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Luciani C, Hager FT, Cerovic V, Lelouard H. Dendritic cell functions in the inductive and effector sites of intestinal immunity. Mucosal Immunol 2022; 15:40-50. [PMID: 34465895 DOI: 10.1038/s41385-021-00448-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/09/2021] [Accepted: 08/15/2021] [Indexed: 02/04/2023]
Abstract
The intestine is constantly exposed to foreign antigens, which are mostly innocuous but can sometimes be harmful. Therefore, the intestinal immune system has the delicate task of maintaining immune tolerance to harmless food antigens while inducing tailored immune responses to pathogens and regulating but tolerating the microbiota. Intestinal dendritic cells (DCs) play a central role in these functions as sentinel cells able to prime and polarize the T cell responses. DCs are deployed throughout the intestinal mucosa but with local specializations along the gut length and between the diffuse effector sites of the gut lamina propria (LP) and the well-organized immune inductive sites comprising isolated lymphoid follicles (ILFs), Peyer's patches (PPs), and other species-specific gut-associated lymphoid tissues (GALTs). Understanding the specificities of each intestinal DC subset, how environmental factors influence DC functions, and how these can be modulated is key to harnessing the therapeutic potential of mucosal adaptive immune responses, whether by enhancing the efficacy of mucosal vaccines or by increasing tolerogenic responses in inflammatory disorders. In this review, we summarize recent findings related to intestinal DCs in steady state and upon inflammation, with a special focus on their functional specializations, highly dependent on their microenvironment.
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Affiliation(s)
| | | | - Vuk Cerovic
- Institute of Molecular Medicine, RWTH Aachen University, Aachen, Germany.
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2
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Islam MA, Rice J, Reesor E, Zope H, Tao W, Lim M, Ding J, Chen Y, Aduluso D, Zetter BR, Farokhzad OC, Shi J. Adjuvant-pulsed mRNA vaccine nanoparticle for immunoprophylactic and therapeutic tumor suppression in mice. Biomaterials 2021; 266:120431. [PMID: 33099060 PMCID: PMC7528902 DOI: 10.1016/j.biomaterials.2020.120431] [Citation(s) in RCA: 105] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 09/15/2020] [Accepted: 09/30/2020] [Indexed: 12/15/2022]
Abstract
Synthetic mRNA represents an exciting cancer vaccine technology for the implementation of effective cancer immunotherapy. However, inefficient in vivo mRNA delivery along with a requirement for immune co-stimulation present major hurdles to achieving anti-tumor therapeutic efficacy. Here, we demonstrate a proof-of-concept adjuvant-pulsed mRNA vaccine nanoparticle (NP) that is composed of an ovalbumin-coded mRNA and a palmitic acid-modified TLR7/8 agonist R848 (C16-R848), coated with a lipid-polyethylene glycol (lipid-PEG) shell. This mRNA vaccine NP formulation retained the adjuvant activity of encapsulated C16-R848 and markedly improved the transfection efficacy of the mRNA (>95%) and subsequent MHC class I presentation of OVA mRNA derived antigen in antigen-presenting cells. The C16-R848 adjuvant-pulsed mRNA vaccine NP approach induced an effective adaptive immune response by significantly improving the expansion of OVA-specific CD8+ T cells and infiltration of these cells into the tumor bed in vivo, relative to the mRNA vaccine NP without adjuvant. The approach led to an effective anti-tumor immunity against OVA expressing syngeneic allograft mouse models of lymphoma and prostate cancer, resulting in a significant prevention of tumor growth when the vaccine was given before tumor engraftment (84% reduction vs. control) and suppression of tumor growth when given post engraftment (60% reduction vs. control). Our findings indicate that C16-R848 adjuvant pulsation to mRNA vaccine NP is a rational design strategy to increase the effectiveness of synthetic mRNA vaccines for cancer immunotherapy.
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Affiliation(s)
- Mohammad Ariful Islam
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jamie Rice
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Emma Reesor
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Harshal Zope
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Wei Tao
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael Lim
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jianxun Ding
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Yunhan Chen
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Dike Aduluso
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bruce R Zetter
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Omid C Farokhzad
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Jinjun Shi
- Center for Nanomedicine and Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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3
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Ueta H, Xu XD, Yu B, Kitazawa Y, Yu E, Hara Y, Morita-Nakagawa M, Zhou S, Sawanobori Y, Ueha S, Rokutan K, Tanaka T, Tokuda N, Matsushima K, Matsuno K. Suppression of liver transplant rejection by anti-donor MHC antibodies via depletion of donor immunogenic dendritic cells. Int Immunol 2020; 33:261-272. [PMID: 33258927 PMCID: PMC8060989 DOI: 10.1093/intimm/dxaa076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/29/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND We previously found two distinct passenger dendritic cell (DC) subsets in the rat liver that played a central role in the liver transplant rejection. In addition, a tolerance-inducing protocol, donor-specific transfusion (DST), triggered systemic polytopical production of depleting alloantibodies to donor class I MHC (MHCI) antigen (DST-antibodies). METHODS We examined the role of DST-antibodies in the trafficking of graft DC subsets and the alloresponses in a rat model. We also examined an anti-donor class II MHC (MHCII) antibody that recognizes donor DCs more selectively. RESULTS Preoperative transfer of DST-antibodies or DST pretreatment eliminated all passenger leukocytes, including both DC subsets and depleted the sessile DCs in the graft to ~20% of control. The CD172a+CD11b/c+ immunogenic subset was almost abolished. The intrahost direct or semi-direct allorecognition pathway was successfully blocked, leading to a significant suppression of the CD8+ T-cell response in the recipient lymphoid organs and the graft with delayed graft rejection. Anti-donor MHCII antibody had similar effects without temporary graft damage. Although DST pretreatment had a priming effect on the proliferative response of recipient regulatory T cells, DST-primed sera and the anti-donor MHCII antibody did not. CONCLUSION DST-antibodies and anti-donor MHCII antibodies could suppress the CD8+ T-cell-mediated liver transplant rejection by depleting donor immunogenic DCs, blocking the direct or semi-direct pathways of allorecognition. Donor MHCII-specific antibodies may be applicable as a selective suppressant of anti-donor immunity for clinical liver transplantation without the cellular damage of donor MHCII- graft cells and recipient cells.
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Affiliation(s)
- Hisashi Ueta
- Department of Anatomy (Macro), Dokkyo Medical University, Tochigi, Japan
| | - Xue-Dong Xu
- Department of General Surgery, Dalian Medical University, The First Affiliated Hospital, Dalian, China
| | - Bin Yu
- Department General Surgery, The First Affiliated Hospital of Soochow University, Jiangsu, China
| | - Yusuke Kitazawa
- Department of Anatomy (Macro), Dokkyo Medical University, Tochigi, Japan
| | - Enqiao Yu
- Department General Surgery, The First Affiliated Hospital of Soochow University, Jiangsu, China
| | | | | | - Shu Zhou
- Department of Obstetrics and Gynecology, Dalian Medical University, The First Affiliated Hospital, Dalian, China
| | - Yasushi Sawanobori
- Department of Anatomy (Macro), Dokkyo Medical University, Tochigi, Japan
| | - Satoshi Ueha
- Division of Molecular Regulation of Inflammatory and Immune Diseases, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | - Kazuhito Rokutan
- Department of Pathophysiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Toshiya Tanaka
- Laboratory for Systems Biology and Medicine, RCAST, The University of Tokyo, Tokyo, Japan
| | - Nobuko Tokuda
- Department of Anatomy (Macro), Dokkyo Medical University, Tochigi, Japan
| | - Kouji Matsushima
- Division of Molecular Regulation of Inflammatory and Immune Diseases, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | - Kenjiro Matsuno
- Department of Anatomy (Macro), Dokkyo Medical University, Tochigi, Japan
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Mbongue JC, Alhoshani A, Rawson J, Garcia PA, Gonzalez N, Ferreri K, Kandeel F, Husseiny MI. Tracking of an Oral Salmonella-Based Vaccine for Type 1 Diabetes in Non-obese Diabetic Mice. Front Immunol 2020; 11:712. [PMID: 32411136 PMCID: PMC7198770 DOI: 10.3389/fimmu.2020.00712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/30/2020] [Indexed: 11/28/2022] Open
Abstract
Type 1 diabetes (T1D) arises secondary to immune-driven destruction of pancreatic β-cells and manifests as insulin-deficient hyperglycemia. We showed that oral vaccination with live attenuated Salmonella, which simultaneously delivers autoantigens and a TGFβ expression vector to immune cells in the gut mucosa, provides protection against the progression of T1D in non-obese diabetic (NOD) mice. In this study we employed the Sleeping Beauty (SB) transposon system that is composed of a transposase and transposon encoding the td-Tomato to express red fluorescent protein (RFP) to permanently mark the cells that take up the Salmonella vaccine. After animal vaccination, the transposon labeled-dendritic cells (DCs) with red fluorescence appeared throughout the secondary lymphoid tissues. Furthermore, Sleeping Beauty containing tgfβ1 gene (SB-tgfβ1) co-expressed TGFβ and RFP. The labeled DCs were detected predominantly in Peyer's patches (PP) and mesenteric lymph nodes (MLN) and expressed CD103 surface marker. CD103+ DCs induced tolerogenic effects and gut homing. TGFβ significantly increased programmed death-ligand-1 (PDL-1 or CD274) expression in the DCs in the MLN and PP of treated mice. Also, TGFβ increased cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) levels in CD4+ cells in MLN and PP. Interestingly, DCs increased in all lymphatic organs of mice vaccinated with oral live Salmonella-based vaccine expressing preproinsulin (PPI), in combination with TGFβ, IL10, and subtherapeutic-doses of anti-CD3 mAb compared with vehicle-treated mice. These DCs are mostly tolerogenic in MLN and PP. Furthermore the DCs obtained from vaccine-treated but not vehicle-treated mice suppressed in vitro T cell proliferation. These data suggest that the MLN and the PP are a central hub for the beneficial anti-diabetic effects of an oral Salmonella-based vaccine prevention of diabetes in rodents.
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Affiliation(s)
- Jacques C. Mbongue
- Department of Translational Research and Cellular Therapeutics, Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, United States
| | - Ali Alhoshani
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Jeffrey Rawson
- Department of Translational Research and Cellular Therapeutics, Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, United States
| | - Pablo A. Garcia
- Department of Translational Research and Cellular Therapeutics, Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, United States
| | - Nelson Gonzalez
- Department of Translational Research and Cellular Therapeutics, Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, United States
| | - Kevin Ferreri
- Department of Translational Research and Cellular Therapeutics, Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, United States
| | - Fouad Kandeel
- Department of Translational Research and Cellular Therapeutics, Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, United States
| | - Mohamed I. Husseiny
- Department of Translational Research and Cellular Therapeutics, Diabetes and Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, United States
- Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
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5
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Scott NA, Mann ER. Regulation of mononuclear phagocyte function by the microbiota at mucosal sites. Immunology 2020; 159:26-38. [PMID: 31777068 PMCID: PMC6904663 DOI: 10.1111/imm.13155] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/16/2019] [Accepted: 10/21/2019] [Indexed: 12/11/2022] Open
Abstract
Mucosal tissues contain distinct microbial communities that differ drastically depending on the barrier site, and as such, mucosal immune responses have evolved to be tailored specifically for their location. Whether protective or regulatory immune responses against invading pathogens or the commensal microbiota occur is controlled by local mononuclear phagocytes (MNPs). Comprising macrophages and dendritic cells (DCs), the functions of these cells are highly dependent on the local environment. For example, the intestine contains the greatest bacterial load of any site in the body, and hence, intestinal MNPs are hyporesponsive to bacterial stimulation. This is thought to be one of the major mechanisms by which harmful immune responses directed against the trillions of harmless bacteria that line the gut lumen are avoided. Regulation of MNP function by the microbiota has been characterized in the most depth in the intestine but there are several mucosal sites that also contain their own microbiota. In this review, we present an overview of how MNP function is regulated by the microbiota at mucosal sites, highlighting recent novel pathways by which this occurs in the intestine, and new studies elucidating these interactions at mucosal sites that have been characterized in less depth, including the urogenital tract.
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Affiliation(s)
- Nicholas A. Scott
- Lydia Becker Institute of Immunology and InflammationUniversity of ManchesterManchesterUK
- Manchester Collaborative Centre for Inflammation ResearchFaculty of Biology, Medicine and HealthManchester Academic Health Science CentreUniversity of ManchesterManchesterUK
| | - Elizabeth R. Mann
- Lydia Becker Institute of Immunology and InflammationUniversity of ManchesterManchesterUK
- Manchester Collaborative Centre for Inflammation ResearchFaculty of Biology, Medicine and HealthManchester Academic Health Science CentreUniversity of ManchesterManchesterUK
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6
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Critical Role of B Cells in Toll-Like Receptor 7-Mediated Protection against Listeria monocytogenes Infection. Infect Immun 2019; 87:IAI.00742-19. [PMID: 31591164 DOI: 10.1128/iai.00742-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 09/27/2019] [Indexed: 11/20/2022] Open
Abstract
Toll-like receptors (TLR) trigger the immune system to mount a rapid innate response capable of protecting the host from a wide variety of bacterial and viral pathogens. There is interest in harnessing TLR agonists to reduce the susceptibility of at-risk populations to infection. However, the widespread prophylactic use of TLR agonists has been compromised by the need to administer them by parenteral injection. An exception is the TLR7/8 agonist R848, which can boost gastrointestinal and systemic immunity when administered orally. This work examines the effect of R848 on host susceptibility to Listeria monocytogenes in a murine challenge model and describes the underlying mechanisms. Results show that prophylactic administration of R848 significantly reduces susceptibility to infection of BALB/c mice, an effect that lasts 1 week. Oral R848 directly stimulated B cells to produce cytokines and Ig. In the absence of B cells, R848-mediated protection was lost. These findings support the use of oral R848 to reduce the susceptibility of at-risk individuals to infection and identify the critical role of B cells in TLR7-mediated resistance to bacterial infection.
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Kitazawa Y, Ueta H, Sawanobori Y, Katakai T, Yoneyama H, Ueha S, Matsushima K, Tokuda N, Matsuno K. Novel Targeting to XCR1 + Dendritic Cells Using Allogeneic T Cells for Polytopical Antibody Responses in the Lymph Nodes. Front Immunol 2019; 10:1195. [PMID: 31191552 PMCID: PMC6548820 DOI: 10.3389/fimmu.2019.01195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 05/10/2019] [Indexed: 01/23/2023] Open
Abstract
Vaccination strategy that induce efficient antibody responses polytopically in most lymph nodes (LNs) against infections has not been established yet. Because donor-specific blood transfusion induces anti-donor class I MHC antibody production in splenectomized rats, we examined the mechanism and significance of this response. Among the donor blood components, T cells were the most efficient immunogens, inducing recipient T cell and B cell proliferative responses not only in the spleen, but also in the peripheral and gut LNs. Donor T cells soon migrated to the splenic T cell area and the LNs, with a temporary significant increase in recipient NK cells. XCR1+ resident dendritic cells (DCs), but not XCR1− DCs, selectively phagocytosed donor class I MHC+ fragments after 1 day. After 1.5 days, both DC subsets formed clusters with recipient CD4+ T cells, which proliferated within these clusters. Inhibition of donor T cell migration or depletion of NK cells by pretreatment with pertussis toxin or anti-asialoGM1 antibody, respectively, significantly suppressed DC phagocytosis and subsequent immune responses. Three allogeneic strains with different NK activities had the same response but with different intensity. Donor T cell proliferation was not required, indicating that the graft vs. host reaction is dispensable. Intravenous transfer of antigen-labeled and mitotic inhibitor-treated allogeneic, but not syngeneic, T cells induced a polytopical antibody response to labeled antigens in the LNs of splenectomized rats. These results demonstrate a novel mechanism of alloresponses polytopically in the secondary lymphoid organs (SLOs) induced by allogeneic T cells. Donor T cells behave as self-migratory antigen ferries to be delivered to resident XCR1+ DCs with negligible commitment of migratory DCs. Allogeneic T cells may be clinically applicable as vaccine vectors for polytopical prophylactic antibody production even in asplenic or hyposplenic individuals.
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Affiliation(s)
- Yusuke Kitazawa
- Department of Anatomy (Macro), School of Medicine, Dokkyo Medical University, Tochigi, Japan
| | - Hisashi Ueta
- Department of Anatomy (Macro), School of Medicine, Dokkyo Medical University, Tochigi, Japan
| | - Yasushi Sawanobori
- Department of Anatomy (Macro), School of Medicine, Dokkyo Medical University, Tochigi, Japan
| | - Tomoya Katakai
- Department of Immunology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | | | - Satoshi Ueha
- Division of Molecular Regulation of Inflammatory and Immune Diseases, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | - Kouji Matsushima
- Division of Molecular Regulation of Inflammatory and Immune Diseases, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | - Nobuko Tokuda
- Department of Anatomy (Macro), School of Medicine, Dokkyo Medical University, Tochigi, Japan
| | - Kenjiro Matsuno
- Department of Anatomy (Macro), School of Medicine, Dokkyo Medical University, Tochigi, Japan
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8
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Thomson CA, van de Pavert SA, Stakenborg M, Labeeuw E, Matteoli G, Mowat AM, Nibbs RJB. Expression of the Atypical Chemokine Receptor ACKR4 Identifies a Novel Population of Intestinal Submucosal Fibroblasts That Preferentially Expresses Endothelial Cell Regulators. THE JOURNAL OF IMMUNOLOGY 2018; 201:215-229. [PMID: 29760193 DOI: 10.4049/jimmunol.1700967] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 04/10/2018] [Indexed: 12/15/2022]
Abstract
Atypical chemokine receptors (ACKRs) are expressed by discrete populations of stromal cells at specific anatomical locations where they control leukocyte migration by scavenging or transporting chemokines. ACKR4 is an atypical receptor for CCL19, CCL21, and CCL25. In skin, ACKR4 plays indispensable roles in regulating CCR7-dependent APC migration, and there is a paucity of migratory APCs in the skin-draining lymph nodes of Ackr4-deficient mice under steady-state and inflammatory conditions. This is caused by loss of ACKR4-mediated CCL19/21 scavenging by keratinocytes and lymphatic endothelial cells. In contrast, we show in this study that Ackr4 deficiency does not affect dendritic cell abundance in the small intestine and mesenteric lymph nodes, at steady state or after R848-induced mobilization. Moreover, Ackr4 expression is largely restricted to mesenchymal cells in the intestine, where it identifies a previously uncharacterized population of fibroblasts residing exclusively in the submucosa. Compared with related Ackr4- mesenchymal cells, these Ackr4+ fibroblasts have elevated expression of genes encoding endothelial cell regulators and lie in close proximity to submucosal blood and lymphatic vessels. We also provide evidence that Ackr4+ fibroblasts form physical interactions with lymphatic endothelial cells, and engage in molecular interactions with these cells via the VEGFD/VEGFR3 and CCL21/ACKR4 pathways. Thus, intestinal submucosal fibroblasts in mice are a distinct population of intestinal mesenchymal cells that can be identified by their expression of Ackr4 and have transcriptional and anatomical properties that strongly suggest roles in endothelial cell regulation.
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Affiliation(s)
- Carolyn A Thomson
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom
| | - Serge A van de Pavert
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, CNRS, INSERM, 13288 Marseille Cedex 9, France; and
| | - Michelle Stakenborg
- Laboratory of Mucosal Immunology, Department of Chronic Diseases, Metabolism and Ageing, Translational Research Center for Gastrointestinal Disorders, Catholic University Leuven, BE-3000 Leuven, Belgium
| | - Evelien Labeeuw
- Laboratory of Mucosal Immunology, Department of Chronic Diseases, Metabolism and Ageing, Translational Research Center for Gastrointestinal Disorders, Catholic University Leuven, BE-3000 Leuven, Belgium
| | - Gianluca Matteoli
- Laboratory of Mucosal Immunology, Department of Chronic Diseases, Metabolism and Ageing, Translational Research Center for Gastrointestinal Disorders, Catholic University Leuven, BE-3000 Leuven, Belgium
| | - Allan McI Mowat
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom
| | - Robert J B Nibbs
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom;
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9
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Immunity to gastrointestinal nematode infections. Mucosal Immunol 2018; 11:304-315. [PMID: 29297502 DOI: 10.1038/mi.2017.113] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/20/2017] [Indexed: 02/06/2023]
Abstract
Numerous species of nematodes have evolved to inhabit the gastrointestinal tract of animals and humans, with over a billion of the world's population infected with at least one species. These large multicellular pathogens present a considerable and complex challenge to the host immune system given that individuals are continually exposed to infective stages, as well as the high prevalence in endemic areas. This review summarizes our current understanding of host-parasite interactions, detailing induction of protective immunity, mechanisms of resistance, and resolution of the response. It is clear from studies of well-defined laboratory model systems that these responses are dominated by innate and adaptive type 2 cytokine responses, regulating cellular and soluble effectors that serve to disrupt the niche in which the parasites live by strengthening the physical mucosal barrier and ultimately promoting tissue repair.
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10
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Angelini C, Varano B, Puddu P, Fiori M, Baldassarre A, Masotti A, Gessani S, Conti L. Direct and Intestinal Epithelial Cell-Mediated Effects of TLR8 Triggering on Human Dendritic Cells, CD14 +CD16 + Monocytes and γδ T Lymphocytes. Front Immunol 2018; 8:1813. [PMID: 29312324 PMCID: PMC5743793 DOI: 10.3389/fimmu.2017.01813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/01/2017] [Indexed: 01/26/2023] Open
Abstract
Toll-like receptor (TLR)7/8 plays a crucial role in host recognition/response to viruses and its mucosal expression directly correlates with intestinal inflammation. The aim of this study was to investigate the role of TLR7/8 stimulation of intestinal epithelium in shaping the phenotype and functions of innate immunity cell subsets, and to define direct and/or epithelial cell-mediated mechanisms of the TLR7/8 agonist R848 immunomodulatory activity. We describe novel, TLR8-mediated, pro- and anti-inflammatory effects of R848 on ex vivo cultured human blood monocytes and γδ T lymphocytes, either induced by direct immune cell stimulation or mediated by intestinal epithelial cells (IEC). Apical stimulation with R848 led to its transport across normal polarized epithelial cell monolayer and resulted in the inhibition of monocyte differentiation toward immunostimulatory dendritic cells and Th1 type response. Furthermore, γδ T lymphocyte activation was promoted following direct exposure of these cells to the agonist. Conversely, a selective enrichment of the CD14+CD16+ monocyte subpopulation was observed, which required a CCL2-mediated inflammatory response of normal epithelial cells to R848. Of note, a TLR-mediated activation of control γδ T lymphocytes was promoted by inflamed intestinal epithelium from active Crohn's disease patients. This study unravels a novel regulatory mechanism linking the activation of the TLR8 pathway in IEC to the monocyte-mediated inflammatory response, and highlights the capacity of the TLR7/8 agonist R848 to directly enhance the activation of γδ T lymphocytes. Overall these results expand the range of cell targets and immune responses controlled by TLR8 triggering that may contribute to the antiviral response, to chronic inflammation, as well as to the adjuvant activity of TLR8 agonists, highlighting the role of intestinal epithelium microenvironment in shaping TLR agonist-induced responses.
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Affiliation(s)
- Costanza Angelini
- Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Barbara Varano
- Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.,Center for Gender-Specific Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Patrizia Puddu
- Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Maurizio Fiori
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | | | - Andrea Masotti
- Bambino Gesù Children's Hospital-IRCCS, Research Laboratories, Rome, Italy
| | - Sandra Gessani
- Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.,Center for Gender-Specific Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Lucia Conti
- Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.,Center for Gender-Specific Medicine, Istituto Superiore di Sanità, Rome, Italy
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11
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Abstract
The intestine is the tissue of the body with the highest constitutive exposure to foreign antigen and is also a common entry portal for many local and systemic pathogens. Therefore, the local immune system has the unenviable task of balancing efficient responses to dangerous pathogens with tolerance toward beneficial microbiota and food antigens. As in most tissues, the decision between tolerance and immunity is critically governed by the activity of local myeloid cells. However, the unique challenges posed by the intestinal environment have necessitated the development of several specialized mononuclear phagocyte populations with distinct phenotypic and functional characteristics that have vital roles in maintaining barrier function and immune homeostasis in the intestine. Intestinal mononuclear phagocyte populations, comprising dendritic cells and macrophages, are crucial for raising appropriate active immune responses against ingested pathogens. Recent technical advances, including microsurgical approaches allowing collection of cells migrating in intestinal lymph, intravital microscopy, and novel gene-targeting approaches, have led to clearer distinctions between mononuclear phagocyte populations in intestinal tissue. In this review, we present an overview of the various subpopulations of intestinal mononuclear phagocytes and discuss their phenotypic and functional characteristics. We also outline their roles in host protection from infection and their regulatory functions in maintaining immune tolerance toward beneficial intestinal antigens.
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12
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Diversity and functions of intestinal mononuclear phagocytes. Mucosal Immunol 2017; 10:845-864. [PMID: 28378807 DOI: 10.1038/mi.2017.22] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/16/2017] [Accepted: 02/22/2017] [Indexed: 02/04/2023]
Abstract
The intestinal lamina propria (LP) contains a diverse array of mononuclear phagocyte (MNP) subsets, including conventional dendritic cells (cDC), monocytes and tissue-resident macrophages (mφ) that collectively play an essential role in mucosal homeostasis, infection and inflammation. In the current review we discuss the function of intestinal cDC and monocyte-derived MNP, highlighting how these subsets play several non-redundant roles in the regulation of intestinal immune responses. While much remains to be learnt, recent findings also underline how the various populations of MNP adapt to deal with the challenges specific to their environment. Understanding these processes should help target individual subsets for 'fine tuning' immunological responses within the intestine, a process that may be of relevance both for the treatment of inflammatory bowel disease (IBD) and for optimized vaccine design.
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Clahsen T, Pabst O, Tenbrock K, Schippers A, Wagner N. Localization of dendritic cells in the gut epithelium requires MAdCAM-1. Clin Immunol 2015; 156:74-84. [DOI: 10.1016/j.clim.2014.11.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/21/2014] [Accepted: 11/12/2014] [Indexed: 11/24/2022]
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Neeland MR, Meeusen EN, de Veer MJ. Afferent lymphatic cannulation as a model system to study innate immune responses to infection and vaccination. Vet Immunol Immunopathol 2014; 158:86-97. [DOI: 10.1016/j.vetimm.2013.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 12/28/2022]
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Farache J, Zigmond E, Shakhar G, Jung S. Contributions of dendritic cells and macrophages to intestinal homeostasis and immune defense. Immunol Cell Biol 2013; 91:232-9. [PMID: 23399695 DOI: 10.1038/icb.2012.79] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Intestinal mononuclear phagocytes have collectively emerged as key players in the maintenance of gut homeostasis, the development of gut inflammation and its resolution. Moreover, recent intense research efforts of many laboratories have revealed evidence for critical labor division between lamina propria-resident CD103(+) dendritic cells and CX3CR1(+) macrophages. In depth understanding of the respective activities of these cells in the mucosal landscape might pave the way for novel treatments of inflammatory bowel disorders (IBD).
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Affiliation(s)
- Julia Farache
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
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Yona S, Kim KW, Wolf Y, Mildner A, Varol D, Breker M, Strauss-Ayali D, Viukov S, Guilliams M, Misharin A, Hume DA, Perlman H, Malissen B, Zelzer E, Jung S. Fate mapping reveals origins and dynamics of monocytes and tissue macrophages under homeostasis. Immunity 2013; 38:79-91. [PMID: 23273845 PMCID: PMC3908543 DOI: 10.1016/j.immuni.2012.12.001] [Citation(s) in RCA: 2140] [Impact Index Per Article: 194.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 12/06/2012] [Indexed: 02/08/2023]
Abstract
Mononuclear phagocytes, including monocytes, macrophages, and dendritic cells, contribute to tissue integrity as well as to innate and adaptive immune defense. Emerging evidence for labor division indicates that manipulation of these cells could bear therapeutic potential. However, specific ontogenies of individual populations and the overall functional organization of this cellular network are not well defined. Here we report a fate-mapping study of the murine monocyte and macrophage compartment taking advantage of constitutive and conditional CX(3)CR1 promoter-driven Cre recombinase expression. We have demonstrated that major tissue-resident macrophage populations, including liver Kupffer cells and lung alveolar, splenic, and peritoneal macrophages, are established prior to birth and maintain themselves subsequently during adulthood independent of replenishment by blood monocytes. Furthermore, we have established that short-lived Ly6C(+) monocytes constitute obligatory steady-state precursors of blood-resident Ly6C(-) cells and that the abundance of Ly6C(+) blood monocytes dynamically controls the circulation lifespan of their progeny.
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Affiliation(s)
- Simon Yona
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Ki-Wook Kim
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Yochai Wolf
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Alexander Mildner
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Diana Varol
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Michal Breker
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Dalit Strauss-Ayali
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Sergey Viukov
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Martin Guilliams
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM U1104, CNRS UMR7280, Marseille, France
| | | | - David A. Hume
- The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, UK
| | - Harris Perlman
- Northwestern University, Department of Medicine, Chicago, USA
| | - Bernard Malissen
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM U1104, CNRS UMR7280, Marseille, France
| | - Elazar Zelzer
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Steffen Jung
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
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Flores-Langarica A, Marshall JL, Hitchcock J, Cook C, Jobanputra J, Bobat S, Ross EA, Coughlan RE, Henderson IR, Uematsu S, Akira S, Cunningham AF. Systemic flagellin immunization stimulates mucosal CD103+ dendritic cells and drives Foxp3+ regulatory T cell and IgA responses in the mesenteric lymph node. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 189:5745-54. [PMID: 23152564 DOI: 10.4049/jimmunol.1202283] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mucosal immunity is poorly activated after systemic immunization with protein Ags. Nevertheless, induction of mucosal immunity in such a manner would be an attractive and simple way to overcome the intrinsic difficulties in delivering Ag to such sites. Flagellin from Salmonella enterica serovar Typhimurium (FliC) can impact markedly on host immunity, in part via its recognition by TLR5. In this study, we show that systemic immunization with soluble FliC (sFliC) drives distinct immune responses concurrently in the mesenteric lymph nodes (MLN) and the spleen after i.p. and s.c. immunization. In the MLN, but not the spleen, sFliC drives a TLR5-dependent recruitment of CD103(+) dendritic cells (DCs), which correlates with a diminution in CD103(+) DC numbers in the lamina propria. In the MLN, CD103(+) DCs carry Ag and are the major primers of endogenous and transgenic T cell priming. A key consequence of these interactions with CD103(+) DCs in the MLN is an increase in local regulatory T cell differentiation. In parallel, systemic sFliC immunization results in a pronounced switching of FliC-specific B cells to IgA in the MLN but not elsewhere. Loss of TLR5 has more impact on MLN than splenic Ab responses, reflected in an ablation of IgA, but not IgG, serum Ab titers. Therefore, systemic sFliC immunization targets CD103(+) DCs and drives distinct mucosal T and B cell responses. This offers a potential "Trojan horse" approach to modulate mucosal immunity by systemically immunizing with sFliC.
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Affiliation(s)
- Adriana Flores-Langarica
- Medical Research Council Centre for Immune Regulation, Division of Immunity and Infection, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Utriainen L, Firmin D, Wright P, Cerovic V, Breban M, McInnes I, Milling S. Expression of HLA-B27 causes loss of migratory dendritic cells in a rat model of spondylarthritis. ARTHRITIS AND RHEUMATISM 2012; 64:3199-209. [PMID: 22674414 PMCID: PMC3553565 DOI: 10.1002/art.34561] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE In rats transgenic for human HLA-B27 and β(2) -microglobulin (B27-transgenic rats), colitis and peripheral inflammation develop spontaneously. Therefore, B27-transgenic rats provide a model of spondylarthritis. Because inflammation in these rats requires CD4+ T lymphocytes and involves intestinal pathology, we hypothesized that dendritic cells (DCs) that migrate from the intestine and control CD4+ T cell differentiation would be aberrant in B27-transgenic rats. METHODS Migrating intestinal lymph DCs were collected via thoracic duct cannulation from B27-transgenic and control (HLA-B7-transgenic or nontransgenic) rats. The phenotypes of these DCs and of mesenteric lymph node DCs were assessed by flow cytometry. The ability of DCs to differentiate from bone marrow precursors in vitro was also assessed. RESULTS Lymph DCs showed increased activation and, strikingly, lacked the specific DC population that is important for maintaining tolerance to self-antigens. This population of DCs was also depleted from the mesenteric lymph nodes of B27-transgenic rats. Furthermore, in vitro culture of DCs from bone marrow precursors revealed a defect in the ability of B27-transgenic rats to produce DCs of the migratory phenotype, although the DCs that were generated induced enhanced interleukin-17 (IL-17) production from naive CD4+ T cells. CONCLUSION We describe 2 different mechanisms by which HLA-B27 may contribute to inflammatory disease: increased apoptotic death of B27-transgenic DCs that normally function to maintain immunologic tolerance and enhanced IL-17 production from CD4+ T cells stimulated by the surviving B27-transgenic DCs.
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Affiliation(s)
| | | | | | | | - Maxime Breban
- Institut Cochin, Université Paris Descartes, and CNRS (UMR 8104), INSERM U1016, Paris, France, and Hôpital Ambroise Paré, AP-HP, and Université de Versailles Saint Quentin en Yvelines, Boulogne-Billancourt, France
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Yu B, Ueta H, Kitazawa Y, Tanaka T, Adachi K, Kimura H, Morita M, Sawanobori Y, Qian HX, Kodama T, Matsuno K. Two immunogenic passenger dendritic cell subsets in the rat liver have distinct trafficking patterns and radiosensitivities. Hepatology 2012; 56:1532-45. [PMID: 22511480 DOI: 10.1002/hep.25795] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
UNLABELLED The aim of this study was to investigate the trafficking patterns, radiation sensitivities, and functions of conventional dendritic cell (DC) subsets in the rat liver in an allotransplantation setting. We examined DCs in the liver, hepatic lymph, and graft tissues and recipient secondary lymphoid organs after liver transplantation from rats treated or untreated by sublethal irradiation. We identified two distinct immunogenic DC subsets. One was a previously reported population that underwent blood-borne migration to the recipient's secondary lymphoid organs, inducing systemic CD8(+) T-cell responses; these DCs are a radiosensitive class II major histocompatibility complex (MHCII)(+) CD103(+) CD172a(+) CD11b(-) CD86(+) subset. Another was a relatively radioresistant MHCII(+) CD103(+) CD172a(+) CD11b(+) CD86(+) subset that steadily appeared in the hepatic lymph. After transplantation, the second subset migrated to the parathymic lymph nodes (LNs), regional peritoneal cavity nodes, or persisted in the graft. Irradiation completely eliminated the migration and immunogenicity of the first subset, but only partly suppressed the migration of the second subset and the CD8(+) T-cell response in the parathymic LNs. The grafts were acutely rejected, and intragraft CD8(+) T-cell and FoxP3(+) regulatory T-cell responses were unchanged. The radioresistant second subset up-regulated CD25 and had high allostimulating activity in the mixed leukocyte reaction, suggesting that this subset induced CD8(+) T-cell responses in the parathymic LNs and in the graft by the direct allorecognition pathway, leading to the rejection. CONCLUSION Conventional rat liver DCs contain at least two distinct immunogenic passenger subsets: a radiosensitive blood-borne migrant and a relatively radioresistant lymph-borne migrant. LNs draining the peritoneal cavity should be recognized as a major site of the intrahost T-cell response by the lymph-borne migrant. This study provides key insights into liver graft rejection and highlights the clinical implications of immunogenic DC subsets.
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Affiliation(s)
- Bin Yu
- Department of Anatomy (Macro), Dokkyo Medical University, Tochigi, Japan
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21
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Abstract
The gastrointestinal system is a common entry point for pathogenic microbes to access the inner environment of the body. Anti-microbial factors produced by the intestinal mucosa limit the translocation of both commensal and pathogenic microbes across the intestinal epithelial cell barrier. The regulation of these host defense mechanisms largely depends on the activation of innate immune receptors by microbial molecules. Under steady-state conditions, the microbiota provides constitutive signals to the innate immune system, which helps to maintain a healthy inflammatory tone within the intestinal mucosa and, thus, enhances resistance to infection with enteric pathogens. During an acute infection, the intestinal epithelial cell barrier is breached, and the detection of microbial molecules in the intestinal lamina propria rapidly stimulates innate immune signaling pathways that coordinate early defense mechanisms. Herein, we review how microbial molecules shed by both commensal and pathogenic microbes direct host defenses at the intestinal mucosa. We highlight the signaling pathways, effector molecules, and cell populations that are activated by microbial molecule recognition and, thereby, are involved in the maintenance of homeostatic levels of host defense and in the early response to acute enteric infection. Finally, we discuss how manipulation of these host defense pathways by stimulating innate immune receptors is a potential therapeutic strategy to prevent or alleviate intestinal disease.
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Affiliation(s)
- Melissa A Kinnebrew
- Infectious Diseases Service, Department of Medicine, Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
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Scott CL, Aumeunier AM, Mowat AM. Intestinal CD103+ dendritic cells: master regulators of tolerance? Trends Immunol 2011; 32:412-9. [PMID: 21816673 DOI: 10.1016/j.it.2011.06.003] [Citation(s) in RCA: 240] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 05/27/2011] [Accepted: 06/06/2011] [Indexed: 01/01/2023]
Abstract
CD103(+) dendritic cells (DCs) in the intestinal mucosa play a crucial role in tolerance to commensal bacteria and food antigens. These cells originate in the lamina propria (LP) and migrate to the mesenteric lymph nodes (MLNs), where they drive the differentiation of gut-homing FoxP3(+) regulatory T cells by producing retinoic acid from dietary vitamin A. Local 'conditioning' factors in the LP might also contribute to this tolerogenic profile of CD103(+) DCs. Considerably less is understood about the generation of active immunity or inflammation in the intestinal mucosa. This might require alterations in pre-existing CD103(+) DCs, arrival of new DCs, or the action of a distinct DC population. Here, we discuss our current knowledge of this as yet incompletely understood population.
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Affiliation(s)
- Charlotte L Scott
- Institute of Infection, Immunology and Inflammation, Sir Graeme Davies Building, University of Glasgow, 120 University Place, Glasgow G12 8TA, UK
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Du M, Butchi NB, Woods T, Peterson KE. Poly-thymidine oligonucleotides mediate activation of murine glial cells primarily through TLR7, not TLR8. PLoS One 2011; 6:e22454. [PMID: 21811614 PMCID: PMC3141064 DOI: 10.1371/journal.pone.0022454] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 06/23/2011] [Indexed: 01/16/2023] Open
Abstract
The functional role of murine TLR8 in the inflammatory response of the central nervous system (CNS) remains unclear. Murine TLR8 does not appear to respond to human TLR7/8 agonists, due to a five amino acid deletion in the ectodomain. However, recent studies have suggested that murine TLR8 may be stimulated by alternate ligands, which include vaccinia virus DNA, phosphothioate oligodeoxynucleotides (ODNs) or the combination of phosphothioate poly-thymidine oligonucleotides (pT-ODNs) with TLR7/8 agonists. In the current study, we analyzed the ability of pT-ODNs to induce activation of murine glial cells in the presence or absence of TLR7/8 agonists. We found that TLR7/8 agonists induced the expression of glial cell activation markers and induced the production of multiple proinflammatory cytokines and chemokines in mixed glial cultures. In contrast, pT-ODNs alone induced only low level expression of two cytokines, CCL2 and CXCL10. The combination of pT-ODNs along with TLR7/8 agonists induced a synergistic response with substantially higher levels of proinflammatory cytokines and chemokines compared to CL075. This enhancement was not due to cellular uptake of the agonist, indicating that the pT-ODN enhancement of cytokine responses was due to effects on an intracellular process. Interestingly, this response was also not due to synergistic stimulation of both TLR7 and TLR8, as the loss of TLR7 abolished the activation of glial cells and cytokine production. Thus, pT-ODNs act in synergy with TLR7/8 agonists to induce strong TLR7-dependent cytokine production in glial cells, suggesting that the combination of pT-ODNs with TLR7 agonists may be a useful mechanism to induce pronounced glial activation in the CNS.
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Affiliation(s)
- Min Du
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Niranjan B. Butchi
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Tyson Woods
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Karin E. Peterson
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
- * E-mail:
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Abstract
The innate immune system provides the first line of host defense against invading pathogens. Innate immune responses are initiated by germline-encoded PRR, which recognize specific structures expressed by microorganisms. TLR are a family of PRR which sense a wide range of microorganisms, including bacteria, fungi, protozoa and viruses. TLR are also expressed in the intestine and are critical for intestinal homeostasis. Recently, cytoplasmic PRR, such as NLR and RLR, have been shown to detect pathogens that have invaded the cytosol. One of the NLR, NOD2, is thought to be involved in the pathogenesis of Crohn's disease. This review focuses on the innate immune responses triggered by PRR in the intestine.
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Affiliation(s)
- Satoshi Uematsu
- Laboratory of Host Defense, World Premier International Immunology Frontier Research Center, Osaka University, 3-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
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Abstract
Dendritic cells (DCs) in the intestine are heterogeneous. Phenotypically different populations of conventional DCs have been identified in the intestinal lamina propria, Peyer's patches, and in the draining mesenteric lymph nodes, to which these DCs constitutively migrate. Markers used to identify these populations include major histocompatibility complex class II, CD11c, CD8 alpha, CD11b, and CD103. Extensive studies in rats, summarized here, which involved collection of migrating DCs by thoracic duct cannulation after mesenteric lymphadenectomy, have clearly demonstrated that the subsets of migrating intestinal lymph DCs have different functional properties. The subsets might play different roles in the induction of oral tolerance and in driving systemic immune responses after vaccination or intestinal stimulation with Toll-like receptor ligands. The use of these surgical techniques allows investigation of the functions of purified subsets of migrating DCs. However, in the rat, these studies are limited by the range of available reagents and are difficult to compare with data from other species in this fast-moving field. Recent refinements have enabled the collection of migrating intestinal DCs from mice; our initial results are described here. We believe that these studies will generate exciting data and have the potential to resolve important questions about the functions of migrating intestinal DC subsets.
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Affiliation(s)
- Simon Milling
- Division of Immunology, Infection and Inflammation, Faculty of Medicine, University of Glasgow, Glasgow, UK.
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Primard C, Rochereau N, Luciani E, Genin C, Delair T, Paul S, Verrier B. Traffic of poly(lactic acid) nanoparticulate vaccine vehicle from intestinal mucus to sub-epithelial immune competent cells. Biomaterials 2010; 31:6060-8. [PMID: 20471085 DOI: 10.1016/j.biomaterials.2010.04.021] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 04/12/2010] [Indexed: 11/17/2022]
Abstract
Mucosal immunization is designed to induce strong immune responses at portal of pathogen entry. Unfortunately, mechanisms underlying the fate of the vaccine vector co-administered with antigens are still partially uncovered and limit further development of mucosal vaccines. Hence, poly(lactic acid) (PLA) nanoparticles being a versatile vaccine vehicle, we have analyzed the fate of these PLA nanoparticles during their uptake at intestinal mucosal sites, both in vivo and ex vivo, to decipher the mechanisms involved during this process. We first designed specific fluorescent PLA nanoparticles exhibiting strong colloidal stability after encapsulation of either 6-coumarin or CellTrace BODIPY before monitoring their transport through mucosa in the mouse ligated ileal loop model. The journey of the particles appears to follow a three-step process. Most particles are first entrapped in the mucus. Then, crossing of the epithelial barrier takes place exclusively through M-cells, leading to an accumulation in Peyer's patches (PP). Lastly, we noticed specific interaction of these PLA nanoparticles with underlying B cells and dendritic cells (DCs) of PP. Furthermore, we could document that DCs engulfing some nanoparticles could exhibit a TLR8+ specific expression. Specific targeting of these two cell types strongly supports the use of PLA nanoparticles as a vaccine delivery system for oral use. Indeed, following oral gavage of mice with PLA nanoparticles, we were able to observe the same biodistribution patterns, indicating that these nanoparticles specifically reach immune target required for oral immunization.
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Affiliation(s)
- Charlotte Primard
- Institut de Biologie et Chimie des Protéines, UMR5086 CNRS, University of Lyon 1, Lyon, France
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Abstract
PURPOSE OF REVIEW The term mono-cyte suggests this population of cells consists of a single homogenous fraction. However, evidence from a number of laboratories indicates that monocytes are composed of several subsets, which differ in phenotype, size, nuclear morphology, granularity and gene profiles. Most importantly, recent data suggest that monocyte subsets are also functionally distinct. Here we summarize the recent advances in our understanding of monocyte subsets and their origins, fates and functions. RECENT FINDINGS The recent past has seen major progress in our understanding of myeloid differentiation. Specifically, the published literature now suggests a dichotomy that starts at the stage of a novel clonotypic bone marrow resident precursor, the macrophage dendritic cell progenitor (MDP). Insights into differential origins of macrophages and dendritic cells, linked with functional specifications, are likely to significantly change our current view of the mononuclear phagocyte system. SUMMARY Contemporary studies have demonstrated that two subsets of monocytes reside in the peripheral circulation. These subsets are surprisingly distinct; with regard to their functions and fates, for example, one subset might be dedicated to generate macrophages upon extravasation from the peripheral circulation, whereas, the other subset under inflammatory conditions may differentiate into inflammatory dendritic cells. The tissue response during pathogenesis seems to differentially mobilize these cells, thereby manipulating the local mononuclear phagocyte composition according to acute needs.
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Abstract
The human intestine is colonized by an estimated 100 trillion bacteria. Some of these bacteria are essential for normal physiology, whereas others have been implicated in the pathogenesis of multiple inflammatory diseases including IBD and asthma. This review examines the influence of signals from intestinal bacteria on the homeostasis of the mammalian immune system in the context of health and disease. We review the bacterial composition of the mammalian intestine, known bacterial-derived immunoregulatory molecules, and the mammalian innate immune receptors that recognize them. We discuss the influence of bacterial-derived signals on immune cell function and the mechanisms by which these signals modulate the development and progression of inflammatory disease. We conclude with an examination of successes and future challenges in using bacterial communities or their products in the prevention or treatment of human disease.
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Affiliation(s)
- David A Hill
- University of Pennsylvania School of Veterinary Medicine, Department of Pathobiology, Philadelphia, 19104-4539, USA
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Schulz O, Jaensson E, Persson EK, Liu X, Worbs T, Agace WW, Pabst O. Intestinal CD103+, but not CX3CR1+, antigen sampling cells migrate in lymph and serve classical dendritic cell functions. ACTA ACUST UNITED AC 2009; 206:3101-14. [PMID: 20008524 PMCID: PMC2806467 DOI: 10.1084/jem.20091925] [Citation(s) in RCA: 513] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chemokine receptor CX3CR1(+) dendritic cells (DCs) have been suggested to sample intestinal antigens by extending transepithelial dendrites into the gut lumen. Other studies identified CD103(+) DCs in the mucosa, which, through their ability to synthesize retinoic acid (RA), appear to be capable of generating typical signatures of intestinal adaptive immune responses. We report that CD103 and CX3CR1 phenotypically and functionally characterize distinct subsets of lamina propria cells. In contrast to CD103(+) DC, CX3CR1(+) cells represent a nonmigratory gut-resident population with slow turnover rates and poor responses to FLT-3L and granulocyte/macrophage colony-stimulating factor. Direct visualization of cells in lymph vessels and flow cytometry of mouse intestinal lymph revealed that CD103(+) DCs, but not CX3CR1-expressing cells, migrate into the gut draining mesenteric lymph nodes (LNs) under steady-state and inflammatory conditions. Moreover, CX3CR1(+) cells displayed poor T cell stimulatory capacity in vitro and in vivo after direct injection of cells into intestinal lymphatics and appeared to be less efficient at generating RA compared with CD103(+) DC. These findings indicate that selectively CD103(+) DCs serve classical DC functions and initiate adaptive immune responses in local LNs, whereas CX3CR1(+) populations might modulate immune responses directly in the mucosa and serve as first line barrier against invading enteropathogens.
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Affiliation(s)
- Olga Schulz
- Institute of Immunology, Hannover Medical School, Hannover 30625, Germany
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30
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Mesenteric lymph nodes confine dendritic cell-mediated dissemination of Salmonella enterica serovar Typhimurium and limit systemic disease in mice. Infect Immun 2009; 77:3170-80. [PMID: 19506012 DOI: 10.1128/iai.00272-09] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In humans with typhoid fever or in mouse strains susceptible to Salmonella enterica serovar Typhimurium (S. Typhimurium) infection, bacteria gain access to extraintestinal tissues, causing severe systemic disease. Here we show that in the gut-draining mesenteric lymph nodes (MLN), the majority of S. Typhimurium-carrying cells show dendritic-cell (DC) morphology and express the DC marker CD11c, indicating that S. Typhimurium bacteria are transported to the MLN by migratory DCs. In vivo FLT-3L-induced expansion of DCs, as well as stimulation of DC migration by Toll-like receptor agonists, results in increased numbers of S. Typhimurium bacteria reaching the MLN. Conversely, genetically impaired DC migration in chemokine receptor CCR7-deficient mice reduces the number of S. Typhimurium bacteria reaching the MLN. This indicates that transport of S. Typhimurium from the intestine into the MLN is limited by the number of migratory DCs carrying S. Typhimurium bacteria. In contrast, modulation of DC migration does not affect the number of S. Typhimurium bacteria reaching systemic tissues, indicating that DC-bound transport of S. Typhimurium does not substantially contribute to systemic S. Typhimurium infection. Surgical removal of the MLN results in increased numbers of S. Typhimurium bacteria reaching systemic sites early after infection, thereby rendering otherwise resistant mice susceptible to fatal systemic disease development. This suggests that the MLN provide a vital barrier shielding systemic compartments from DC-mediated dissemination of S. Typhimurium. Thus, confinement of S. Typhimurium in gut-associated lymphoid tissue and MLN delays massive extraintestinal dissemination and at the same time allows for the establishment of protective adaptive immune responses.
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Cerovic V, Jenkins CD, Barnes AGC, Milling SWF, MacPherson GG, Klavinskis LS. Hyporesponsiveness of intestinal dendritic cells to TLR stimulation is limited to TLR4. THE JOURNAL OF IMMUNOLOGY 2009; 182:2405-15. [PMID: 19201895 DOI: 10.4049/jimmunol.0802318] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Dendritic cells (DCs) are crucial to intestinal immune regulation because of their roles in inducing protective immunity against pathogens while maintaining tolerance to commensal bacteria. Nonetheless, relatively little is known about intestinal DC responsiveness to innate immune stimuli via TLRs. We have previously shown that DCs migrating from the rat intestine in lymph (iLDCs) are hyporesponsive to LPS stimulation, thus possibly preventing harmful immune responses being induced to commensal flora. In this study, to understand how iLDC function is regulated by innate immune stimuli, we have characterized the expression and function of TLRs in iLDCs isolated from the thoracic duct lymph of mesenteric lymphadenectomized rats and compared these with DCs grown from bone marrow in the presence of Flt3 ligand. We show that iLDCs express mRNAs for all TLRs, but express significantly less TLR4 mRNA than bone marrow-derived DCs. Functionally, iLDCs could be activated by TLR agonists representing intestinal pathogen-associated molecular patterns, with the important exception of the TLR4 agonist LPS. Furthermore, we show that DCs in the intestinal wall interact directly with noninvasive bacteria (Bacillus subtilis spores), leading to an increase in the output of activated iLDCs into lymph, and that DCs containing spores are activated selectively. These data highlight a functional difference between TLR4 and other TLRs. As iLDCs can respond to TLR stimulation in vitro, there must be other mechanisms that prevent their activation by commensal bacteria under steady-state conditions.
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Affiliation(s)
- Vuk Cerovic
- Peter Gorer Department of Immunobiology, King's College London, London, United Kingdom
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Steady-state migrating intestinal dendritic cells induce potent inflammatory responses in naive CD4+ T cells. Mucosal Immunol 2009; 2:156-65. [PMID: 19129754 DOI: 10.1038/mi.2008.71] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Steady-state dendritic cells (DCs) migrating in the lymph from the intestine induce tolerance to harmless intestinal antigens, preventing inflammatory responses. To determine if such DCs are inherently tolerogenic we collected intestinal lymph DCs (L-DCs) by cannulation of the thoracic duct of rats after mesenteric lymphadenectomy, and examined their capacity to activate naive CD4+ lymphocytes in an allogeneic mixed leucocyte reaction. L-DCs stimulated strong proliferative responses, induced secretion of inflammatory cytokines including interferon-gamma, and induced FoxP3-positive lymphocytes to divide. To determine if the activated CD4+ T cells had been tolerized, they were rested and restimulated with irradiated splenocytes. The restimulated CD4+ T cells again proliferated and secreted inflammatory cytokines. These data demonstrate that the DCs, which migrate from the intestine in the steady state, are paradoxically able to induce strong inflammatory responses from naive T cells, despite their role in the maintenance of oral tolerance.
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Cerovic V, McDonald V, Nassar MA, Paulin SM, Macpherson GG, Milling SWF. New insights into the roles of dendritic cells in intestinal immunity and tolerance. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 272:33-105. [PMID: 19121816 DOI: 10.1016/s1937-6448(08)01602-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Dendritic cells (DCs) play a critical key role in the initiation of immune responses to pathogens. Paradoxically, they also prevent potentially damaging immune responses being directed against the multitude of harmless antigens, to which the body is exposed daily. These roles are particularly important in the intestine, where only a single layer of epithelial cells provides a barrier against billions of commensal microorganisms, pathogens, and food antigens, over a huge surface area. In the intestine, therefore, DCs are required to perform their dual roles very efficiently to protect the body from the dual threats of invading pathogens and unwanted inflammatory reactions. In this review, we first describe the biology of DCs and their interactions with other cells types, paying particular attention to intestinal DCs. We, then, examine the ways in which this biology may become misdirected, resulting in inflammatory bowel disease. Finally, we discuss how DCs potentiate immune responses against viral, bacterial, parasitic infections, and their importance in the pathogenesis of prion diseases. We, therefore, provide an overview of the complex cellular interactions that affect intestinal DCs and control the balance between immunity and tolerance.
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Affiliation(s)
- Vuk Cerovic
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
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Varol C, Yona S, Jung S. Origins and tissue-context-dependent fates of blood monocytes. Immunol Cell Biol 2008; 87:30-8. [PMID: 19048016 DOI: 10.1038/icb.2008.90] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Peripheral blood monocytes play a central role in the mononuclear phagocyte system by providing a critical link between the bone marrow (BM), as major site of adult hematopoiesis, and peripheral, terminally differentiated mononuclear phagocyte populations, as represented macrophages and dendritic cells. Moreover, recent experimental evidence highlights the plasticity of these ephemeral mobile cells and their direct involvement in the establishment and resolution of inflammatory reactions. Here we summarize the recent advance in our understanding of monocyte origins, subset dynamics and monocyte fates. In particular, we will focus on emerging evidence for monocyte recirculation to the BM and discuss its potential implications in health and disease.
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Affiliation(s)
- Chen Varol
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
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Abstract
The gastrointestinal innate and adaptive immune system continuously faces the challenge of potent stimuli from the commensal microflora and food constituents. These local immune responses require a tight control, the outcome of which is in most cases the induction of tolerance. Local T cell immunity is an important compartment of the specific intestinal immune system. T cell reactivity is programmed during the initial stage of its activation by professional presenting cells. Mucosal dendritic cells (DCs) are assumed to play key roles in regulating immune responses in the antigen-rich gastrointestinal environment. Mucosal DCs are a heterogeneous population that can either initiate (innate and adaptive) immune responses, or control intestinal inflammation and maintain tolerance. Defects in this regulation are supposed to lead to the two major forms of inflammatory bowel disease (IBD), Crohn’s disease (CD) and ulcerative colitis (UC). This review will discuss the emerging role of mucosal DCs in regulating intestinal inflammation and immune responses.
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Dummer R, Hauschild A, Becker JC, Grob JJ, Schadendorf D, Tebbs V, Skalsky J, Kaehler KC, Moosbauer S, Clark R, Meng TC, Urosevic M. An exploratory study of systemic administration of the toll-like receptor-7 agonist 852A in patients with refractory metastatic melanoma. Clin Cancer Res 2008; 14:856-64. [PMID: 18245549 DOI: 10.1158/1078-0432.ccr-07-1938] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE A topical Toll-like receptor 7 (TLR7) agonist induces regression of cutaneous melanocytic neoplasms. We explored antitumor activity of a systemically administered TLR7 agonist, 852A, in patients with metastatic melanoma. EXPERIMENTAL DESIGN We undertook a phase II, multicenter, open-label study in patients with chemotherapy-refractory metastatic melanoma. Patients received i.v. 852A, starting at 0.6 mg/m(2) and increasing to 0.9 mg/m(2) based on tolerance, thrice per week for 12 weeks. Clinical response was determined by Response Evaluation Criteria in Solid Tumors. Immune effects of 852A were monitored by measuring serum type I IFN and IP-10 together with assessment of immune cell markers in peripheral blood. RESULTS Twenty-one patients were enrolled. Thirteen patients completed the initial 12-week treatment cycle, with two discontinuing for adverse events considered to be possibly related to study drug. Four (19%) patients had disease stabilization for >100 days. One patient had a partial remission after two treatment cycles, but progressed during the third. Dose-limiting toxicity was observed in two patients. Serum type I IFN and IP-10 increased in most patients on 852A administration. Serum type I IFN increases were greater after dosing with 852A 0.9 mg/m(2) than after 0.6 mg/m(2) (P = 0.009). The maximal increase in IP-10 compared with baseline correlated with the maximal increase in type I IFN (P = 0.003). In the eight patients with immune cell marker data, CD86 expression on monocytes increased significantly post-first dose (P = 0.007). CONCLUSION Intravenous 852A was well tolerated and induced systemic immune activation that eventually resulted in prolonged disease stabilization in some patients with stage IV metastatic melanoma who had failed chemotherapy.
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Affiliation(s)
- Reinhard Dummer
- Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
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Blázquez AB, Berin MC. Gastrointestinal Dendritic Cells Promote Th2 Skewing via OX40L. THE JOURNAL OF IMMUNOLOGY 2008; 180:4441-50. [DOI: 10.4049/jimmunol.180.7.4441] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Moghaddami M, Cleland LG, Radisic G, Mayrhofer G. Recruitment of dendritic cells and macrophages during T cell-mediated synovial inflammation. Arthritis Res Ther 2008; 9:R120. [PMID: 18028548 PMCID: PMC2246239 DOI: 10.1186/ar2328] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 10/08/2007] [Accepted: 11/20/2007] [Indexed: 12/31/2022] Open
Abstract
Adoptive transfer of adjuvant-induced arthritis was used in this study to examine local macrophages and dendritic cells (DCs) during T cell-mediated synovial inflammation. We studied the influx of CD11b+CD11c+ putative myeloid DCs and other non-lymphoid CD45+ cells into synovium-rich tissues (SRTs) of the affected hind paws in response to a pulse of autoreactive thoracic duct cells. Cells were prepared from the SRTs using a collagenase perfusion-digestion technique, thus allowing enumeration and phenotypic analysis by flow cytometry. Numbers of CD45+ cells increased during the first 6 days, with increases in CD45+MHC (major histocompatibility complex) II+ monocyte-like cells from as early as day 3 after transfer. In contrast, typical MHC II- monocytes, mainly of the CD4- subset, did not increase until 12 to 14 days after cell transfer, coinciding with the main influx of polymorphonuclear cells. By day 14, CD45+MHC IIhi cells constituted approximately half of all CD45+ cells in SRT. Most of the MHC IIhi cells expressed CD11c and CD11b and represented putative myeloid DCs, whereas only approximately 20% were CD163+ macrophages. Less than 5% of the MHC IIhi cells in inflamed SRT were CD11b-, setting a maximum for any influx of plasmacytoid DCs. Of the putative myeloid DCs, a third expressed CD4 and both the CD4+ and the CD4- subsets expressed the co-stimulatory molecule CD172a. Early accumulation of MHC IIhiCD11c+ monocyte-like cells during the early phase of T cell-mediated inflammation, relative to typical MHC II- blood monocytes, suggests that recruited monocytes differentiate rapidly toward the DC lineage at this stage in the disease process. However, it is possible also that the MHC IIhiCD11c+ cells originate from a specific subset of DC-like circulating mononuclear cells.
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Affiliation(s)
- Mahin Moghaddami
- Arthritis Research Laboratory, Hanson Research Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, South Australia, 5000, Australia.
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Harrison LI, Astry C, Kumar S, Yunis C. Pharmacokinetics of 852A, an imidazoquinoline Toll-like receptor 7-specific agonist, following intravenous, subcutaneous, and oral administrations in humans. J Clin Pharmacol 2007; 47:962-9. [PMID: 17660481 DOI: 10.1177/0091270007303766] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
852A is an imidazoquinoline Toll-like receptor 7 agonist undergoing evaluation for the systemic treatment of cancer. 852A was administered to 6 healthy subjects as 3 rising subcutaneous doses (0.5 to 1.0 to 2.0 mg), to 6 subjects as 3 oral doses (10.0 to 20.0 to 15.0 mg, the third dose being a de-escalation), and to 6 subjects as a 2.0-mg dose by the subcutaneous, intravenous, and oral routes in crossover fashion. The subcutaneous and intravenous doses were well tolerated. One subject withdrew following the 20.0-mg oral dose because of hypotension. The 2.0-mg subcutaneous dose had 80.5% +/- 12.8% (mean +/- SD) bioavailability and gave serum concentrations comparable to intravenous administration by 30 minutes. Linear kinetics and an interferon-alpha dose response were observed for the 3 subcutaneous doses. Serum concentrations following the 2.0-mg oral dose were always lower than those following the same intravenous dose, and the oral route had a bioavailability of 26.5% +/- 7.84%. Concentrations appeared to increase with oral dose; however, large variabilities in both the rate and extent of absorption were seen between individuals. Approximately 40% of an absorbed dose was excreted unchanged in the urine. Overall, the study suggests that subcutaneous administration may be an acceptable method to deliver 852A for systemic applications.
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Affiliation(s)
- Lester I Harrison
- Department of Pharmacokinetics/Drug Metabolism, 3M Pharmaceuticals, Center Bldg 270-3S-05, St Paul, MN 55144, USA.
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Ma Y, Haynes RL, Sidman RL, Vartanian T. TLR8: an innate immune receptor in brain, neurons and axons. Cell Cycle 2007; 6:2859-68. [PMID: 18000403 DOI: 10.4161/cc.6.23.5018] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Toll-like receptors (TLRs) play essential roles in generating innate immune responses, and are evolutionarily conserved across species. In mammals, TLRs specifically recognize the conserved microbial structural motifs referred to as pathogen-associated molecular patterns (PAMPs). Ligand recognition by TLRs activates signaling cascades that culminate in proinflammatory cytokine production and eventual elimination of invading pathogens. Although TLRs in mammals are expressed predominantly in the immune system, certain TLRs with poorly characterized function are also found in neurons. We recently profiled TLR8 expression during mouse brain development and established its localization in neurons and axons. We uncovered a novel role for TLR8 as a suppressor of neurite outgrowth as well as an inducer of neuronal apoptosis, and found that TLR8 functions in neurons through an NF-kappaB-independent mechanism. These findings add a new layer of complexity for TLR signaling, and expand the realm of mammalian TLR function to the CNS beyond the originally discovered immune context. Herein, we complement our earlier report with additional data, discuss their biological and mechanistic implications in central nervous system (CNS) developmental and pathological processes, and thus further our perspective on TLR signaling and potential physiological roles in mammals.
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Affiliation(s)
- Yinghua Ma
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
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Wick MJ. Monocyte and dendritic cell recruitment and activation during oral Salmonella infection. Immunol Lett 2007; 112:68-74. [PMID: 17720254 DOI: 10.1016/j.imlet.2007.07.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 07/13/2007] [Accepted: 07/15/2007] [Indexed: 12/24/2022]
Abstract
Immunity to bacterial infection involves the joint effort of the innate and adaptive immune systems. The innate immune response is triggered when the body senses bacterial components, such as lipopolysaccharide, that alarm the body of the invader. An array of cell types function in the innate response. These cells are rapidly recruited to the infection site and activated to optimally perform their functions. The adaptive immune response follows the innate response, and one cell type in particular, dendritic cells (DCs), are the critical link between the innate and adaptive responses. This review will summarize recent data concerning the events that occur early during oral infection with the intracellular pathogen Salmonella, with emphasis on the phagocytic cells involved in combating the infection in the gut-associated lymphoid tissues. In particular, recent findings concerning the recruitment and activation of mononuclear phagocyte populations and dendritic cell subsets will be presented after an overview of the Salmonella infection model.
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Affiliation(s)
- Mary Jo Wick
- Department of Microbiology and Immunology, Göteborg University, Box 435, S-405 30 Göteborg, Sweden.
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