scholarly journals DC-SIGN Mediates the Interaction Between Neutrophils and Leishmania amazonensis-Infected Dendritic Cells to Promote DC Maturation and Parasite Elimination

2021 ◽  
Vol 12 ◽  
Author(s):  
Rafael Tiburcio ◽  
Léon Dimitri Melo ◽  
Sara Nunes ◽  
Ana Luísa Augusto Barbosa ◽  
Elaine Carvalho de Oliveira ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Direct Contact ◽  
Immune Cell ◽  
Large Body ◽  
Leishmania Amazonensis ◽  
Dependent Manner ◽  
Immunological Responses ◽  
Cell Functions ◽  
Dc Maturation

BackgroundLeishmaniasis is a neglected arthropod-borne disease that affects millions of people worldwide. Successful Leishmania infections require the mitigation of immune cell functions leading to parasite survival and proliferation. A large body of evidence highlights the involvement of neutrophils (PMNs) and dendritic cells (DCs) in the establishment of immunological responses against these parasites. However, few studies, contemplate to what extent these cells interact synergistically to constrain Leishmania infection.ObjectiveWe sought to investigate how PMNs and infected DCs interact in an in vitro model of Leishmania amazonensis infection.Material and MethodsBriefly, human PMNs and DCs were purified from the peripheral blood of healthy donors. Next, PMNs were activated with fibronectin and subsequently co-cultured with L. amazonensis-infected DCs.ResultsWe observed that L. amazonensis-infected DC exhibited lower rates of infection when co-cultivated with either resting or activated PMNs. Surprisingly, we found that the release of neutrophil enzymes was not involved in Leishmania killing. Next, we showed that the interaction between PMNs and infected-DCs was intermediated by DC-SIGN, further suggesting that parasite elimination occurs in a contact-dependent manner. Furthermore, we also observed that TNFα and ROS production was dependent on DC-SIGN-mediated contact, as well as parasite elimination is dependent on TNFα production in the co-culture. Finally, we observed that direct contact between PMNs and DCs are required to restore the expression of DC maturation molecules during L. amazonensis infection.ConclusionOur findings suggest that the engagement of direct contact between PMNs and L. amazonensis-infected DC via DC-SIGN is required for the production of inflammatory mediators with subsequent parasite elimination and DC maturation.

scholarly journals The Extracellular Domain of CD83 Inhibits Dendritic Cell–mediated T Cell Stimulation and Binds to a Ligand on Dendritic Cells

2001 ◽  
Vol 194 (12) ◽  
pp. 1813-1821 ◽  
Author(s):  
Matthias Lechmann ◽  
Daniëlle J.E.B. Krooshoop ◽  
Diana Dudziak ◽  
Elisabeth Kremmer ◽  
Christine Kuhnt ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Functional Aspects ◽  
T Cell Stimulation ◽  
Ig Superfamily ◽  
Ig Domain ◽  
Dc Maturation

CD83 is an immunoglobulin (Ig) superfamily member that is upregulated during the maturation of dendritic cells (DCs). It has been widely used as a marker for mature DCs, but its function is still unknown. To approach its potential functional role, we have expressed the extracellular Ig domain of human CD83 (hCD83ext) as a soluble protein. Using this tool we could show that immature as well as mature DCs bind to CD83. Since CD83 binds a ligand also expressed on immature DCs, which do not express CD83, indicates that binding is not a homophilic interaction. In addition we demonstrate that hCD83ext interferes with DC maturation downmodulating the expression of CD80 and CD83, while no phenotypical effects were observed on T cells. Finally, we show that hCD83ext inhibits DC-dependent allogeneic and peptide-specific T cell proliferation in a concentration dependent manner in vitro. This is the first report regarding functional aspects of CD83 and the binding of CD83 to DCs.

scholarly journals Contact-dependent Stimulation and Inhibition of Dendritic Cells by Natural Killer Cells

2002 ◽  
Vol 195 (3) ◽  
pp. 335-341 ◽  
Author(s):  
Diego Piccioli ◽  
Silverio Sbrana ◽  
Emiliano Melandri ◽  
Nicholas M. Valiante
Keyword(s):  
Dendritic Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Types ◽  
Cell Contact ◽  
Dependent Manner ◽  
Tnf Α ◽  
Dominant Feature ◽  
Dc Maturation

Natural killer (NK) cells and dendritic cells (DCs) are two distinct cell types of innate immunity. It is known that the in vitro interaction of human NK cells with autologous DCs results in DC lysis. Here we show that contact-dependent interactions between activated human NK cells and immature DCs (iDCs) provides a “control switch” for the immune system. At low NK/DC ratios, this interaction dramatically amplifies DC responses, whereas at high ratios it completely turns off their responses. Specifically, culture of activated human NK cells with iDCs, at low NK/DC ratios (1:5), led to exponential increases in DC cytokine production, which were completely dependent on cell-to-cell contact. DC maturation was also driven by cognate interactions with NK cells and maturation was dependent on endogenously produced TNF-α in the culture. At slightly higher NK/DC ratios (5:1), inhibition of DC functions was the dominant feature due to potent killing by the autologous NK cells. Resting NK cells also stimulated autologous DC maturation in a TNF-α/contact-dependent manner, however, increasing the NK/DC ratio only led to an enhancement of this effect.

Functional Studies on the C-Type Lectin Receptor CD302 Present on Dendritic Cells and Macrophages

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2198-2198
Author(s):  
Derek NJ Hart ◽  
Pablo Silveira ◽  
Tsun Ho Lo ◽  
Nirupama Verma ◽  
Ai Vu ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Dendritic Cells ◽  
Immune Cell ◽  
Blood Monocytes ◽  
Lectin Receptors ◽  
Functional Studies ◽  
Cell Functions ◽  
Equity Ownership

Abstract Introduction: C-type lectin receptors (CLR) play an important role in the immune system by recognising molecular patterns expressed by exogenous and endogenous threats. They have been shown to capture and internalise antigens and to mediate other important immune cell functions. DEC205 and CLEC9A are being actively investigated as targets for clinical therapeutic cancer vaccines. We discovered CD302 as a new CLR expressed on human dendritic cells (DC), monocytes and macrophages (J Immunol 2007;179:6052). Our initial studies suggested the molecule could play a role in cell adhesion or migration due to its co-localisation with migratory structures on macrophages. Our study set out to investigate the potential immunological function of CD302 using mouse models and to define its wider tissue expression in man. Methods: We generated CD302 knockout (KO) mice lacking exon 1 of its gene, abrogating transcription, for functional studies. We characterised the transcriptional expression of CD302 in mouse immune cells using real-time PCR. We developed monoclonal mAb to mCD302. Human studies utilized the anti-CD302 mAbs, MMRI-20 & 21 in flow cytometry and confocal microscopy studies of human immune cell populations. Results: CD302 was primarily expressed in mouse liver, lungs, lymph nodes (LN) and spleen. In spleen, macrophages, granulocytes and dendritic cells (DC) expressed CD302. Analysis of LN DC subsets revealed 2.5-fold higher CD302 mRNA expression in migratory compared to resident DC populations. Enumeration of various immune populations in lymphoid organs by flow cytometry uncovered a modest deficiency in migratory DC number and proportion within LN of CD302 KO mice compared to wild-type (WT) mice. In vitro studies showed CD302 KO and WT DC had an equivalent capacity to be activated by various stimuli, prime T cells and migrate towards the lymphoid-homing chemokines CCL19/CCL21. CD302 KO migratory DC exhibited a reduced in vivo migratory capacity to LN after FITC skin-painting. However, CD302 KO macrophages migrated similarly to WT macrophages in vivo in response to thioglycollate. In man, CD302 was present in high density in liver and peripheral blood monocytes and myeloid but not plasmacytoid DC. Current studies are aimed at clarifying its distribution on tissue DC and macrophage subsets. Anti-CD302 coated microbeads were taken up by human monocyte derived macrophages and anti-CD302 mAb was also internalized by DC. Confocal studies showed that CD302 co-localized with F-actin structures at the near basal surface such as filopodia and lamellipodia and podosomes of human macrophages and EGFP tagged CD302 expressed in COS-1 cells associated with F-actin. Conclusion: Our data suggests that CD302 may play a specialist role in DC and macrophage membrane functions. This appears to relate to its ability to associate with F-actin and may contribute to the membrane interactions required for DC to migrate towards the draining LN. Disclosures Hart: DendroCyte BioTech Pty Ltd: Equity Ownership. Clark:DendroCyte BioTech Pty Ltd: Equity Ownership.

scholarly journals Semaphorin 3E deficiency dysregulates dendritic cell functions: In vitro and in vivo evidence

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252868
Author(s):  
Hesam Movassagh ◽  
Lianyu Shan ◽  
Latifa Koussih ◽  
Abdulaziz Alamri ◽  
Nazila Ariaee ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Dendritic Cell ◽  
Actin Polymerization ◽  
Underlying Mechanism ◽  
Dependent Manner ◽  
Migration Ability ◽  
Cell Functions ◽  
Airway Pathology

Regulation of dendritic cell functions is a complex process in which several mediators play diverse roles as a network in a context-dependent manner. The precise mechanisms underlying dendritic cell functions have remained to be addressed. Semaphorins play crucial roles in regulation of various cell functions. We previously revealed that Semaphorin 3E (Sema3E) contributes to regulation of allergen-induced airway pathology partly mediated by controlling recruitment of conventional dendritic cell subsets in vivo, though the underlying mechanism remained elusive. In this study, we investigate the potential regulatory role of Sema3E in dendritic cells. We demonstrated that bone marrow-derived dendritic cells differentiated from Sema3e-/- progenitors have an enhanced migration capacity both at the baseline and in response to CCL21. The enhanced migration ability of Sema3E dendritic cells was associated with an overexpression of the chemokine receptor (CCR7), elevated Rac1 GTPase activity and F-actin polymerization. Using a mouse model of allergic airway sensitization, we observed that genetic deletion of Sema3E leads to a time dependent upregulation of CCR7 on CD11b+ conventional dendritic cells in the lungs and mediastinal lymph nodes. Furthermore, aeroallergen sensitization of Sema3e-/- mice lead to an enhanced expression of PD-L2 and IRF-4 as well as enhanced allergen uptake in pulmonary CD11b+ DC, compared to wild type littermates. Collectively, these data suggest that Sema3E implicates in regulation of dendritic cell functions which could be considered a basis for novel immunotherapeutic strategies for the diseases associated with defective dendritic cells in the future.

scholarly journals DDRE-09. DEVELOPING IDO-PROTACS TO IMPROVE IMMUNOTHERAPEUTIC EFFICACY IN PATIENTS WITH GLIOBLASTOMA

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii63-ii63
Author(s):  
Lakshmi Bollu ◽  
Derek Wainwright ◽  
Lijie Zhai ◽  
Erik Ladomersky ◽  
Kristen Lauing ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Time Course ◽  
Immune Cell ◽  
Enzyme Inhibitors ◽  
Tumor Development ◽  
Ubiquitin Proteasome System ◽  
Degradation Pathway ◽  
Specific Protein ◽  
Cell Functions

Abstract INTRODUCTION Indoleamine 2,3-dioxygenase 1 (IDO; IDO1) is a rate-limiting enzyme that metabolizes the essential amino acid tryptophan into kynurenine. Recent work by our group has revealed that IDO promotes tumor development and suppresses immune cell functions independent of its enzyme activity. Moreover, pharmacologic IDO enzyme inhibitors that currently serve as the only class of drugs available for targeting immunosuppressive IDO activity, fail to improve the survival of patients with GBM. Here, we developed IDO-Proteolysis Targeting Chimeras (IDO-PROTACs). PROTACs bind to a specific protein and recruit an E3 ubiquitin ligase that enhance proteasome-mediated degradation of the target protein. METHODS A library of ≥100 IDO-PROTACs were developed by joining BMS986205 (IDO binder) with a linker group to various E3-ligase ligands. Western blot analysis of PROTAC-induced IDO degradation was tested in vitro among multiple human and mouse GBM cell lines including U87, GBM6, GBM43 and GL261 along a time course ranging between 1–96 hours of treatment and at varying concentrations. The mechanism of IDO protein degradation was investigated using pharmacologic ligands that inhibit or compete with the proteasome-mediated protein degradation pathway. RESULTS Primary screening identified several IDO-PROTACs with IDO protein degradation potential. Secondary screening showed that our lead compound has a DC50 value of ~0.5µM with an ability to degrade IDO in all GBM cells analyzed, and an initial activity within 12 hours of treatment that extended for up to 96 hours. Mutating the CRBN-binding ligand, pretreatment with the ubiquitin proteasome system inhibitors MG132 or MLN4924 or using unmodified parental compound all inhibited IDO protein degradation. CONCLUSIONS This study developed an initial IDO-PROTAC technology that upon further optimization, can neutralize both IDO enzyme and non-enzyme immunosuppressive effects. When combined with other forms of immunotherapy, IDO-PROTACs have the potential to substantially enhance immunotherapeutic efficacy in patients with GBM.

scholarly journals Tolerogenic Splenic IDO+Dendritic Cells from the Mice Treated with Induced-Treg Cells Suppress Collagen-Induced Arthritis

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Jie Yang ◽  
Yiming Yang ◽  
Huahua Fan ◽  
Hejian Zou
Keyword(s):  
Dendritic Cells ◽  
Immune Responses ◽  
Foxp3 Expression ◽  
Treated Group ◽  
Treg Cells ◽  
Therapeutic Effects ◽  
Dependent Manner ◽  
Collagen Induced Arthritis

TGF-β-induced regulatory T cells (iTregs) retain Foxp3 expression and immune-suppressive activity in collagen-induced arthritis (CIA). However, the mechanisms whereby transferred iTregs suppress immune responses, particularly the interplay between iTregs and dendritic cells (DCs)in vivo, remain incompletely understood. In this study, we found that after treatment with iTregs, splenic CD11c+DCs, termed “DCiTreg,” expressed tolerogenic phenotypes, secreted high levels of IL-10, TGF-β, and IDO, and showed potent immunosuppressive activityin vitro. After reinfusion with DCiTreg, marked antiarthritic activity improved clinical scores and histological end-points were observed. The serological levels of inflammatory cytokines and anti-CII antibodies were low and TGF-βproduction was high in the DCiTreg-treated group. DCiTregalso induced new iTregsin vivo. Moreover, the inhibitory activity of DCiTregon CIA was lost following pretreatment with the inhibitor of indoleamine 2,3-dioxygenase (IDO). Collectively, these findings suggest that transferred iTregs could induce tolerogenic characteristics in splenic DCs and these cells could effectively dampen CIA in an IDO-dependent manner. Thus, the potential therapeutic effects of iTregs in CIA are likely maintained through the generation of tolerogenic DCsin vivo.

425 In-vitro regulation of immune cell functions by human IgE

1991 ◽  
Vol 87 (1) ◽  
pp. 246
Author(s):  
R PARHAR ◽  
P ERNST ◽  
F ALMOHANNA ◽  
A KWAASI ◽  
K SHETH ◽  
...  
Keyword(s):  
Immune Cell ◽  
Cell Functions

scholarly journals Adenovirus-Mediated CCR7 and BTLA Overexpression Enhances Immune Tolerance and Migration in Immature Dendritic Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Haiming Xin ◽  
Jinhong Zhu ◽  
Hongcheng Miao ◽  
Zhenyu Gong ◽  
Xiaochen Jiang ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Immune Tolerance ◽  
Transplant Recipients ◽  
T Helper ◽  
T Helper 2 ◽  
Immature Dendritic Cells ◽  
And Migration ◽  
Mixed Lymphocyte Reactions ◽  
Dc Maturation

Our previous report revealed that immature dendritic cells (imDCs) with adenovirus-mediated CCR7 overexpression acquired an enhanced migratory ability but also exhibited the lower immune tolerance observed in more mature cells. In the present study, we aimed to investigate whether BTLA overexpression was sufficient to preserve immune tolerance in imDCs with exogenous CCR7 overexpression. Scanning electron microscopy and surface antigens analysis revealed that BTLA overexpression suppressed DC maturation, an effect further potentiated in CCR7 and BTLA cooverexpressing cells. Correspondingly, in vitro chemotaxis assays and mixed lymphocyte reactions demonstrated increased migratory potential and immune tolerance in CCR7 and BTLA coexpressing cells. Furthermore, CCR7 and BTLA cooverexpressed imDCs suppressed IFN-γ and IL-17 expression and promoted IL-4 and TGF-beta expression of lymphocyte, indicating an increase of T helper 2 (Th2) regulatory T cell (Treg). Thus, these data indicate that CCR7 and BTLA cooverexpression imparts an intermediate immune phenotype in imDCs when compared to that in CCR7- or BTLA-expressing counterparts that show a more immunocompetent or immunotolerant phenotype, respectively. All these results indicated that adenovirus-mediated CCR7 and BTLA overexpression could enhance immune tolerance and migration of imDCs. Our study provides a basis for further studies on imDCs in immune tolerance, with the goal of developing effective cellular immunotherapies for transplant recipients.

scholarly journals Resolvins as Regulators of the Immune System

2010 ◽  
Vol 10 ◽  
pp. 818-831 ◽  
Author(s):  
Hiroyuki Seki ◽  
Takaharu Sasaki ◽  
Tomomi Ueda ◽  
Makoto Arita
Keyword(s):  
Immune System ◽  
Acute Inflammation ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Bioactive Metabolites ◽  
Cell Functions ◽  
First Response ◽  
Beneficial Impact

Inflammation is the first response of the immune system to infection or injury, but excessive or inappropriate inflammatory responses contribute to a range of acute and chronic human diseases. Clinical assessment of dietary supplementation of ω-3 polyunsaturated fatty acids (i.e., eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) indicate that they have beneficial impact on these diseases, although the mechanisms are poorly understood at the molecular level. In this decade, it has been revealed that EPA and DHA are enzymatically converted to bioactive metabolites in the course of acute inflammation and resolution. These metabolites were shown to regulate immune cell functions and to display potent anti-inflammatory actions bothin vitroandin vivo. Because of their ability to resolve an acute inflammatory response, they are referred to as proresolving mediators, or resolvins. In this review, we provide an overview of the formation and actions of these lipid mediators.

scholarly journals Decidual glycodelin-A polarizes human monocytes into a decidual macrophage-like phenotype through Siglec-7

2020 ◽  
Vol 133 (14) ◽  
pp. jcs244400 ◽  
Author(s):  
Madhavi Vijayan ◽  
Cheuk-Lun Lee ◽  
Vera H. H. Wong ◽  
Xia Wang ◽  
Kungfeng Bai ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Immune Cell ◽  
Fetal Loss ◽  
Cell Types ◽  
Dependent Manner ◽  
Human Monocytes ◽  
Placental Development ◽  
Cell Functions ◽  
Surface Marker Expression ◽  
Glycodelin A

ABSTRACTDecidual macrophages constitute 20–30% of the total leukocytes in the uterus of pregnant women, regulating the maternal immune tolerance and placenta development. Abnormal number or activities of decidual macrophages (dMs) are associated with fetal loss and pregnancy complications, such as preeclampsia. Monocytes differentiate into dMs in a decidua-specific microenvironment. Despite their important roles in pregnancy, the exact factors that regulate the differentiation into dMs remain unclear. Glycodelin-A (PAEP, hereafter referred to as GdA) is a glycoprotein that is abundantly present in the decidua, and plays an important role in fetomaternal defense and placental development. It modulates the differentiation and activity of several immune cell types residing in the decidua. In this study, we demonstrated that GdA induces the differentiation of human monocytes into dM-like phenotypes in terms of transcriptome, cell surface marker expression, secretome, and regulation of trophoblast and endothelial cell functions. We found that Sialic acid-binding Ig-like lectin 7 (Siglec-7) mediates the binding and biological actions of GdA in a sialic acid-dependent manner. We, therefore, suggest that GdA, induces the polarization of monocytes into dMs to regulate fetomaternal tolerance and placental development.

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