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1.
Allergy ; 77(1): 118-129, 2022 01.
Article in English | MEDLINE | ID: covidwho-1597019

ABSTRACT

BACKGROUND: COVID-19 can present with lymphopenia and extraordinary complex multiorgan pathologies that can trigger long-term sequela. AIMS: Given that inflammasome products, like caspase-1, play a role in the pathophysiology of a number of co-morbid conditions, we investigated caspases across the spectrum of COVID-19 disease. MATERIALS & METHODS: We assessed transcriptional states of multiple caspases and using flow cytometry, the expression of active caspase-1 in blood cells from COVID-19 patients in acute and convalescent stages of disease. Non-COVID-19 subject presenting with various comorbid conditions served as controls. RESULTS: Single-cell RNA-seq data of immune cells from COVID-19 patients showed a distinct caspase expression pattern in T cells, neutrophils, dendritic cells, and eosinophils compared with controls. Caspase-1 was upregulated in CD4+ T-cells from hospitalized COVID-19 patients compared with unexposed controls. Post-COVID-19 patients with lingering symptoms (long-haulers) also showed upregulated caspase-1activity in CD4+ T-cells that ex vivo was attenuated with a select pan-caspase inhibitor. We observed elevated caspase-3/7levels in red blood cells from COVID-19 patients compared with controls that was reduced following caspase inhibition. DISCUSSION: Our preliminary results suggest an exuberant caspase response in COVID-19 that may facilitate immune-related pathological processes leading to severe outcomes. Further clinical correlations of caspase expression in different stages of COVID-19 will be needed. CONCLUSION: Pan-caspase inhibition could emerge as a therapeutic strategy to ameliorate or prevent severe COVID-19.


Subject(s)
COVID-19 , Caspase Inhibitors , CD4-Positive T-Lymphocytes , COVID-19/complications , COVID-19/drug therapy , Caspase 1 , Caspase 3 , Caspase 7 , Caspase Inhibitors/therapeutic use , Caspases/genetics , Humans
2.
Clin Infect Dis ; 73(11): 2073-2082, 2021 12 06.
Article in English | MEDLINE | ID: covidwho-1560084

ABSTRACT

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic poses an urgent need for the development of effective therapies for coronavirus disease 2019 (COVID-19). METHODS: We first tested SARS-CoV-2-specific T-cell (CοV-2-ST) immunity and expansion in unexposed donors, COVID-19-infected individuals (convalescent), asymptomatic polymerase chain reaction (PCR)-positive subjects, vaccinated individuals, non-intensive care unit (ICU) hospitalized patients, and ICU patients who either recovered and were discharged (ICU recovered) or had a prolonged stay and/or died (ICU critical). CoV-2-STs were generated from all types of donors and underwent phenotypic and functional assessment. RESULTS: We demonstrate causal relationship between the expansion of endogenous CoV-2-STs and the disease outcome; insufficient expansion of circulating CoV-2-STs identified hospitalized patients at high risk for an adverse outcome. CoV-2-STs with a similarly functional and non-alloreactive, albeit highly cytotoxic, profile against SARS-CoV-2 could be expanded from both convalescent and vaccinated donors generating clinical-scale, SARS-CoV-2-specific T-cell products with functional activity against both the unmutated virus and its B.1.1.7 and B.1.351 variants. In contrast, critical COVID-19 patient-originating CoV-2-STs failed to expand, recapitulating the in vivo failure of CoV-2-specific T-cell immunity to control the infection. CoV-2-STs generated from asymptomatic PCR-positive individuals presented only weak responses, whereas their counterparts originating from exposed to other seasonal coronaviruses subjects failed to kill the virus, thus disempowering the hypothesis of protective cross-immunity. CONCLUSIONS: Overall, we provide evidence on risk stratification of hospitalized COVID-19 patients and the feasibility of generating powerful CoV-2-ST products from both convalescent and vaccinated donors as an "off-the shelf" T-cell immunotherapy for high-risk patients.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Immunotherapy, Adoptive , T-Lymphocytes
3.
Am J Trop Med Hyg ; 105(2): 395-400, 2021 Jun 17.
Article in English | MEDLINE | ID: covidwho-1374604

ABSTRACT

Data on the longevity of humoral and cell-mediated immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with coronavirus disease 2019 (COVID-19) are limited. We evaluated the detailed kinetics of antibody and T-cell responses at the acute, convalescent, and post-convalescent phases in COVID-19 patients with a wide range of severity. We enrolled patients with COVID-19 prospectively from four hospitals and one community treatment center between February 2020 and January 2021. symptom severity was classified as mild, moderate, or severe/critical. Patient blood samples were collected at 1 week (acute), 1 month (convalescent), and 2 months after symptom onset (post-convalescent). Human SARS-CoV-2 IgG and IgM antibodies were measured using in-house-developed ELISA. The SARS-CoV-2-specific T-cell responses against overlapping peptides of spike proteins and nucleoprotein were measured by interferon-γ enzyme-linked immunospot assays. Twenty-five COVID-19 patients were analyzed (mild, n = 5; moderate, n = 9; severe/critical, n = 11). IgM and IgG antibody responses peaked at 1 month after symptom onset and decreased at 2 months. IgG response levels were significantly greater in the severe/critical group compared with other groups. Interferon-γ-producing T-cell responses increased between 1 week and 1 month after symptom onset, and had a trend toward decreasing at 2 months, but did not show significant differences according to severity. Our data indicate that SARS-CoV-2-specific antibody responses were greater in those with severe symptoms and waned after reaching a peak around 1 month after symptom onset. However, SARS-CoV-2-specific T-cell responses were not significantly different according to symptom severity, and decreased slowly during the post-convalescent phase.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Severity of Illness Index , T-Lymphocytes/immunology , Acute Disease , Adult , Aged , Antibodies, Neutralizing/blood , COVID-19/blood , COVID-19/pathology , Convalescence , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Interferon-gamma/analysis , Kinetics , Male , Middle Aged , Prospective Studies
4.
Front Immunol ; 12: 631821, 2021.
Article in English | MEDLINE | ID: covidwho-1344260

ABSTRACT

Neutrophils or polymorphonuclear leukocytes (PMN) are key participants in the innate immune response for their ability to execute different effector functions. These cells express a vast array of membrane receptors that allow them to recognize and eliminate infectious agents effectively and respond appropriately to microenvironmental stimuli that regulate neutrophil functions, such as activation, migration, generation of reactive oxygen species, formation of neutrophil extracellular traps, and mediator secretion, among others. Currently, it has been realized that activated neutrophils can accomplish their effector functions and simultaneously activate mechanisms of cell death in response to different intracellular or extracellular factors. Although several studies have revealed similarities between the mechanisms of cell death of neutrophils and other cell types, neutrophils have distinctive properties, such as a high production of reactive oxygen species (ROS) and nitrogen species (RNS), that are important for their effector function in infections and pathologies such as cancer, autoimmune diseases, and immunodeficiencies, influencing their cell death mechanisms. The present work offers a synthesis of the conditions and molecules implicated in the regulation and activation of the processes of neutrophil death: apoptosis, autophagy, pyroptosis, necroptosis, NETosis, and necrosis. This information allows to understand the duality encountered by PMNs upon activation. The effector functions are carried out to eliminate invading pathogens, but in several instances, these functions involve activation of signaling cascades that culminate in the death of the neutrophil. This process guarantees the correct elimination of pathogenic agents, damaged or senescent cells, and the timely resolution of the inflammation that is essential for the maintenance of homeostasis in the organism. In addition, they alert the organism when the immunological system is being deregulated, promoting the activation of other cells of the immune system, such as B and T lymphocytes, which produce cytokines that potentiate the microbicide functions.


Subject(s)
Cell Death/immunology , Neutrophils/pathology , Apoptosis/immunology , Apoptosis Regulatory Proteins/metabolism , Autophagy/immunology , Extracellular Traps/immunology , Extracellular Traps/metabolism , Free Radicals/metabolism , Humans , Necroptosis/immunology , Necrosis/immunology , Necrosis/metabolism , Neutrophil Activation , Neutrophils/immunology , Neutrophils/metabolism , Phagocytosis/immunology , Pyroptosis/immunology , Receptors, Death Domain/metabolism
5.
Commun Biol ; 4(1): 631, 2021 05 27.
Article in English | MEDLINE | ID: covidwho-1283664

ABSTRACT

IL22 is an important cytokine involved in the intestinal defense mechanisms against microbiome. By using ileum-derived organoids, we show that the expression of anti-microbial peptides (AMPs) and anti-viral peptides (AVPs) can be induced by IL22. In addition, we identified a bacterial and a viral route, both leading to IL22 production by T cells, but via different pathways. Bacterial products, such as LPS, induce enterocyte-secreted SAA1, which triggers the secretion of IL6 in fibroblasts, and subsequently IL22 in T cells. This IL22 induction can then be enhanced by macrophage-derived TNFα in two ways: by enhancing the responsiveness of T cells to IL6 and by increasing the expression of IL6 by fibroblasts. Viral infections of intestinal cells induce IFNß1 and subsequently IL7. IFNß1 can induce the expression of IL6 in fibroblasts and the combined activity of IL6 and IL7 can then induce IL22 expression in T cells. We also show that IL22 reduces the expression of viral entry receptors (e.g. ACE2, TMPRSS2, DPP4, CD46 and TNFRSF14), increases the expression of anti-viral proteins (e.g. RSAD2, AOS, ISG20 and Mx1) and, consequently, reduces the viral infection of neighboring cells. Overall, our data indicates that IL22 contributes to the innate responses against both bacteria and viruses.


Subject(s)
Interleukins/biosynthesis , Interleukins/metabolism , Animals , Anti-Bacterial Agents/metabolism , Antiviral Agents/metabolism , Cell Culture Techniques , Cytokines/immunology , Cytokines/metabolism , Disease Models, Animal , Enterocytes/immunology , Enterocytes/metabolism , Female , Fibroblasts/immunology , Fibroblasts/metabolism , Interleukins/immunology , Intestinal Mucosa/metabolism , Intestines/physiology , Mice , Mice, Inbred C57BL , Myeloid Cells/immunology , Myeloid Cells/metabolism , Organoids/metabolism , Pore Forming Cytotoxic Proteins/genetics , Pore Forming Cytotoxic Proteins/metabolism
6.
J Virol ; 95(17): e0066721, 2021 08 10.
Article in English | MEDLINE | ID: covidwho-1274527

ABSTRACT

Cellular immune responses play a key role in the control of viral infection. The nucleocapsid (N) protein of infectious bronchitis virus (IBV) is a major immunogenic protein that can induce protective immunity. To screen for potential T-cell epitopes on IBV N protein, 40 overlapping peptides covering the entirety of the N protein were designed and synthesized. Four T-cell epitope peptides were identified by gamma interferon (IFN-γ) enzyme-linked immunosorbent spot (ELISpot), intracellular cytokine staining, and carboxyfluorescein succinimidyl ester (CFSE) lymphocyte proliferation assays; among them, three peptides (N211-230, N271-290, and N381-400) were cytotoxic T lymphocyte (CTL) epitopes, and one peptide (N261-280) was a dual-specific T-cell epitope, which can be recognized by both CD8+ and CD4+ T cells. Multi-epitope gene transcription cassettes comprising four neutralizing epitope domains and four T-cell epitope peptides were synthesized and inserted into the genome of Newcastle disease virus strain La Sota between the P and M genes. Recombinant IBV multi-epitope vaccine candidate rLa Sota/SBNT was generated via reverse genetics, and its immune protection efficacy was evaluated in specific-pathogen-free chickens. Our results show that rLa Sota/SBNT induced IBV-specific neutralizing antibody and T-cell responses and provided significant protection against homologous and heterologous IBV challenge. Thus, the T-cell epitope peptides identified in this study could be good candidates for IBV vaccine development, and recombinant Newcastle disease virus-expressing IBV multi-epitope genes represent a safe and effective vaccine candidate for controlling infectious bronchitis. IMPORTANCE T-cell-mediated immune responses are critical for the elimination of IBV-infected cells. To screen conserved T-cell epitopes in the IBV N protein, 40 overlapping peptides covering the entirety of the N protein were designed and synthesized. By combining IFN-γ ELISpot, intracellular cytokine staining, and CFSE lymphocyte proliferation assays, we identified three CTL epitopes and one dual-specific T-cell epitope. The value of T-cell epitope peptides identified in the N protein was further verified by the design of an IBV multi-epitope vaccine. Results show that IBV multi-epitope vaccine candidate rLa Sota/SBNT provided cross protection against challenges with a QX-like or a TW-like IBV strain. So, T-cell-mediated immune responses play an important role in the control of viral infection, and conserved T-cell epitopes serve as promising candidates for use in multi-epitope vaccine construction. Our results provide a new perspective for the development of a safer and more effective IBV vaccine.


Subject(s)
Coronavirus Infections/prevention & control , Epitopes, T-Lymphocyte/immunology , Immunity, Cellular/immunology , Infectious bronchitis virus/immunology , Nucleocapsid Proteins/immunology , Poultry Diseases/prevention & control , Viral Vaccines/administration & dosage , Animals , Chickens , Coronavirus Infections/immunology , Coronavirus Infections/virology , Immunity, Cellular/drug effects , Poultry Diseases/immunology , Specific Pathogen-Free Organisms , T-Lymphocytes, Cytotoxic/immunology , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunology , Viral Vaccines/immunology
7.
Nat Commun ; 12(1): 3010, 2021 05 21.
Article in English | MEDLINE | ID: covidwho-1237999

ABSTRACT

Resident memory T cells (TRM) positioned within the respiratory tract are probably required to limit SARS-CoV-2 spread and COVID-19. Importantly, TRM are mostly non-recirculating, which reduces the window of opportunity to examine these cells in the blood as they move to the lung parenchyma. Here, we identify circulating virus-specific T cell responses during acute infection with functional, migratory and apoptotic patterns modulated by viral proteins and associated with clinical outcome. Disease severity is associated predominantly with IFNγ and IL-4 responses, increased responses against S peptides and apoptosis, whereas non-hospitalized patients have increased IL-12p70 levels, degranulation in response to N peptides and SARS-CoV-2-specific CCR7+ T cells secreting IL-10. In convalescent patients, lung-TRM are frequently detected even 10 months after initial infection, in which contemporaneous blood does not reflect tissue-resident profiles. Our study highlights a balanced anti-inflammatory antiviral response associated with a better outcome and persisting TRM cells as important for future protection against SARS-CoV-2 infection.


Subject(s)
COVID-19/immunology , Immunologic Memory/immunology , Lung/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Apoptosis/immunology , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , COVID-19/virology , Cell Movement/immunology , Humans , Interferon-gamma/immunology , Interferon-gamma/metabolism , Interleukin-4/immunology , Interleukin-4/metabolism , Lung/virology , SARS-CoV-2/physiology , T-Lymphocytes/metabolism
8.
Thorax ; 76(10): 1010-1019, 2021 10.
Article in English | MEDLINE | ID: covidwho-1180971

ABSTRACT

BACKGROUND: Knowledge of the pathophysiology of COVID-19 is almost exclusively derived from studies that examined the immune response in blood. We here aimed to analyse the pulmonary immune response during severe COVID-19 and to compare this with blood responses. METHODS: This was an observational study in patients with COVID-19 admitted to the intensive care unit (ICU). Mononuclear cells were purified from bronchoalveolar lavage fluid (BALF) and blood, and analysed by spectral flow cytometry; inflammatory mediators were measured in BALF and plasma. FINDINGS: Paired blood and BALF samples were obtained from 17 patients, four of whom died in the ICU. Macrophages and T cells were the most abundant cells in BALF, with a high percentage of T cells expressing the ƴδ T cell receptor. In the lungs, both CD4 and CD8 T cells were predominantly effector memory cells (87·3% and 83·8%, respectively), and these cells expressed higher levels of the exhaustion marker programmad death-1 than in peripheral blood. Prolonged ICU stay (>14 days) was associated with a reduced proportion of activated T cells in peripheral blood and even more so in BALF. T cell activation in blood, but not in BALF, was higher in fatal COVID-19 cases. Increased levels of inflammatory mediators were more pronounced in BALF than in plasma. INTERPRETATION: The bronchoalveolar immune response in COVID-19 has a unique local profile that strongly differs from the immune profile in peripheral blood. Fully elucidating COVID-19 pathophysiology will require investigation of the pulmonary immune response.


Subject(s)
COVID-19/immunology , Immunity, Cellular/physiology , Inflammation Mediators/metabolism , Aged , Bronchoalveolar Lavage Fluid/chemistry , Bronchoalveolar Lavage Fluid/cytology , COVID-19/blood , COVID-19/pathology , Critical Care , Critical Illness , Female , Flow Cytometry , Humans , Macrophages/physiology , Male , Middle Aged , T-Lymphocytes/physiology
9.
Crit Care Explor ; 3(4): e0378, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1174966

ABSTRACT

OBJECTIVES: Corticosteroid therapy has become standard of care therapy for hospitalized patients infected with the severe acute respiratory syndrome coronavirus-2 global pandemic-causing virus. Whereas systemic inflammation is a notably important feature in coronavirus disease 2019 pathogenesis, adaptive immune suppression and the inability to eradicate effectively the virus remain significant factors as well. We sought to evaluate the in vitro effects of dexamethasone phosphate on T cell function in peripheral blood mononuclear cells derived from patients with acute, severe, and moderate coronavirus disease 2019. DESIGN: Prospective in vitro laboratory study. SETTING: Coronavirus disease 2019-specific medical wards and ICUs at a single-center, quaternary-care academic hospital between October 1, 2020, and November 15, 2020. PATIENTS: Eleven patients diagnosed with coronavirus disease 2019 admitted to either the ICU or hospital coronavirus disease 2019 unit. Three patients had received at least one dose of dexamethasone prior to enrollment. INTERVENTIONS: Fresh whole blood was collected, and peripheral blood mononuclear cells were immediately isolated and plated onto precoated enzyme-linked immunospot plates for detection of interferon-γ production. Samples were incubated with CD3/CD28 antibodies alone and with three concentrations of dexamethasone. These conditions were also stimulated with recombinant human interleukin-7. Following overnight incubation, the plates were washed and stained for analysis using Cellular Technology Limited ImmunoSpot S6 universal analyzer (ImmunoSpot by Cellular Technology Limited, Cleveland, OH). MEASUREMENTS AND MAIN RESULTS: Functional cytokine production was assessed by quantitation of cell spot number and total well intensity after calculation for each enzyme-linked immunospot well using the Cellular Technology Limited ImmunoSpot Version 7.0 professional software (CTL Analyzers, Shaker Heights, OH). Comparisons were made using t test and using a nonparametric analysis of variance Friedman test. The number of functional T cells producing interferon-γ and the intensity of the response decrease significantly with exposure to 1.2-µg/mL dexamethasone. About 0.12 µg/mL does not significantly affect the functional immune response on enzyme-linked immunospot. Interleukin-7 increases the overall number of activated T cells, including those exposed to dexamethasone. CONCLUSIONS: Further evaluation of the effect of immunomodulatory therapies is warranted in coronavirus disease 2019. A refined functional, precision medicine approach that evaluates the cellular immune function of individual patients with coronavirus disease 2019 is needed to better define which therapies could have benefit or cause harm for specific patients.

10.
Eur J Immunol ; 51(6): 1325-1333, 2021 06.
Article in English | MEDLINE | ID: covidwho-1159066

ABSTRACT

T follicular helper (Tfh) cells play an essential role in regulating the GC reaction and, consequently, the generation of high-affinity antibodies and memory B cells. Therefore, Tfh cells are critical for potent humoral immune responses against various pathogens and their dysregulation has been linked to autoimmunity and cancer. Tfh cell differentiation is a multistep process, in which cognate interactions with different APC types, costimulatory and coinhibitory pathways, as well as cytokines are involved. However, it is still not fully understood how a subset of activated CD4+ T cells begins to express the Tfh cell-defining chemokine receptor CXCR5 during the early stage of the immune response, how some CXCR5+ pre-Tfh cells enter the B-cell follicles and mature further into GC Tfh cells, and how Tfh cells are maintained in the memory compartment. In this review, we discuss recent advances on how antigen and cognate interactions are important for Tfh cell differentiation and long-term persistence of Tfh cell memory, and how this is relevant to the current understanding of COVID-19 pathogenesis and the development of potent SARS-CoV-2 vaccines.


Subject(s)
Antigens, Viral/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , Cell Differentiation/immunology , Immunologic Memory , SARS-CoV-2/immunology , T-Lymphocytes, Helper-Inducer/immunology , Animals , COVID-19/pathology , COVID-19/prevention & control , COVID-19 Vaccines/therapeutic use , Humans , T-Lymphocytes, Helper-Inducer/pathology
11.
Am J Transplant ; 21(8): 2749-2761, 2021 08.
Article in English | MEDLINE | ID: covidwho-1147230

ABSTRACT

The description of protective humoral and T cell immune responses specific against SARS-CoV-2 has been reported among immunocompetent (IC) individuals developing COVID-19 infection. However, its characterization and determinants of poorer outcomes among the at-risk solid organ transplant (SOT) patient population have not been thoroughly investigated. Cytokine-producing T cell responses, such as IFN-γ, IL-2, IFN-γ/IL-2, IL-6, IL-21, and IL-5, against main immunogenic SARS-CoV-2 antigens and IgM/IgG serological immunity were tracked in SOT (n = 28) during acute infection and at two consecutive time points over the following 40 days of convalescence and were compared to matched IC (n = 16) patients admitted with similar moderate/severe COVID-19. We describe the development of a robust serological and functional T cell immune responses against SARS-CoV-2 among SOT patients, similar to IC patients during early convalescence. However, at the infection onset, SOT displayed lower IgG seroconversion rates (77% vs. 100%; p = .044), despite no differences on IgG titers, and a trend toward decreased SARS-CoV-2-reactive T cell frequencies, especially against the membrane protein (7 [0-34] vs. 113 [15-245], p = .011, 2 [0-9] vs. 45 [5-74], p = .009, and 0 [0-2] vs. 13 [1-24], p = .020, IFN-γ, IL-2, and IFN-γ/IL-2 spots, respectively). In summary, our data suggest that despite a certain initial delay, SOT population achieve comparable functional immune responses than the general population after moderate/severe COVID-19.


Subject(s)
COVID-19 , Organ Transplantation , Antibodies, Viral , Antibody Formation , Convalescence , Humans , SARS-CoV-2 , T-Lymphocytes
12.
Sci Rep ; 11(1): 5402, 2021 03 08.
Article in English | MEDLINE | ID: covidwho-1123146

ABSTRACT

Most multiple sclerosis (MS) patients given currently available disease-modifying drugs (DMDs) experience progressive disability. Accordingly, there is a need for new treatments that can limit the generation of new waves T cell autoreactivity that drive disease progression. Notably, immune cells express GABAA-receptors (GABAA-Rs) whose activation has anti-inflammatory effects such that GABA administration can ameliorate disease in models of type 1 diabetes, rheumatoid arthritis, and COVID-19. Here, we show that oral GABA, which cannot cross the blood-brain barrier (BBB), does not affect the course of murine experimental autoimmune encephalomyelitis (EAE). In contrast, oral administration of the BBB-permeable GABAA-R-specific agonist homotaurine ameliorates monophasic EAE, as well as advanced-stage relapsing-remitting EAE (RR-EAE). Homotaurine treatment beginning after the first peak of paralysis reduced the spreading of Th17 and Th1 responses from the priming immunogen to a new myelin T cell epitope within the CNS. Antigen-presenting cells (APC) isolated from homotaurine-treated mice displayed an attenuated ability to promote autoantigen-specific T cell proliferation. The ability of homotaurine treatment to limit epitope spreading within the CNS, along with its safety record, makes it an excellent candidate to help treat MS and other inflammatory disorders of the CNS.


Subject(s)
Central Nervous System/pathology , Multiple Sclerosis/immunology , T-Lymphocytes/immunology , Taurine/analogs & derivatives , Animals , Antigen Presentation/drug effects , Antigen-Presenting Cells/drug effects , Antigen-Presenting Cells/immunology , Cell Proliferation/drug effects , Central Nervous System/drug effects , Central Nervous System/immunology , Disease Models, Animal , Disease Progression , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/pathology , Female , Mice, Inbred C57BL , Multiple Sclerosis/pathology , Myelin Proteolipid Protein/immunology , Peptide Fragments/immunology , Recurrence , Spleen/pathology , T-Lymphocytes/drug effects , Taurine/pharmacology , gamma-Aminobutyric Acid/pharmacology
13.
Cell Rep ; 34(11): 108863, 2021 03 16.
Article in English | MEDLINE | ID: covidwho-1108116

ABSTRACT

It is unclear why some SARS-CoV-2 patients readily resolve infection while others develop severe disease. By interrogating metabolic programs of immune cells in severe and recovered coronavirus disease 2019 (COVID-19) patients compared with other viral infections, we identify a unique population of T cells. These T cells express increased Voltage-Dependent Anion Channel 1 (VDAC1), accompanied by gene programs and functional characteristics linked to mitochondrial dysfunction and apoptosis. The percentage of these cells increases in elderly patients and correlates with lymphopenia. Importantly, T cell apoptosis is inhibited in vitro by targeting the oligomerization of VDAC1 or blocking caspase activity. We also observe an expansion of myeloid-derived suppressor cells with unique metabolic phenotypes specific to COVID-19, and their presence distinguishes severe from mild disease. Overall, the identification of these metabolic phenotypes provides insight into the dysfunctional immune response in acutely ill COVID-19 patients and provides a means to predict and track disease severity and/or design metabolic therapeutic regimens.


Subject(s)
COVID-19/immunology , COVID-19/metabolism , Immunity/immunology , Adult , Aged , Aged, 80 and over , Apoptosis/immunology , Caspases/immunology , Caspases/metabolism , Female , Humans , Lymphopenia/immunology , Lymphopenia/metabolism , Male , Middle Aged , Mitochondria/immunology , Mitochondria/metabolism , Myeloid-Derived Suppressor Cells/immunology , Myeloid-Derived Suppressor Cells/metabolism , SARS-CoV-2/immunology , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Voltage-Dependent Anion Channel 1/metabolism , Young Adult
14.
Virol Sin ; 36(5): 859-868, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1070952

ABSTRACT

The COVID-19 pandemic, caused by the SARS-CoV-2 infection, is a global health crisis. While many patients have clinically recovered, little is known about long-term alterations in T cell responses of COVID-19 convalescents. In this study, T cell responses in peripheral blood mononuclear cells of a long-time COVID-19 clinically recovered (20-26 weeks) cohort (LCR) were measured via flow cytometry and ELISpot. The T cell responses of LCR were comparatively analyzed against an age and sex matched short-time clinically recovered (4-9 weeks) cohort (SCR) and a healthy donor cohort (HD). All volunteers were recruited from Wuhan Jinyintan Hospital, China. Phenotypic analysis showed that activation marker PD-1 expressing on CD4+ T cells of LCR was still significantly lower than that of HD. Functional analysis indicated that frequencies of Tc2, Th2 and Th17 in LCR were comparable to those of HD, but Tc17 was higher than that of HD. In LCR, compared to the HD, there were fewer IFN-γ producing T cells but more IL-2 secreting T cells. In addition, the circulating Tfh cells in LCR were still slightly lower compared to HD, though the subsets composition had recovered. Remarkably, SARS-CoV-2 specific T cell responses in LCR were comparable to that of SCR. Collectively, T cell responses experienced long-term alterations in phenotype and functional potential of LCR cohort. However, after clinical recovery, SARS-CoV-2 specific T cell responses could be sustained at least for six months, which may be helpful in resisting re-infection.


Subject(s)
COVID-19 , Cohort Studies , Humans , Leukocytes, Mononuclear , Pandemics , Phenotype , SARS-CoV-2
15.
Vaccines (Basel) ; 9(2)2021 Feb 06.
Article in English | MEDLINE | ID: covidwho-1069887

ABSTRACT

The rapid transmission of SARS-CoV-2 in the USA and worldwide necessitates the development of multiple vaccines to combat the COVID-19 global pandemic. Previously, we showed that a particulate adjuvant system, quil-A-loaded chitosan (QAC) nanoparticles, can elicit robust immunity combined with plasmid vaccines when used against avian coronavirus. Here, we report on the immune responses elicited by mucosal homologous plasmid and a heterologous immunization strategy using a plasmid vaccine and a Modified Vaccinia Ankara (MVA) expressing SARS-CoV-2 spike (S) and nucleocapsid (N) antigens. Only the heterologous intranasal immunization strategy elicited neutralizing antibodies against SARS-CoV-2 in serum and bronchoalveolar lavage of mice, suggesting a protective vaccine. The same prime/boost strategy led to the induction of type 1 and type 17 T-cell responses and polyfunctional T-cells expressing multiple type 1 cytokines (e.g., IFN-γ, TNFα, IL-2) in the lungs and spleens of vaccinated mice. In contrast, the plasmid homologous vaccine strategy led to the induction of local mono and polyfunctional T-cells secreting IFN-γ. Outcomes of this study support the potential of QAC-nano vaccines to elicit significant mucosal immune responses against respiratory coronaviruses.

16.
Cell ; 184(1): 169-183.e17, 2021 01 07.
Article in English | MEDLINE | ID: covidwho-1064911

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is causing a global pandemic, and cases continue to rise. Most infected individuals experience mildly symptomatic coronavirus disease 2019 (COVID-19), but it is unknown whether this can induce persistent immune memory that could contribute to immunity. We performed a longitudinal assessment of individuals recovered from mild COVID-19 to determine whether they develop and sustain multifaceted SARS-CoV-2-specific immunological memory. Recovered individuals developed SARS-CoV-2-specific immunoglobulin (IgG) antibodies, neutralizing plasma, and memory B and memory T cells that persisted for at least 3 months. Our data further reveal that SARS-CoV-2-specific IgG memory B cells increased over time. Additionally, SARS-CoV-2-specific memory lymphocytes exhibited characteristics associated with potent antiviral function: memory T cells secreted cytokines and expanded upon antigen re-encounter, whereas memory B cells expressed receptors capable of neutralizing virus when expressed as monoclonal antibodies. Therefore, mild COVID-19 elicits memory lymphocytes that persist and display functional hallmarks of antiviral immunity.


Subject(s)
COVID-19/immunology , COVID-19/physiopathology , Immunologic Memory , SARS-CoV-2/physiology , Adult , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , B-Lymphocytes/immunology , COVID-19/blood , Female , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Male , Middle Aged , SARS-CoV-2/chemistry , Severity of Illness Index , Spike Glycoprotein, Coronavirus/metabolism , T-Lymphocytes/immunology
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.
Nature ; 590(7847): 635-641, 2021 02.
Article in English | MEDLINE | ID: covidwho-1019856

ABSTRACT

Some patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) develop severe pneumonia and acute respiratory distress syndrome1 (ARDS). Distinct clinical features in these patients have led to speculation that the immune response to virus in the SARS-CoV-2-infected alveolus differs from that in other types of pneumonia2. Here we investigate SARS-CoV-2 pathobiology by characterizing the immune response in the alveoli of patients infected with the virus. We collected bronchoalveolar lavage fluid samples from 88 patients with SARS-CoV-2-induced respiratory failure and 211 patients with known or suspected pneumonia from other pathogens, and analysed them using flow cytometry and bulk transcriptomic profiling. We performed single-cell RNA sequencing on 10 bronchoalveolar lavage fluid samples collected from patients with severe coronavirus disease 2019 (COVID-19) within 48 h of intubation. In the majority of patients with SARS-CoV-2 infection, the alveolar space was persistently enriched in T cells and monocytes. Bulk and single-cell transcriptomic profiling suggested that SARS-CoV-2 infects alveolar macrophages, which in turn respond by producing T cell chemoattractants. These T cells produce interferon-γ to induce inflammatory cytokine release from alveolar macrophages and further promote T cell activation. Collectively, our results suggest that SARS-CoV-2 causes a slowly unfolding, spatially limited alveolitis in which alveolar macrophages containing SARS-CoV-2 and T cells form a positive feedback loop that drives persistent alveolar inflammation.


Subject(s)
COVID-19/immunology , COVID-19/virology , Macrophages, Alveolar/immunology , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , SARS-CoV-2/pathogenicity , T-Lymphocytes/immunology , Bronchoalveolar Lavage Fluid/chemistry , Bronchoalveolar Lavage Fluid/immunology , COVID-19/genetics , Cohort Studies , Humans , Interferon-gamma/immunology , Interferons/immunology , Interferons/metabolism , Macrophages, Alveolar/metabolism , Macrophages, Alveolar/virology , Pneumonia, Viral/genetics , RNA-Seq , SARS-CoV-2/immunology , Signal Transduction/immunology , Single-Cell Analysis , T-Lymphocytes/metabolism , Time Factors
19.
Virology ; 554: 97-105, 2021 02.
Article in English | MEDLINE | ID: covidwho-1003123

ABSTRACT

We examined the pathogenicity of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in cynomolgus macaques for 28 days to establish an animal model of COVID-19 for the development of vaccines and antiviral drugs. Cynomolgus macaques infected with SARS-CoV-2 showed body temperature rises and X-ray radiographic pneumonia without life-threatening clinical signs of disease. A neutralizing antibody against SARS-CoV-2 and T-lymphocytes producing interferon (IFN)-γ specifically for SARS-CoV-2 N-protein were detected on day 14 in one of three macaques with viral pneumonia. In the other two macaques, in which a neutralizing antibody was not detected, T-lymphocytes producing IFN-γ specifically for SARS-CoV-2 N protein increased on day 7 to day 14, suggesting that not only a neutralizing antibody but also cellular immunity has a role in the elimination of SARS-CoV-2. Thus, because of similar symptoms to approximately 80% of patients, cynomolgus macaques are appropriate to extrapolate the efficacy of vaccines and antiviral drugs for humans.


Subject(s)
Antibodies, Neutralizing/immunology , COVID-19/immunology , Disease Models, Animal , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/pathology , COVID-19/virology , Cytokines/blood , Female , Interferon-gamma/immunology , Macaca fascicularis , Male , Mouth/virology , Nasal Cavity/virology , Pneumonia, Viral/immunology , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology , Viral Load
20.
Front Immunol ; 11: 607069, 2020.
Article in English | MEDLINE | ID: covidwho-993358

ABSTRACT

Upon recognition of microbial DNA or self-DNA, the cyclic-GMP-AMP synthase (cGAS) of the host catalyzes the production of the cyclic dinucleotide cGAMP. cGAMP is the main activator of STING, stimulator of interferon genes, leading to interferon synthesis through the STING-TBK1-IRF3 pathway. STING is also a hub for activation of NF-κB and autophagy. The present review details the striking similarities between T and B cell responses in severe coronavirus disease 2019 (COVID-19) and both animal or human models of STING gain of function (SAVI syndromes: STING-associated vasculopathy with onset in infancy). Those similarities may be further clues for a delayed activation of STING in severe COVID-19 patients, due to DNA damages following severe acute respiratory syndrome coronaviruses (SARS-CoV-2) infection and unusual role of STING in SARS-CoV-2 control. In early stages, Th2 differentiation are noticed in both severe COVID-19 and SAVI syndromes; then, CD4+ and CD8+ T cells functional exhaustion/senescent patterns due to TCR hyper-responsiveness are observed. T cell delayed over-responses can contribute to pneumonitis and delayed cytokine secretion with over-production of IL-6. Last, STING over-activation induces progressive CD4+ and CD8+ T lymphopenia in SAVI syndromes, which parallels what is observed in severe COVID-19. ACE2, the main receptor of SARS-CoV-2, is rarely expressed in immune cells, and it has not been yet proven that some human lymphocytes could be infected by SARS-CoV-2 through CD147 or CD26. However, STING, expressed in humans T cells, might be triggered following excessive transfer of cGAMP from infected antigen presenting cells into activated CD4+ and CD8+ T cells lymphocytes. Indeed, those lymphocytes highly express the cGAMP importer SLC19A1. Whereas STING is not expressed in human B cells, B cells counts are much less affected, either in COVID-19 or SAVI syndromes. The recognition of delayed STING over-activation in severe COVID-19 patients could prompt to target STING with specific small molecules inhibitors already designed and/or aspirin, which inhibits cGAS.


Subject(s)
B-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Membrane Proteins/immunology , SARS-CoV-2/immunology , Th2 Cells/immunology , Angiotensin-Converting Enzyme 2/immunology , Animals , B-Lymphocytes/pathology , Basigin/immunology , CD8-Positive T-Lymphocytes/pathology , COVID-19/pathology , Dipeptidyl Peptidase 4/immunology , Humans , Interferon Regulatory Factor-3/immunology , Nucleotidyltransferases/immunology , Signal Transduction/immunology , Th2 Cells/pathology
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