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1.
Immunity ; 55(3): 423-441.e9, 2022 03 08.
Article in English | MEDLINE | ID: covidwho-1693372

ABSTRACT

Cell death plays an important role during pathogen infections. Here, we report that interferon-γ (IFNγ) sensitizes macrophages to Toll-like receptor (TLR)-induced death that requires macrophage-intrinsic death ligands and caspase-8 enzymatic activity, which trigger the mitochondrial apoptotic effectors, BAX and BAK. The pro-apoptotic caspase-8 substrate BID was dispensable for BAX and BAK activation. Instead, caspase-8 reduced pro-survival BCL-2 transcription and increased inducible nitric oxide synthase (iNOS), thus facilitating BAX and BAK signaling. IFNγ-primed, TLR-induced macrophage killing required iNOS, which licensed apoptotic caspase-8 activity and reduced the BAX and BAK inhibitors, A1 and MCL-1. The deletion of iNOS or caspase-8 limited SARS-CoV-2-induced disease in mice, while caspase-8 caused lethality independent of iNOS in a model of hemophagocytic lymphohistiocytosis. These findings reveal that iNOS selectively licenses programmed cell death, which may explain how nitric oxide impacts disease severity in SARS-CoV-2 infection and other iNOS-associated inflammatory conditions.


Subject(s)
COVID-19/immunology , Caspase 8/metabolism , Interferon-gamma/metabolism , Lymphohistiocytosis, Hemophagocytic/immunology , Macrophages/immunology , Mitochondria/metabolism , SARS-CoV-2/physiology , Animals , Caspase 8/genetics , Cells, Cultured , Cytotoxicity, Immunologic , Humans , Interferon-gamma/genetics , Macrophage Activation , Mice , Mice, Inbred C57BL , Mice, Knockout , Nitric Oxide Synthase Type II/metabolism , Pathogen-Associated Molecular Pattern Molecules/immunology , Signal Transduction , bcl-2 Homologous Antagonist-Killer Protein/genetics , bcl-2 Homologous Antagonist-Killer Protein/metabolism , bcl-2-Associated X Protein/genetics , bcl-2-Associated X Protein/metabolism
2.
Mol Cells ; 44(6): 401-407, 2021 Jun 30.
Article in English | MEDLINE | ID: covidwho-1687545

ABSTRACT

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which is an ongoing pandemic disease. SARS-CoV-2-specific CD4+ and CD8+ T-cell responses have been detected and characterized not only in COVID-19 patients and convalescents, but also unexposed individuals. Here, we review the phenotypes and functions of SARS-CoV-2-specific T cells in COVID-19 patients and the relationships between SARS-CoV-2-specific T-cell responses and COVID-19 severity. In addition, we describe the phenotypes and functions of SARS-CoV-2-specific memory T cells after recovery from COVID-19 and discuss the presence of SARS-CoV-2-reactive T cells in unexposed individuals and SARS-CoV-2-specific T-cell responses elicited by COVID-19 vaccines. A better understanding of T-cell responses is important for effective control of the current COVID-19 pandemic.


Subject(s)
Antibodies, Neutralizing/biosynthesis , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Immunity, Cellular , SARS-CoV-2/pathogenicity , Antibodies, Viral/biosynthesis , CD4-Positive T-Lymphocytes/classification , CD4-Positive T-Lymphocytes/virology , CD8-Positive T-Lymphocytes/classification , CD8-Positive T-Lymphocytes/virology , COVID-19/pathology , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/administration & dosage , Convalescence , Cytokines/biosynthesis , Cytotoxicity, Immunologic , Host-Pathogen Interactions/immunology , Humans , Immunity, Humoral , Immunologic Memory , Immunophenotyping , SARS-CoV-2/immunology , Severity of Illness Index
3.
Rev Med Virol ; 31(6): e2236, 2021 11.
Article in English | MEDLINE | ID: covidwho-1573896

ABSTRACT

Modifications in HLA-I expression are found in many viral diseases. They represent one of the immune evasion strategies most widely used by viruses to block antigen presentation and NK cell response, and SARS-CoV-2 is no exception. These alterations result from a combination of virus-specific factors, genetically encoded mechanisms, and the status of host defences and range from loss or upregulation of HLA-I molecules to selective increases of HLA-I alleles. In this review, I will first analyse characteristic features of altered HLA-I expression found in SARS-CoV-2. I will then discuss the potential factors underlying these defects, focussing on HLA-E and class-I-related (like) molecules and their receptors, the most documented HLA-I alterations. I will also draw attention to potential differences between cells transfected to express viral proteins and those presented as part of authentic infection. Consideration of these factors and others affecting HLA-I expression may provide us with improved possibilities for research into cellular immunity against viral variants.


Subject(s)
Antigenic Variation , COVID-19/immunology , Clonal Anergy , Histocompatibility Antigens Class I/immunology , Immune Evasion , SARS-CoV-2/genetics , Alleles , COVID-19/pathology , COVID-19/virology , Cytokines/genetics , Cytokines/immunology , Cytotoxicity, Immunologic , Gene Expression , Histocompatibility Antigens Class I/genetics , Humans , Immunity, Cellular , Killer Cells, Natural/immunology , Killer Cells, Natural/virology , NK Cell Lectin-Like Receptor Subfamily C/genetics , NK Cell Lectin-Like Receptor Subfamily C/immunology , NK Cell Lectin-Like Receptor Subfamily D/genetics , NK Cell Lectin-Like Receptor Subfamily D/immunology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , T-Lymphocytes, Cytotoxic/immunology , T-Lymphocytes, Cytotoxic/virology
4.
Cell Immunol ; 371: 104454, 2022 01.
Article in English | MEDLINE | ID: covidwho-1509640

ABSTRACT

Immune dysregulation is commonly observed in patients with coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces severe lung inflammation and innate immune cell dysregulation. However, the precise interaction between SARS-CoV-2 and the innate immune system is currently unknown. To understand the interaction between SARS-CoV-2 and natural killer (NK) cells, several SARS-CoV-2 S protein peptides capable of binding to the NKG2D receptor were screened by in silico analysis. Among them, two peptides, cov1 and cov2, bound to NK cells and NKG2D receptors. These cov peptides increased NK cytotoxicity toward lung cancer cells, stimulated interferon gamma (IFN-γ) production by NK cells, and likely mediated these responses through the phosphorylation of Vav1, a key downstream-signaling molecule of NKG2D and NK activation genes. The direct interaction between SARS-CoV-2 and NK cells is a novel finding, and modulation of this interaction has potential clinical application as a therapeutic target for COVID-19.


Subject(s)
COVID-19/immunology , Killer Cells, Natural/immunology , NK Cell Lectin-Like Receptor Subfamily K/immunology , Peptides/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Amino Acid Sequence , COVID-19/metabolism , COVID-19/virology , Cell Line, Tumor , Cytotoxicity, Immunologic/immunology , Humans , Interferon-gamma/immunology , Interferon-gamma/metabolism , Killer Cells, Natural/metabolism , Lung/immunology , Lung/pathology , Lung/virology , Lymphocyte Activation/immunology , NK Cell Lectin-Like Receptor Subfamily K/metabolism , Peptides/metabolism , Protein Binding , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Signal Transduction/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
5.
J Clin Invest ; 131(21)2021 11 01.
Article in English | MEDLINE | ID: covidwho-1495789

ABSTRACT

To explore how the immune system controls clearance of SARS-CoV-2, we used a single-cell, mass cytometry-based proteomics platform to profile the immune systems of 21 patients who had recovered from SARS-CoV-2 infection without need for admission to an intensive care unit or for mechanical ventilation. We focused on receptors involved in interactions between immune cells and virus-infected cells. We found that the diversity of receptor repertoires on natural killer (NK) cells was negatively correlated with the viral clearance rate. In addition, NK subsets expressing the receptor DNAM1 were increased in patients who more rapidly recovered from infection. Ex vivo functional studies revealed that NK subpopulations with high DNAM1 expression had cytolytic activities in response to target cell stimulation. We also found that SARS-CoV-2 infection induced the expression of CD155 and nectin-4, ligands of DNAM1 and its paired coinhibitory receptor TIGIT, which counterbalanced the cytolytic activities of NK cells. Collectively, our results link the cytolytic immune responses of NK cells to the clearance of SARS-CoV-2 and show that the DNAM1 pathway modulates host-pathogen interactions during SARS-CoV-2 infection.


Subject(s)
COVID-19/immunology , COVID-19/virology , Killer Cells, Natural/immunology , Receptors, Natural Killer Cell/immunology , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Animals , Antigens, Differentiation, T-Lymphocyte/immunology , Cell Adhesion Molecules/immunology , Cohort Studies , Cytotoxicity, Immunologic , Female , Heterografts , Host Microbial Interactions/immunology , Humans , Immunophenotyping , In Vitro Techniques , Ligands , Male , Mice , Mice, SCID , Middle Aged , NK Cell Lectin-Like Receptor Subfamily D/immunology , Pandemics , Receptors, Immunologic/immunology , Receptors, Virus/immunology , Viral Load , Young Adult
6.
Hum Immunol ; 83(1): 86-98, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1401492

ABSTRACT

The global outbreak of coronavirus-2019 (COVID-19) still claims more lives daily around the world due to the lack of a definitive treatment and the rapid tendency of virus to mutate, which even jeopardizes vaccination efficacy. At the forefront battle against SARS-CoV-2, an effective innate response to the infection has a pivotal role in the initial control and treatment of disease. However, SARS-CoV-2 subtly interrupts the equations of immune responses, disrupting the cytolytic antiviral effects of NK cells, while seriously activating infected macrophages and other immune cells to induce an unleashed "cytokine storm", a dangerous and uncontrollable inflammatory response causing life-threatening symptoms in patients. Notably, the NK cell exhaustion with ineffective cytolytic function against the sources of exaggerated cytokine release, acts as an Achilles' heel which exacerbates the severity of COVID-19. Given this, approaches that improve NK cell cytotoxicity may benefit treatment protocols. As a suggestion, adoptive transfer of NK or CAR-NK cells with proper cytotolytic potentials and the lowest capacity of cytokine-release (for example CD56dim NK cells brightly express activating receptors), to severe COVID-19 patients may provide an effective cure especially in cases suffering from cytokine storms. More intriguingly, the ongoing evidence for persistent clonal expansion of NK memory cells characterized by an activating phenotype in response to viral infections, can benefit the future studies on vaccine development and adoptive NK cell therapy in COVID-19. Whether vaccinated volunteers or recovered patients can also be considered as suitable candidates for cell donation could be the subject of future research.


Subject(s)
Adoptive Transfer , COVID-19/therapy , Cytokine Release Syndrome/therapy , Cytokines/immunology , Killer Cells, Natural/transplantation , SARS-CoV-2/immunology , Adoptive Transfer/adverse effects , Animals , COVID-19/immunology , COVID-19/metabolism , COVID-19/virology , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/metabolism , Cytokine Release Syndrome/virology , Cytokines/metabolism , Cytotoxicity, Immunologic , Host-Pathogen Interactions , Humans , Immunologic Memory , Killer Cells, Natural/immunology , Killer Cells, Natural/metabolism , Killer Cells, Natural/virology , SARS-CoV-2/pathogenicity , Treatment Outcome
7.
J Gerontol A Biol Sci Med Sci ; 76(10): 1775-1783, 2021 09 13.
Article in English | MEDLINE | ID: covidwho-1358442

ABSTRACT

Aging and comorbidities make individuals at greatest risk of COVID-19 serious illness and mortality due to senescence-related events and deleterious inflammation. Long-living individuals (LLIs) are less susceptible to inflammation and develop more resiliency to COVID-19. As demonstrated, LLIs are characterized by high circulating levels of BPIFB4, a protein involved in homeostatic response to inflammatory stimuli. Also, LLIs show enrichment of homozygous genotype for the minor alleles of a 4 missense single-nucleotide polymorphism haplotype (longevity-associated variant [LAV]) in BPIFB4, able to counteract progression of diseases in animal models. Thus, the present study was designed to assess the presence and significance of BPIFB4 level in COVID-19 patients and the potential therapeutic use of LAV-BPIFB4 in fighting COVID-19. BPIFB4 plasma concentration was found significantly higher in LLIs compared to old healthy controls while it significantly decreased in 64 COVID-19 patients. Further, the drop in BPIFB4 values correlated with disease severity. Accordingly to the LAV-BPIFB4 immunomodulatory role, while lysates of SARS-CoV-2-infected cells induced an inflammatory response in healthy peripheral blood mononuclear cells in vitro, the co-treatment with recombinant protein (rh) LAV-BPIFB4 resulted in a protective and self-limiting reaction, culminating in the downregulation of CD69 activating-marker for T cells (both TCD4+ and TCD8+) and in MCP-1 reduction. On the contrary, rhLAV-BPIFB4 induced a rapid increase in IL-18 and IL-1b levels, shown largely protective during the early stages of the virus infection. This evidence, along with the ability of rhLAV-BPIFB4 to counteract the cytotoxicity induced by SARS-CoV-2 lysate in selected target cell lines, corroborates BPIFB4 prognostic value and open new therapeutic possibilities in more vulnerable people.


Subject(s)
COVID-19 , Intercellular Signaling Peptides and Proteins , Longevity/immunology , Aged, 80 and over , Biomarkers/blood , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/immunology , Cell Line , Cytokines/blood , Cytotoxicity, Immunologic/drug effects , Female , Humans , Immunologic Factors/immunology , Immunologic Factors/pharmacology , Inflammation/blood , Inflammation/immunology , Intercellular Signaling Peptides and Proteins/blood , Intercellular Signaling Peptides and Proteins/immunology , Italy/epidemiology , Male , Prognosis , Recombinant Proteins/immunology , Recombinant Proteins/pharmacology , SARS-CoV-2/immunology , Severity of Illness Index
8.
Mol Cells ; 44(6): 401-407, 2021 Jun 30.
Article in English | MEDLINE | ID: covidwho-1268430

ABSTRACT

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which is an ongoing pandemic disease. SARS-CoV-2-specific CD4+ and CD8+ T-cell responses have been detected and characterized not only in COVID-19 patients and convalescents, but also unexposed individuals. Here, we review the phenotypes and functions of SARS-CoV-2-specific T cells in COVID-19 patients and the relationships between SARS-CoV-2-specific T-cell responses and COVID-19 severity. In addition, we describe the phenotypes and functions of SARS-CoV-2-specific memory T cells after recovery from COVID-19 and discuss the presence of SARS-CoV-2-reactive T cells in unexposed individuals and SARS-CoV-2-specific T-cell responses elicited by COVID-19 vaccines. A better understanding of T-cell responses is important for effective control of the current COVID-19 pandemic.


Subject(s)
Antibodies, Neutralizing/biosynthesis , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Immunity, Cellular , SARS-CoV-2/pathogenicity , Antibodies, Viral/biosynthesis , CD4-Positive T-Lymphocytes/classification , CD4-Positive T-Lymphocytes/virology , CD8-Positive T-Lymphocytes/classification , CD8-Positive T-Lymphocytes/virology , COVID-19/pathology , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/administration & dosage , Convalescence , Cytokines/biosynthesis , Cytotoxicity, Immunologic , Host-Pathogen Interactions/immunology , Humans , Immunity, Humoral , Immunologic Memory , Immunophenotyping , SARS-CoV-2/immunology , Severity of Illness Index
9.
Front Immunol ; 12: 665329, 2021.
Article in English | MEDLINE | ID: covidwho-1268251

ABSTRACT

Infection by novel coronavirus SARS-CoV-2 causes different presentations of COVID-19 and some patients may progress to a critical, fatal form of the disease that requires their admission to ICU and invasive mechanical ventilation. In order to predict in advance which patients could be more susceptible to develop a critical form of COVID-19, it is essential to define the most adequate biomarkers. In this study, we analyzed several parameters related to the cellular immune response in blood samples from 109 patients with different presentations of COVID-19 who were recruited in Hospitals and Primary Healthcare Centers in Madrid, Spain, during the first pandemic peak between April and June 2020. Hospitalized patients with the most severe forms of COVID-19 showed a potent inflammatory response that was not translated into an efficient immune response. Despite the high levels of effector cytotoxic cell populations such as NK, NKT and CD8+ T cells, they displayed immune exhaustion markers and poor cytotoxic functionality against target cells infected with pseudotyped SARS-CoV-2 or cells lacking MHC class I molecules. Moreover, patients with critical COVID-19 showed low levels of the highly cytotoxic TCRγδ+ CD8+ T cell subpopulation. Conversely, CD4 count was greatly reduced in association to high levels of Tregs, low plasma IL-2 and impaired Th1 differentiation. The relative importance of these immunological parameters to predict COVID-19 severity was analyzed by Random Forest algorithm and we concluded that the most important features were related to an efficient cytotoxic response. Therefore, efforts to fight against SARS-CoV-2 infection should be focused not only to decrease the disproportionate inflammatory response, but also to elicit an efficient cytotoxic response against the infected cells and to reduce viral replication.


Subject(s)
COVID-19/epidemiology , COVID-19/immunology , Cytotoxicity, Immunologic , Intensive Care Units , Leukocytes, Mononuclear/immunology , Patient Admission/statistics & numerical data , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , Antibodies, Viral/blood , Antibodies, Viral/immunology , Biomarkers , COVID-19/diagnosis , COVID-19/virology , Comorbidity , Cytokines/metabolism , Female , Humans , Immunophenotyping , Leukocytes, Mononuclear/metabolism , Male , Middle Aged , Severity of Illness Index , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism
10.
Cancer Treat Res Commun ; 28: 100406, 2021.
Article in English | MEDLINE | ID: covidwho-1258358

ABSTRACT

Covid-19 Pneumonia of SARS-CoV-2 pandemic infection, persists to have high disease burden especially in cancer patients. Increased inflammation and thromboembolic processes are blamed to influence cancer patients more than the others but due to lack of knowledge regarding the pathophysiology of the both the virus itself and the response of the host, more basic and translational disease modeling research is needed to understand Cancer-Covid-19 interaction. In this study, serum samples from the patients, who were hospitalized due to Covid-19 pneumonia, applied to different cancer cells and cytotoxicity, motility, proliferation and gene expression analysis were performed. Serum samples derived from healthy volunteers and the fetal bovine serum that is used regularly in cell culture experiments used as controls. Hospitalized Covid-19 patients who had also cancer, were retrospectively screened, and their clinical course were recorded. Overall 12 Patient (PS) and 4 healthy serums (CS) were included in the experiments. PS applied cells showed increased motility in A549 cells as well as lost cell to cell connection in MCF7 and HCT116 cells, and induced expression of VIM, ZEB1 and SNAIL2 mRNA levels. Eight cancer diagnosed patients who were hospitalized due to Covid-19 between April and September 2020 were also reviewed retrospectively, which 5 of them were dead during SARS-CoV-2 infection. Thorax CT images of the 2 patients showed increased metastatic nodules in the lungs as of January 2021. The results of the study indicate that metastasis may be one of the prolonged consequences of COVID-19 pandemic in cancer sufferers.


Subject(s)
COVID-19/immunology , Epithelial-Mesenchymal Transition/physiology , Immune Sera , Neoplasms/pathology , Adult , Aged , COVID-19/complications , Cell Line, Tumor , Cell Movement , Cell Proliferation , Cytotoxicity, Immunologic , Female , Humans , Immune Sera/adverse effects , Immune Sera/toxicity , Lung Neoplasms/secondary , Lung Neoplasms/virology , Male , Middle Aged , Neoplasms/immunology
11.
mBio ; 12(2)2021 04 27.
Article in English | MEDLINE | ID: covidwho-1206004

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affected over 120 million people and killed over 2.7 million individuals by March 2021. While acute and intermediate interactions between SARS-CoV-2 and the immune system have been studied extensively, long-term impacts on the cellular immune system remain to be analyzed. Here, we comprehensively characterized immunological changes in peripheral blood mononuclear cells in 49 COVID-19-convalescent individuals (CI) in comparison to 27 matched SARS-CoV-2-unexposed individuals (UI). Despite recovery from the disease for more than 2 months, CI showed significant decreases in frequencies of invariant NKT and NKT-like cells compared to UI. Concomitant with the decrease in NKT-like cells, an increase in the percentage of annexin V and 7-aminoactinomycin D (7-AAD) double-positive NKT-like cells was detected, suggesting that the reduction in NKT-like cells results from cell death months after recovery. Significant increases in regulatory T cell frequencies and TIM-3 expression on CD4 and CD8 T cells were also observed in CI, while the cytotoxic potential of T cells and NKT-like cells, defined by granzyme B (GzmB) expression, was significantly diminished. However, both CD4 and CD8 T cells of CI showed increased Ki67 expression and were fully able to proliferate and produce effector cytokines upon T cell receptor (TCR) stimulation. Collectively, we provide a comprehensive characterization of immune signatures in patients recovering from SARS-CoV-2 infection, suggesting that the cellular immune system of COVID-19 patients is still under a sustained influence even months after the recovery from disease.IMPORTANCE Wuhan was the very first city hit by SARS-CoV-2. Accordingly, the patients who experienced the longest phase of convalescence following COVID-19 reside here. This enabled us to investigate the "immunological scar" left by SARS-CoV-2 on cellular immunity after recovery from the disease. In this study, we characterized the long-term impact of SARS-CoV-2 infection on the immune system and provide a comprehensive picture of cellular immunity of a convalescent COVID-19 patient cohort with the longest recovery time. We revealed that the cellular immune system of COVID-19 patients is still under a sustained influence even months after the recovery from disease; in particular, a profound NKT cell impairment was found in the convalescent phase of COVID-19.


Subject(s)
COVID-19/immunology , Convalescence , Immunity, Cellular , Natural Killer T-Cells/immunology , Adult , Apoptosis , COVID-19/diagnosis , Cohort Studies , Cytokines/immunology , Cytotoxicity, Immunologic , Female , Humans , Leukocytes, Mononuclear/immunology , Male , Middle Aged , Phenotype , SARS-CoV-2/immunology , T-Lymphocyte Subsets/immunology
12.
Front Immunol ; 12: 666983, 2021.
Article in English | MEDLINE | ID: covidwho-1186803

ABSTRACT

The emergence of viruses with pandemic potential such as the SARS-CoV-2 coronavirus causing COVID-19 poses a global health challenge. There is remarkable progress in vaccine technology in response to this threat, but their design often overlooks the innate arm of immunity. Gamma Delta (γδ) T cells are a subset of T cells with unique features that gives them a key role in the innate immune response to a variety of homeostatic alterations, from cancer to microbial infections. In the context of viral infection, a growing body of evidence shows that γδ T cells are particularly equipped for early virus detection, which triggers their subsequent activation, expansion and the fast deployment of antiviral functions such as direct cytotoxic pathways, secretion of cytokines, recruitment and activation of other immune cells and mobilization of a trained immunity memory program. As such, γδ T cells represent an attractive target to stimulate for a rapid and effective resolution of viral infections. Here, we review the known aspects of γδ T cells that make them crucial component of the immune response to viruses, and the ways that their antiviral potential can be harnessed to prevent or treat viral infection.


Subject(s)
COVID-19/immunology , COVID-19/virology , Host-Pathogen Interactions , Receptors, Antigen, T-Cell, gamma-delta/metabolism , SARS-CoV-2/immunology , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , Adaptive Immunity , Animals , COVID-19/drug therapy , Combined Modality Therapy , Cytotoxicity, Immunologic , Disease Management , Disease Susceptibility/immunology , Host-Pathogen Interactions/immunology , Humans , Immunity, Innate , Receptors, Immunologic/metabolism
13.
Immunity ; 54(5): 1083-1095.e7, 2021 05 11.
Article in English | MEDLINE | ID: covidwho-1179682

ABSTRACT

Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening post-infectious complication occurring unpredictably weeks after mild or asymptomatic SARS-CoV-2 infection. We profiled MIS-C, adult COVID-19, and healthy pediatric and adult individuals using single-cell RNA sequencing, flow cytometry, antigen receptor repertoire analysis, and unbiased serum proteomics, which collectively identified a signature in MIS-C patients that correlated with disease severity. Despite having no evidence of active infection, MIS-C patients had elevated S100A-family alarmins and decreased antigen presentation signatures, indicative of myeloid dysfunction. MIS-C patients showed elevated expression of cytotoxicity genes in NK and CD8+ T cells and expansion of specific IgG-expressing plasmablasts. Clinically severe MIS-C patients displayed skewed memory T cell TCR repertoires and autoimmunity characterized by endothelium-reactive IgG. The alarmin, cytotoxicity, TCR repertoire, and plasmablast signatures we defined have potential for application in the clinic to better diagnose and potentially predict disease severity early in the course of MIS-C.


Subject(s)
COVID-19/immunology , COVID-19/pathology , SARS-CoV-2/immunology , Systemic Inflammatory Response Syndrome/immunology , Systemic Inflammatory Response Syndrome/pathology , Adolescent , Alarmins/immunology , Autoantibodies/immunology , CD8-Positive T-Lymphocytes/immunology , Child , Child, Preschool , Cytotoxicity, Immunologic/genetics , Endothelium/immunology , Endothelium/pathology , Humans , Killer Cells, Natural/immunology , Myeloid Cells/immunology , Plasma Cells/immunology , Receptors, Antigen, T-Cell/genetics , Receptors, Antigen, T-Cell/immunology , Severity of Illness Index
14.
Front Immunol ; 12: 655934, 2021.
Article in English | MEDLINE | ID: covidwho-1156126

ABSTRACT

COVID-19 manifests with a wide diversity of clinical phenotypes characterized by dysfunctional and exaggerated host immune responses. Many results have been described on the status of the immune system of patients infected with SARS-CoV-2, but there are still aspects that have not been fully characterized or understood. In this study, we have analyzed a cohort of patients with mild, moderate and severe disease. We performed flow cytometric studies and correlated the data with the clinical characteristics and clinical laboratory values of the patients. Both conventional and unsupervised data analyses concluded that patients with severe disease are characterized, among others, by a higher state of activation in all T cell subsets (CD4, CD8, double negative and T follicular helper cells), higher expression of perforin and granzyme B in cytotoxic cells, expansion of adaptive NK cells and the accumulation of activated and immature dysfunctional monocytes which are identified by a low expression of HLA-DR and an intriguing shift in the expression pattern of CD300 receptors. More importantly, correlation analysis showed a strong association between the alterations in the immune cells and the clinical signs of severity. These results indicate that patients with severe COVID-19 have a broad perturbation of their immune system, and they will help to understand the immunopathogenesis of COVID-19.


Subject(s)
COVID-19/immunology , Cytotoxicity, Immunologic , Killer Cells, Natural/immunology , Lymphocyte Activation , Monocytes/immunology , Receptors, Immunologic/blood , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Aged , COVID-19/blood , COVID-19/diagnosis , COVID-19/virology , Case-Control Studies , Cross-Sectional Studies , Female , Flow Cytometry , Host-Pathogen Interactions , Humans , Immunophenotyping , Killer Cells, Natural/metabolism , Killer Cells, Natural/virology , Male , Middle Aged , Monocytes/metabolism , Monocytes/virology , Phenotype , Severity of Illness Index , T-Lymphocytes/metabolism , T-Lymphocytes/virology
17.
Viruses ; 13(2)2021 01 28.
Article in English | MEDLINE | ID: covidwho-1060540

ABSTRACT

There have been reports of neurological abnormalities associated with the Zika virus (ZIKV), such as congenital Zika syndrome (CZS) in children born to mothers infected during pregnancy. We investigated how the immune response to ZIKV during pregnancy is primed and conduct a thorough evaluation of the inflammatory and cytotoxic profiles as well as the expression of CCR5 and CX3CR1. We compared the reactivity of T cells to ZIKV peptides in convalescent mothers infected during pregnancy. The child's clinical outcome (i.e., born with or without CZS) was taken to be the variable. The cells were stimulated in vitro with ZIKV peptides and evaluated using the ELISPOT and flow cytometry assays. After in vitro stimulation with ZIKV peptides, we observed a tendency toward a higher Interferon gamma (IFN-γ)-producing T cell responses in mothers who had asymptomatic children and a higher CD107a expression in T cells in mothers who had children with CZS. We found a higher frequency of T cells expressing CD107a+ and co-expressing CX3CR1+CCR5+, which is much clearer in the T cells of mothers who had CZS children. We suggest that this differential profile influenced the clinical outcome of babies. These data need to be further investigated, including the evaluation of other ZIKV peptides and markers and functional assays.


Subject(s)
CX3C Chemokine Receptor 1/metabolism , Pregnancy Complications, Infectious/immunology , Receptors, CCR5/metabolism , T-Lymphocytes/immunology , Zika Virus Infection/immunology , Adult , Cross-Sectional Studies , Cytotoxicity, Immunologic , Female , Humans , Infant , Interferon-gamma/metabolism , Lysosome-Associated Membrane Glycoproteins/metabolism , Pregnancy , Pregnancy Outcome , T-Lymphocytes/metabolism , Young Adult , Zika Virus/immunology
18.
Blood Adv ; 4(20): 5035-5039, 2020 10 27.
Article in English | MEDLINE | ID: covidwho-873910

ABSTRACT

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-driven coronavirus disease 2019 (COVID-19) has caused unprecedented human death and has seriously threatened the global economy. Early data suggest a surge in proinflammatory cytokines in patients with severe COVID-19, which has been associated with poor outcomes. We recently postulated that the inflammatory response in patients with severe COVID-19 disease is not inhibited by natural killer (NK) cells, resulting in a "cytokine storm." Here, we assessed the NK-cell functional activity and the associated cytokines and soluble mediators in hospitalized COVID-19 patients. Significantly impaired NK-cell counts and cytolytic activity were observed in COVID-19 patients when compared with healthy controls. Also, cytokines like interleukin 12 (IL12), IL15, and IL21 that are important for NK-cell activity were not detected systematically. Serum concentrations of soluble CD25 (sCD25)/soluble IL2 receptor α (sIL2-Rα) were significantly elevated and were inversely correlated with the percentage of NK cells. Impaired NK-cell cytolytic activity together with other laboratory trends including elevated sCD25 were consistent with a hyperinflammatory state in keeping with macrophage-activation syndrome. Our findings suggest that impaired counts and cytolytic activity of NK cells are important characteristics of severe COVID-19 and can potentially facilitate strategies for immunomodulatory therapies.


Subject(s)
Coronavirus Infections/immunology , Cytotoxicity, Immunologic , Killer Cells, Natural/immunology , Pneumonia, Viral/immunology , Adolescent , Adult , Aged , Betacoronavirus/immunology , COVID-19 , Coronavirus Infections/blood , Female , Humans , Inflammation/blood , Inflammation/immunology , Interleukin-2 Receptor alpha Subunit/blood , Interleukin-2 Receptor alpha Subunit/immunology , Interleukins/blood , Interleukins/immunology , Lymphocyte Count , Male , Middle Aged , Pandemics , Pneumonia, Viral/blood , SARS-CoV-2 , Severity of Illness Index , Young Adult
20.
J Clin Invest ; 130(9): 4694-4703, 2020 09 01.
Article in English | MEDLINE | ID: covidwho-401302

ABSTRACT

BACKGROUNDCoronavirus disease 19 (COVID-19) is an emerging infectious disease caused by SARS-CoV-2. Antiviral immune response is crucial to achieve pathogen clearance; however, in some patients an excessive and aberrant host immune response can lead to an acute respiratory distress syndrome. The comprehension of the mechanisms that regulate pathogen elimination, immunity, and pathology is essential to better characterize disease progression and widen the spectrum of therapeutic options.METHODSWe performed a flow cytometric characterization of immune cell subsets from 30 patients with COVID-19 and correlated these data with clinical outcomes.RESULTSPatients with COVID-19 showed decreased numbers of circulating T, B, and NK cells and exhibited a skewing of CD8+ T cells toward a terminally differentiated/senescent phenotype. In agreement, CD4+ T and CD8+ T, but also NK cells, displayed reduced antiviral cytokine production capability. Moreover, a reduced cytotoxic potential was identified in patients with COVID-19, particularly in those who required intensive care. The latter group of patients also showed increased serum IL-6 levels that inversely correlated to the frequency of granzyme A-expressing NK cells. Off-label treatment with tocilizumab restored the cytotoxic potential of NK cells.CONCLUSIONThe association between IL-6 serum levels and the impairment of cytotoxic activity suggests the possibility that targeting this cytokine may restore antiviral mechanisms.FUNDINGThis study was supported by funds from the Department of Experimental and Clinical Medicine of University of Florence (the ex-60% fund and the "Excellence Departments 2018-2022 Project") derived from Ministero dell'Istruzione, dell'Università e della Ricerca (Italy).


Subject(s)
Betacoronavirus , Coronavirus Infections/immunology , Cytotoxicity, Immunologic , Interleukin-6/immunology , Pneumonia, Viral/immunology , Adult , Aged , Aged, 80 and over , B-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19 , Coronavirus Infections/blood , Coronavirus Infections/epidemiology , Critical Care , Cytokines/blood , Cytokines/immunology , Female , Granzymes/blood , Granzymes/immunology , Humans , Interleukin-6/blood , Killer Cells, Natural/immunology , Male , Middle Aged , Models, Immunological , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/epidemiology , SARS-CoV-2
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