101
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Varol C, Zigmond E, Jung S. Securing the immune tightrope: mononuclear phagocytes in the intestinal lamina propria. Nat Rev Immunol 2010; 10:415-26. [PMID: 20498668 DOI: 10.1038/nri2778] [Citation(s) in RCA: 157] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The intestinal landscape comprises the host's own tissue and immune cells, as well as a diverse intestinal microbiota. Intricate regulatory mechanisms have evolved to maintain peaceful coexistence at this site, the breakdown of which can result in devastating inflammatory bowel diseases (IBDs). Mononuclear phagocytes promote both innate and adaptive immune responses in the gut and, as such, are essential for the maintenance of intestinal homeostasis. Here, we review the origins and functions of the mononuclear phagocytes found in the intestinal lamina propria, highlighting the problems that have arisen from their classification. Understanding these cells in their physiological context will be important for developing new therapies for IBDs.
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Affiliation(s)
- Chen Varol
- Gastroenterology and Hepatology Institute, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel
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102
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Persson EK, Jaensson E, Agace WW. The diverse ontogeny and function of murine small intestinal dendritic cell/macrophage subsets. Immunobiology 2010; 215:692-7. [PMID: 20580119 DOI: 10.1016/j.imbio.2010.05.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 05/20/2010] [Indexed: 12/21/2022]
Abstract
Intestinal dendritic cell and macrophage subsets are believed to play key roles in maintaining intestinal homeostasis in the steady state and in driving protective immune responses in the setting of intestinal infection. This mini-review focuses on recent progress regarding the ontogeny and function of small intestinal lamina propria dendritic cell/macrophage subsets. In particular we discuss recent findings suggesting that small intestinal CD103(+) dendritic cells and Cx3cr1(+) cells derive from distinct precursor populations and that CD103(+) dendritic cells represent the major migratory population of cells with a key role in initiating adaptive immune responses in the draining mesenteric lymph node. In contrast, Cx3cr1(+) cells appear to represent a tissue resident population, phenotypically indistinguishable from tissue resident macrophages. These latter observations suggest an important division of labour between dendritic cell/macrophage subsets in the regulation of intestinal immune responses in the steady state.
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103
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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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104
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Fagarasan S, Kawamoto S, Kanagawa O, Suzuki K. Adaptive immune regulation in the gut: T cell-dependent and T cell-independent IgA synthesis. Annu Rev Immunol 2010; 28:243-73. [PMID: 20192805 DOI: 10.1146/annurev-immunol-030409-101314] [Citation(s) in RCA: 358] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In mammals, the gastrointestinal tract harbors an extraordinarily dense and complex community of microorganisms. The gut microbiota provide strong selective pressure to the host to evolve adaptive immune responses required for the maintenance of local and systemic homeostasis. The continuous antigenic presence in the gut imposes a dynamic remodeling of gut-associated lymphoid tissues (GALT) and the selection of multiple layered strategies for immunoglobulin (Ig) A production. The composite and dynamic gut environment also necessitates heterogeneous, versatile, and convertible T cells, capable of inhibiting (Foxp3(+) T cells) or helping (T(FH) cells) local immune responses. In this review, we describe recent advances in our understanding of dynamic pathways that lead to IgA synthesis, in gut follicular structures and in extrafollicular sites, by T cell-dependent and T cell-independent mechanisms. We discuss the finely tuned regulatory mechanisms for IgA production and emphasize the role of mucosal IgA in the selection and maintenance of the appropriate microbial composition that is necessary for immune homeostasis.
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105
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Niess JH. What are CX3CR1+ mononuclear cells in the intestinal mucosa? Gut Microbes 2010; 1:396-400. [PMID: 21468223 PMCID: PMC3056106 DOI: 10.4161/gmic.1.6.13939] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 09/22/2010] [Accepted: 10/13/2010] [Indexed: 02/03/2023] Open
Abstract
Intestinal dendritic cells (DC) and macrophages play a key role for the maintenance of intestinal integrity by initiating innate and adaptive immune responses. Although DC and macrophages have been viewed as distinct lineages, the reliability of surface markers for the definition of DC and macrophages has recently been questioned. Here, I will discuss the ontogeny and function of CX(3)CR1(+) mononuclear cells in the small and large intestine.
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106
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Abstract
Dendritic cells (DCs) are specialized antigen-presenting cells that orchestrate innate and adaptive immune responses. The intestinal mucosa contains numerous DCs that are highly specialized in function. Mucosal DCs display a unique response to toll-like receptor ligands, are capable of driving immunoglobulin isotype switching to IgA, can imprint gut-homing receptors on T and B cells, and drive either T regulatory or Th17 cells depending on the analyzed subtype. These functions are partly cell autonomous and partly conferred by the local microenvironment. In this review, we will summarize the different DC subtypes present in the intestine and in the gut-associated lymphoid tissue (GALT), the unique characteristics of these subtypes, and how the local microenvironment can shape DC function.
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Affiliation(s)
- Maria Rescigno
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
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107
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Nicoletti C, Arques JL, Bertelli E. CX₃CR1 is critical for Salmonella-induced migration of dendritic cells into the intestinal lumen. Gut Microbes 2010; 1:131-4. [PMID: 21327020 PMCID: PMC3023593 DOI: 10.4161/gmic.1.3.11711] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 02/26/2010] [Accepted: 03/04/2010] [Indexed: 02/03/2023] Open
Abstract
We have demonstrated that direct antigen sampling of bacteria by intestinal dendritic cells (DCs) is accompanied by a rapid migration of CD11c+CX3CR1+MHCII+CD8α-CD11b− DCs into the intestinal lumen upon exposure to non-invasive ΔSPI1-Salmonella. Importantly, intraluminal DCs internalized Salmonella but were not able to cross the epithelium to return into tissue, thus showing that these DCs do not function as antigen-presenting cells and participate in the conventional regulation of immune responses to intestinal pathogens. Here we show that the presence of the chemokine receptor CX3CR1, that plays a vital role in DC-mediated antigen sampling and clearance in the gut, is also instrumental for the transepithelial migration of DCs. The latter observation, along with the notion that CX3CR1-deficient mice displayed higher susceptibility to Salmonella infection compared to wild-type mice raises the possibility that Salmonella-induced migration of “bacteria-capturing” DCs into the lumen may be an important mechanism of mucosal defence and clearance.
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Affiliation(s)
- Claudio Nicoletti
- Laboratory of Mucosal Immunology; Programme of Integrated Biology of the GI Tract; Institute of Food Research; Norwich, UK
| | - Juan L Arques
- Laboratory of Mucosal Immunology; Programme of Integrated Biology of the GI Tract; Institute of Food Research; Norwich, UK,Department Tecnología de Alimentos; INIA; Madrid, Spain
| | - Eugenio Bertelli
- Department of Pharmacology “G. Segre”; University of Siena; Siena, Italy
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108
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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: 522] [Impact Index Per Article: 34.8] [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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109
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Shen R, Smythies LE, Clements RH, Novak L, Smith PD. Dendritic cells transmit HIV-1 through human small intestinal mucosa. J Leukoc Biol 2009; 87:663-70. [PMID: 20007245 DOI: 10.1189/jlb.0909605] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
To dissect the early events in the transmission of HIV-1 from mother to child, we investigated whether DCs participate in HIV-1 entry into human small intestinal mucosa. We isolated human MNLs from jejunal lamina propria and identified a subpopulation of CD11c(+)HLA-DR(+) MNLs that expressed DC-SIGN, CD83, CD86, CD206, and CCR7, indicating a DC phenotype. Jejunal DCs also expressed the HIV-1 receptor CD4 and coreceptors CCR5 and CXCR4 and in suspension rapidly took up cell-free HIV-1. HIV-1 inoculated onto the apical surface of explanted jejunum was transported by lamina propria DCs through the mucosa and transmitted in trans to blood and intestinal lymphocytes. These findings indicate that in addition to intestinal epithelial cells, which we showed previously transcytose infectious HIV-1 to indicator cells, intestinal DCs play an important role in transporting HIV-1 through the intestinal mucosa and the subsequent transmission to T cells.
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Affiliation(s)
- Ruizhong Shen
- Departmentsof Medicine (Gastroenterology), University of Alabama at Birmingham, Birmingham, AL 35294-2182, USA
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110
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Varol C, Vallon-Eberhard A, Elinav E, Aychek T, Shapira Y, Luche H, Fehling HJ, Hardt WD, Shakhar G, Jung S. Intestinal lamina propria dendritic cell subsets have different origin and functions. Immunity 2009; 31:502-12. [PMID: 19733097 DOI: 10.1016/j.immuni.2009.06.025] [Citation(s) in RCA: 569] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 05/31/2009] [Accepted: 06/22/2009] [Indexed: 12/12/2022]
Abstract
The intestinal immune system discriminates between tolerance toward the commensal microflora and robust responses to pathogens. Maintenance of this critical balance is attributed to mucosal dendritic cells (DCs) residing in organized lymphoid tissue and dispersed in the subepithelial lamina propria. In situ parameters of lamina propria DCs (lpDCs) remain poorly understood. Here, we combined conditional cell ablation and precursor-mediated in vivo reconstitution to establish that lpDC subsets have distinct origins and functions. CD103(+) CX(3)CR1(-) lpDCs arose from macrophage-DC precursors (MDPs) via DC-committed intermediates (pre-cDCs) through a Flt3L growth-factor-mediated pathway. CD11b(+) CD14(+) CX(3)CR1(+) lpDCs were derived from grafted Ly6C(hi) but not Ly6C(lo) monocytes under the control of GM-CSF. Mice reconstituted exclusively with CX(3)CR1(+) lpDCs when challenged in an innate colitis model developed severe intestinal inflammation that was driven by graft-derived TNF-alpha-secreting CX(3)CR1(+) lpDCs. Our results highlight the critical importance of the lpDC subset balance for robust gut homeostasis.
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Affiliation(s)
- Chen Varol
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel 76100
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111
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Arques JL, Hautefort I, Ivory K, Bertelli E, Regoli M, Clare S, Hinton JCD, Nicoletti C. Salmonella induces flagellin- and MyD88-dependent migration of bacteria-capturing dendritic cells into the gut lumen. Gastroenterology 2009; 137:579-87, 587.e1-2. [PMID: 19375423 DOI: 10.1053/j.gastro.2009.04.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 02/15/2009] [Accepted: 04/09/2009] [Indexed: 12/24/2022]
Abstract
BACKGROUND & AIMS Intestinal dendritic cells (DCs) sample bacteria, such as Salmonella, by extending cellular processes into the lumen to capture bacteria and shuttle them across the epithelium; however, direct evidence of bacteria-loaded DCs travelling back into the tissue is lacking. We hypothesized that sampling is paralleled by migration of DCs into the lumen prior to or following the internalization of Salmonella. METHODS The small intestine and the colon of BALB/c and C57BL/6 mice were challenged with noninvasive Salmonella enterica serovar Typhimurium SL1344-DeltaSalmonella pathogenicity island (SPI) 1 or Escherichia coli DH5alpha by using isolated loops or oral administration by gavage. Transepithelial migration of DCs was documented by immunohistochemistry, microscopy, and flow cytometry. The role of flagellin was determined by using flagellin (DeltafliC DeltafljB)- and SPI1-SPI2 (DeltaSPI1 DeltassrA)-deficient Salmonella, flagellated E coli K12, and MyD88 mice. RESULTS Salmonella DeltaSPI1 induced migration of CD11c(+)CX(3)CR1(+)MHCII(+)CD11b(-)CD8alpha(-) DCs into the small intestine, whereas flagellin- and SPI1-SPI2-deficient Salmonella, soluble flagellin, and E coli DH5alpha or flagellated K12, failed to do so. DC migration did not occur in the colon; it was not observed in MyD88 mice, and intraluminal DCs internalized Salmonella but did not cross the epithelium to return into tissues. Finally, DC migration was not linked to Salmonella-induced damage of the epithelium. CONCLUSIONS DC-mediated sampling of Salmonella is accompanied by flagellin- and MyD88-dependent migration of Salmonella-capturing DCs into the intestinal lumen. We suggest that the rapid intraluminal migration of Salmonella-capturing DCs may play a role in the protection of the intestinal mucosa against bacterial infection.
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Affiliation(s)
- Juan L Arques
- Programme of GI Tract Biology, Institute of Food Research, Norwich, United Kingdom
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112
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Suzuki K, Fagarasan S. How host-bacterial interactions lead to IgA synthesis in the gut. Trends Immunol 2009; 29:523-31. [PMID: 18838301 DOI: 10.1016/j.it.2008.08.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2008] [Revised: 08/01/2008] [Accepted: 08/18/2008] [Indexed: 12/30/2022]
Abstract
In mammals, the gut is populated with an extremely dense and diverse bacterial community. One response following intestinal colonization is the production of immunoglobulin (Ig) A by B cells present in the gut-associated lymphoid tissues (GALT). In this review, we summarize recent advances in our understanding of the sites, mechanisms, and functions of intestinal IgA synthesis. We discuss here the pathways leading to IgA production, in organized structures as well as nonorganized tissues, by T-dependent as well as T-independent mechanisms. In addition, we discuss new insights into the role of gut IgA in the regulation of bacterial communities and maintenance of immune homeostasis.
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Affiliation(s)
- Keiichiro Suzuki
- Laboratory for Mucosal Immunity, RIKEN Research Center for Allergy and Immunology, 230-0045 Tsurumi, Yokohama, Japan.
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113
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Caminschi I, Lahoud MH, Shortman K. Enhancing immune responses by targeting antigen to DC. Eur J Immunol 2009; 39:931-8. [PMID: 19197943 DOI: 10.1002/eji.200839035] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
mAb that recognise various cell surface receptors have been used to deliver antigen to DC and thereby elicit immune responses. The encouraging data obtained in mouse models suggests that this immunisation strategy is efficient and could lead to clinical trials. We discuss a number of issues pertinent to this vaccination approach. These include which molecules are the best targets for delivering antigen to DC, which DC subtypes should be targeted, the types of immune responses to be generated and whether additional adjuvants are required. Finally, we discuss some progress towards targeting antigen to human DC.
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Affiliation(s)
- Irina Caminschi
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
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114
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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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115
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Hume DA. Macrophages as APC and the dendritic cell myth. THE JOURNAL OF IMMUNOLOGY 2009; 181:5829-35. [PMID: 18941170 DOI: 10.4049/jimmunol.181.9.5829] [Citation(s) in RCA: 353] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Dendritic cells have been considered an immune cell type that is specialized for the presentation of Ag to naive T cells. Considerable effort has been applied to separate their lineage, pathways of differentiation, and effectiveness in Ag presentation from those of macrophages. This review summarizes evidence that dendritic cells are a part of the mononuclear phagocyte system and are derived from a common precursor, responsive to the same growth factors (including CSF-1), express the same surface markers (including CD11c), and have no unique adaptation for Ag presentation that is not shared by other macrophages.
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Affiliation(s)
- David A Hume
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Scotland, United Kingdom.
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116
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Ueno T, Tanaka K, Jurewicz M, Murayama T, Guleria I, Fiorina P, Paez JC, Augello A, Vergani A, Wong M, Smith RN, Abdi R. Divergent role of donor dendritic cells in rejection versus tolerance of allografts. J Am Soc Nephrol 2009; 20:535-44. [PMID: 19129312 DOI: 10.1681/asn.2008040377] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Little is known about heart tissue/donor dendritic cells, which play a key role in mounting alloimmune responses. In this report, we focus on three primary features of donor dendritic cells: their generation, their trafficking after transplantation, and their role in regulating tolerance versus rejection. Using transgenic mice as donors of heart allografts enabled us to monitor trafficking of donor dendritic cells after transplantation. Donor dendritic cells rapidly migrated into secondary lymphoid tissues within 3 h of transplantation. We found that the chemokine receptor CX3CR1 regulates the generation of heart tissue dendritic cells constitutively. Compared with wild-type hearts, CX3CR1(-/-) hearts contained fewer dendritic cells, and heart allografts from CX3CR1(-/-) donors survived significantly longer without immunosuppression. Unexpectedly, though, co-stimulatory blockade with anti-CD154 or CTLA4-Ig induced long-term survival for wild-type heart allografts but not for CX3CR1(-/-) heart allografts. Increasing the dendritic cell frequency in CX3CR1(-/-) hearts by treatment with Flt3L restored the anti-CD154-induced prolongation of CX3CR1(-/-) heart allograft survival. Compared with wild-type donors, depleting transgenic donors of dendritic cells before heart transplantation also markedly worsened chronic rejection under anti-CD154 treatment. These data indicate the importance of the CX3CR1 pathway in the generation of heart tissue dendritic cells and the divergent role of tissue/dendritic cells in rejection versus tolerance.
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Affiliation(s)
- Takuya Ueno
- Transplantation Research Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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117
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Varol C, Landsman L, Jung S. Probing in vivo origins of mononuclear phagocytes by conditional ablation and reconstitution. Methods Mol Biol 2009; 531:71-87. [PMID: 19347312 DOI: 10.1007/978-1-59745-396-7_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Dendritic cells (DCs) and macrophages (MPhis), collectively termed mononuclear phagocytes (MP), are crucial for homeostatic tissue maintenance as well as the innate and adaptive host defense. These pleiotropic functions are likely to be covered by distinct DC and MPhi subsets, defined by anatomic location and molecular make-up. However, task division within the MP system remains poorly defined. A key to understanding of this issue, which might have important implications for the development of future therapeutic strategies, is the elucidation of the in vivo origins of DCs and MPhis, whose study recently gained striking momentum. Here we present methods to investigate the role of MP progenitors, such as monocytes and MPhi/DC precursors (MDPs), in the replenishment of the peripheral MP system.
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Affiliation(s)
- Chen Varol
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
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118
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Ruitenberg MJ, Vukovic J, Blomster L, Hall JM, Jung S, Filgueira L, McMenamin PG, Plant GW. CX3CL1/fractalkine regulates branching and migration of monocyte-derived cells in the mouse olfactory epithelium. J Neuroimmunol 2008; 205:80-5. [DOI: 10.1016/j.jneuroim.2008.09.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 09/08/2008] [Accepted: 09/08/2008] [Indexed: 12/11/2022]
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119
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Kelsall B. Recent progress in understanding the phenotype and function of intestinal dendritic cells and macrophages. Mucosal Immunol 2008; 1:460-9. [PMID: 19079213 PMCID: PMC4780321 DOI: 10.1038/mi.2008.61] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mucosal immune responses must be tightly controlled, particularly in the intestine. As members of the mononuclear phagocyte family, dendritic cells (DCs) and macrophages are well represented in intestinal tissues and have developed unique functional niches. This review will focus on recent findings on antigen uptake and processing in the intestine and the role of DCs in the imprinting of homing receptors on T and B cells, the induction of immunoglobulin A B-cell responses, and the differentiation of regulatory T cells. It will also address the unique phenotype of intestinal macrophages and briefly what is known regarding the relationships between these cell types.
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Affiliation(s)
- Brian Kelsall
- Mucosal Immunobiology Section, Laboratory of Molecular Immunology, 10/11N111, 10 Center Drive, NIAID NIH, Bethesda, MD 20892,
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120
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Abstract
Cells of the mononuclear phagocyte system (MPS) are found in large numbers in every organ of the body, where they contribute to innate and acquired immunity and homeostasis. This review considers the locations of MPS cells, surface markers that distinguish subsets of monocytes and macrophages, the pathways of MPS differentiation, and the growth factors and transcription factors that guide them. Although the number of MPS sub-populations that can be defined is infinite, the features that unite the MPS remain compelling. Those features clearly include antigen-presenting dendritic cells within the MPS and argue against any basis for separating them from macrophages.
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121
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Efficient clearance of Aspergillus fumigatus in murine lungs by an ultrashort antimicrobial lipopeptide, palmitoyl-lys-ala-DAla-lys. Antimicrob Agents Chemother 2008; 52:3118-26. [PMID: 18606837 DOI: 10.1128/aac.00526-08] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic fungal pathogen responsible for invasive aspergillosis in immunocompromised individuals. The inefficiency of antifungal agents and high mortality rate resulting from invasive aspergillosis remain major clinical concerns. Recently, we reported on a new family of ultrashort cationic lipopeptides active in vitro against fungi. Mode of action studies supported a membranolytic or a detergent-like effect. Here, we screened several lipopeptides in vitro for their anti-A. fumigatus activity. To investigate the therapeutic properties of the selected peptides in vivo, we challenged immunosuppressed C57BL/6 wild-type mice intranasally with DsRed-labeled A. fumigatus conidia and subsequently treated the animals locally with the lipopeptides. Confocal microscopic analysis revealed the degradation of DsRed-labeled hyphal forms and residual conidia in the lungs of the mice. The most efficient peptide was tested further using a survival assay and was found to significantly prolong the life of the treated animals, whereas no mice survived with the current standard antifungal treatment with amphotericin B. Moreover, as opposed to the drug-treated lungs, the peptide-treated lungs did not display any toxicity of the peptide. Our results highlight the potential of this family of lipopeptides for the treatment of pulmonary invasive aspergillosis.
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122
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Artis D. Epithelial-cell recognition of commensal bacteria and maintenance of immune homeostasis in the gut. Nat Rev Immunol 2008; 8:411-20. [PMID: 18469830 DOI: 10.1038/nri2316] [Citation(s) in RCA: 758] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mucosal surfaces such as the intestinal tract are continuously exposed to both potential pathogens and beneficial commensal microorganisms. This creates a requirement for a homeostatic balance between tolerance and immunity that represents a unique regulatory challenge to the mucosal immune system. Recent findings suggest that intestinal epithelial cells, although once considered a simple physical barrier, are a crucial cell lineage for maintaining intestinal immune homeostasis. This Review discusses recent findings that identify a cardinal role for epithelial cells in sampling the intestinal microenvironment, discriminating pathogenic and commensal microorganisms and influencing the function of antigen-presenting cells and lymphocytes.
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Affiliation(s)
- David Artis
- Department of Pathobiology, University of Pennsylvania, Philadelphia, Philadelphia 19104-4539, USA.
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123
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Bambury N, Coffey JC, Burke J, Redmond HP, Kirwan WO. Sulphomucin expression in ileal pouches: emerging differences between ulcerative colitis and familial adenomatous polyposis pouches. Dis Colon Rectum 2008; 51:561-7. [PMID: 18299930 DOI: 10.1007/s10350-008-9200-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 09/06/2007] [Accepted: 10/17/2007] [Indexed: 02/08/2023]
Abstract
PURPOSE We characterized the expression of sialomucin and sulphomucin in pouches fashioned for familial adenomatous polyposis and ulcerative colitis. We correlated sulphomucin expression with bacterial colonization and mucosal inflammation. METHODS Ethical approval and informed consent were obtained. Mucosal biopsies from 9 patients with familial adenomatous polyposis and 12 with ulcerative colitis were obtained. Sulphomucin levels were assessed by using the high iron-diamine stain. Mucous gel layer composition was correlated with villous height, crypt depth, and total mucosal thickness. Mucous gel layer composition was correlated with acute and chronic inflammatory infiltrates. Colonization by a panel of seven bacterial species (including sulphate reducing bacteria) was established and correlated with sulphomucin levels. RESULTS High-iron-diamine positivity (i.e., sulphomucin expression) was greater in ulcerative colitis pouch mucous gel (2.083 +/- 0.5 vs. 0.556 +/- 0.4, P = 0.003). Sulphomucin expression correlated with reduced crypt depth, villous height, and total mucosal thickness. In the ulcerative colitis group, chronic inflammatory infiltrate scores were significantly greater for high-iron-diamine-positive patients. Colonization by sulphate reducing bacteria was increased in high-iron-diamine-positive patients. CONCLUSIONS Sulphomucin expression is increased in the mucous gel layer of the ulcerative colitis pouch compared with that of the familial adenomatous polyposis pouch. Sulphomucin expression is associated with colonization by sulphate-reducing bacteria and increased chronic inflammation.
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Affiliation(s)
- Niamh Bambury
- Department of Surgery, University College Cork and Cork University Hospital, National University of Ireland, Dublin, Ireland
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124
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Germain RN, Bajénoff M, Castellino F, Chieppa M, Egen JG, Huang AYC, Ishii M, Koo LY, Qi H. Making friends in out-of-the-way places: how cells of the immune system get together and how they conduct their business as revealed by intravital imaging. Immunol Rev 2008; 221:163-81. [PMID: 18275481 DOI: 10.1111/j.1600-065x.2008.00591.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A central characteristic of the immune system is the constantly changing location of most of its constituent cells. Lymphoid and myeloid cells circulate in the blood, and subsets of these cells enter, move, and interact within, then leave organized lymphoid tissues. When inflammation is present, various hematopoietic cells also exit the vasculature and migrate within non-lymphoid tissues, where they carry out effector functions that support host defense or result in autoimmune pathology. Effective innate and adaptive immune responses involve not only the action of these individual cells but also productive communication among them, often requiring direct membrane contact between rare antigen-specific or antigen-bearing cells. Here, we describe our ongoing studies using two-photon intravital microscopy to probe the in situ behavior of the cells of the immune system and their interactions with non-hematopoietic stromal elements. We emphasize the importance of non-random cell migration within lymphoid tissues and detail newly established mechanisms of traffic control that operate at multiple organizational scales to facilitate critical cell contacts. We also describe how the methods we have developed for imaging within lymphoid sites are being applied to other tissues and organs, revealing dynamic details of host-pathogen interactions previously inaccessible to direct observation.
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Affiliation(s)
- Ronald N Germain
- Laboratory of Immunology, Lymphocyte Biology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1892, USA.
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125
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Cavanagh LL, Weninger W. Dendritic cell behaviour
in vivo
: lessons learned from intravital two‐photon microscopy. Immunol Cell Biol 2008; 86:428-38. [DOI: 10.1038/icb.2008.25] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Lois L Cavanagh
- Immune Imaging Program, Centenary Institute of Cancer Medicine and Cell BiologyNewtownNew South WalesAustralia
| | - Wolfgang Weninger
- Immune Imaging Program, Centenary Institute of Cancer Medicine and Cell BiologyNewtownNew South WalesAustralia
- Discipline of Dermatology, University of SydneySydneyNew South WalesAustralia
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126
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Lee AY, Chang SY, Kim JI, Cha HR, Jang M, Yamamoto M, Kweon MN. Dendritic cells in colonic patches and iliac lymph nodes are essential in mucosal IgA induction following intrarectal administrationvia CCR7 interaction. Eur J Immunol 2008; 38:1127-37. [DOI: 10.1002/eji.200737442] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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127
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Waeytens A, Ferdinande L, Neirynck S, Rottiers P, De Vos M, Steidler L, Cuvelier CA. Paracellular entry of interleukin-10 producing Lactococcus lactis in inflamed intestinal mucosa in mice. Inflamm Bowel Dis 2008; 14:471-9. [PMID: 18092343 DOI: 10.1002/ibd.20346] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Genetically modified Lactococcus lactis secreting interleukin-10 (IL-10) has been demonstrated to provide localized delivery of a therapeutic agent through active in situ synthesis in murine colitis. At present, many aspects of the exact mechanism by which the beneficial effect of the IL-10-producing L. lactis on the mucosa is mediated remain to be clarified. METHODS Our aim was to determine the interaction of L. lactis with the intestinal mucosa. Therefore, we administered IL-10-producing L. lactis to healthy mice and in 2 mouse models of chronic colitis. Paraffin sections of ileum and colon samples were examined with confocal and transmission electron microscopy. Ileum and colon homogenates were prepared after flushing and after removal of mucus layer and epithelium. These homogenates and homogenates of mesenteric lymph nodes and spleen were plated on agar and immunoblotting for L. lactis and IL-10 was performed. RESULTS Both confocal and electron microscopy showed the presence of lactococci in inflamed intestinal mucosa of mice with colitis. We recovered viable bacteria that could still produce IL-10 from homogenates of inflamed ileum and colon of which mucous and epithelial layers were removed. We did not find lactococci in mesenteric lymph nodes or in the spleen of mice with colitis. CONCLUSIONS This study demonstrates uptake of IL-10-secreting L. lactis by the paracellular route in inflamed mucosal tissue. We suggest that IL-10 production by L. lactis residing inside the mucosa in the vicinity of responsive cells can improve the local action of interleukin-10 in inflamed tissue and the efficiency of the treatment.
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Affiliation(s)
- Anouk Waeytens
- Department of Pathology, Ghent University, Ghent, Belgium.
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128
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Hapfelmeier S, Müller AJ, Stecher B, Kaiser P, Barthel M, Endt K, Eberhard M, Robbiani R, Jacobi CA, Heikenwalder M, Kirschning C, Jung S, Stallmach T, Kremer M, Hardt WD. Microbe sampling by mucosal dendritic cells is a discrete, MyD88-independent step in DeltainvG S. Typhimurium colitis. ACTA ACUST UNITED AC 2008; 205:437-50. [PMID: 18268033 PMCID: PMC2271026 DOI: 10.1084/jem.20070633] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Intestinal dendritic cells (DCs) are believed to sample and present commensal bacteria to the gut-associated immune system to maintain immune homeostasis. How antigen sampling pathways handle intestinal pathogens remains elusive. We present a murine colitogenic Salmonella infection model that is highly dependent on DCs. Conditional DC depletion experiments revealed that intestinal virulence of S. Typhimurium SL1344 ΔinvG mutant lacking a functional type 3 secretion system-1 (ΔinvG)critically required DCs for invasion across the epithelium. The DC-dependency was limited to the early phase of infection when bacteria colocalized with CD11c+CX3CR1+ mucosal DCs. At later stages, the bacteria became associated with other (CD11c−CX3CR1−) lamina propria cells, DC depletion no longer attenuated the pathology, and a MyD88-dependent mucosal inflammation was initiated. Using bone marrow chimeric mice, we showed that the MyD88 signaling within hematopoietic cells, which are distinct from DCs, was required and sufficient for induction of the colitis. Moreover, MyD88-deficient DCs supported transepithelial uptake of the bacteria and the induction of MyD88-dependent colitis. These results establish that pathogen sampling by DCs is a discrete, and MyD88-independent, step during the initiation of a mucosal innate immune response to bacterial infection in vivo.
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129
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Muixí L, Alvarez I, Jaraquemada D. Peptides presented in vivo by HLA-DR in thyroid autoimmunity. Adv Immunol 2008; 99:165-209. [PMID: 19117535 DOI: 10.1016/s0065-2776(08)00606-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The association of the major histocompatibility complex (MHC) genes with autoimmune diseases together with the ectopic expression of class II molecules by epithelial cells of the target tissue gives to these molecules a central role in the pathogenesis of the disease, in its regulation and in the persistence of the immune response in situ. HLA-DR molecules expressed by thyroid follicular cells in thyroid autoimmune diseases are compact molecules stably associated with peptides. The nature of these peptides is of vital importance in the understanding of the disease, since these MHC-II-peptide complexes are going to be recognized by both effector and regulatory T cells in situ. In this chapter, we review the current state of the analysis of naturally processed peptides presented by MHC class II molecules in the context of autoimmunity and we discuss our data of natural HLA-DR ligands eluted from Graves' disease affected thyroid glands, from where autoantigen-derived peptides have been identified.
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Affiliation(s)
- Laia Muixí
- Immunology Unit, Institut de Biotechnologia i Biomedicina, Universitat Autònoma de Barcelona, Campus de Bellaterra, Barcelona, Spain
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130
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Conventional dendritic cells regulate the outcome of colonic inflammation independently of T cells. Proc Natl Acad Sci U S A 2007; 104:17022-7. [PMID: 17942668 DOI: 10.1073/pnas.0708469104] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We explored the physiological role of conventional dendritic cells (cDCs) in acute colitis induced by a single cycle of dextran sodium sulfate administration. Depending on their mode of activation and independently of T cells, cDCs can enhance or attenuate the severity of dextran sodium sulfate-induced colitis. The latter beneficial effect was achieved, in part, by IFN-1 induced by Toll-like receptor 9-activated cDCs. IFN-1 inhibits colonic inflammation by regulating neutrophil and monocyte trafficking to the inflamed colon and restraining the inflammatory products of tissue macrophages. These data highlight a novel role of cDCs in the regulation of other innate immune cells and position them as major players in acute colonic inflammation.
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131
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Cleret A, Quesnel-Hellmann A, Vallon-Eberhard A, Verrier B, Jung S, Vidal D, Mathieu J, Tournier JN. Lung dendritic cells rapidly mediate anthrax spore entry through the pulmonary route. THE JOURNAL OF IMMUNOLOGY 2007; 178:7994-8001. [PMID: 17548636 DOI: 10.4049/jimmunol.178.12.7994] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Inhalational anthrax is a life-threatening infectious disease of considerable concern, especially because anthrax is an emerging bioterrorism agent. The exact mechanisms leading to a severe clinical form through the inhalational route are still unclear, particularly how immobile spores are captured in the alveoli and transported to the lymph nodes in the early steps of infection. We investigated the roles of alveolar macrophages and lung dendritic cells (LDC) in spore migration. We demonstrate that alveolar macrophages are the first cells to phagocytose alveolar spores, and do so within 10 min. However, interstitial LDCs capture spores present in the alveoli within 30 min without crossing the epithelial barrier suggesting a specific mechanism for rapid alveolus sampling by transepithelial extension. We show that interstitial LDCs constitute the cell population that transports spores into the thoracic lymph nodes from within 30 min to 72 h after intranasal infection. Our results demonstrate that LDCs are central to spore transport immediately after infection. The rapid kinetics of pathogen transport may contribute to the clinical features of inhalational anthrax.
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Affiliation(s)
- Aurélie Cleret
- Unité Interactions Hôte-Pathogène, Département de Biologie des Agents Transmissibles, Centre de Recherches du Service de Santé des Armées, 24 Avenue des Maquis du Grésivaudan, 38702 La Tronche, France
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132
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Sapoznikov A, Fischer JAA, Zaft T, Krauthgamer R, Dzionek A, Jung S. Organ-dependent in vivo priming of naive CD4+, but not CD8+, T cells by plasmacytoid dendritic cells. ACTA ACUST UNITED AC 2007; 204:1923-33. [PMID: 17646404 PMCID: PMC2118686 DOI: 10.1084/jem.20062373] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plasmacytoid dendritic cells (PDCs) play a pivotal role as cytokine-secreting accessory cells in the antimicrobial immune defense. In contrast, the capacity of PDCs to act as antigen-presenting cells in naive T cell priming remains unclear. By studying T cell responses in mice that lack conventional DCs (cDCs), and by the use of a PDC-specific antigen-targeting strategy, we show that PDCs can initiate productive naive CD4+ T cell responses in lymph nodes, but not in the spleen. PDC-triggered CD4+ T cell responses differed from cDC-driven responses in that they were not associated with concomitant CD8+ T cell priming. Our results establish PDCs as a bona fide DC subset that initiates unique CD4+ Th cell–dominated primary immune responses.
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Affiliation(s)
- Anita Sapoznikov
- Department of Immunology, The Weizmann Institute of Science, 76100 Rehovot, Israel
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133
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Abstract
The internal surfaces of the human body are covered by distinct types of epithelial cells and mucus-secreting cells. The mucosal surfaces serve many vital functions, such as respiration (nasal passage and lung), absorption (gastrointestinal tract), excretion (lung, urinary tract, large intestine), and reproduction (reproductive tract). In performing these functions, the host is inevitably exposed to environmental antigens, food particles, commensal flora, and pathogens. Mucosal surfaces contain specialized dendritic cells (DCs) capable of sensing these external stimuli and mounting appropriate local responses depending on the nature of the elements they encounter. In the absence of pathogens, mucosal DCs either ignore the antigen or induce regulatory responses. Upon recognition of microorganisms that invade the mucosal barrier, mucosal DCs mount robust protective immunity. This review highlights progress in our understanding of how mucosal DCs process external information and direct appropriate responses by mobilizing various cells of the innate and adaptive immune systems to achieve homeostasis and protection.
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Affiliation(s)
- Akiko Iwasaki
- Section of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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134
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Pabst O, Bernhardt G, Förster R. The impact of cell-bound antigen transport on mucosal tolerance induction. J Leukoc Biol 2007; 82:795-800. [PMID: 17565048 DOI: 10.1189/jlb.0307144] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mucosal surfaces are exposed continuously to a flood of foreign antigens demanding a tightly controlled balance between immunity and tolerance induction. Tolerance toward food and inhaled antigens, known as oral and respiratory tolerance, respectively, evokes a body-wide nonresponsiveness against the plethora of environmental antigens. Key issues in understanding the induction of mucosal tolerance relate to the site of antigen entrance, the mechanisms of antigen transport, and the exact anatomical location where lymphocytes meet their cognate antigens. In this regard, opposing ideas have been put forward: In one scenario, antigens taken up at mucosal surfaces are considered to spread throughout the body, thus potentially evoking tolerogenic immune responses in all secondary lymphoid organs. Alternatively, tolerance induction might be confined to the draining regional lymph nodes (LN). Recent observations strongly supported the latter scenario, emphasizing the importance of regional LN and their network of afferent lymphatics in this process. In this model, air-borne and intestinal antigens are captured at mucosal sites by dendritic cells, which then migrate exclusively in a CCR7-dependent way to draining regional LN. Tolerance is then induced actively by the activation of antigen-specific T cells, which are subsequently deleted, become anergic, or alternatively, differentiate into regulatory T cells. Thus, the concept of local induction of immune responses seems to hold true for the majority of immune reactions, regardless of whether they are tolerogenic or defensive in their outcome.
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Affiliation(s)
- Oliver Pabst
- Institute of Immunology, Hannover Medical School, Carl-Neuberg Strasse 1, 30625 Hannover, Germany.
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135
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Gonen E, Vallon-Eberhard A, Elazar S, Harmelin A, Brenner O, Rosenshine I, Jung S, Shpigel NY. Toll-like receptor 4 is needed to restrict the invasion of Escherichia coli P4 into mammary gland epithelial cells in a murine model of acute mastitis. Cell Microbiol 2007; 9:2826-38. [PMID: 17608742 DOI: 10.1111/j.1462-5822.2007.00999.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mastitis, an inflammatory response of the mammary tissue to invading pathogenic bacteria, is a common disease in breast-feeding women and dairy animals. Escherichia coli is a leading cause of mastitis in dairy animals. During the course of the disease the host mounts a strong inflammatory response, but specific bacterial virulence factors have not yet been identified. Here we report the use of a murine mastitis model to investigate the innate inflammatory reaction of the mammary gland. We show that lipopolysaccharide (LPS) infusion induces mastitis in wild-type mice (C3H/HeN), but not in mice expressing mutated Toll-like receptor 4 (TLR4) (C3H/HeJ). The wild-type phenotype was restored by adoptive transfer of TLR4-expressing macrophages into the alveolar milk space of C3H/HeJ mice. In contrast to the LPS treatment, infection with E. coli P4 (ECP4) resulted in inflammation even in the absence of LPS/TLR4 signalling, indicating that additional factors play a role in the pathogenesis of the intact bacteria. Furthermore, in the absence of functional TLR4 the infecting ECP4 invade the epithelial cells with high efficiency, forming intracellular microcolonies. However, adoptive transfer with TLR4-expressing macrophages drastically reduced the epithelial invasion. Taken together, these results indicate that ECP4 has an invasive potential, which is restricted by alveolar macrophages in response to the LPS/TLR4 signalling.
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Affiliation(s)
- Erez Gonen
- The Koret School of Veterinary Medicine, Faculty of Agriculture, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel
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136
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Schenk M, Mueller C. Adaptations of intestinal macrophages to an antigen-rich environment. Semin Immunol 2007; 19:84-93. [PMID: 17055292 DOI: 10.1016/j.smim.2006.09.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2006] [Accepted: 09/08/2006] [Indexed: 02/06/2023]
Abstract
Intestinal macrophages, preferentially located in the subepithelial lamina propria, represent in humans the largest pool of tissue macrophages. To comply with their main task, i.e. the efficient removal of microbes and particulate matter that might have gained access to the mucosa from the intestinal lumen while maintaining local tissue homeostasis, several phenotypic and functional adaptations evolved. Most notably, microbe-associated molecular pattern (MAMP) receptors, including the lipopolysaccharide receptors CD14 and TLR4, but also the Fc receptors for IgA and IgG are absent on most intestinal Mø. Here we review recent findings on the phenotypic and functional adaptations of intestinal Mø and their implications for the pathogenesis of inflammatory bowel diseases.
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Affiliation(s)
- Mirjam Schenk
- Institute of Pathology, University of Bern, Murtenstrasse 31, CH-3010 Bern, Switzerland
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137
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Halle S, Bumann D, Herbrand H, Willer Y, Dähne S, Förster R, Pabst O. Solitary intestinal lymphoid tissue provides a productive port of entry for Salmonella enterica serovar Typhimurium. Infect Immun 2007; 75:1577-85. [PMID: 17283101 PMCID: PMC1865728 DOI: 10.1128/iai.01392-06] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Oral infection of mice with Salmonella enterica serovar Typhimurium results in the colonization of Peyer's patches, triggering a vigorous inflammatory response and immunopathology at these sites. Here we demonstrate that in parallel to Peyer's patches a strong inflammatory response occurs in the intestine, resulting in the appearance of numerous inflammatory foci in the intestinal mucosa. These foci surround small lymphoid cell clusters termed solitary intestinal lymphoid tissue (SILT). Salmonella can be observed inside SILT at early stages of infection, and the number of infected structures matches the number of inflammatory foci arising at later time points. Infection leads to enlargement and morphological destruction of SILT but does not trigger de novo formation of lymphoid tissue. In conclusion, SILT, a lymphoid compartment mostly neglected in earlier studies, represents a major site for Salmonella invasion and ensuing mucosal pathology.
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Affiliation(s)
- Stephan Halle
- Institute of Immunology, Hannover Medical School, Carl-Neuberg Strasse 1, 30625 Hannover, Germany
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138
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Landsman L, Varol C, Jung S. Distinct Differentiation Potential of Blood Monocyte Subsets in the Lung. THE JOURNAL OF IMMUNOLOGY 2007; 178:2000-7. [PMID: 17277103 DOI: 10.4049/jimmunol.178.4.2000] [Citation(s) in RCA: 250] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Peripheral blood monocytes are a population of circulating mononuclear phagocytes that harbor potential to differentiate into macrophages and dendritic cells. As in humans, monocytes in the mouse comprise two phenotypically distinct subsets that are Gr1(high)CX(3)CR1(int) and Gr1(low)CX(3)CR1(high), respectively. The question remains whether these populations contribute differentially to the generation of peripheral mononuclear phagocytes. In this study, we track the fate of adoptively transferred, fractionated monocyte subsets in the lung of recipient mice. We show that under inflammatory and noninflammatory conditions, both monocyte subsets give rise to pulmonary dendritic cells. In contrast, under the conditions studied, only Gr1(low)CX(3)CR1(high) monocytes, but not Gr1(high)CX(3)CR1(int) cells, had the potential to differentiate into lung macrophages. However, Gr1(high)CX(3)CR1(int) monocytes could acquire this potential upon conversion into Gr1(low)CX(3)CR1(high) cells. Our results therefore indicate an intrinsic dichotomy in the differentiation potential of the two main blood monocyte subsets.
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Affiliation(s)
- Limor Landsman
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
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139
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Johansson-Lindbom B, Agace WW. Generation of gut-homing T cells and their localization to the small intestinal mucosa. Immunol Rev 2007; 215:226-42. [PMID: 17291292 DOI: 10.1111/j.1600-065x.2006.00482.x] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The intestinal mucosa represents the largest body surface toward the external environment and harbors numerous T lymphocytes that take up resident within the intestinal epithelium or in the underlying lamina propria (LP). The intraepithelial lymphocytes include subsets of 'unconventional' T cells with unclear ontogeny and reactivity that localize to this site independently of antigen-specific activation in secondary lymphoid organs. In contrast, the majority of the 'conventional' gut T cells are recruited into the intestinal mucosa subsequent to their activation in intestinal inductive sites, including Peyer's patches (PPs) and mesenteric lymph nodes (MLNs). T cells homing to the small intestine express a distinct pattern of homing molecules, allowing them to interact with and transmigrate across intestinal postcapillary endothelium. At least some of these homing molecules, including the integrin alpha(4)beta(7) and the chemokine receptor CCR9, are induced on T cells during their activation in PPs or MLNs. Mucosal dendritic cells (DCs) play a key role in this process, but not all intestinal DCs possess the ability to confer a gut-homing capacity to T cells. Instead, functionally specialized CD103(+) DCs derived from the small intestinal LP appear to selectively regulate T-cell homing to the small intestine.
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140
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Hebel K, Griewank K, Inamine A, Chang HD, Müller-Hilke B, Fillatreau S, Manz RA, Radbruch A, Jung S. Plasma cell differentiation in T-independent type 2 immune responses is independent of CD11c(high) dendritic cells. Eur J Immunol 2007; 36:2912-9. [PMID: 17051619 DOI: 10.1002/eji.200636356] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Dendritic cells (DC) play an important role as antigen-presenting cells in T cell stimulation. Interestingly, a number of recent studies also imply DC as critical accessory cells in B cell activation, isotype switching and plasma blast maintenance. Here we use the conditional in vivo ablation of CD11c(high) DC to investigate the role of these cells in T-independent type 2 immune responses. We show that CD11c(high) DC are dispensable for the initiation and maintenance of a primary immune response against the T-independent type 2 antigen (4-hydroxy-3-nirophenyl)acetyl-Ficoll. Our results suggest that support for plasma cell formation in T cell-independent immune responses can be provided by non-DC such as stromal cells, or is independent of external signals. Interestingly, we found plasma blasts to express CD11c and to be diphtheria toxin-sensitive in CD11c-diphtheria toxin receptor-transgenic mice, providing a unique tool for future analysis of in vivo aspects of plasma cell biology.
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Affiliation(s)
- Katrin Hebel
- German Arthritis Research Center Berlin, Berlin, Germany
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141
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Lee JW, Epardaud M, Sun J, Becker JE, Cheng AC, Yonekura AR, Heath JK, Turley SJ. Peripheral antigen display by lymph node stroma promotes T cell tolerance to intestinal self. Nat Immunol 2006; 8:181-90. [PMID: 17195844 DOI: 10.1038/ni1427] [Citation(s) in RCA: 275] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Accepted: 11/21/2006] [Indexed: 01/21/2023]
Abstract
The intestinal epithelium functions to absorb nutrients and to protect the organism against microbes. To prevent autoimmune attack on this vital tissue, T cell tolerance to intestinal self-antigens must be established. Central tolerance mechanisms involve medullary thymic epithelial cells (mTECs), which use endogenously expressed peripheral-tissue antigens (PTAs) to delete self-reactive thymocytes. The prevailing model for the induction of peripheral tolerance involves cross-presentation of tissue antigens by quiescent dendritic cells. Here we show that lymph node stromal cells present endogenously expressed PTAs to T cells. Moreover, antigen presentation by lymph node stroma is sufficient to induce primary activation and subsequent tolerance among CD8(+) T cells. Thus, lymph node stromal cells are functionally akin to mTECs and provide a direct strategy for purging the peripheral repertoire of self-reactive T cells.
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Affiliation(s)
- Je-Wook Lee
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Institute, Boston, Massachusetts 02115, USA
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142
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Varol C, Landsman L, Fogg DK, Greenshtein L, Gildor B, Margalit R, Kalchenko V, Geissmann F, Jung S. Monocytes give rise to mucosal, but not splenic, conventional dendritic cells. ACTA ACUST UNITED AC 2006; 204:171-80. [PMID: 17190836 PMCID: PMC2118434 DOI: 10.1084/jem.20061011] [Citation(s) in RCA: 490] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mononuclear phagocyte (MP) system is a body-wide macrophage (MPhi) and dendritic cell (DC) network, which contributes to tissue homeostasis, inflammation, and immune defense. The in vivo origins of MPs remain poorly understood. Here, we use an adoptive precursor cell transfer strategy into MP-depleted mice to establish the in vivo differentiation sequence from a recently identified MPhi/DC-restricted bone marrow (BM) precursor (MDP) via BM and blood intermediates to peripheral MPhis and DCs. We show that MDPs are in vivo precursors of BM and blood monocytes. Interestingly, grafted Gr1high "inflammatory" blood monocytes shuttle back to the BM in the absence of inflammation, convert into Gr1low monocytes, and contribute further to MP generation. The grafted monocytes give rise to DCs in the intestinal lamina propria and lung, but not to conventional CD11chigh DCs in the spleen, which develop during homeostasis from MDPs without a monocytic intermediate.
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Affiliation(s)
- Chen Varol
- Department of Immunology, The Weizmann Institute of Science, 76100 Rehovot, Israel
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143
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Chieppa M, Rescigno M, Huang AYC, Germain RN. Dynamic imaging of dendritic cell extension into the small bowel lumen in response to epithelial cell TLR engagement. ACTA ACUST UNITED AC 2006; 203:2841-52. [PMID: 17145958 PMCID: PMC2118178 DOI: 10.1084/jem.20061884] [Citation(s) in RCA: 534] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cells lining the gastrointestinal tract serve as both a barrier to and a pathway for infectious agent entry. Dendritic cells (DCs) present in the lamina propria under the columnar villus epithelium of the small bowel extend processes across this epithelium and capture bacteria, but previous studies provided limited information on the nature of the stimuli, receptors, and signaling events involved in promoting this phenomenon. Here, we use immunohistochemical as well as dynamic explant and intravital two-photon imaging to investigate this issue. Analysis of CD11c–enhanced green fluorescent protein (EGFP) or major histocompatibility complex CII-EGFP mice revealed that the number of trans-epithelial DC extensions, many with an unusual “balloon” shape, varies along the length of the small bowel. High numbers of such extensions were found in the proximal jejunum, but only a few were present in the terminal ileum. The extensions in the terminal ileum markedly increased upon the introduction of invasive or noninvasive Salmonella organisms, and chimeric mouse studies revealed the key role of MyD88-dependent Toll-like receptor (TLR) signaling by nonhematopoietic (epithelial) elements in the DC extension response. Collectively, these findings support a model in which epithelial cell TLR signaling upon exposure to microbial stimuli induces active DC sampling of the gut lumen at sites distant from organized lymphoid tissues.
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MESH Headings
- Animals
- CD11c Antigen/genetics
- CD11c Antigen/metabolism
- CX3C Chemokine Receptor 1
- Cell Surface Extensions/drug effects
- Cell Surface Extensions/physiology
- Chemokine CCL20
- Chemokines, CC/genetics
- Chemokines, CC/metabolism
- Dendritic Cells/cytology
- Dendritic Cells/immunology
- Dendritic Cells/microbiology
- Epithelial Cells/drug effects
- Epithelial Cells/immunology
- Gene Expression
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/metabolism
- Intestine, Small/cytology
- Intestine, Small/immunology
- Intestine, Small/microbiology
- Laser Scanning Cytometry
- Macrophage Inflammatory Proteins/genetics
- Macrophage Inflammatory Proteins/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Mucous Membrane/cytology
- Mucous Membrane/immunology
- Mucous Membrane/microbiology
- Myeloid Differentiation Factor 88/genetics
- Oligodeoxyribonucleotides/pharmacology
- Polysaccharides, Bacterial/pharmacology
- Receptors, Chemokine/genetics
- Receptors, Chemokine/metabolism
- Salmonella Infections/immunology
- Salmonella Infections/microbiology
- Salmonella typhimurium/immunology
- Signal Transduction/immunology
- Toll-Like Receptors/agonists
- Toll-Like Receptors/physiology
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Affiliation(s)
- Marcello Chieppa
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD 20892, USA
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144
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Soos TJ, Sims TN, Barisoni L, Lin K, Littman DR, Dustin ML, Nelson PJ. CX3CR1+ interstitial dendritic cells form a contiguous network throughout the entire kidney. Kidney Int 2006; 70:591-6. [PMID: 16760907 DOI: 10.1038/sj.ki.5001567] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Dendritic cells (DCs) interface innate and adaptive immunity in nonlymphoid organs; however, the exact distribution and types of DC within the kidney are not known. We utilized CX3CR1GFP/+ mice to characterize the anatomy and phenotype of tissue-resident CX3CR1+ DCs within normal kidney. Laser-scanning confocal microscopy revealed an extensive, contiguous network of stellate-shaped CX3CR1+ DCs throughout the interstitial and mesangial spaces of the entire kidney. Intravital microscopy of the superficial cortex showed stationary interstitial CX3CR1+ DCs that continually probe the surrounding tissue environment through dendrite extensions. Flow cytometry of renal CX3CR1+ DCs showed significant coexpression of CD11c and F4/80, high major histocompatibility complex class II and FcR expression, and immature costimulatory but competent phagocytic ability indicative of tissue-resident, immature DCs ready to respond to environment cues. Thus, within the renal parenchyma, there exists little immunological privilege from the surveillance provided by renal CX3CR1+ DCs, a major constituent of the heterogeneous mononuclear phagocyte system populating normal kidney.
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Affiliation(s)
- T J Soos
- Division of Nephrology, New York University School of Medicine, New York, New York 10016, USA.
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145
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Barnes PD, Bergman MA, Mecsas J, Isberg RR. Yersinia pseudotuberculosis disseminates directly from a replicating bacterial pool in the intestine. ACTA ACUST UNITED AC 2006; 203:1591-601. [PMID: 16754724 PMCID: PMC2118325 DOI: 10.1084/jem.20060905] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dissemination of Yersinia pseudotuberculosis within mice after oral inoculation was analyzed. Y. pseudotuberculosis translocated to organs such as the liver and spleen shortly after oral inoculation, but was quickly cleared. In contrast, a second temporally distinct bacterial translocation event resulted in successful hepatosplenic replication of the bacteria. Replicating pools of bacteria could be established in these organs in mouse mutants that lacked Peyer's patches. These animals frequently had sterile mesenteric lymph nodes, a finding consistent with translocation taking place independently of regional lymph node colonization. In further contradiction to accepted models for dissemination of enteropathogens, clonal analysis revealed that bacteria causing disease in the spleen and liver of C57BL/6J mice were derived from populations located outside the intestinal lymph nodes. Replication of bacteria in the intestine before translocation appeared critical for dissemination, as transient selective suppression by streptomycin of bacterial growth in the intestine delayed dissemination of Y. pseudotuberculosis. These results collectively indicate that hepatosplenic colonization appears intimately connected with the ability of Y. pseudotuberculosis to successfully establish replication in the intestinal lumen and does not result from ordered spread leading from the intestine to regional lymph nodes before dissemination.
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Affiliation(s)
- Penelope D Barnes
- Howard Hughes Medical Institute, Tufts University School of Medicine, Boston, MA 02111, USA
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