scholarly journals Siglec-1 on dendritic cells mediates SARS-CoV-2 trans-infection of target cells while on macrophages triggers proinflammatory responses

2021 ◽  
Author(s):  
Daniel Perez-Zsolt ◽  
Jordana Munoz Basagoiti ◽  
Jordi Rodo ◽  
Marc Elousa ◽  
Dalia Raich Regue ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Single Cell Analysis ◽  
Target Cells ◽  
Trans Infection ◽  
Sialic Acid Binding ◽  
Proinflammatory Responses ◽  
To Come ◽  
Cellular Compartments ◽  
Antigen Presenting

COVID-19 pandemic is not yet under control by vaccination, and effective antivirals are critical for preparedness. Here we report that macrophages and dendritic cells, key antigen presenting myeloid cells (APCs), are largely resistant to SARS-CoV-2 infection. APCs effectively captured viruses within cellular compartments that lead to antigen degradation. Macrophages sense SARS-CoV-2 and released higher levels of cytokines, including those related to cytokine storm in severe COVID-19. The sialic acid-binding Ig-like lectin 1 (Siglec-1/CD169) present on APCs, which interacts with sialylated gangliosides on membranes of retroviruses or filoviruses, also binds SARS-CoV-2 via GM1. Blockage of Siglec-1 receptors by monoclonal antibodies reduces SARS-CoV-2 uptake and transfer to susceptible target cells. APCs expressing Siglec-1 and carrying SARS-CoV-2 are found in pulmonary tissues of non-human primates. Single cell analysis reveals the in vivo induction of cytokines in those macrophages. Targeting Siglec-1 could offer cross-protection against SARS-CoV-2 and other enveloped viruses that exploit APCs for viral dissemination, including those yet to come in future outbreaks.

scholarly journals Retroviral and Lentiviral Vectors for the Induction of Immunological Tolerance

Scientifica ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Inès Dufait ◽  
Therese Liechtenstein ◽  
Alessio Lanna ◽  
Christopher Bricogne ◽  
Roberta Laranga ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Lentiviral Vector ◽  
Lentiviral Vectors ◽  
Immunological Tolerance ◽  
Target Cells ◽  
Intracellular Signalling Pathways ◽  
Tolerogenic Dendritic Cells ◽  
Antigen Presenting ◽  
Immunosuppressive Cytokines

Retroviral and lentiviral vectors have proven to be particularly efficient systems to deliver genes of interest into target cells, either in vivo or in cell cultures. They have been used for some time for gene therapy and the development of gene vaccines. Recently retroviral and lentiviral vectors have been used to generate tolerogenic dendritic cells, key professional antigen presenting cells that regulate immune responses. Thus, three main approaches have been undertaken to induce immunological tolerance; delivery of potent immunosuppressive cytokines and other molecules, modification of intracellular signalling pathways in dendritic cells, and de-targeting transgene expression from dendritic cells using microRNA technology. In this review we briefly describe retroviral and lentiviral vector biology, and their application to induce immunological tolerance.

scholarly journals Polyglutamine-related aggregates serve as a potent antigen source for cross presentation by dendritic cells

2019 ◽  
Author(s):  
Shira Tabachnick-Cherny ◽  
Dikla Berko ◽  
Sivan Pinto ◽  
Caterina Curato ◽  
Yochai Wolf ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Target Cells ◽  
Protein Aggregate ◽  
Mhc I ◽  
Cross Presentation ◽  
Cell Immunity ◽  
Antigen Presenting

AbstractProtective MHC-I dependent immune responses require an overlap between repertoires of proteins directly presented on target cells and cross-presented by professional antigen presenting cells (APC), specifically dendritic cells (DCs). How stable proteins that rely on DRiPs for direct presentation are captured for cell-to-cell transfer remains enigmatic. Here we address this issue using a combination of in vitro and in vivo approaches involving stable and unstable versions of ovalbumin model antigens displaying DRiP-dependent and -independent antigen presentation, respectively. Apoptosis, but not necrosis of donor cells was found associated with robust p62-dependent global protein aggregate formation and captured stable proteins permissive for DC cross-presentation. Potency of aggregates to serve as antigen source was directly demonstrated using polyglutamine-equipped model substrates. Collectively, our data implicate global protein aggregation in apoptotic cells as a mechanism that ensures the overlap between MHC-I epitopes presented directly or cross-presented by APC and demonstrate the unusual ability of DC to process stable protein aggregates.SummaryProtective T cell immunity relies on the overlap of the antigen repertoire expressed by cells and the repertoire presented by dendritic cells that are required to trigger naïve T cells. We suggest a mechanism that contributes to ensure this antigenic overlap. Our findings demonstrate that upon apoptosis stable proteins are aggregated in p62-dependent pathway and that dendritic cells are capable to efficiently process these aggregates to retrieve antigens for T cell stimulation.

Anti-β2 Glycoprotein I Antibodies Cause Inflammation and Recruit Dendritic Cells in Platelet Clearance

2001 ◽  
Vol 86 (11) ◽  
pp. 1257-1263 ◽  
Author(s):  
Attilio Bondanza ◽  
Angelo Manfredi ◽  
Valérie Zimmermann ◽  
Matteo Iannacone ◽  
Angela Tincani ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Inflammatory Responses ◽  
Glycoprotein I ◽  
Activated Platelets ◽  
Tnf Α ◽  
Per Se ◽  
Antigen Presenting ◽  
Antiinflammatory Cytokine

SummaryScavenger phagocytes are mostly responsible for the in vivo clearance of activated or senescent platelets. In contrast to other particulate substrates, the phagocytosis of platelets does not incite pro-inflammatory responses in vivo. This study assessed the contribution of macrophages and dendritic cells (DCs) to the clearance of activated platelets. Furthermore, we verified whether antibodies against the β2 Glycoprotein I (β2GPI), which bind to activated platelets, influence the phenomenon. DCs did not per se internalise activated platelets. In contrast, macrophages efficiently phagocytosed platelets. In agreement with the uneventful nature of the clearance of platelets in vivo, phagocytosing macrophages did not release IL-1β, TNF-α or IL-10. β2GPI bound to activated platelets and was required for their recognition by anti-ββ2GPI antibodies. DCs internalised platelets opsonised by anti-ββ2GPI antibodies. The phagocytosis of opsonised platelets determined the release of TNF-α and IL-1β by DCs and macrophages. Phagocytosing macrophages, but not DCs, secreted the antiinflammatory cytokine IL-1β0. We conclude that anti-ββ2GPI antibodies cause inflammation during platelet clearance and shuttle platelet antigens to antigen presenting DCs.

scholarly journals 714 Selective expansion of antigen-specific CD8 T cells with engineered antigen presenting exosome

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A743-A743
Author(s):  
Tomoyoshi Yamano ◽  
Xiabing Lyu ◽  
Rikinari Hanayama
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Cd8 T Cells ◽  
Costimulatory Molecule ◽  
Animal Experiments ◽  
Surface Proteins ◽  
Hek293 Cells ◽  
Target Cells ◽  
Single Chain ◽  
Antigen Presenting

BackgroundExosomes are vesicular granules of about 100 nm and are secreted by many types of cells. Exosomes contain various proteins, lipids, and RNAs that are transported to target cells which induce functional and physiological changes. Exosomes are promising nano-vesicles for clinical application, owing to their high biocompatibility, low immunogenicity, and high drug delivery efficacy. Recent studies have demonstrated that exosomes from tumor cells or antigen presenting cells (APCs) regulate immune responses. Tumor derived exosomes express PD-L1 on their surface and suppress tumor immunity systemically. On the other hand, mature dendritic cells derived exosomes exert immune activation, and tumor immunotherapy using DCs exosome has been developed. However, few studies have been found to exert a significant effect on cancer treatment, may be because of low expression of costimulatory molecules and lack of cytokines on DCs derived exosomes.MethodsIt has been demonstrated that GFP can be conveyed into exosomes by conjugating GFP with tetraspanins, exosome-specific surface proteins. First, we generated a tetraspanin fusion protein with a single-chain MHCI trimer (scMHCI). IL-2 is inserted on the second extracellular loop of CD81, allowing robust and functional expression of IL-2 on the exosome. We collected exosomes from HEK293 cells culture, which stably express scMHCI-CD81-IL2 and CD80-MFGE8, and used as Antigen-presenting exosome(AP-Exo).ResultsAP-Exo expresses high expression of MHCI-peptide complex, costimulatory molecule, and cytokine, activating cognate CD8 T cells as dendritic cells do. AP-Exo selectively delivered co-stimulation and IL-2 to antigen-specific CD8 T cells, resulting in a massive expansion of antigen-specific CD8 T cells without severe adverse effects in mice. AP-Exo can expand endogenous tumor-specific CD8 T cells and induce the potent anti-tumor effect.ConclusionsOur strategy for building engineered exosomes that work like APCs might develop novel methods for cancer immunotherapy.Ethics ApprovalAll mice were housed in a specific pathogen-free facility, and all animal experiments were performed according to a protocol approved by Kanazawa University, Kanazawa, Japan.

scholarly journals Between biology and medicine: perspectives on the use of dendritic cells in anticancer therapy

2017 ◽  
Vol 71 (0) ◽  
pp. 0-0
Author(s):  
Agnieszka Szczygieł ◽  
Elżbieta Pajtasz-Piasecka
Keyword(s):  
Dendritic Cells ◽  
Ex Vivo ◽  
Anticancer Therapy ◽  
Point Of View ◽  
Proper Function ◽  
Innate And Adaptive Immunity ◽  
Factors Affecting ◽  
Antigen Presenting

Dendritic cells (DCs), as a link between innate and adaptive immunity, play a pivotal role in maintaining homeostasis of the immune system. The DC population is characterized by heterogeneity; it consists of many subpopulations which, despite their phenotypic and localization differences, play an essential function – they are professional antigen presenting cells. Due to their role, DCs can be utilized in a new cancer treatment strategy. Their main purpose is to generate an anticancer response leading to the elimination of cancer cells. The tumor microenvironment, abundant in immunosuppressive factors (e.g. IL-10, TGF-β, Arg1, IDO), impairs the proper function of DCs. For this reason, various strategies are necessary for ex vivo preparation of DC-based vaccines and for the support of in vivo DCs to fight against tumors. DC-based vaccines are combined with other forms of immunotherapy (e.g. blockade of immune checkpoint molecules, e.g. PD-1 or CTLA-4) or conventional types of therapies (e.g. chemotherapy). Despite the enormous progress that has been made in anticancer therapy in the past two decades, there are still many unresolved issues regarding the effectiveness of the DCs usage. In this paper we described, in both a mouse and a human subject, a series of DC subpopulations, differentiating in normal conditions or under the influence of cancer microenvironment. We listed factors affecting the quality of the in vivo and ex vivo generations of antitumoral responses, significant from a therapeutic point of view. Moreover, the most important strategies for the use of DCs in anticancer therapies, as well as further developments on this field, have been discussed.

scholarly journals Rotavirus VP6 Adjuvant Effect on Norovirus GII.4 Virus-Like Particle Uptake and Presentation by Bone Marrow-Derived Dendritic Cells In Vitro and In Vivo

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Kirsi Tamminen ◽  
Suvi Heinimäki ◽  
Timo Vesikari ◽  
Vesna Blazevic
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
Adjuvant Effect ◽  
Particle Uptake ◽  
Virus Like Particle ◽  
Norovirus Gii ◽  
Immortalized Cell ◽  
Antigen Presenting

We have previously shown that rotavirus (RV) inner capsid protein VP6 has an adjuvant effect on norovirus (NoV) virus-like particle- (VLP-) induced immune responses and studied the adjuvant mechanism in immortalized cell lines used as antigen-presenting cells (APCs). Here, we investigated the uptake and presentation of RV VP6 and NoV GII.4 VLPs by primary bone marrow-derived dendritic cells (BMDCs). The adjuvant effect of VP6 on GII.4 VLP presentation and NoV-specific immune response induction by BMDC in vivo was also studied. Intracellular staining demonstrated that BMDCs internalized both antigens, but VP6 more efficiently than NoV VLPs. Both antigens were processed and presented to antigen-primed T cells, which responded by robust interferon γ secretion. When GII.4 VLPs and VP6 were mixed in the same pulsing reaction, a subpopulation of the cells had uptaken both antigens. Furthermore, VP6 copulsing increased GII.4 VLP uptake by 37% and activated BMDCs to secrete 2-5-fold increased levels of interleukin 6 and tumor necrosis factor α compared to VLP pulsing alone. When in vitro-pulsed BMDCs were transferred to syngeneic BALB/c mice, VP6 improved NoV-specific antibody responses. The results of this study support the earlier findings of VP6 adjuvant effect in vitro and in vivo.

scholarly journals Induction of Polyomavirus-Specific CD8+T Lymphocytes by Distinct Dendritic Cell Subpopulations

2001 ◽  
Vol 75 (1) ◽  
pp. 544-547 ◽  
Author(s):  
Donald R. Drake ◽  
Mandy L. Shawver ◽  
Annette Hadley ◽  
Eric Butz ◽  
Charles Maliszewski ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Cell Epitope ◽  
T Cell Responses ◽  
T Cell Epitope ◽  
Cell Responses ◽  
Cd8 T Lymphocytes ◽  
Cell Subpopulations ◽  
Antigen Presenting

ABSTRACT Dendritic cells are pivotal antigen-presenting cells for generating adaptive T-cell responses. Here, we show that dendritic cells belonging to either the myeloid-related or lymphoid-related subset are permissive for infection by mouse polyomavirus and, when loaded with a peptide corresponding to the immunodominant anti-polyomavirus CD8+T-cell epitope or infected by polyomavirus, are each capable of driving expansion of primary polyomavirus-specific CD8+ T-cell responses in vivo.

scholarly journals Dendritic cells are potent antigen-presenting cells for microbial superantigens.

1992 ◽  
Vol 175 (1) ◽  
pp. 267-273 ◽  
Author(s):  
N Bhardwaj ◽  
S M Friedman ◽  
B C Cole ◽  
A J Nisanian
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Antigen Presenting Cells ◽  
Small Subset ◽  
Cell Functions ◽  
Cell Responses ◽  
Antigen Presenting

Dendritic cells are a small subset of human blood mononuclear cells that are potent stimulators of several T cell functions. Here we show they are 10-50-fold more potent than monocytes or B cells in inducing T cell responses to a panel of superantigens. Furthermore, dendritic cells can present femtomolar concentrations of superantigen to T cells even at numbers where other antigen-presenting cells (APCs) are inactive. Although dendritic cells express very high levels of the major histocompatibility complex products that are required to present superantigens, it is only necessary to pulse these APCs for 1 hour with picomolar levels of one superantigen, staphylococcal enterotoxin B, to maximally activate T cells. Our results suggest that very small amounts of superantigen will be immunogenic in vivo if presented on dendritic cells.

Mycophenolate Acid Has a Negative Effect on the Maturation and Immune Function of the Murine Bone Marrow-Derived Dendritic Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3808-3808
Author(s):  
Zhen Cai ◽  
Wenye Huang ◽  
Wenji Sun
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Dendritic Cells ◽  
Immune Function ◽  
De Novo ◽  
Th2 Cytokines ◽  
Negative Effect ◽  
Antigen Presenting

Abstract Mycophenolate mofetil (MMF) is a newly developed immunosuppressor, currently widely used in allogeneic bone marrow transplantation. Its active metabolite, mycophenolic acid (MPA) is a noncompetitive, reversible inhibitor of the enzyme inosine 59-monophosphate dehydrogenase, which plays a major role in the de novo synthesis of guanosine nucleotides. Unlike other cells that also use the salvage pathway for purine biosynthesis, proliferating B and T cells are dependent on the de novo pathway generate guanosine. Thus, MMF exerts its immunosuppressive effects of lymphocyte proliferation. Recently, some studies found that MPA could inhibit the immun immune function of antigen presenting cells. Dendritic cells (DCs), the most potent antigen presenting cells with the unique ability to prime naive T cells, play a central role in antigen processing and presentation to induce T cell response in vitro and in vivo. This study is to evaluate the effects of MPA, the in vivo active metabolite of MMF, on the maturation and immune function of murine bone marrow-derived dendritic cells, and to explore the underlying mechanisms of MMF in graft versus host disease. Bone marrow-derived dendritic cells (DC) were cultured with GM-CSF and IL-4 in the presence of MPA at doses of 0.01 and 0.1μmol/L. The ability of the allostimulatory activities of the DCs on allogeneic T cells was assessed by MLR. IL-12 production in culture supernatant and the Th1/Th2 cytokines such as IL-2, IFN-g, IL-4 and IL-10 levels in mixed lymphocyte reaction (MLR) supernatant were examined by ELISA assays. The activity of NF-κB in DCs was measured with Western blot assays. Our results showed that DCs cultured in the presence of MPA expressed lower levels of CD40, CD80 and CD86, exhibited weaker activity of stimulating the allogeneic T cell proliferation and weaker in antigen presenting function with a concurrent reduction of IL-12 production. MPA-treated DCs stimulated allogeneic T cells to secrete higher levels of Th2 cytokines IL-4 and IL-10 but lower levels of Th1 cytokines IL-2 and IFN-g than did DCs not treated with MPA. The activity of NF-κB was decreased in DCs treated with MPA in a dose-dependent manner. We conclude that MPA, and hence MMF, exerts a negative effect on the maturation and immune function of in vitro cultured DCs, and drives a shift of Th1 cytokines to Th2 cytokines in MLR. This negative effect is associated with a decrease in NF-κB activity. Say something about the significance of this finding regarding GVHD.

The long pentraxin PTX3 binds to apoptotic cells and regulates their clearance by antigen-presenting dendritic cells

Blood ◽  
2000 ◽  
Vol 96 (13) ◽  
pp. 4300-4306 ◽  
Author(s):  
Patrizia Rovere ◽  
Giuseppe Peri ◽  
Fausto Fazzini ◽  
Barbara Bottazzi ◽  
Andrea Doni ◽  
...  
Keyword(s):  
Cell Death ◽  
Dendritic Cells ◽  
Acute Phase Proteins ◽  
Inflammatory Reactions ◽  
Reactive Protein ◽  
Factor Α ◽  
Antigen Presenting ◽  
Dying Cells

Pentraxins are acute-phase proteins produced in vivo during inflammatory reactions. Classical short pentraxins, C-reactive protein, and serum amyloid P component are generated in the liver in response to interleukin (IL)–6. The long pentraxin PTX3 is produced in tissues under the control of primary proinflammatory signals, such as lipopolysaccharide, IL-1β, and tumor necrosis factor-α, which also promote maturation of dendritic cells (DCs). Cell death commonly occurs during inflammatory reactions. In this study, it is shown that PTX3 specifically binds to dying cells. The binding was dose dependent and saturable. Recognition was restricted to extranuclear membrane domains and to a chronological window after UV irradiation or after CD95 cross-linking–induced or spontaneous cell death in vitro. PTX3 bound to necrotic cells to a lesser extent. Human DCs failed to internalize dying cells in the presence of PTX3, while they took up normally soluble or inert particulate substrates. These results suggest that PTX3 sequesters cell remnants from antigen-presenting cells, possibly contributing to preventing the onset of autoimmune reactions in inflamed tissues.

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