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1.
Front Immunol ; 13: 834988, 2022.
Article in English | MEDLINE | ID: covidwho-1753370

ABSTRACT

Patients with COVID-19 present with a wide variety of clinical manifestations. Thromboembolic events constitute a significant cause of morbidity and mortality in patients infected with SARS-CoV-2. Severe COVID-19 has been associated with hyperinflammation and pre-existing cardiovascular disease. Platelets are important mediators and sensors of inflammation and are directly affected by cardiovascular stressors. In this report, we found that platelets from severely ill, hospitalized COVID-19 patients exhibited higher basal levels of activation measured by P-selectin surface expression and had poor functional reserve upon in vitro stimulation. To investigate this question in more detail, we developed an assay to assess the capacity of plasma from COVID-19 patients to activate platelets from healthy donors. Platelet activation was a common feature of plasma from COVID-19 patients and correlated with key measures of clinical outcome including kidney and liver injury, and APACHEIII scores. Further, we identified ferritin as a pivotal clinical marker associated with platelet hyperactivation. The COVID-19 plasma-mediated effect on control platelets was highest for patients that subsequently developed inpatient thrombotic events. Proteomic analysis of plasma from COVID-19 patients identified key mediators of inflammation and cardiovascular disease that positively correlated with in vitro platelet activation. Mechanistically, blocking the signaling of the FcγRIIa-Syk and C5a-C5aR pathways on platelets, using antibody-mediated neutralization, IgG depletion or the Syk inhibitor fostamatinib, reversed this hyperactivity driven by COVID-19 plasma and prevented platelet aggregation in endothelial microfluidic chamber conditions. These data identified these potentially actionable pathways as central for platelet activation and/or vascular complications and clinical outcomes in COVID-19 patients. In conclusion, we reveal a key role of platelet-mediated immunothrombosis in COVID-19 and identify distinct, clinically relevant, targetable signaling pathways that mediate this effect.


Subject(s)
Blood Platelets/immunology , COVID-19/immunology , Complement C5a/metabolism , Receptor, Anaphylatoxin C5a/metabolism , Receptors, IgG/metabolism , SARS-CoV-2/physiology , Thromboembolism/immunology , Adult , Aminopyridines/pharmacology , Cells, Cultured , Female , Hospitalization , Humans , Male , Morpholines/pharmacology , Platelet Activation , Pyrimidines/pharmacology , Severity of Illness Index , Signal Transduction , Syk Kinase/antagonists & inhibitors
2.
PLoS One ; 17(3): e0257930, 2022.
Article in English | MEDLINE | ID: covidwho-1731590

ABSTRACT

The novel coronavirus, SARS-CoV-2 that causes COVID-19 has resulted in the death of nearly 4 million people within the last 18 months. While preventive vaccination, and monoclonal antibody therapies have been rapidly developed and deployed, early in the pandemic the use of COVID-19 convalescent plasma (CCP) was a common means of passive immunization with a theoretical risk of antibody-dependent enhancement (ADE) of viral infection. Though vaccines elicit a strong and protective immune response and transfusion of CCP with high titers of neutralization activity are correlated with better clinical outcomes, the question of whether antibodies in CCP can enhance infection of SARS-CoV-2 has not been directly addressed. In this study, we analyzed for and observed passive transfer of neutralization activity with CCP transfusion. Furthermore, to specifically understand if antibodies against the spike protein (S) enhance infection, we measured the anti-S IgG, IgA, and IgM responses and adapted retroviral-pseudotypes to measure virus neutralization with target cells expressing the ACE2 virus receptor and the Fc alpha receptor (FcαR) or Fc gamma receptor IIA (FcγRIIA). Whereas neutralizing activity of CCP correlated best with higher titers of anti-S IgG antibodies, the neutralizing titer was not affected when Fc receptors were present on target cells. These observations support the absence of antibody-dependent enhancement of infection (ADE) by IgG and IgA isotypes found in CCP. The results presented, therefore, not only supports the therapeutic use of currently available antibody-based treatment, including the continuation of CCP transfusion strategies, but also the use of various vaccine platforms in a prophylactic approach.


Subject(s)
COVID-19/therapy , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/blood , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , COVID-19/virology , Female , HEK293 Cells , Humans , Immunization, Passive , Immunoglobulin A/blood , Immunoglobulin A/therapeutic use , Immunoglobulin G/blood , Immunoglobulin G/therapeutic use , Male , Middle Aged , Neutralization Tests , Receptors, IgG/genetics , Receptors, IgG/metabolism , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Young Adult
3.
Viruses ; 14(1)2021 12 28.
Article in English | MEDLINE | ID: covidwho-1715736

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) infection induces elevated levels of inflammatory cytokines, which are mainly produced by the innate response to the virus. The role of NK cells, which are potent producers of IFN-γ and cytotoxicity, has not been sufficiently studied in the setting of SARS-CoV-2 infection. We confirmed a different distribution of NK cell subsets in hospitalized COVID-19 patients despite their NK cell deficiency. The impairment of this innate defense is mainly focused on the cytotoxic capacity of the CD56dim NK cells. On the one hand, we found an expansion of the CD56dimCD16neg NK subset, lower cytotoxic capacities, and high frequencies of inhibitory 2DL1 and 2DL1/S1 KIR receptors in COVID-19 patients. On the other hand, the depletion of CD56dimCD16dim/bright NK cell subsets, high cytotoxic capacities, and high frequencies of inhibitory 2DL1 KIR receptors were found in COVID-19 patients. In contrast, no differences in the distribution of CD56bright NK cell subsets were found in this study. These alterations in the distribution and phenotype of NK cells might enhance the impairment of this crucial innate line of defense during COVID-19 infection.


Subject(s)
COVID-19/immunology , Killer Cells, Natural/metabolism , Lymphocyte Subsets/metabolism , Receptors, KIR/metabolism , Aged , CD56 Antigen/metabolism , COVID-19/blood , Female , GPI-Linked Proteins/metabolism , Hospitalization , Humans , Inflammation , Male , Middle Aged , Receptors, IgG/metabolism , SARS-CoV-2
4.
Genome Med ; 14(1): 16, 2022 02 17.
Article in English | MEDLINE | ID: covidwho-1690882

ABSTRACT

BACKGROUND: Understanding the host genetic architecture and viral immunity contributes to the development of effective vaccines and therapeutics for controlling the COVID-19 pandemic. Alterations of immune responses in peripheral blood mononuclear cells play a crucial role in the detrimental progression of COVID-19. However, the effects of host genetic factors on immune responses for severe COVID-19 remain largely unknown. METHODS: We constructed a computational framework to characterize the host genetics that influence immune cell subpopulations for severe COVID-19 by integrating GWAS summary statistics (N = 969,689 samples) with four independent scRNA-seq datasets containing healthy controls and patients with mild, moderate, and severe symptom (N = 606,534 cells). We collected 10 predefined gene sets including inflammatory and cytokine genes to calculate cell state score for evaluating the immunological features of individual immune cells. RESULTS: We found that 34 risk genes were significantly associated with severe COVID-19, and the number of highly expressed genes increased with the severity of COVID-19. Three cell subtypes that are CD16+monocytes, megakaryocytes, and memory CD8+T cells were significantly enriched by COVID-19-related genetic association signals. Notably, three causal risk genes of CCR1, CXCR6, and ABO were highly expressed in these three cell types, respectively. CCR1+CD16+monocytes and ABO+ megakaryocytes with significantly up-regulated genes, including S100A12, S100A8, S100A9, and IFITM1, confer higher risk to the dysregulated immune response among severe patients. CXCR6+ memory CD8+ T cells exhibit a notable polyfunctionality including elevation of proliferation, migration, and chemotaxis. Moreover, we observed an increase in cell-cell interactions of both CCR1+ CD16+monocytes and CXCR6+ memory CD8+T cells in severe patients compared to normal controls among both PBMCs and lung tissues. The enhanced interactions of CXCR6+ memory CD8+T cells with epithelial cells facilitate the recruitment of this specific population of T cells to airways, promoting CD8+T cell-mediated immunity against COVID-19 infection. CONCLUSIONS: We uncover a major genetics-modulated immunological shift between mild and severe infection, including an elevated expression of genetics-risk genes, increase in inflammatory cytokines, and of functional immune cell subsets aggravating disease severity, which provides novel insights into parsing the host genetic determinants that influence peripheral immune cells in severe COVID-19.


Subject(s)
CD8-Positive T-Lymphocytes/virology , COVID-19/genetics , COVID-19/pathology , Monocytes/virology , Single-Cell Analysis/methods , COVID-19/immunology , Computational Biology/methods , GPI-Linked Proteins/metabolism , Genetic Predisposition to Disease , Genome-Wide Association Study , Humans , Megakaryocyte Progenitor Cells/immunology , Megakaryocyte Progenitor Cells/virology , Monocytes/metabolism , Quantitative Trait Loci , Receptors, CCR1/immunology , Receptors, CCR1/metabolism , Receptors, CXCR6/immunology , Receptors, CXCR6/metabolism , Receptors, IgG/metabolism , Sequence Analysis, RNA , Severity of Illness Index
5.
Front Immunol ; 12: 799558, 2021.
Article in English | MEDLINE | ID: covidwho-1662582

ABSTRACT

The poor outcome of the coronavirus disease-2019 (COVID-19), caused by SARS-CoV-2, is associated with systemic hyperinflammatory response and immunopathology. Although inflammasome and oxidative stress have independently been implicated in COVID-19, it is poorly understood whether these two pathways cooperatively contribute to disease severity. Herein, we found an enrichment of CD14highCD16- monocytes displaying inflammasome activation evidenced by caspase-1/ASC-speck formation in severe COVID-19 patients when compared to mild ones and healthy controls, respectively. Those cells also showed aberrant levels of mitochondrial superoxide and lipid peroxidation, both hallmarks of the oxidative stress response, which strongly correlated with caspase-1 activity. In addition, we found that NLRP3 inflammasome-derived IL-1ß secretion by SARS-CoV-2-exposed monocytes in vitro was partially dependent on lipid peroxidation. Importantly, altered inflammasome and stress responses persisted after short-term patient recovery. Collectively, our findings suggest oxidative stress/NLRP3 signaling pathway as a potential target for host-directed therapy to mitigate early COVID-19 hyperinflammation and also its long-term outcomes.


Subject(s)
COVID-19/metabolism , Inflammasomes/metabolism , Lipopolysaccharide Receptors/metabolism , Monocytes/metabolism , Oxidative Stress/physiology , Receptors, IgG/metabolism , Aged , COVID-19/pathology , Caspase 1/metabolism , Female , GPI-Linked Proteins/metabolism , Humans , Interleukin-1beta/metabolism , Male , Middle Aged , Mitochondria/metabolism , Mitochondria/pathology , Monocytes/pathology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , SARS-CoV-2/metabolism , Signal Transduction/physiology
6.
Int J Mol Sci ; 22(16)2021 Aug 21.
Article in English | MEDLINE | ID: covidwho-1662690

ABSTRACT

Infection with viruses, such as the lactate dehydrogenase-elevating virus (LDV), is known to trigger the onset of autoimmune anemia through the enhancement of the phagocytosis of autoantibody-opsonized erythrocytes by activated macrophages. Type I interferon receptor-deficient mice show enhanced anemia, which suggests a protective effect of these cytokines, partly through the control of type II interferon production. The development of anemia requires the expression of Fcγ receptors (FcγR) I, III, and IV. Whereas LDV infection decreases FcγR III expression, it enhances FcγR I and IV expression in wild-type animals. The LDV-associated increase in the expression of FcγR I and IV is largely reduced in type I interferon receptor-deficient mice, through both type II interferon-dependent and -independent mechanisms. Thus, the regulation of the expression of FcγR I and IV, but not III, by interferons may partly explain the exacerbating effect of LDV infection on anemia that results from the enhanced phagocytosis of IgG autoantibody-opsonized erythrocytes.


Subject(s)
Anemia, Hemolytic, Autoimmune/immunology , Arterivirus Infections/immunology , Interferons/metabolism , Lactate dehydrogenase-elevating virus/immunology , Receptors, IgG/metabolism , Anemia, Hemolytic, Autoimmune/virology , Animals , Arterivirus Infections/virology , Host-Pathogen Interactions , Mice, Inbred C57BL , Mice, Knockout , Phagocytosis
8.
J Exp Med ; 219(2)2022 02 07.
Article in English | MEDLINE | ID: covidwho-1594167

ABSTRACT

In rare instances, pediatric SARS-CoV-2 infection results in a novel immunodysregulation syndrome termed multisystem inflammatory syndrome in children (MIS-C). We compared MIS-C immunopathology with severe COVID-19 in adults. MIS-C does not result in pneumocyte damage but is associated with vascular endotheliitis and gastrointestinal epithelial injury. In MIS-C, the cytokine release syndrome is characterized by IFNγ and not type I interferon. Persistence of patrolling monocytes differentiates MIS-C from severe COVID-19, which is dominated by HLA-DRlo classical monocytes. IFNγ levels correlate with granzyme B production in CD16+ NK cells and TIM3 expression on CD38+/HLA-DR+ T cells. Single-cell TCR profiling reveals a skewed TCRß repertoire enriched for TRBV11-2 and a superantigenic signature in TIM3+/CD38+/HLA-DR+ T cells. Using NicheNet, we confirm IFNγ as a central cytokine in the communication between TIM3+/CD38+/HLA-DR+ T cells, CD16+ NK cells, and patrolling monocytes. Normalization of IFNγ, loss of TIM3, quiescence of CD16+ NK cells, and contraction of patrolling monocytes upon clinical resolution highlight their potential role in MIS-C immunopathogenesis.


Subject(s)
COVID-19/complications , Hepatitis A Virus Cellular Receptor 2/metabolism , Interferon-gamma/metabolism , Killer Cells, Natural/immunology , Monocytes/metabolism , Receptors, IgG/metabolism , Systemic Inflammatory Response Syndrome/immunology , T-Lymphocytes/immunology , Adolescent , Alveolar Epithelial Cells/pathology , B-Lymphocytes/immunology , Blood Vessels/pathology , COVID-19/immunology , COVID-19/pathology , Cell Proliferation , Child , Cohort Studies , Complement Activation , Cytokines/metabolism , Enterocytes/pathology , Female , Humans , Immunity, Humoral , Inflammation/pathology , Interferon Type I/metabolism , Interleukin-15/metabolism , Lymphocyte Activation/immunology , Male , Receptors, Antigen, T-Cell/metabolism , SARS-CoV-2/immunology , Superantigens/metabolism , Systemic Inflammatory Response Syndrome/pathology
9.
Viruses ; 13(12)2021 12 11.
Article in English | MEDLINE | ID: covidwho-1572660

ABSTRACT

Patients with COVID-19 generally raise antibodies against SARS-CoV-2 following infection, and the antibody level is positively correlated to the severity of disease. Whether the viral antibodies exacerbate COVID-19 through antibody-dependent enhancement (ADE) is still not fully understood. Here, we conducted in vitro assessment of whether convalescent serum enhanced SARS-CoV-2 infection or induced excessive immune responses in immune cells. Our data revealed that SARS-CoV-2 infection of primary B cells, macrophages and monocytes, which express variable levels of FcγR, could be enhanced by convalescent serum from COVID-19 patients. We also determined the factors associated with ADE, and found which showed a time-dependent but not viral-dose dependent manner. Furthermore, the ADE effect is not associated with the neutralizing titer or RBD antibody level when testing serum samples collected from different patients. However, it is higher in a medium level than low or high dilutions in a given sample that showed ADE effect, which is similar to dengue. Finally, we demonstrated more viral genes or dysregulated host immune gene expression under ADE conditions compared to the no-serum infection group. Collectively, our study provides insight into the understanding of an association of high viral antibody titer and severe lung pathology in severe patients with COVID-19.


Subject(s)
Antibody-Dependent Enhancement/immunology , Leukocytes/virology , SARS-CoV-2/pathogenicity , COVID-19/immunology , Cells, Cultured , Gene Expression Profiling , Humans , Immune Sera/immunology , Leukocytes/metabolism , Receptors, IgG/metabolism , Virus Replication/immunology
10.
mBio ; 12(5): e0198721, 2021 10 26.
Article in English | MEDLINE | ID: covidwho-1494967

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has raised concerns about the detrimental effects of antibodies. Antibody-dependent enhancement (ADE) of infection is one of the biggest concerns in terms of not only the antibody reaction to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) upon reinfection with the virus but also the reaction to COVID-19 vaccines. In this study, we evaluated ADE of infection by using COVID-19 convalescent-phase plasma and BHK cells expressing human Fcγ receptors (FcγRs). We found that FcγRIIA and FcγRIIIA mediated modest ADE of infection against SARS-CoV-2. Although ADE of infection was observed in monocyte-derived macrophages infected with SARS-CoV-2, including its variants, proinflammatory cytokine/chemokine expression was not upregulated in macrophages. SARS-CoV-2 infection thus produces antibodies that elicit ADE of infection, but these antibodies do not contribute to excess cytokine production by macrophages. IMPORTANCE Viruses infect cells mainly via specific receptors at the cell surface. Antibody-dependent enhancement (ADE) of infection is an alternative mechanism of infection for viruses to infect immune cells that is mediated by antibodies and IgG receptors (FcγRs). Because ADE of infection contributes to the pathogenesis of some viruses, such as dengue virus and feline coronavirus, it is important to evaluate the precise mechanism of ADE and its contribution to the pathogenesis of SARS-CoV-2. Here, using convalescent-phase plasma from COVID-19 patients, we found that two types of FcγRs, FcγRIIA and FcγRIIIA, mediate ADE of SARS-CoV-2 infection. Although ADE of infection was observed for SARS-CoV-2 and its recent variants, proinflammatory cytokine production in monocyte-derived macrophages was not upregulated. These observations suggest that SARS-CoV-2 infection produces antibodies that elicit ADE of infection, but these antibodies may not be involved in aberrant cytokine release by macrophages during SARS-CoV-2 infection.


Subject(s)
Cytokines/metabolism , Macrophages/metabolism , Receptors, IgG/metabolism , SARS-CoV-2/pathogenicity , Animals , Antibody-Dependent Enhancement/physiology , Cell Line , Cricetinae , Humans , Real-Time Polymerase Chain Reaction , Receptors, IgG/genetics
11.
Cell Rep ; 37(1): 109798, 2021 10 05.
Article in English | MEDLINE | ID: covidwho-1415262

ABSTRACT

Despite the worldwide effect of the coronavirus disease 2019 (COVID-19) pandemic, the underlying mechanisms of fatal viral pneumonia remain elusive. Here, we show that critical COVID-19 is associated with enhanced eosinophil-mediated inflammation when compared to non-critical cases. In addition, we confirm increased T helper (Th)2-biased adaptive immune responses, accompanying overt complement activation, in the critical group. Moreover, enhanced antibody responses and complement activation are associated with disease pathogenesis as evidenced by formation of immune complexes and membrane attack complexes in airways and vasculature of lung biopsies from six fatal cases, as well as by enhanced hallmark gene set signatures of Fcγ receptor (FcγR) signaling and complement activation in myeloid cells of respiratory specimens from critical COVID-19 patients. These results suggest that SARS-CoV-2 infection may drive specific innate immune responses, including eosinophil-mediated inflammation, and subsequent pulmonary pathogenesis via enhanced Th2-biased immune responses, which might be crucial drivers of critical disease in COVID-19 patients.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , Complement System Proteins/immunology , Eosinophils/immunology , Inflammation/immunology , Pneumonia, Viral/immunology , SARS-CoV-2/immunology , Adaptive Immunity , Adult , Aged , Aged, 80 and over , Antigen-Antibody Complex/metabolism , COVID-19/metabolism , COVID-19/virology , Complement Activation , Complement Membrane Attack Complex/metabolism , Eosinophils/virology , Female , Humans , Inflammation/metabolism , Inflammation/virology , Lung Injury/immunology , Lung Injury/pathology , Lung Injury/virology , Male , Middle Aged , Pneumonia, Viral/metabolism , Receptors, IgG/immunology , Receptors, IgG/metabolism , Severity of Illness Index , Signal Transduction , Th2 Cells/immunology , Viral Load , Young Adult
12.
Front Immunol ; 12: 674079, 2021.
Article in English | MEDLINE | ID: covidwho-1305644

ABSTRACT

At homeostasis the vast majority of neutrophils in the circulation expresses CD16 and CD62L within a narrow expression range, but this quickly changes in disease. Little is known regarding the changes in kinetics of neutrophils phenotypes in inflammatory conditions. During acute inflammation more heterogeneity was found, characterized by an increase in CD16dim banded neutrophils. These cells were probably released from the bone marrow (left shift). Acute inflammation induced by human experimental endotoxemia (LPS model) was additionally accompanied by an immediate increase in a CD62Llow neutrophil population, which was not as explicit after injury/trauma induced acute inflammation. The situation in sub-acute inflammation was more complex. CD62Llow neutrophils appeared in the peripheral blood several days (>3 days) after trauma with a peak after 10 days. A similar situation was found in the blood of COVID-19 patients returning from the ICU. Sorted CD16low and CD62Llow subsets from trauma and COVID-19 patients displayed the same nuclear characteristics as found after experimental endotoxemia. In diseases associated with chronic inflammation (stable COPD and treatment naive HIV) no increases in CD16low or CD62Llow neutrophils were found in the peripheral blood. All neutrophil subsets were present in the bone marrow during homeostasis. After LPS rechallenge, these subsets failed to appear in the circulation, but continued to be present in the bone marrow, suggesting the absence of recruitment signals. Because the subsets were reported to have different functionalities, these results on the kinetics of neutrophil subsets in a range of inflammatory conditions contribute to our understanding on the role of neutrophils in health and disease.


Subject(s)
COVID-19/immunology , Endotoxemia/immunology , Inflammation/immunology , Neutrophils/immunology , SARS-CoV-2/physiology , Wounds and Injuries/immunology , Acute Disease , Adult , Aged , Cell Movement , Cells, Cultured , Chronic Disease , Female , Humans , L-Selectin/metabolism , Lipopolysaccharides/immunology , Male , Middle Aged , Receptors, IgG/metabolism , Young Adult
13.
Front Immunol ; 12: 700429, 2021.
Article in English | MEDLINE | ID: covidwho-1285298

ABSTRACT

The rapid spread of SARS-CoV-2 has induced a global pandemic. Severe forms of COVID-19 are characterized by dysregulated immune response and "cytokine storm". The role of IgG and IgM antibodies in COVID-19 pathology is reasonably well studied, whereas IgA is neglected. To improve clinical outcome of patients, immune modulatory drugs appear to be beneficial. Such drugs include intravenous immunoglobulin preparations, which were successfully tested in severe COVID-19 patients. Here we established a versatile in vitro model to study inflammatory as well as anti-inflammatory processes by therapeutic human immunoglobulins. We dissect the inflammatory activation on neutrophil-like HL60 cells, using an immune complex consisting of latex beads coated with spike protein of SARS-CoV-2 and opsonized with specific immunoglobulins from convalescent plasma. Our data clarifies the role of Fc-receptor-dependent phagocytosis via IgA-FcαRI and IgG-FcγR for COVID-19 disease followed by cytokine release. We show that COVID-19 associated inflammation could be reduced by addition of human immunoglobulin preparations (IVIG and trimodulin), while trimodulin elicits stronger immune modulation by more powerful ITAMi signaling. Besides IgG, the IgA component of trimodulin in particular, is of functional relevance for immune modulation in this assay setup, highlighting the need to study IgA mediated immune response.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Antigens, CD/metabolism , COVID-19/therapy , Cytokine Release Syndrome/therapy , Immunoglobulins, Intravenous/pharmacology , Neutrophils/immunology , Receptors, Fc/metabolism , Receptors, IgG/metabolism , SARS-CoV-2/physiology , Antibodies, Viral/metabolism , Antigen-Antibody Complex , Cell Line , Humans , Immunization, Passive , Immunomodulation , Phagocytosis , Signal Transduction , Spike Glycoprotein, Coronavirus/metabolism
14.
Cell ; 184(16): 4203-4219.e32, 2021 08 05.
Article in English | MEDLINE | ID: covidwho-1275187

ABSTRACT

SARS-CoV-2-neutralizing antibodies (NAbs) protect against COVID-19. A concern regarding SARS-CoV-2 antibodies is whether they mediate disease enhancement. Here, we isolated NAbs against the receptor-binding domain (RBD) or the N-terminal domain (NTD) of SARS-CoV-2 spike from individuals with acute or convalescent SARS-CoV-2 or a history of SARS-CoV infection. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific modes of binding. Select RBD NAbs also demonstrated Fc receptor-γ (FcγR)-mediated enhancement of virus infection in vitro, while five non-neutralizing NTD antibodies mediated FcγR-independent in vitro infection enhancement. However, both types of infection-enhancing antibodies protected from SARS-CoV-2 replication in monkeys and mice. Three of 46 monkeys infused with enhancing antibodies had higher lung inflammation scores compared to controls. One monkey had alveolar edema and elevated bronchoalveolar lavage inflammatory cytokines. Thus, while in vitro antibody-enhanced infection does not necessarily herald enhanced infection in vivo, increased lung inflammation can rarely occur in SARS-CoV-2 antibody-infused macaques.


Subject(s)
Antibodies, Neutralizing/immunology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Viral/immunology , Bronchoalveolar Lavage Fluid/chemistry , COVID-19/pathology , COVID-19/virology , Cytokines/metabolism , Female , Haplorhini , Humans , Lung/pathology , Lung/virology , Male , Mice , Mice, Inbred BALB C , Protein Domains , RNA, Guide/metabolism , Receptors, IgG/metabolism , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/chemistry , Viral Load , Virus Replication
16.
Front Immunol ; 12: 665773, 2021.
Article in English | MEDLINE | ID: covidwho-1264333

ABSTRACT

The COVID-19 pandemic has caused more than three million deaths globally. The severity of the disease is characterized, in part, by a dysregulated immune response. CD16+ monocytes are innate immune cells involved in inflammatory responses to viral infections, and tissue repair, among other functions. We characterized the transcriptional changes in CD16+ monocytes from PBMC of people with COVID-19, and from healthy individuals using publicly available single cell RNA sequencing data. CD16+ monocytes from people with COVID-19 compared to those from healthy individuals expressed transcriptional changes indicative of increased cell activation, and induction of a migratory phenotype. We also analyzed COVID-19 cases based on severity of the disease and found that mild cases were characterized by upregulation of interferon response and MHC class II related genes, whereas the severe cases had dysregulated expression of mitochondrial and antigen presentation genes, and upregulated inflammatory, cell movement, and apoptotic gene signatures. These results suggest that CD16+ monocytes in people with COVID-19 contribute to a dysregulated host response characterized by decreased antigen presentation, and an elevated inflammatory response with increased monocytic infiltration into tissues. Our results show that there are transcriptomic changes in CD16+ monocytes that may impact the functions of these cells, contributing to the pathogenesis and severity of COVID-19.


Subject(s)
COVID-19/virology , Monocytes/virology , Receptors, IgG/metabolism , SARS-CoV-2/pathogenicity , Transcription, Genetic , Transcriptome , Adult , Aged , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , COVID-19/genetics , COVID-19/immunology , COVID-19/metabolism , Case-Control Studies , Cytokines/genetics , Cytokines/metabolism , Female , GPI-Linked Proteins/metabolism , Gene Expression Profiling , Host-Pathogen Interactions , Humans , Inflammation Mediators/metabolism , Interferon Regulatory Factors/genetics , Interferon Regulatory Factors/metabolism , Male , Middle Aged , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , Monocytes/immunology , Monocytes/metabolism , RNA-Seq , SARS-CoV-2/immunology , Severity of Illness Index , Single-Cell Analysis , Young Adult
17.
Front Immunol ; 12: 651656, 2021.
Article in English | MEDLINE | ID: covidwho-1211812

ABSTRACT

Although immune dysfunction is a key feature of coronavirus disease 2019 (COVID-19), the metabolism-related mechanisms remain elusive. Here, by reanalyzing single-cell RNA sequencing data, we delineated metabolic remodeling in peripheral blood mononuclear cells (PBMCs) to elucidate the metabolic mechanisms that may lead to the progression of severe COVID-19. After scoring the metabolism-related biological processes and signaling pathways, we found that mono-CD14+ cells expressed higher levels of glycolysis-related genes (PKM, LDHA and PKM) and PPP-related genes (PGD and TKT) in severe patients than in mild patients. These genes may contribute to the hyperinflammation in mono-CD14+ cells of patients with severe COVID-19. The mono-CD16+ cell population in COVID-19 patients showed reduced transcription levels of genes related to lysine degradation (NSD1, KMT2E, and SETD2) and elevated transcription levels of genes involved in OXPHOS (ATP6V1B2, ATP5A1, ATP5E, and ATP5B), which may inhibit M2-like polarization. Plasma cells also expressed higher levels of the OXPHOS gene ATP13A3 in COVID-19 patients, which was positively associated with antibody secretion and survival of PCs. Moreover, enhanced glycolysis or OXPHOS was positively associated with the differentiation of memory B cells into plasmablasts or plasma cells. This study comprehensively investigated the metabolic features of peripheral immune cells and revealed that metabolic changes exacerbated inflammation in monocytes and promoted antibody secretion and cell survival in PCs in COVID-19 patients, especially those with severe disease.


Subject(s)
COVID-19/immunology , Glycolysis/genetics , Lysine/metabolism , Monocytes/metabolism , Single-Cell Analysis/methods , Adenosine Triphosphatases/blood , Adenosine Triphosphatases/genetics , Antibodies/metabolism , COVID-19/metabolism , COVID-19/physiopathology , Databases, Genetic , GPI-Linked Proteins/metabolism , Gene Ontology , Hematopoiesis/genetics , Humans , Inflammation/genetics , Inflammation/immunology , Inflammation/metabolism , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/metabolism , Leukocytes, Mononuclear/pathology , Lipopolysaccharide Receptors/metabolism , Lysine/genetics , Membrane Transport Proteins/blood , Membrane Transport Proteins/genetics , Metabolic Networks and Pathways/genetics , Metabolic Networks and Pathways/physiology , Monocytes/immunology , Monocytes/pathology , Oxidative Phosphorylation , RNA-Seq , Receptors, IgG/metabolism , Signal Transduction/genetics , Signal Transduction/immunology , Transcriptome/genetics
18.
Thromb Haemost ; 121(11): 1395-1399, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1182893

ABSTRACT

A series of cases with rare thromboembolic incidents including cerebral sinus vein thrombosis (some of them fatal) and concomitant thrombocytopenia occurring shortly after vaccination with the coronavirus disease 2019 (COVID-19) vaccine AZD1222 (Vaxzevria) have caused significant concern and led to its temporary suspension in many countries. Immediate laboratory efforts in four of these patients have identified a tentative pathomechanism underlying this syndrome termed initially vaccine-induced prothrombotic immune thrombocytopenia (VIPIT) and renamed recently vaccine-induced immune thrombotic thrombocytopenia (VITT). It encompasses the presence of platelet-activating antibodies to platelet factor-4/heparin complexes, possibly emulated by polyanionic constituents of AZD1222, and thus resembles heparin-induced thrombocytopenia (HIT). Because these immune complexes bind and activate platelets via Fcγ receptor IIA (FcγRIIA), high-dose intravenous immunoglobulin G has been suggested for treatment of VITT in addition to non-heparin anticoagulants. Here we propose inhibitors of Bruton tyrosine kinase (Btk) approved for B cell malignancies (e.g., ibrutinib) as another therapeutic option in VITT, as they are expected to pleiotropically target multiple pathways downstream of FcγRIIA-mediated Btk activation, for example, as demonstrated for the effective inhibition of platelet aggregation, dense granule secretion, P-selectin expression and platelet-neutrophil aggregate formation stimulated by FcγRIIA cross-linking. Moreover, C-type lectin-like receptor CLEC-2- and GPIb-mediated platelet activation, the interactions and activation of monocytes and the release of neutrophil extracellular traps, as encountered in HIT, could be attenuated by Btk inhibitors. As a paradigm for emergency repurposing of approved drugs in COVID-19, off-label use of Btk inhibitors in a low-dose range not affecting haemostatic functions could thus be considered a sufficiently safe option to treat VITT.


Subject(s)
Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Blood Platelets/drug effects , COVID-19 Vaccines/adverse effects , Platelet Activation/drug effects , Protein Kinase Inhibitors/therapeutic use , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Vaccination/adverse effects , Agammaglobulinaemia Tyrosine Kinase/metabolism , Animals , Autoantibodies/blood , Blood Platelets/enzymology , Blood Platelets/immunology , COVID-19 Vaccines/administration & dosage , Humans , Molecular Targeted Therapy , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/enzymology , Purpura, Thrombocytopenic, Idiopathic/immunology , Receptors, IgG/metabolism , Signal Transduction
19.
Nat Immunol ; 22(1): 67-73, 2021 01.
Article in English | MEDLINE | ID: covidwho-1065904

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 infections can cause coronavirus disease 2019 (COVID-19), which manifests with a range of severities from mild illness to life-threatening pneumonia and multi-organ failure. Severe COVID-19 is characterized by an inflammatory signature, including high levels of inflammatory cytokines, alveolar inflammatory infiltrates and vascular microthrombi. Here we show that patients with severe COVID-19 produced a unique serologic signature, including an increased likelihood of IgG1 with afucosylated Fc glycans. This Fc modification on severe acute respiratory syndrome coronavirus 2 IgGs enhanced interactions with the activating Fcγ receptor FcγRIIIa; when incorporated into immune complexes, Fc afucosylation enhanced production of inflammatory cytokines by monocytes, including interleukin-6 and tumor necrosis factor. These results show that disease severity in COVID-19 correlates with the presence of proinflammatory IgG Fc structures, including afucosylated IgG1.


Subject(s)
COVID-19/immunology , Cytokines/immunology , Immunoglobulin G/immunology , Receptors, IgG/immunology , SARS-CoV-2/immunology , Adolescent , Adult , Aged , COVID-19/metabolism , COVID-19/virology , Child , Cytokines/metabolism , Female , Glycosylation , Humans , Immunoglobulin G/metabolism , Interleukin-6 , Male , Middle Aged , Receptors, IgG/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Severity of Illness Index , Tumor Necrosis Factor-alpha/immunology , Tumor Necrosis Factor-alpha/metabolism
20.
Front Immunol ; 11: 580250, 2020.
Article in English | MEDLINE | ID: covidwho-918140

ABSTRACT

Little is known about the time-dependent immune responses in severe COVID-19. Data of 15 consecutive patients were sequentially recorded from intensive care unit admission. Lymphocyte subsets and total monocyte and subsets counts were monitored as well as the expression of HLA-DR. For 5 patients, SARS-CoV-2-specific T-cell polyfunctionality was assessed against Spike and Nucleoprotein SARS-CoV-2 peptides. Non-specific inflammation markers were increased in all patients. Median monocyte HLA-DR expression was below the 8,000 AB/C threshold defining acquired immunodepression. A "V" trend curve for lymphopenia, monocyte numbers, and HLA-DR expression was observed with a nadir between days 11 and 14 after symptoms' onset. Intermediate CD14++CD16+ monocytes increased early with a reduction in classic CD14++CD16- monocytes. Polyfunctional SARS-Cov-2-specific CD4 T-cells were present and functional, whereas virus-specific CD8 T-cells were less frequent and not efficient. We report a temporal variation of both innate and adaptive immunity in severe COVID-19 patients, helpful in guiding therapeutic decisions (e.g. anti-inflammatory vs. immunostimulatory ones). We describe a defect in virus-specific CD8 T-cells, a potential biomarker of clinical severity. These combined data also provide helpful knowledge for vaccine design. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/, identifier NCT04386395.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Monocytes/immunology , SARS-CoV-2/immunology , Severity of Illness Index , Aged , Biomarkers , COVID-19/virology , Female , GPI-Linked Proteins/metabolism , HLA-DR Antigens/immunology , Humans , Immunity, Cellular , Lipopolysaccharide Receptors/metabolism , Longitudinal Studies , Male , Middle Aged , Prospective Studies , Receptors, IgG/metabolism , SARS-CoV-2/genetics
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