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1.
J Infect Dis ; 225(6): 938-946, 2022 03 15.
Article in English | MEDLINE | ID: covidwho-1740891

ABSTRACT

BACKGROUND: Although coronavirus disease 2019 (COVID-19) vaccinations have provided a significant reduction in infections, effective COVID-19 treatments remain an urgent need. METHODS: Functional characterization of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hyperimmune immunoglobulin (hIG) from human convalescent plasma was performed by different virus neutralization methodologies (plaque reduction, virus-induced cytotoxicity, median tissue culture infectious dose [TCID50] reduction, and immunofluorimetry) at different laboratories using geographically different SARS-CoV-2 isolates (USA [1], Italy [1], and Spain [2]; 2 containing the D614G mutation). Neutralization capacity against the original Wuhan SARS-CoV-2 strain and variants (D614G mutant, B.1.1.7, P.1, and B.1.351) was evaluated using a pseudovirus expressing the corresponding spike (S) protein. Antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) was also evaluated. RESULTS: All SARS-CoV-2 isolates were potently neutralized by hIG as shown by all 4 methodologies. Wild-type SARS-CoV-2 and variants were effectively neutralized using the pseudovirus. The hIG (IgG type) induced ADCC and ADCP against SARS-CoV-2 N and S proteins but not E protein. Very low concentrations (25-100 µg IgG/mL) were required. A potent effect was triggered by antibodies in hIG solutions against the SARS-CoV-2 S and N proteins. CONCLUSIONS: Beyond neutralization, IgG Fc-dependent pathways may play a role in combatting SARS-CoV-2 infections using COVID-19 hIG. This could be especially relevant for the treatment of more neutralization-resistant SARS-CoV-2 variants.


Subject(s)
Antibodies, Viral/immunology , Antibody-Dependent Cell Cytotoxicity , COVID-19/blood , COVID-19/therapy , Phagocytosis/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Viral/blood , COVID-19/immunology , Humans , Immunization, Passive , Immunoglobulin G/blood , Immunoglobulin G/immunology , Spike Glycoprotein, Coronavirus/genetics
2.
Am J Physiol Cell Physiol ; 322(2): C218-C230, 2022 02 01.
Article in English | MEDLINE | ID: covidwho-1673516

ABSTRACT

Selective autophagy of mitochondria, known as mitophagy, is a major quality control pathway in the heart that is involved in removing unwanted or dysfunctional mitochondria from the cell. Baseline mitophagy is critical for maintaining fitness of the mitochondrial network by continuous turnover of aged and less-functional mitochondria. Mitophagy is also critical in adapting to stress associated with mitochondrial damage or dysfunction. The removal of damaged mitochondria prevents reactive oxygen species-mediated damage to proteins and DNA and suppresses activation of inflammation and cell death. Impairments in mitophagy are associated with the pathogenesis of many diseases, including cancers, inflammatory diseases, neurodegeneration, and cardiovascular disease. Mitophagy is a highly regulated and complex process that requires the coordination of labeling dysfunctional mitochondria for degradation while simultaneously promoting de novo autophagosome biogenesis adjacent to the cargo. In this review, we provide an update on our current understanding of these steps in mitophagy induction and discuss the physiological and pathophysiological consequences of altered mitophagy in the heart.


Subject(s)
COVID-19/metabolism , Cardiovascular Diseases/metabolism , Cardiovascular System/metabolism , Mitochondria/metabolism , Mitophagy/physiology , Reactive Oxygen Species/metabolism , Animals , COVID-19/pathology , Cardiovascular Diseases/pathology , Cardiovascular System/pathology , Humans , Mitochondria/pathology , Phagocytosis/physiology
3.
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
4.
Front Immunol ; 12: 808932, 2021.
Article in English | MEDLINE | ID: covidwho-1662585

ABSTRACT

Spike-specific antibodies are central to effective COVID19 immunity. Research efforts have focused on antibodies that neutralize the ACE2-Spike interaction but not on non-neutralizing antibodies. Antibody-dependent phagocytosis is an immune mechanism enhanced by opsonization, where typically, more bound antibodies trigger a stronger phagocyte response. Here, we show that Spike-specific antibodies, dependent on concentration, can either enhance or reduce Spike-bead phagocytosis by monocytes independently of the antibody neutralization potential. Surprisingly, we find that both convalescent patient plasma and patient-derived monoclonal antibodies lead to maximum opsonization already at low levels of bound antibodies and is reduced as antibody binding to Spike protein increases. Moreover, we show that this Spike-dependent modulation of opsonization correlate with the outcome in an experimental SARS-CoV-2 infection model. These results suggest that the levels of anti-Spike antibodies could influence monocyte-mediated immune functions and propose that non-neutralizing antibodies could confer protection to SARS-CoV-2 infection by mediating phagocytosis.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , Phagocytosis/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Monoclonal/immunology , Cell Line , HEK293 Cells , Humans , Neutralization Tests/methods
5.
Sci Immunol ; 7(68): eabn8014, 2022 02 18.
Article in English | MEDLINE | ID: covidwho-1651046

ABSTRACT

Current coronavirus disease 2019 (COVID-19) vaccines effectively reduce overall morbidity and mortality and are vitally important to controlling the pandemic. Individuals who previously recovered from COVID-19 have enhanced immune responses after vaccination (hybrid immunity) compared with their naïve-vaccinated peers; however, the effects of post-vaccination breakthrough infections on humoral immune response remain to be determined. Here, we measure neutralizing antibody responses from 104 vaccinated individuals, including those with breakthrough infections, hybrid immunity, and no infection history. We find that human immune sera after breakthrough infection and vaccination after natural infection broadly neutralize SARS-CoV-2 (severe acute respiratory coronavirus 2) variants to a similar degree. Although age negatively correlates with antibody response after vaccination alone, no correlation with age was found in breakthrough or hybrid immune groups. Together, our data suggest that the additional antigen exposure from natural infection substantially boosts the quantity, quality, and breadth of humoral immune response regardless of whether it occurs before or after vaccination.


Subject(s)
Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Vaccination , Adult , Aged , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antigens, Viral/immunology , COVID-19/epidemiology , COVID-19/immunology , Chlorocebus aethiops , Enzyme-Linked Immunosorbent Assay , Humans , Immunogenicity, Vaccine , Middle Aged , Phagocytosis , SARS-CoV-2/growth & development , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/immunology , THP-1 Cells , Time Factors , Vero Cells , Viral Load
6.
Cell Commun Signal ; 20(1): 2, 2022 01 03.
Article in English | MEDLINE | ID: covidwho-1590514

ABSTRACT

Scavenger receptors belong to a superfamily of proteins that are structurally heterogeneous and encompass the miscellaneous group of transmembrane proteins and soluble secretory extracellular domain. They are functionally diverse as they are involved in various disorders and biological pathways and their major function in innate immunity and homeostasis. Numerous scavenger receptors have been discovered so far and are apportioned in various classes (A-L). Scavenger receptors are documented as pattern recognition receptors and known to act in coordination with other co-receptors such as Toll-like receptors in generating the immune responses against a repertoire of ligands such as microbial pathogens, non-self, intracellular and modified self-molecules through various diverse mechanisms like adhesion, endocytosis and phagocytosis etc. Unlike, most of the scavenger receptors discussed below have both membrane and soluble forms that participate in scavenging; the role of a potential scavenging receptor Angiotensin-Converting Enzyme-2 has also been discussed whereby only its soluble form might participate in preventing the pathogen entry and replication, unlike its membrane-bound form. This review majorly gives an insight on the functional aspect of scavenger receptors in host defence and describes their mode of action extensively in various immune pathways involved with each receptor type. Video abstract.


Subject(s)
Immunity, Innate , Toll-Like Receptors , Endocytosis , Phagocytosis , Receptors, Scavenger/metabolism
7.
Cell Death Dis ; 12(12): 1156, 2021 12 14.
Article in English | MEDLINE | ID: covidwho-1585874

ABSTRACT

Lots of cell death initiator and effector molecules, signalling pathways and subcellular sites have been identified as key mediators in both cell death processes in cancer. The XDeathDB visualization platform provides a comprehensive cell death and their crosstalk resource for deciphering the signaling network organization of interactions among different cell death modes associated with 1461 cancer types and COVID-19, with an aim to understand the molecular mechanisms of physiological cell death in disease and facilitate systems-oriented novel drug discovery in inducing cell deaths properly. Apoptosis, autosis, efferocytosis, ferroptosis, immunogenic cell death, intrinsic apoptosis, lysosomal cell death, mitotic cell death, mitochondrial permeability transition, necroptosis, parthanatos, and pyroptosis related to 12 cell deaths and their crosstalk can be observed systematically by the platform. Big data for cell death gene-disease associations, gene-cell death pathway associations, pathway-cell death mode associations, and cell death-cell death associations is collected by literature review articles and public database from iRefIndex, STRING, BioGRID, Reactom, Pathway's commons, DisGeNET, DrugBank, and Therapeutic Target Database (TTD). An interactive webtool, XDeathDB, is built by web applications with R-Shiny, JavaScript (JS) and Shiny Server Iso. With this platform, users can search specific interactions from vast interdependent networks that occur in the realm of cell death. A multilayer spectral graph clustering method that performs convex layer aggregation to identify crosstalk function among cell death modes for a specific cancer. 147 hallmark genes of cell death could be observed in detail in these networks. These potential druggable targets are displayed systematically and tailoring networks to visualize specified relations is available to fulfil user-specific needs. Users can access XDeathDB for free at https://pcm2019.shinyapps.io/XDeathDB/ .


Subject(s)
Cell Death/physiology , Regulated Cell Death/physiology , Signal Transduction/physiology , Animals , COVID-19/metabolism , COVID-19/physiopathology , Cluster Analysis , Databases, Factual , Humans , Necroptosis , Neoplasms/metabolism , Neoplasms/physiopathology , Phagocytosis , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Signal Transduction/drug effects , Software
8.
Chem Biol Interact ; 352: 109776, 2022 Jan 25.
Article in English | MEDLINE | ID: covidwho-1568541

ABSTRACT

Boosting or suppressing our immune system represents an attractive adjunct in the treatment of infections including SARS-CoV-2, cancer, AIDS, malnutrition, age related problems and some inflammatory disorders. Thus, there has been a growing interest in exploring and developing novel drugs, natural or synthetic, that can manipulate our defence mechanism. Many of such studies, reported till date, have been designed to explore effect of the therapeutic on function of macrophages, being a key component in innate immune system. Indeed, RAW264.7, J774A.1, THP-1 and U937 cell lines act as ideal model systems for preliminary investigation and selection of dose for in vivo studies. Several bioassays have been standardized so far where many techniques require high throughput instruments, cost effective reagents and technical assistance that may hinder many scholars to perform a method demanding compilation of available protocols. In this review, we have taken an attempt for the first time to congregate commonly used in vitro immune-modulating techniques explaining their principles. The study detected that among about 40 different assays and more than 150 sets of primers, the methods of cell proliferation by MTT, phagocytosis by neutral red, NO detection by Griess reaction and estimation of expression of TLRs, COX-2, iNOS, TNF-α, IL-6 and IL-1ß by PCR have been the most widely used to screen the therapeutics under investigation.


Subject(s)
Immunity, Innate/immunology , Immunomodulation/immunology , Animals , Cell Line , Cell Line, Tumor , Cell Proliferation/physiology , Humans , Inflammation/immunology , Phagocytosis/immunology
9.
Ann Hematol ; 101(3): 513-520, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1549412

ABSTRACT

Hyperferritinemia comes to light frequently in general practice. However, the characteristics of COVID-19-associated hyperferritinemia and the relationship with the prognosis were not well described. The retrospective study included 268 documented COVID-19 patients. They were divided into the hyperferritinemia group (≥ 500 µg/L) and the non-hyperferritinemia group (< 500 µg/L). The prevalence of fever and thrombocytopenia and the proportion of patients with mechanical ventilator support and in-hospital death were much higher in the hyperferritinemia group (P < 0.001). The hyperferritinemia patients showed higher median IL-6, D-dimer, and hsCRP (P < 0.001) and lowered FIB level (P = 0.036). The hyperferritinemia group had a higher proportion of patients with AKI, ARDS, and CSAC (P < 0.001). According to the multivariate analysis, age, chronic pulmonary disease, and hyperferritinemia were found to be significant independent predictors for in-hospital mortality [HR 1.041 (95% CI 1.015-1.068), P = 0.002; HR 0.427 (95% CI 0.206-0.882), P = 0.022; HR 6.176 (95% CI 2.447-15.587), P < 0.001, respectively]. The AUROC curve was 0.88, with a cut-off value of ≥ 971 µg/L. COVID-19 patients with hyperferritinemia had a high proportion of organ dysfunction, were more likely to show hyper-inflammation, progressed to hemophagocytic lymphohistiocytosis, and indicated a higher proportion of death.


Subject(s)
COVID-19/blood , Hyperferritinemia/blood , Phagocytosis , SARS-CoV-2/metabolism , Aged , C-Reactive Protein/immunology , C-Reactive Protein/metabolism , COVID-19/complications , COVID-19/mortality , Female , Fibrin Fibrinogen Degradation Products/immunology , Fibrin Fibrinogen Degradation Products/metabolism , Hospital Mortality , Humans , Hyperferritinemia/etiology , Hyperferritinemia/immunology , Hyperferritinemia/mortality , Inflammation/blood , Inflammation/immunology , Inflammation/mortality , Interleukin-6/blood , Interleukin-6/immunology , Male , Middle Aged , Prevalence , Retrospective Studies , SARS-CoV-2/immunology
10.
Blood ; 139(8): 1222-1233, 2022 02 24.
Article in English | MEDLINE | ID: covidwho-1528672

ABSTRACT

The newly identified 13-series (T-series) resolvins (RvTs) regulate phagocyte functions and accelerate resolution of infectious inflammation. Because severe acute respiratory syndrome coronavirus 2 elicits uncontrolled inflammation involving neutrophil extracellular traps (NETs), we tested whether stereochemically defined RvTs regulate NET formation. Using microfluidic devices capturing NETs in phorbol 12-myristate 13-acetate-stimulated human whole blood, the RvTs (RvT1-RvT4; 2.5 nM each) potently reduced NETs. With interleukin-1ß-stimulated human neutrophils, each RvT dose and time dependently decreased NETosis, conveying ∼50% potencies at 10 nM, compared with a known NETosis inhibitor (10 µM). In a murine Staphylococcus aureus infection, RvTs (50 ng each) limited neutrophil infiltration, bacterial titers, and NETs. In addition, each RvT enhanced NET uptake by human macrophages; RvT2 was the most potent of the four RvTs, giving a >50% increase in NET-phagocytosis. As part of the intracellular signaling mechanism, RvT2 increased cyclic adenosine monophosphate and phospho-AMP-activated protein kinase (AMPK) within human macrophages, and RvT2-stimulated NET uptake was abolished by protein kinase A and AMPK inhibition. RvT2 also stimulated NET clearance by mouse macrophages in vivo. Together, these results provide evidence for novel pro-resolving functions of RvTs, namely reducing NETosis and enhancing macrophage NET clearance via a cyclic adenosine monophosphate-protein kinase A-AMPK axis. Thus, RvTs open opportunities for regulating NET-mediated collateral tissue damage during infection as well as monitoring NETs.


Subject(s)
Extracellular Traps/immunology , Staphylococcal Infections/immunology , Staphylococcus aureus/immunology , Animals , COVID-19/immunology , Humans , Inflammation/immunology , Macrophages/immunology , Mice , Neutrophils/immunology , Phagocytosis , SARS-CoV-2/immunology
11.
J Immunol ; 207(7): 1776-1784, 2021 10 01.
Article in English | MEDLINE | ID: covidwho-1497460

ABSTRACT

Acquired neutrophil dysfunction frequently develops during critical illness, independently increasing the risk for intensive care unit-acquired infection. PI3Kδ is implicated in driving neutrophil dysfunction and can potentially be targeted pharmacologically. The aims of this study were to determine whether PI3Kδ inhibition reverses dysfunction in neutrophils from critically ill patients and to describe potential mechanisms. Neutrophils were isolated from blood taken from critically ill patients requiring intubation and mechanical ventilation, renal support, or blood pressure support. In separate validation experiments, neutrophil dysfunction was induced pharmacologically in neutrophils from healthy volunteers. Phagocytosis and bacterial killing assays were performed, and activity of RhoA and protein kinase A (PKA) was assessed. Inhibitors of PI3Kδ, 3-phosphoinositide-dependent protein kinase-1 (PDK1), and PKA were used to determine mechanisms of neutrophil dysfunction. Sixty-six patients were recruited. In the 27 patients (40.9%) with impaired neutrophil function, PI3Kδ inhibition consistently improved function and significantly increased bacterial killing. These findings were validated in neutrophils from healthy volunteers with salbutamol-induced dysfunction and extended to demonstrate that PI3Kδ inhibition restored killing of clinical isolates of nine pathogens commonly associated with intensive care unit-acquired infection. PI3Kδ activation was associated with PDK1 activation, which in turn phosphorylated PKA, which drove phosphorylation and inhibition of the key regulator of neutrophil phagocytosis, RhoA. These data indicate that, in a significant proportion of critically ill patients, PI3Kδ inhibition can improve neutrophil function through PDK1- and PKA-dependent processes, suggesting that therapeutic use of PI3Kδ inhibitors warrants investigation in this setting.


Subject(s)
COVID-19/immunology , Class I Phosphatidylinositol 3-Kinases/metabolism , Critical Illness , Neutrophils/immunology , Pneumonia/immunology , SARS-CoV-2/physiology , Sepsis/immunology , 3-Phosphoinositide-Dependent Protein Kinases/pharmacology , Adult , Aged , Aged, 80 and over , Bacterial Load , Bacteriolysis , Cells, Cultured , Cyclic AMP-Dependent Protein Kinases/metabolism , Female , Humans , Male , Middle Aged , Phagocytosis , Phosphoinositide-3 Kinase Inhibitors/pharmacology , Respiratory Insufficiency , Risk
12.
J Am Soc Nephrol ; 32(1): 69-85, 2021 01.
Article in English | MEDLINE | ID: covidwho-1496661

ABSTRACT

BACKGROUND: In children, the acute pyelonephritis that can result from urinary tract infections (UTIs), which commonly ascend from the bladder to the kidney, is a growing concern because it poses a risk of renal scarring and irreversible loss of kidney function. To date, the cellular mechanisms underlying acute pyelonephritis-driven renal scarring remain unknown. METHODS: We used a preclinical model of uropathogenic Escherichia coli-induced acute pyelonephritis to determine the contribution of neutrophils and monocytes to resolution of the condition and the subsequent development of kidney fibrosis. We used cell-specific monoclonal antibodies to eliminate neutrophils, monocytes, or both. Bacterial ascent and the cell dynamics of phagocytic cells were assessed by biophotonic imaging and flow cytometry, respectively. We used quantitative RT-PCR and histopathologic analyses to evaluate inflammation and renal scarring. RESULTS: We found that neutrophils are critical to control bacterial ascent, which is in line with previous studies suggesting a protective role for neutrophils during a UTI, whereas monocyte-derived macrophages orchestrate a strong, but ineffective, inflammatory response against uropathogenic, E. coli-induced, acute pyelonephritis. Experimental neutropenia during acute pyelonephritis resulted in a compensatory increase in the number of monocytes and heightened macrophage-dependent inflammation in the kidney. Exacerbated macrophage-mediated inflammatory responses promoted renal scarring and compromised renal function, as indicated by elevated serum creatinine, BUN, and potassium. CONCLUSIONS: These findings reveal a previously unappreciated outcome for neutrophil-macrophage imbalance in promoting host susceptibility to acute pyelonephritis and the development of permanent renal damage. This suggests targeting dysregulated macrophage responses might be a therapeutic tool to prevent renal scarring during acute pyelonephritis.


Subject(s)
Cicatrix/physiopathology , Kidney/physiopathology , Macrophages/cytology , Neutrophils/cytology , Pyelonephritis/metabolism , Animals , Escherichia coli , Female , Fibrosis/microbiology , Fibrosis/physiopathology , Inflammation , Kidney/microbiology , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , Neutrophils/metabolism , Phagocytosis , Pyelonephritis/microbiology , Pyelonephritis/physiopathology , Urinary Tract Infections/microbiology , Urinary Tract Infections/physiopathology
13.
J Infect Dis ; 225(6): 938-946, 2022 03 15.
Article in English | MEDLINE | ID: covidwho-1483459

ABSTRACT

BACKGROUND: Although coronavirus disease 2019 (COVID-19) vaccinations have provided a significant reduction in infections, effective COVID-19 treatments remain an urgent need. METHODS: Functional characterization of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hyperimmune immunoglobulin (hIG) from human convalescent plasma was performed by different virus neutralization methodologies (plaque reduction, virus-induced cytotoxicity, median tissue culture infectious dose [TCID50] reduction, and immunofluorimetry) at different laboratories using geographically different SARS-CoV-2 isolates (USA [1], Italy [1], and Spain [2]; 2 containing the D614G mutation). Neutralization capacity against the original Wuhan SARS-CoV-2 strain and variants (D614G mutant, B.1.1.7, P.1, and B.1.351) was evaluated using a pseudovirus expressing the corresponding spike (S) protein. Antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) was also evaluated. RESULTS: All SARS-CoV-2 isolates were potently neutralized by hIG as shown by all 4 methodologies. Wild-type SARS-CoV-2 and variants were effectively neutralized using the pseudovirus. The hIG (IgG type) induced ADCC and ADCP against SARS-CoV-2 N and S proteins but not E protein. Very low concentrations (25-100 µg IgG/mL) were required. A potent effect was triggered by antibodies in hIG solutions against the SARS-CoV-2 S and N proteins. CONCLUSIONS: Beyond neutralization, IgG Fc-dependent pathways may play a role in combatting SARS-CoV-2 infections using COVID-19 hIG. This could be especially relevant for the treatment of more neutralization-resistant SARS-CoV-2 variants.


Subject(s)
Antibodies, Viral/immunology , Antibody-Dependent Cell Cytotoxicity , COVID-19/blood , COVID-19/therapy , Phagocytosis/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Viral/blood , COVID-19/immunology , Humans , Immunization, Passive , Immunoglobulin G/blood , Immunoglobulin G/immunology , Spike Glycoprotein, Coronavirus/genetics
14.
Front Immunol ; 12: 712572, 2021.
Article in English | MEDLINE | ID: covidwho-1472386

ABSTRACT

The complement system is central to first-line defense against invading pathogens. However, excessive complement activation and/or the loss of complement regulation contributes to the development of autoimmune diseases, systemic inflammation, and thrombosis. One of the three pathways of the complement system, the alternative complement pathway, plays a vital role in amplifying complement activation and pathway signaling. Complement factor D, a serine protease of this pathway that is required for the formation of C3 convertase, is the rate-limiting enzyme. In this review, we discuss the function of factor D within the alternative pathway and its implication in both healthy physiology and disease. Because the alternative pathway has a role in many diseases that are characterized by excessive or poorly mediated complement activation, this pathway is an enticing target for effective therapeutic intervention. Nonetheless, although the underlying disease mechanisms of many of these complement-driven diseases are quite well understood, some of the diseases have limited treatment options or no approved treatments at all. Therefore, in this review we explore factor D as a strategic target for advancing therapeutic control of pathological complement activation.


Subject(s)
Complement Factor D/antagonists & inhibitors , Complement Pathway, Alternative/drug effects , Molecular Targeted Therapy , Adipose Tissue/metabolism , Aging/immunology , Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis/drug therapy , Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis/immunology , Antibodies, Monoclonal, Humanized/therapeutic use , Autoimmune Diseases/immunology , Autoimmune Diseases/therapy , Complement Factor D/biosynthesis , Complement Factor D/deficiency , Complement Factor D/physiology , Energy Metabolism , Geographic Atrophy/genetics , Geographic Atrophy/immunology , Hemoglobinuria, Paroxysmal/drug therapy , Hemoglobinuria, Paroxysmal/genetics , Hemoglobinuria, Paroxysmal/immunology , Hepatocytes , Humans , Kidney Diseases/immunology , Liver/injuries , Oligonucleotides, Antisense/therapeutic use , Peptides, Cyclic/therapeutic use , Phagocytosis
15.
Proc Natl Acad Sci U S A ; 118(41)2021 10 12.
Article in English | MEDLINE | ID: covidwho-1450313

ABSTRACT

Cancer therapy reduces tumor burden via tumor cell death ("debris"), which can accelerate tumor progression via the failure of inflammation resolution. Thus, there is an urgent need to develop treatment modalities that stimulate the clearance or resolution of inflammation-associated debris. Here, we demonstrate that chemotherapy-generated debris stimulates metastasis by up-regulating soluble epoxide hydrolase (sEH) and the prostaglandin E2 receptor 4 (EP4). Therapy-induced tumor cell debris triggers a storm of proinflammatory and proangiogenic eicosanoid-driven cytokines. Thus, targeting a single eicosanoid or cytokine is unlikely to prevent chemotherapy-induced metastasis. Pharmacological abrogation of both sEH and EP4 eicosanoid pathways prevents hepato-pancreatic tumor growth and liver metastasis by promoting macrophage phagocytosis of debris and counterregulating a protumorigenic eicosanoid and cytokine storm. Therefore, stimulating the clearance of tumor cell debris via combined sEH and EP4 inhibition is an approach to prevent debris-stimulated metastasis and tumor growth.


Subject(s)
Eicosanoids/metabolism , Epoxide Hydrolases/biosynthesis , Macrophages/immunology , Neoplasm Metastasis/pathology , Receptors, Prostaglandin E, EP4 Subtype/biosynthesis , Animals , Antineoplastic Agents/adverse effects , Antineoplastic Agents/therapeutic use , Carcinoma, Hepatocellular/pathology , Cell Death/drug effects , Cell Line, Tumor , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/prevention & control , Cytokines/metabolism , Hep G2 Cells , Humans , Liver Neoplasms/drug therapy , Liver Neoplasms/pathology , Male , Mice , Mice, Inbred C57BL , Neoplasm Metastasis/prevention & control , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/pathology , Phagocytosis/immunology , RAW 264.7 Cells
16.
Pak J Biol Sci ; 24(9): 920-927, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-1431004

ABSTRACT

<b>Background and Objective:</b> COVID-19 is a fast-spreading worldwide pandemic caused by SARS-CoV-2. The World Health Organization recommended wearing face masks. Masks have become an urgent necessity throughout the pandemic, the study's goal was to track the impact of wearing masks on immunological responses. <b>Materials and Methods:</b> This study was conducted on 40 healthy people who were working in health care at Nineveh Governorate Hospitals from September-December, 2020. They wore face masks at work for more than 8 months for an average of 6 hrs a day. The control sample included 40 healthy individuals, who wore masks for very short periods. All samples underwent immunological and physiological tests to research the effects of wearing masks for extended periods within these parameters. <b>Results:</b> The results showed a significant decrease in total White Blood Count and the absolute number of neutrophils, lymphocytes, monocytes and phagocytic activity. However, there was a significant increase in the absolute number of eosinophils in participants compared with the control. The results also suggested there were no significant differences in IgE, haemoglobin concentration and blood O<sub>2 </sub>saturation in participants who wore masks for more than 6 hrs compared to the control group. The results showed a significant increase in pulse rate in participants who wore masks for more than 6 hrs compared to the control group. The results also showed a strong correlation coefficient between the time of wearing masks and some immunological, haematological parameters. <b>Conclusion:</b> Wearing masks for long periods alters immunological parameters that initiate the immune response, making the body weaker in its resistance to infectious agents.


Subject(s)
COVID-19/prevention & control , Inhalation Exposure/prevention & control , Leukocytes/immunology , Masks , Occupational Exposure/prevention & control , Phagocytes/immunology , SARS-CoV-2/pathogenicity , Adult , Biomarkers/blood , COVID-19/transmission , Case-Control Studies , Female , Heart Rate , Hemoglobins/metabolism , Humans , Immunoglobulin E/blood , Inhalation Exposure/adverse effects , Leukocyte Count , Male , Masks/adverse effects , Middle Aged , Occupational Exposure/adverse effects , Occupational Health , Oxygen/blood , Personnel, Hospital , Phagocytosis , Time Factors
17.
Immun Inflamm Dis ; 9(4): 1186-1196, 2021 12.
Article in English | MEDLINE | ID: covidwho-1384181

ABSTRACT

Neutrophils play multiple roles in acute viral infections. They restrict viral replication and diffusion through phagocytosis, degranulation, respiratory burst, secretion of cytokines, and the release of neutrophil extracellular traps, as well as, activate the adaptive immune response. However, the overactivation of neutrophils may cause tissue damage and lead to poor outcomes. Additionally, some characteristics and functions of neutrophils, such as cell number, lifespan, and antiviral capability, can be influenced while eliminating viruses. This review provides a general description of the protective and pathological roles of neutrophils in acute viral infection.


Subject(s)
Extracellular Traps , Virus Diseases , Adaptive Immunity , Humans , Neutrophils , Phagocytosis
19.
Cell Host Microbe ; 29(8): 1216-1217, 2021 08 11.
Article in English | MEDLINE | ID: covidwho-1350899

ABSTRACT

Engagement of LC3-associated phagocytosis (LAP) in response to the uptake of certain particles modulates innate immune responses. Now in Cell Host and Microbe, Akoumianaki et al. (2021) show how a regulatory role of IL-6 on LAP may be at the core of susceptibility to secondary infection during severe sepsis.


Subject(s)
Autophagy , Phagosomes , Humans , Immunity, Innate , Microtubule-Associated Proteins , Phagocytosis
20.
Front Immunol ; 12: 669103, 2021.
Article in English | MEDLINE | ID: covidwho-1348487

ABSTRACT

Targeted therapeutics for the treatment of coronavirus disease 2019 (COVID-19), especially severe cases, are currently lacking. As macrophages have unique effector functions as a first-line defense against invading pathogens, we genetically armed human macrophages with chimeric antigen receptors (CARs) to reprogram their phagocytic activity against SARS-CoV-2. After investigation of CAR constructs with different intracellular receptor domains, we found that although cytosolic domains from MERTK (CARMERTK) did not trigger antigen-specific cellular phagocytosis or killing effects, unlike those from MEGF10, FcRγ and CD3ζ did, these CARs all mediated similar SARS-CoV-2 clearance in vitro. Notably, we showed that CARMERTK macrophages reduced the virion load without upregulation of proinflammatory cytokine expression. These results suggest that CARMERTK drives an 'immunologically silent' scavenger effect in macrophages and pave the way for further investigation of CARs for the treatment of individuals with COVID-19, particularly those with severe cases at a high risk of hyperinflammation.


Subject(s)
COVID-19/drug therapy , COVID-19/immunology , Immunotherapy, Adoptive , Macrophages/immunology , SARS-CoV-2/immunology , Virion/immunology , Animals , COVID-19/genetics , Chlorocebus aethiops , Humans , Phagocytosis , SARS-CoV-2/genetics , THP-1 Cells , Vero Cells , Virion/genetics
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