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1.
Front Immunol ; 13: 815833, 2022.
Article in English | MEDLINE | ID: covidwho-1731775

ABSTRACT

The coronavirus disease-2019 (COVID-19) caused by the SARS-CoV-2 virus may vary from asymptomatic to severe infection with multi-organ failure and death. Increased levels of circulating complement biomarkers have been implicated in COVID-19-related hyperinflammation and coagulopathy. We characterized systemic complement activation at a cellular level in 49-patients with COVID-19. We found increases of the classical complement sentinel C1q and the downstream C3 component on circulating blood monocytes from COVID-19 patients when compared to healthy controls (HCs). Interestingly, the cell surface-bound complement inhibitor CD55 was also upregulated in COVID-19 patient monocytes in comparison with HC cells. Monocyte membrane-bound C1q, C3 and CD55 levels were associated with plasma inflammatory markers such as CRP and serum amyloid A during acute infection. Membrane-bounds C1q and C3 remained elevated even after a short recovery period. These results highlight systemic monocyte-associated complement activation over a broad range of COVID-19 disease severities, with a compensatory upregulation of CD55. Further evaluation of complement and its interaction with myeloid cells at the membrane level could improve understanding of its role in COVID-19 pathogenesis.


Subject(s)
COVID-19/immunology , Complement Activation/immunology , Complement System Proteins/immunology , Monocytes/immunology , Adult , Biomarkers/blood , COVID-19/blood , COVID-19/virology , Complement Inactivating Agents/immunology , Cytokines/immunology , Female , Humans , Immunologic Factors/immunology , Male , Middle Aged , Monocytes/virology , SARS-CoV-2/immunology
2.
Rev Med Virol ; 31(6): e2221, 2021 11.
Article in English | MEDLINE | ID: covidwho-1575100

ABSTRACT

The current pandemic caused by SARS-CoV-2 virus infection is known as Covid-19 (coronavirus disease 2019). This disease can be asymptomatic or can affect multiple organ systems. Damage induced by the virus is related to dysfunctional activity of the immune system, but the activity of molecules such as C-reactive protein (CRP) as a factor capable of inducing an inflammatory status that may be involved in the severe evolution of the disease, has not been extensively evaluated. A systematic review was performed using the NCBI-PubMed database to find articles related to Covid-19 immunity, inflammatory response, and CRP published from December 2019 to December 2020. High levels of CRP were found in patients with severe evolution of Covid-19 in which several organ systems were affected and in patients who died. CRP activates complement, induces the production of pro-inflammatory cytokines and induces apoptosis which, together with the inflammatory status during the disease, can lead to a severe outcome. Several drugs can decrease the level or block the effect of CRP and might be useful in the treatment of Covid-19. From this review it is reasonable to conclude that CRP is a factor that can contribute to severe evolution of Covid-19 and that the use of drugs able to lower CRP levels or block its activity should be evaluated in randomized controlled clinical trials.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , C-Reactive Protein/antagonists & inhibitors , COVID-19/drug therapy , Complement System Proteins/immunology , Cytokine Release Syndrome/drug therapy , SARS-CoV-2/pathogenicity , ADAM17 Protein/antagonists & inhibitors , ADAM17 Protein/genetics , ADAM17 Protein/immunology , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/immunology , Biomarkers/blood , C-Reactive Protein/genetics , C-Reactive Protein/immunology , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , Celecoxib/therapeutic use , Complement System Proteins/genetics , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/pathology , Cytokine Release Syndrome/virology , Cytokines/antagonists & inhibitors , Cytokines/genetics , Cytokines/immunology , Disease Progression , Doxycycline/therapeutic use , Gene Expression Regulation , Humans , Randomized Controlled Trials as Topic , Severity of Illness Index , Survival Analysis
3.
Front Immunol ; 12: 775168, 2021.
Article in English | MEDLINE | ID: covidwho-1555043

ABSTRACT

COVID-19 is characterized by virus-induced injury leading to multi-organ failure, together with inflammatory reaction, endothelial cell (EC) injury, and prothrombotic coagulopathy with thrombotic events. Complement system (C) via its cross-talk with the contact and coagulation systems contributes significantly to the severity and pathological consequences due to SARS-CoV-2 infection. These immunopathological mechanisms overlap in COVID-19 and pre-eclampsia (PE). Thus, mothers contracting SARS-CoV-2 infection during pregnancy are more vulnerable to developing PE. SARS-CoV-2 infection of ECs, via its receptor ACE2 and co-receptor TMPRSS2, can provoke endothelial dysfunction and disruption of vascular integrity, causing hyperinflammation and hypercoagulability. This is aggravated by bradykinin increase due to inhibition of ACE2 activity by the virus. C is important for the progression of normal pregnancy, and its dysregulation can impact in the form of PE-like syndrome as a consequence of SARS-CoV-2 infection. Thus, there is also an overlap between treatment regimens of COVID-19 and PE. C inhibitors, especially those targeting C3 or MASP-2, are exciting options for treating COVID-19 and consequent PE. In this review, we examine the role of C, contact and coagulation systems as well as endothelial hyperactivation with respect to SARS-CoV-2 infection during pregnancy and likely development of PE.


Subject(s)
COVID-19/immunology , Complement System Proteins/immunology , Pre-Eclampsia/immunology , Pregnancy Complications, Infectious/immunology , COVID-19/drug therapy , COVID-19/physiopathology , Complement Inactivator Proteins/therapeutic use , Endothelium/immunology , Female , Humans , Pre-Eclampsia/physiopathology , Pre-Eclampsia/prevention & control , Pregnancy , Pregnancy Complications, Infectious/drug therapy , Pregnancy Complications, Infectious/physiopathology , SARS-CoV-2 , Thrombosis/immunology
4.
Front Immunol ; 12: 767981, 2021.
Article in English | MEDLINE | ID: covidwho-1528824

ABSTRACT

The ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to constitute a serious public health threat worldwide. Protective antibody-mediated viral neutralization in response to SARS-CoV-2 infection has been firmly characterized. Where the effects of the antibody response are generally considered to be beneficial, an important biological question regarding potential negative outcomes of a SARS-CoV-2 antibody response has yet to be answered. We determined the distribution of IgG subclasses and complement activation levels in plasma from convalescent individuals using in-house developed ELISAs. The IgG response towards SARS-CoV-2 receptor-binding domain (RBD) after natural infection appeared to be mainly driven by IgG1 and IgG3 subclasses, which are the main ligands for C1q mediated classical complement pathway activation. The deposition of the complement components C4b, C3bc, and TCC as a consequence of SARS-CoV-2 specific antibodies were depending primarily on the SARS-CoV-2 RBD and significantly correlated with both IgG levels and disease severity, indicating that individuals with high levels of IgG and/or severe disease, might have a more prominent complement activation during viral infection. Finally, freshly isolated monocytes and a monocyte cell line (THP-1) were used to address the cellular mediated inflammatory response as a consequence of Fc-gamma receptor engagement by SARS-CoV-2 specific antibodies. Monocytic Fc gamma receptor charging resulted in a significant rise in the secretion of the pro-inflammatory cytokine TNF-α. Our results indicate that SARS-CoV-2 antibodies might drive significant inflammatory responses through the classical complement pathway and via cellular immune-complex activation that could have negative consequences during COVID-19 disease. We found that increased classical complement activation was highly associated to COVID-19 disease severity. The combination of antibody-mediated complement activation and subsequent cellular priming could constitute a significant risk of exacerbating COVID-19 severity.


Subject(s)
Antibodies, Viral/blood , COVID-19/immunology , Complement System Proteins/immunology , Immunoglobulin G/blood , SARS-CoV-2/immunology , COVID-19/blood , Complement Activation , Cytokines/immunology , Humans , Inflammation/immunology , Receptors, IgG/immunology , THP-1 Cells
5.
Front Immunol ; 12: 767347, 2021.
Article in English | MEDLINE | ID: covidwho-1528823

ABSTRACT

Infection with SARS-CoV-2 triggers the simultaneous activation of innate inflammatory pathways including the complement system and the kallikrein-kinin system (KKS) generating in the process potent vasoactive peptides that contribute to severe acute respiratory syndrome (SARS) and multi-organ failure. The genome of SARS-CoV-2 encodes four major structural proteins - the spike (S) protein, nucleocapsid (N) protein, membrane (M) protein, and the envelope (E) protein. However, the role of these proteins in either binding to or activation of the complement system and/or the KKS is still incompletely understood. In these studies, we used: solid phase ELISA, hemolytic assay and surface plasmon resonance (SPR) techniques to examine if recombinant proteins corresponding to S1, N, M and E: (a) bind to C1q, gC1qR, FXII and high molecular weight kininogen (HK), and (b) activate complement and/or the KKS. Our data show that the viral proteins: (a) bind C1q and activate the classical pathway of complement, (b) bind FXII and HK, and activate the KKS in normal human plasma to generate bradykinin and (c) bind to gC1qR, the receptor for the globular heads of C1q (gC1q) which in turn could serve as a platform for the activation of both the complement system and KKS. Collectively, our data indicate that the SARS-CoV-2 viral particle can independently activate major innate inflammatory pathways for maximal damage and efficiency. Therefore, if efficient therapeutic modalities for the treatment of COVID-19 are to be designed, a strategy that includes blockade of the four major structural proteins may provide the best option.


Subject(s)
Antigens, Viral/immunology , COVID-19/immunology , Complement System Proteins/immunology , Kallikrein-Kinin System , SARS-CoV-2/immunology , Viral Structural Proteins/immunology , Carrier Proteins/genetics , Carrier Proteins/immunology , Hemolysis , Humans , Mitochondrial Proteins/genetics , Mitochondrial Proteins/immunology , Recombinant Proteins/immunology , Viral Structural Proteins/genetics
6.
Front Immunol ; 12: 765330, 2021.
Article in English | MEDLINE | ID: covidwho-1518489

ABSTRACT

AIMS: Although the exact factors promoting disease progression in COVID-19 are not fully elucidated, unregulated activation of the complement system (CS) seems to play a crucial role in the pathogenesis of acute lung injury (ALI) induced by SARS-CoV-2. In particular, the lectin pathway (LP) has been implicated in previous autopsy studies. The primary purpose of our study is to investigate the role of the CS in hospitalized COVID-19 patients with varying degrees of disease severity. METHODS: In a single-center prospective observational study, 154 hospitalized patients with PCR-confirmed SARS-CoV-2 infection were included. Serum samples on admission to the COVID-19 ward were collected for analysis of CS pathway activities and concentrations of LP proteins [mannose-binding lectin (MBL) and ficolin-3 (FCN-3)] & C1 esterase inhibitor (C1IHN). The primary outcome was mechanical ventilation or in-hospital death. RESULTS: The patients were predominately male and had multiple comorbidities. ICU admission was required in 16% of the patients and death (3%) or mechanical ventilation occurred in 23 patients (15%). There was no significant difference in LP activity, MBL and FCN-3 concentrations according to different peak disease severities. The median alternative pathway (AP) activity was significantly lower (65%, IQR 50-94) in patients with death/invasive ventilation compared to patients without (87%, IQR 68-102, p=0.026). An optimal threshold of <65.5% for AP activity was derived from a ROC curve resulting in increased odds for death or mechanical ventilation (OR 4,93; 95% CI 1.70-14.33, p=0.003) even after adjustment for confounding factors. Classical pathway (CP) activity was slightly lower in patients with more severe disease (median 101% for death/mechanical ventilation vs 109%, p=0.014). C1INH concentration correlated positively with length of stay, inflammatory markers and disease severity on admission but not during follow-up. CONCLUSION: Our results point to an overactivated AP in critically ill COVID-19 patients in vivo leading to complement consumption and consequently to a significantly reduced AP activity in vitro. The LP does not seem to play a role in the progression to severe COVID-19. Apart from its acute phase reaction the significance of C1INH in COVID-19 requires further studies.


Subject(s)
COVID-19/immunology , Complement System Proteins/immunology , SARS-CoV-2 , Adult , Aged , COVID-19/blood , COVID-19/mortality , COVID-19/therapy , Complement C1 Inhibitor Protein/immunology , Critical Illness , Female , Hospital Mortality , Hospitalization , Humans , Lectins/immunology , Male , Middle Aged , Prospective Studies , Respiration, Artificial , Severity of Illness Index
7.
J Gen Virol ; 102(10)2021 10.
Article in English | MEDLINE | ID: covidwho-1490495

ABSTRACT

The highly pathogenic Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a severe respiratory virus. Recent reports indicate additional central nervous system (CNS) involvement. In this study, human DPP4 transgenic mice were infected with MERS-CoV, and viral antigens were first detected in the midbrain-hindbrain 4 days post-infection, suggesting the virus may enter the brainstem via peripheral nerves. Neurons and astrocytes throughout the brain were infected, followed by damage of the blood brain barrier (BBB), as well as microglial activation and inflammatory cell infiltration, which may be caused by complement activation based on the observation of deposition of complement activation product C3 and high expression of C3a receptor (C3aR) and C5a receptor (C5aR1) in neurons and glial cells. It may be concluded that these effects were mediated by complement activation in the brain, because of their reduction resulted from the treatment with mouse C5aR1-specific mAb. Such mAb significantly reduced nucleoprotein expression, suppressed microglial activation and decreased activation of caspase-3 in neurons and p38 phosphorylation in the brain. Collectively, these results suggest that MERS-CoV infection of CNS triggers complement activation, leading to inflammation-mediated damage of brain tissue, and regulating of complement activation could be a promising intervention and adjunctive treatment for CNS injury by MERS-CoV and other coronaviruses.


Subject(s)
Brain/pathology , Complement System Proteins/immunology , Coronavirus Infections/pathology , Dipeptidyl Peptidase 4/genetics , Middle East Respiratory Syndrome Coronavirus/pathogenicity , Animals , Blood-Brain Barrier/immunology , Blood-Brain Barrier/pathology , Brain/blood supply , Brain/immunology , Brain/virology , Complement Activation/drug effects , Complement Inactivating Agents/therapeutic use , Coronavirus Infections/drug therapy , Coronavirus Infections/immunology , Coronavirus Infections/virology , Disease Models, Animal , Humans , Inflammation , Mice , Mice, Transgenic , Microglia/immunology , Microglia/pathology
8.
Front Immunol ; 12: 742446, 2021.
Article in English | MEDLINE | ID: covidwho-1441112

ABSTRACT

Background: The SARS-CoV-2 infection triggers excessive immune response resulting in increased levels of pro-inflammatory cytokines, endothelial injury, and intravascular coagulopathy. The complement system (CS) activation participates to this hyperinflammatory response. However, it is still unclear which activation pathways (classical, alternative, or lectin pathway) pilots the effector mechanisms that contribute to critical illness. To better understand the immune correlates of disease severity, we performed an analysis of CS activation pathways and components in samples collected from COVID-19 patients hospitalized in Grenoble Alpes University Hospital between 1 and 30 April 2020 and of their relationship with the clinical outcomes. Methods: We conducted a retrospective, single-center study cohort in 74 hospitalized patients with RT-PCR-proven COVID-19. The functional activities of classical, alternative, and mannose-binding lectin (MBL) pathways and the antigenic levels of the individual components C1q, C4, C3, C5, Factor B, and MBL were measured in patients' samples during hospital admission. Hierarchical clustering with the Ward method was performed in order to identify clusters of patients with similar characteristics of complement markers. Age was included in the model. Then, the clusters were compared with the patient clinical features: rate of intensive care unit (ICU) admission, corticoid treatment, oxygen requirement, and mortality. Results: Four clusters were identified according to complement parameters. Among them, two clusters revealed remarkable profiles: in one cluster (n = 15), patients exhibited activation of alternative and lectin pathways and low antigenic levels of MBL, C4, C3, Factor B, and C5 compared to all the other clusters; this cluster had the higher proportion of patients who died (27%) and required oxygen support (80%) or ICU care (53%). In contrast, the second cluster (n = 19) presented inflammatory profile with high classical pathway activity and antigenic levels of complement components; a low proportion of patients required ICU care (26%) and no patient died in this group. Conclusion: These findings argue in favor of prominent activation of the alternative and MBL complement pathways in severe COVID-19, but the spectrum of complement involvement seems to be heterogeneous requiring larger studies.


Subject(s)
COVID-19/immunology , COVID-19/mortality , Complement Pathway, Mannose-Binding Lectin , SARS-CoV-2 , Adult , Aged , Aged, 80 and over , Complement System Proteins/immunology , Female , Humans , Male , Middle Aged , Retrospective Studies
9.
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
10.
Molecules ; 25(12)2020 Jun 26.
Article in English | MEDLINE | ID: covidwho-1389454

ABSTRACT

Viruses can be spread from one person to another; therefore, they may cause disorders in many people, sometimes leading to epidemics and even pandemics. New, previously unstudied viruses and some specific mutant or recombinant variants of known viruses constantly appear. An example is a variant of coronaviruses (CoV) causing severe acute respiratory syndrome (SARS), named SARS-CoV-2. Some antiviral drugs, such as remdesivir as well as antiretroviral drugs including darunavir, lopinavir, and ritonavir are suggested to be effective in treating disorders caused by SARS-CoV-2. There are data on the utilization of antiretroviral drugs against SARS-CoV-2. Since there are many studies aimed at the identification of the molecular mechanisms of human immunodeficiency virus type 1 (HIV-1) infection and the development of novel therapeutic approaches against HIV-1, we used HIV-1 for our case study to identify possible molecular pathways shared by SARS-CoV-2 and HIV-1. We applied a text and data mining workflow and identified a list of 46 targets, which can be essential for the development of infections caused by SARS-CoV-2 and HIV-1. We show that SARS-CoV-2 and HIV-1 share some molecular pathways involved in inflammation, immune response, cell cycle regulation.


Subject(s)
Coronavirus Infections/epidemiology , Coronavirus Infections/metabolism , Data Mining/methods , HIV Infections/epidemiology , HIV Infections/metabolism , Host-Pathogen Interactions/immunology , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/metabolism , Anti-Inflammatory Agents/therapeutic use , Antigens, Differentiation/genetics , Antigens, Differentiation/immunology , Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Betacoronavirus/immunology , Betacoronavirus/pathogenicity , COVID-19 , Complement System Proteins/genetics , Complement System Proteins/immunology , Coronavirus Infections/drug therapy , Coronavirus Infections/immunology , Databases, Genetic , Gene Expression Regulation , HIV Infections/drug therapy , HIV Infections/immunology , HIV-1/drug effects , HIV-1/immunology , HIV-1/pathogenicity , Host-Pathogen Interactions/drug effects , Host-Pathogen Interactions/genetics , Humans , Immunity, Innate/drug effects , Immunologic Factors/therapeutic use , Inflammation , Interferons/genetics , Interferons/immunology , Interleukins/genetics , Interleukins/immunology , Metabolic Networks and Pathways/drug effects , Metabolic Networks and Pathways/genetics , Metabolic Networks and Pathways/immunology , Pneumonia, Viral/drug therapy , Pneumonia, Viral/immunology , Repressor Proteins/genetics , Repressor Proteins/immunology , SARS-CoV-2 , Signal Transduction , Toll-Like Receptors/genetics , Toll-Like Receptors/immunology , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/immunology
11.
Viruses ; 13(5)2021 05 02.
Article in English | MEDLINE | ID: covidwho-1251799

ABSTRACT

The complement system represents a crucial part of innate immunity. It contains a diverse range of soluble activators, membrane-bound receptors, and regulators. Its principal function is to eliminate pathogens via activation of three distinct pathways: classical, alternative, and lectin. In the case of viruses, the complement activation results in effector functions such as virion opsonisation by complement components, phagocytosis induction, virolysis by the membrane attack complex, and promotion of immune responses through anaphylatoxins and chemotactic factors. Recent studies have shown that the addition of individual complement components can neutralise viruses without requiring the activation of the complement cascade. While the complement-mediated effector functions can neutralise a diverse range of viruses, numerous viruses have evolved mechanisms to subvert complement recognition/activation by encoding several proteins that inhibit the complement system, contributing to viral survival and pathogenesis. This review focuses on these complement-dependent and -independent interactions of complement components (especially C1q, C4b-binding protein, properdin, factor H, Mannose-binding lectin, and Ficolins) with several viruses and their consequences.


Subject(s)
Complement Activation/immunology , Complement System Proteins/immunology , Immunity, Innate , Receptors, Pattern Recognition/immunology , Viruses/immunology , Complement System Proteins/genetics , Cytokine Release Syndrome , Cytopathogenic Effect, Viral , Humans
12.
Front Immunol ; 12: 714511, 2021.
Article in English | MEDLINE | ID: covidwho-1320579

ABSTRACT

Early and persistent activation of complement is considered to play a key role in the pathogenesis of COVID-19. Complement activation products orchestrate a proinflammatory environment that might be critical for the induction and maintenance of a severe inflammatory response to SARS-CoV-2 by recruiting cells of the cellular immune system to the sites of infection and shifting their state of activation towards an inflammatory phenotype. It precedes pathophysiological milestone events like the cytokine storm, progressive endothelial injury triggering microangiopathy, and further complement activation, and causes an acute respiratory distress syndrome (ARDS). To date, the application of antiviral drugs and corticosteroids have shown efficacy in the early stages of SARS-CoV-2 infection, but failed to ameliorate disease severity in patients who progressed to severe COVID-19 pathology. This report demonstrates that lectin pathway (LP) recognition molecules of the complement system, such as MBL, FCN-2 and CL-11, bind to SARS-CoV-2 S- and N-proteins, with subsequent activation of LP-mediated C3b and C4b deposition. In addition, our results confirm and underline that the N-protein of SARS-CoV-2 binds directly to the LP- effector enzyme MASP-2 and activates complement. Inhibition of the LP using an inhibitory monoclonal antibody against MASP-2 effectively blocks LP-mediated complement activation. FACS analyses using transfected HEK-293 cells expressing SARS-CoV-2 S protein confirm a robust LP-dependent C3b deposition on the cell surface which is inhibited by the MASP-2 inhibitory antibody. In light of our present results, and the encouraging performance of our clinical candidate MASP-2 inhibitor Narsoplimab in recently published clinical trials, we suggest that the targeting of MASP-2 provides an unsurpassed window of therapeutic efficacy for the treatment of severe COVID-19.


Subject(s)
COVID-19/blood , Complement Activation/immunology , Complement System Proteins/metabolism , Lectins/blood , Renal Insufficiency, Chronic/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Adult , Aged , Aged, 80 and over , Biomarkers/blood , COVID-19/complications , COVID-19/pathology , COVID-19/physiopathology , Cohort Studies , Complement System Proteins/immunology , Female , Humans , Male , Middle Aged , Renal Insufficiency, Chronic/complications , Renal Insufficiency, Chronic/virology , Severity of Illness Index
13.
Nature ; 595(7866): 283-288, 2021 07.
Article in English | MEDLINE | ID: covidwho-1233713

ABSTRACT

COVID-19 manifests with a wide spectrum of clinical phenotypes that are characterized by exaggerated and misdirected host immune responses1-6. Although pathological innate immune activation is well-documented in severe disease1, the effect of autoantibodies on disease progression is less well-defined. Here we use a high-throughput autoantibody discovery technique known as rapid extracellular antigen profiling7 to screen a cohort of 194 individuals infected with SARS-CoV-2, comprising 172 patients with COVID-19 and 22 healthcare workers with mild disease or asymptomatic infection, for autoantibodies against 2,770 extracellular and secreted proteins (members of the exoproteome). We found that patients with COVID-19 exhibit marked increases in autoantibody reactivities as compared to uninfected individuals, and show a high prevalence of autoantibodies against immunomodulatory proteins (including cytokines, chemokines, complement components and cell-surface proteins). We established that these autoantibodies perturb immune function and impair virological control by inhibiting immunoreceptor signalling and by altering peripheral immune cell composition, and found that mouse surrogates of these autoantibodies increase disease severity in a mouse model of SARS-CoV-2 infection. Our analysis of autoantibodies against tissue-associated antigens revealed associations with specific clinical characteristics. Our findings suggest a pathological role for exoproteome-directed autoantibodies in COVID-19, with diverse effects on immune functionality and associations with clinical outcomes.


Subject(s)
Autoantibodies/analysis , Autoantibodies/immunology , COVID-19/immunology , COVID-19/metabolism , Proteome/immunology , Proteome/metabolism , Animals , Antigens, Surface/immunology , COVID-19/pathology , COVID-19/physiopathology , Case-Control Studies , Complement System Proteins/immunology , Cytokines/immunology , Disease Models, Animal , Disease Progression , Female , Humans , Male , Mice , Organ Specificity/immunology
14.
Front Immunol ; 11: 573583, 2020.
Article in English | MEDLINE | ID: covidwho-1226976

ABSTRACT

Complement, a part of the innate arm of the immune system, is integral to the frontline defense of the host against innumerable pathogens, which includes RNA viruses. Among the major groups of viruses, RNA viruses contribute significantly to the global mortality and morbidity index associated with viral infection. Despite multiple routes of entry adopted by these viruses, facing complement is inevitable. The initial interaction with complement and the nature of this interaction play an important role in determining host resistance versus susceptibility to the viral infection. Many RNA viruses are potent activators of complement, often resulting in virus neutralization. Yet, another facet of virus-induced activation is the exacerbation in pathogenesis contributing to the overall morbidity. The severity in disease and death associated with RNA virus infections shows a tip in the scale favoring viruses. Growing evidence suggest that like their DNA counterparts, RNA viruses have co-evolved to master ingenious strategies to remarkably restrict complement. Modulation of host genes involved in antiviral responses contributed prominently to the adoption of unique strategies to keep complement at bay, which included either down regulation of activation components (C3, C4) or up regulation of complement regulatory proteins. All this hints at a possible "hijacking" of the cross-talk mechanism of the host immune system. Enveloped RNA viruses have a selective advantage of not only modulating the host responses but also recruiting membrane-associated regulators of complement activation (RCAs). This review aims to highlight the significant progress in the understanding of RNA virus-complement interactions.


Subject(s)
Adaptive Immunity , Complement Activation , Complement System Proteins/immunology , Immunity, Innate , RNA Virus Infections/virology , RNA Viruses/pathogenicity , Animals , Complement System Proteins/genetics , Complement System Proteins/metabolism , Evolution, Molecular , Gene Expression Regulation, Viral , Host-Pathogen Interactions , Humans , RNA Virus Infections/genetics , RNA Virus Infections/immunology , RNA Virus Infections/mortality , RNA Viruses/genetics , RNA Viruses/immunology , Severity of Illness Index
17.
Clin Immunol ; 227: 108733, 2021 06.
Article in English | MEDLINE | ID: covidwho-1198654

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for many pathological processes, including altered vascular disease development, dysfunctional thrombosis and a heightened inflammatory response. However, there is limited work to determine the underlying cellular responses induced by exposure to SARS-CoV-2 structural proteins. Thus, our objective was to investigate how human arterial adventitial fibroblasts inflammation, thrombosis and diabetic disease markers are altered in response to Spike, Nucleocapsid and Membrane-Envelope proteins. We hypothesized that after a short-term exposure to SARS-CoV-2 proteins, adventitial fibroblasts would have a higher expression of inflammatory, thrombotic and diabetic proteins, which would support a mechanism for altered vascular disease progression. After incubation, the expression of gC1qR, ICAM-1, tissue factor, RAGE and GLUT-4 was significantly up-regulated. In general, the extent of expression was different for each SARS-CoV-2 protein, suggesting that SARS-CoV-2 proteins interact with cells through different mechanisms. Thus, SARS-CoV-2 protein interaction with vascular cells may regulate vascular disease responses.


Subject(s)
COVID-19/immunology , Cardiovascular Diseases/virology , Diabetes Mellitus/virology , Fibroblasts/metabolism , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Thrombosis/virology , Aorta/cytology , Aorta/metabolism , Cardiovascular Diseases/complications , Cardiovascular Diseases/immunology , Cardiovascular Diseases/metabolism , Carrier Proteins/metabolism , Cell Survival/immunology , Cell Survival/physiology , Complement System Proteins/immunology , Coronavirus Envelope Proteins/immunology , Coronavirus Nucleocapsid Proteins/immunology , Coronavirus Nucleocapsid Proteins/metabolism , Diabetes Mellitus/metabolism , Glucose Transporter Type 4/metabolism , Humans , Inflammation/metabolism , Inflammation/virology , Intercellular Adhesion Molecule-1/metabolism , Mitochondrial Proteins/metabolism , Receptor for Advanced Glycation End Products/metabolism , Thrombosis/complications , Thrombosis/metabolism
20.
Med Microbiol Immunol ; 210(2-3): 101-109, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1163038

ABSTRACT

The current outbreak of coronavirus disease 2019 (COVID-19) has affected people around the world. Typically, COVID-19 originates in the lung, but lately it can extend to other organs and lead to tissue injury and multiorgan failure in severe patients, such as acute respiratory distress syndrome (ARDS), kidney failure and sepsis or systemic inflammation. Given that COVID-19 has been detected in a range of other organs, the COVID-19-associated disease is an alert of aberrant activation of host immune response which drives un-controlled inflammation that affects multiple organs. Complement is a vital component of innate immunity where it forms the first line of defense against potentially harmful microbes, but its role in COVID-19 is still not clear. Notably, the abnormal activation and continuous deposits of complement components were identified in the pre-clinical samples from COVID-19 patients, which have been confirmed in animal models. Recent evidence has revealed that the administration of complement inhibitors leads to relieve inflammatory response in ARDS. Hence, we speculate that the targeting complement system could be a potential treatment option for organ damage in COVID-19 patients.


Subject(s)
COVID-19/immunology , Complement System Proteins/immunology , Immunity, Innate , Inflammation/immunology , Respiratory Distress Syndrome/immunology , Animals , COVID-19/pathology , Complement Inactivating Agents/pharmacology , Humans , Inflammation/virology , Lung/immunology , Lung/virology , Respiratory Distress Syndrome/virology
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