severe COVID-19 is accompanied by rampant immune dysregulation in the lung and periphery, with immune cells of both compartments contributing to systemic distress. The extent to which immune cells of the lung and blood enter similar or distinct pathological states during severe disease remains unknown. Here, we leveraged 96 publicly available single-cell RNA sequencing datasets to elucidate common and compartment-specific features of severe to critical COVID-19 at the levels of transcript expression, biological pathways, and ligand-receptor signaling networks. Comparing severe patients to milder and healthy donors, we identified distinct differential gene expression signatures between compartments and a core set of co-directionally regulated surface markers. A majority of severity-enriched pathways were shared, whereas TNF and interferon responses were polarized. Severity-specific ligand-receptor networks appeared to be differentially active in both compartments. Overall, our results describe a nuanced response during severe COVID-19 where compartment plays a role in dictating the pathological state of immune cells.

7.
Immunity ; 54(6): 1186-1199.e7, 2021 06 08.
Article in English | MEDLINE | ID: covidwho-1207036

ABSTRACT

A cardinal feature of COVID-19 is lung inflammation and respiratory failure. In a prospective multi-country cohort of COVID-19 patients, we found that increased Notch4 expression on circulating regulatory T (Treg) cells was associated with disease severity, predicted mortality, and declined upon recovery. Deletion of Notch4 in Treg cells or therapy with anti-Notch4 antibodies in conventional and humanized mice normalized the dysregulated innate immunity and rescued disease morbidity and mortality induced by a synthetic analog of viral RNA or by influenza H1N1 virus. Mechanistically, Notch4 suppressed the induction by interleukin-18 of amphiregulin, a cytokine necessary for tissue repair. Protection by Notch4 inhibition was recapitulated by therapy with Amphiregulin and, reciprocally, abrogated by its antagonism. Amphiregulin declined in COVID-19 subjects as a function of disease severity and Notch4 expression. Thus, Notch4 expression on Treg cells dynamically restrains amphiregulin-dependent tissue repair to promote severe lung inflammation, with therapeutic implications for COVID-19 and related infections.


Subject(s)
Host-Pathogen Interactions , Immunity, Cellular , Pneumonia, Viral/etiology , Pneumonia, Viral/metabolism , Receptor, Notch4/metabolism , Signal Transduction , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , Amphiregulin/pharmacology , Animals , Biomarkers , Cytokines/metabolism , Disease Models, Animal , Disease Susceptibility , Host-Pathogen Interactions/immunology , Humans , Immunohistochemistry , Immunomodulation/drug effects , Inflammation Mediators/metabolism , Influenza A virus/physiology , Lung/immunology , Lung/metabolism , Lung/pathology , Lung/virology , Mice , Mice, Transgenic , Pneumonia, Viral/pathology , Receptor, Notch4/antagonists & inhibitors , Receptor, Notch4/genetics , Severity of Illness Index
8.
Clin Microbiol Rev ; 34(3)2021 06 16.
Article in English | MEDLINE | ID: covidwho-1166352

ABSTRACT

Several viruses target the human respiratory tract, causing different clinical manifestations spanning from mild upper airway involvement to life-threatening acute respiratory distress syndrome (ARDS). As dramatically evident in the ongoing SARS-CoV-2 pandemic, the clinical picture is not always easily predictable due to the combined effect of direct viral and indirect patient-specific immune-mediated damage. In this review, we discuss the main RNA (orthomyxoviruses, paramyxoviruses, and coronaviruses) and DNA (adenoviruses, herpesviruses, and bocaviruses) viruses with respiratory tropism and their mechanisms of direct and indirect cell damage. We analyze the thin line existing between a protective immune response, capable of limiting viral replication, and an unbalanced, dysregulated immune activation often leading to the most severe complication. Our comprehension of the molecular mechanisms involved is increasing and this should pave the way for the development and clinical use of new tailored immune-based antiviral strategies.


Subject(s)
DNA Viruses , Lung Injury , RNA Viruses , Respiratory Tract Infections , Virus Diseases , Adult , Aged , Antiviral Agents/therapeutic use , COVID-19 , Child , Child, Preschool , Female , Humans , Immunologic Factors/therapeutic use , Infant , Infant, Newborn , Interferons/therapeutic use , Lung/immunology , Lung/virology , Lung Injury/diagnosis , Lung Injury/drug therapy , Lung Injury/immunology , Lung Injury/virology , Male , Middle Aged , Pandemics , SARS-CoV-2
9.
Science ; 369(6504): 706-712, 2020 08 07.
Article in English | MEDLINE | ID: covidwho-717344

ABSTRACT

Viral infections of the lower respiratory tract are a leading cause of mortality. Mounting evidence indicates that most severe cases are characterized by aberrant immune responses and do not depend on viral burden. In this study, we assessed how type III interferons (IFN-λ) contribute to the pathogenesis induced by RNA viruses. We report that IFN-λ is present in the lower, but not upper, airways of patients with coronavirus disease 2019 (COVID-19). In mice, we demonstrate that IFN-λ produced by lung dendritic cells in response to a synthetic viral RNA induces barrier damage, causing susceptibility to lethal bacterial superinfections. These findings provide a strong rationale for rethinking the pathophysiological role of IFN-λ and its possible use in clinical practice against endemic viruses, such as influenza virus as well as the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.


Subject(s)
Betacoronavirus , Coronavirus Infections/immunology , Coronavirus Infections/metabolism , Dendritic Cells/metabolism , Interferons/physiology , Lung/metabolism , Lung/pathology , Pneumonia, Viral/immunology , Pneumonia, Viral/metabolism , Animals , Bronchoalveolar Lavage Fluid/immunology , COVID-19 , Cell Proliferation , Cytokines/metabolism , Humans , Interferon Type I/metabolism , Interferons/metabolism , Lung/immunology , Mice , Mice, Inbred C57BL , Nasopharynx/immunology , Pandemics , Poly I-C/administration & dosage , Respiratory Mucosa/pathology , SARS-CoV-2 , Signal Transduction , Staphylococcal Infections/metabolism , Superinfection , Toll-Like Receptor 3/metabolism
11.
J Exp Med ; 217(5)2020 05 04.
Article in English | MEDLINE | ID: covidwho-60343

ABSTRACT

With the first reports on coronavirus disease 2019 (COVID-19), which is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the scientific community working in the field of type III IFNs (IFN-λ) realized that this class of IFNs could play an important role in this and other emerging viral infections. In this Viewpoint, we present our opinion on the benefits and potential limitations of using IFN-λ to prevent, limit, and treat these dangerous viral infections.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/metabolism , Interferons/metabolism , Pneumonia, Viral/metabolism , COVID-19 , Humans , Pandemics , SARS-CoV-2 , Virus Internalization
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