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Mukhopadhyay S, Plüddemann A, Hoe JC, Williams KJ, Varin A, Makepeace K, Aknin ML, Bowdish DM, Smale ST, Barclay AN, Gordon S. Immune Inhibitory Ligand CD200 Induction by TLRs and NLRs Limits Macrophage Activation to Protect the Host from Meningococcal Septicemia. Cell Host Microbe 2010; 8:236-47. [DOI: 10.1016/j.chom.2010.08.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 03/26/2010] [Accepted: 07/15/2010] [Indexed: 02/02/2023]
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Abstract
BACKGROUND The novel immunosuppressive molecule, CD200, has been reported to induce immunoregulation after interaction with its receptor(s), CD200R(s), in part at least through augmented induction of regulatory T-cell populations. Independent studies have also described increased expression of indoleamine-2,3-dioxygenase after CD200R triggering, whereas others have provided evidence that TGF-beta is important for the induction or function of many populations of regulatory T cells. We have asked whether a hybrid molecule in which a soluble fusion protein containing CD200, CD200Fc, was linked to TGF-beta through a glycine linker (Gly6) functions as a superior immunosuppressant molecule when compared with CD200Fc or TGF-beta alone, or in combination. METHODS The hybrid molecule CD200FcGly6TGF-beta was expressed by transient transfection in CHO cells and purified over a protein A column. Functional activity of this and recombinant CD200Fc or TGF-beta alone were assessed in mixed leukocyte cultures (MLCs) and in skin graft rejection in vivo. RESULTS Immunosuppression mediated by CD200FcGly6TGF-beta is dependent on both functional CD200 and TGF-beta moieties, as indicated by inhibition of suppression using anti-CD200 or anti-TGF-beta antibodies. Using as responder cells, using antigen-presenting cell from mice with a deletion of the CD200R gene and responder T cells from mice with siRNA-mediated suppression of expression of the TGF-betaII receptor, we show that suppression follows binding to TGF-betaRII on T cells, and CD200R1 on antigen-presenting cells. Indoleamine-2,3-dioxygenase inhibitors did not attenuate suppression by CD200FcGly6TGF-beta. CONCLUSION CD200FcGly6TGF-beta is a potent immunosuppressant in vivo and in vitro.
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Chen Z, Ma X, Zhang J, Hu J, Gorczynski RM. Alternative splicing of CD200 is regulated by an exonic splicing enhancer and SF2/ASF. Nucleic Acids Res 2010; 38:6684-96. [PMID: 20558599 PMCID: PMC2965252 DOI: 10.1093/nar/gkq554] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
CD200, a type I membrane glycoprotein, plays an important role in prevention of inflammatory disorders, graft rejection, autoimmune diseases and spontaneous fetal loss. It also regulates tumor immunity. A truncated CD200 (CD200tr) resulting from alternative splicing has been identified and characterized as a functional antagonist to full-length CD200. Thus, it is important to explore the mechanism(s) controlling alternative splicing of CD200. In this study, we identified an exonic splicing enhancer (ESE) located in exon 2, which is a putative binding site for a splicing regulatory protein SF2/ASF. Deletion or mutation of the ESE site decreased expression of the full-length CD200. Direct binding of SF2/ASF to the ESE site was confirmed by RNA electrophoretic mobility shift assay (EMSA). Knockdown of expression of SF2/ASF resulted in the same splicing pattern as seen after deletion or mutation of the ESE, whereas overexpression of SF2/ASF increased expression of the full-length CD200. In vivo studies showed that viral infection reversed the alternative splicing pattern of CD200 with increased expression of SF2/ASF and the full-length CD200. Taken together, our data suggest for the first time that SF2/ASF regulates the function of CD200 by controlling CD200 alternative splicing, through direct binding to an ESE located in exon 2 of CD200.
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Affiliation(s)
- Zhiqi Chen
- Transplant Research Division, Department of Surgery and Immunology, The Toronto Hospital, University of Toronto, Toronto, Canada.
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Stumpfova M, Ratner D, Desciak EB, Eliezri YD, Owens DM. The immunosuppressive surface ligand CD200 augments the metastatic capacity of squamous cell carcinoma. Cancer Res 2010; 70:2962-72. [PMID: 20332223 DOI: 10.1158/0008-5472.can-09-4380] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
CD200 (OX-2) is a cell surface glycoprotein that imparts immune privileges by suppressing alloimmune and autoimmune responses through its receptor, CD200R, expressed primarily on myeloid cells. The ability of CD200 to suppress myeloid cell activation is critical for maintaining normal tissue homeostasis but may also enhance the survival of migratory neoplastic cells. We show that CD200 expression is largely absent in well-differentiated primary squamous cell carcinoma (SCC) of the skin, but is highly induced in SCC metastases to the lymph node and other solid tissues. CD200 does not influence the proliferative or invasive capacity of SCC cells or their ability to reconstitute primary skin tumors. However, loss of CD200 impairs the ability of SCC cells to metastasize and seed secondary tumors, indicating that the survival of CD200(+) SCC cells may depend on their ability to interact with CD200R(+) immune cells. The predominant population of CD200R(+) stromal cells was CD11b(+)Gr-1(+) myeloid-derived suppressor cells, which release elevated levels of granulocyte colony-stimulating factor and granulocyte macrophage colony-stimulating factor when in the presence of SCC cells in a CD200-dependent manner. Collectively, our findings implicate CD200 as a hallmark of SCC metastasis and suggest that the ability of CD200(+) SCC keratinocytes to directly engage and modulate CD200R(+) myeloid-derived suppressor cells is essential to metastatic survival.
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Affiliation(s)
- Magda Stumpfova
- Departments of Pathology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
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55
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CD200R1 agonist attenuates mechanisms of chronic disease in a murine model of multiple sclerosis. J Neurosci 2010; 30:2025-38. [PMID: 20147531 DOI: 10.1523/jneurosci.4272-09.2010] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
To assess the effects and mechanisms of a CD200R1 agonist administered during the progressive stage of a multiple sclerosis model, we administered CD200R1 agonist (CD200Fc) or control IgG2a during the chronic phase of disease (days 10-30) in mice with experimental autoimmune encephalomyelitis (EAE), induced using myelin oligodendrocyte glycoprotein peptide 35-55 (MOG35-55) peptide. We found that administration of CD200Fc during the chronic stages of EAE reduced disease severity, demyelination, and axonal damage, through the modulation of several key disease mechanisms. CD200Fc treatment suppressed macrophage and microglial accumulation within the CNS, in part through downregulation of adhesion molecules VLA-4 and LFA-1, which are necessary for macrophage migration. Additionally, expression of activation markers MHC-II and CD80 and production of proinflammatory cytokines IL-6, tumor necrosis factor-alpha, and nitric oxide by CD11b(+) cells were decreased in both the spleen and CNS in CD200Fc-treated animals. Antigen-presenting cell function in the spleen and CNS was suppressed in CD200Fc-treated mice, but there were no significant alterations on T cell activation or phenotype. CD200Fc increased apoptosis of CD11b(+) cells but not astrocytes. In contrast, addition of CD200Fc treatment protected oligodendrocytes from apoptosis in vitro and in vivo. Our results demonstrate that CD200R1 agonists modulate both myeloid- and non-myeloid-related mechanisms of chronic disease in the EAE model and may be effective in the treatment of progressive multiple sclerosis and other neurodegenerative diseases.
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56
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Microglia activation and anti-inflammatory regulation in Alzheimer's disease. Mol Neurobiol 2010; 41:115-28. [PMID: 20195797 DOI: 10.1007/s12035-010-8106-8] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 02/04/2010] [Indexed: 12/16/2022]
Abstract
Inflammatory regulators, including endogenous anti-inflammatory systems, can down-regulate inflammation thus providing negative feedback. Chronic inflammation can result from imbalance between levels of inflammatory mediators and regulators during immune responses. As a consequence, there are heightened inflammatory responses and irreversible tissue damage associated with many age-related chronic diseases. Alzheimer's disease (AD) brain is marked by prominent inflammatory features, in which microglial activation is the driving force for the elaboration of an inflammatory cascade. How the regulation of inflammation loses its effectiveness during AD pathogenesis remains largely unclear. In this article, we will first review current knowledge of microglial activation and its association with AD pathology. We then discuss four examples of anti-inflammatory systems that could play a role in regulating microglial activation: CD200/CD200 receptor, vitamin D receptor, peroxisome proliferator-activated receptors, and soluble receptor for advanced glycation end products. Through this, we hope to illustrate the diverse aspects of inflammatory regulatory systems in brain and neurodegenerative diseases such as AD. We also propose the importance of neuronal defense systems, because they are part of the integral inflammatory and anti-inflammatory systems. Augmenting the anti-inflammatory defenses of neurons can be included in the strategy for restoration of balanced immune responses during aging and neurodegenerative diseases.
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57
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A novel anti-inflammatory role of NCAM-derived mimetic peptide, FGL. Neurobiol Aging 2010; 31:118-28. [DOI: 10.1016/j.neurobiolaging.2008.03.017] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 03/03/2008] [Accepted: 03/20/2008] [Indexed: 11/22/2022]
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58
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Mihrshahi R, Barclay AN, Brown MH. Essential roles for Dok2 and RasGAP in CD200 receptor-mediated regulation of human myeloid cells. THE JOURNAL OF IMMUNOLOGY 2009; 183:4879-86. [PMID: 19786546 DOI: 10.4049/jimmunol.0901531] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The CD200 receptor (CD200R) acts as a negative regulator of myeloid cells by interacting with its widely expressed ligand CD200. Using mutants expressed in U937 cells, we show that inhibition is mediated by the PTB domain binding motif (NPLY) in the receptor's cytoplasmic region. The adaptor protein downstream of tyrosine kinase 2 (Dok2) bound directly to the phosphorylated NPLY motif with a 10-fold higher affinity (K(D) of approximately 1 microM at 37 degrees C) than the closely related Dok1. Both of these proteins have been suggested to play a role in CD200R signaling in murine cells. Dok2 was phosphorylated in response to CD200R engagement and recruited RAS p21 protein activator 1 (RasGAP). Knockdown of Dok2 and RasGAP by RNA interference revealed that these proteins are required for CD200R signaling, while knockdown of Dok1 and the inositol 5-phosphatase SHIP did not affect CD200R-mediated inhibition. We conclude that CD200R inhibits the activation of human myeloid cells through direct recruitment of Dok2 and subsequent activation of RasGAP, which distinguishes this receptor from the majority of inhibitory receptors that utilize ITIMs and recruit phosphatases.
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Affiliation(s)
- Robin Mihrshahi
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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59
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Gorczynski RM, Chen Z, He W, Khatri I, Sun Y, Yu K, Boudakov I. Expression of a CD200 transgene is necessary for induction but not maintenance of tolerance to cardiac and skin allografts. THE JOURNAL OF IMMUNOLOGY 2009; 183:1560-8. [PMID: 19592654 DOI: 10.4049/jimmunol.0900200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CD200, a type 2 transmembrane molecule of the Ig supergene family, can induce immunosuppression in a number of biological systems, as well as promote increased graft acceptance, following binding to its receptors (CD200Rs). Skin and cardiac allograft acceptance are readily induced in transgenic mice overexpressing CD200 under control of a doxycycline-inducible promoter, both of which are associated with increased intragraft expression of mRNAs for a number of genes associated with altered T cell subset differentiation, including GATA-3, type 2 cytokines (IL-4, IL-13), GITR, and Foxp3. Interestingly, some 12-15 days after grafting, induction of transgenic CD200 expression can be stopped (by doxycycline withdrawal), without obvious significant effect on graft survival. However, neutralization of all CD200 expression (including endogenous CD200 expression) by anti-CD200 mAb caused graft loss, as did introduction of an acute inflammatory stimulus (LPS, 10 microg/mouse, delivered by i.p. injection). We conclude that even with apparently stably accepted tissue allografts, disruption of the immunoregulatory balance by an intense inflammatory stimulus can cause graft loss.
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60
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Role of a distal enhancer in the transcriptional responsiveness of the human CD200 gene to interferon-γ and tumor necrosis factor-α. Mol Immunol 2009; 46:1951-63. [DOI: 10.1016/j.molimm.2009.03.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Revised: 02/18/2009] [Accepted: 03/19/2009] [Indexed: 11/20/2022]
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61
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Khatri I, Alexander C, Brandenburg K, Fournier K, Mach JP, Rietschel ET, Ulmer AJ, Terzioglu E, Waelli T, Gorczynski RM. Induction of tolerogenic vs immunogenic dendritic cells (DCs) in the presence of GM-CSF is regulated by the strength of signaling from monophosphoryl lipid A (MPLA) in association with glutathione and fetal hemoglobin gamma-chain. Immunol Lett 2009; 124:44-9. [PMID: 19379773 DOI: 10.1016/j.imlet.2009.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 03/31/2009] [Accepted: 04/07/2009] [Indexed: 12/22/2022]
Abstract
Previous studies showed a fetal sheep liver extract (FSLE), in association with monophosphoryl lipid A, MPLA (a bioactive component of lipid A of LPS), could interact to induce the development of dendritic cells (DCs) which regulated production of Foxp3+ Treg. This interaction was associated with an altered gene expression both of distinct subsets of TLRs and of CD200Rs. Prior studies had suggested that major interacting components within FSLE were gamma-chain of fetal hemoglobin (Hgbgamma) and glutathione (GSH). We investigated whether differentiation/maturation of DCs in vitro in the presence of either GM-CSF or Flt3L to produce preferentially either immunogenic or tolerogenic DCs was itself controlled by an interaction between MPLA, GSH and Hgbgamma. At low (approximately 10 microg/ml) Hgbgamma concentrations, DCs developing in culture with GSH and MPLA produced optimal stimulation of allogeneic CTL cell responses in vitro (and enhanced skin graft rejection in vivo). At higher concentrations (>40 microg/ml Hgbgamma) and equivalent concentrations of MPLA and GSH, the DCs induce populations of Treg which can suppress the induction of allogeneic CTL and graft rejection in vivo. These different populations of DCs express different patterns of mRNAs for the CD200R family. Addition of anti-TLR or anti-MD-1 mAbs to DCs developing in this mixture (Hgbgamma+GSH+MPLA), suggests that one effect of (GSH+Hgbgamma) on MPLA stimulation may involve altered signaling through TLR4.
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Affiliation(s)
- Ismat Khatri
- Department of Surgery, University Health Network, Toronto, Ont., Canada
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62
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Tian L, Rauvala H, Gahmberg CG. Neuronal regulation of immune responses in the central nervous system. Trends Immunol 2009; 30:91-9. [PMID: 19144568 DOI: 10.1016/j.it.2008.11.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 11/21/2008] [Accepted: 11/21/2008] [Indexed: 10/21/2022]
Abstract
The central nervous system (CNS) has traditionally been considered to be immunologically privileged, but over the years there has been a re-evaluation of this dogma. To date, studies have tended to focus on the immune functions of glial cells, whereas the roles of neurons have been regarded as passive and their immune-regulatory properties have been less examined. However, recent findings indicate that CNS neurons actively participate in immune regulation by controlling their glial cell counterparts and infiltrated T cells. Here, we describe the immune-regulatory roles of CNS neurons by both contact-dependent and contact-independent mechanisms. In addition, we specifically deal with the immune functions of neuronal cell adhesion molecules, many of which are key modulators of neuronal synaptic formation and plasticity.
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Affiliation(s)
- Li Tian
- Neuroscience Center, University of Helsinki, Viikinkaari 4, FIN-00014, Helsinki, Finland.
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63
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Identification of an Expressed Truncated Form of CD200, CD200tr, which is a Physiologic Antagonist of CD200-Induced Suppression. Transplantation 2008; 86:1116-24. [DOI: 10.1097/tp.0b013e318186fec2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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64
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Walker DG, Dalsing-Hernandez JE, Campbell NA, Lue LF. Decreased expression of CD200 and CD200 receptor in Alzheimer's disease: a potential mechanism leading to chronic inflammation. Exp Neurol 2008; 215:5-19. [PMID: 18938162 DOI: 10.1016/j.expneurol.2008.09.003] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 08/17/2008] [Accepted: 09/04/2008] [Indexed: 12/24/2022]
Abstract
Inflammatory activation of microglia in response to neurodegenerative changes in diseases such as Alzheimer's disease (AD) and Parkinson's disease has been extensively described. These observations have suggested that inflammation could be contributing to disease progression. In this paper, the potential role of CD200 and CD200 receptor (CD200R), whose known functions are to activate anti-inflammatory pathways and induce immune tolerance through binding of CD200 to CD200 receptor (CD200R), was studied in AD. Quantitative studies showed a significant decrease in CD200 protein and mRNA in AD hippocampus and inferior temporal gyrus, but not cerebellum. Immunohistochemistry of brain tissue sections of hippocampus, superior frontal gyrus, inferior temporal gyrus and cerebellum from AD and non-demented cases demonstrated a predominant, though heterogeneous, neuronal localization for CD200. Decreased neuronal expression was apparent in brain regions affected by AD pathology. There was also a significant decrease in CD200R mRNA expression in AD hippocampus and inferior temporal gyrus, but not cerebellum. Low expression of CD200R by microglia was confirmed at the mRNA and protein level using cultured human microglia compared to blood-derived macrophages. Treatment of microglia and macrophages with interleukin-4 and interleukin-13 significantly increased expression of CD200R. Expression of these cytokines was not generally detectable in brain. These data indicate that the anti-inflammatory CD200/CD200R system may be deficient in AD brains. Mechanisms aimed at increasing levels of CD200 and CD200R could have therapeutic potential for controlling inflammation in human neurodegenerative diseases.
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Affiliation(s)
- Douglas G Walker
- Laboratory of Neuroinflammation, Sun Health Research Institute, 10515 West Santa Fe Drive, Sun City, Arizona 85351, USA.
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65
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Khatri I, Alexander C, Brandenburg K, Fournier K, Lee L, Mach J, Rietschel E, Ulmer A, Waelli T, Gorczynski R. A role for altered TLR gene expression in association with increased expression of CD200R in the induction of mucosal tissue CD4+ Treg in aged mice following gavage with a liver extract along with intramuscular monophosphoryl lipid A (MPLA) injection. Exp Gerontol 2008; 43:771-81. [DOI: 10.1016/j.exger.2008.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 04/16/2008] [Accepted: 05/06/2008] [Indexed: 12/30/2022]
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66
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A critical function for CD200 in lung immune homeostasis and the severity of influenza infection. Nat Immunol 2008; 9:1074-83. [PMID: 18660812 DOI: 10.1038/ni.1637] [Citation(s) in RCA: 345] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 06/25/2008] [Indexed: 01/13/2023]
Abstract
The lung must maintain a high threshold of immune 'ignorance' to innocuous antigens to avoid inflammatory disease that depends on the balance of positive inflammatory signals and repressor pathways. We demonstrate here that airway macrophages had higher expression of the negative regulator CD200 receptor (CD200R) than did their systemic counterparts. Lung macrophages were restrained by CD200 expressed on airway epithelium. Mice lacking CD200 had more macrophage activity and enhanced sensitivity to influenza infection, which led to delayed resolution of inflammation and, ultimately, death. The administration of agonists that bind CD200R, however, prevented inflammatory lung disease. Thus, CD200R is critical for lung macrophage immune homeostasis in the resting state and limits inflammatory amplitude and duration during pulmonary influenza infection.
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67
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Gorczynski R, Khatri I, Lee L, Boudakov I. An Interaction between CD200 and Monoclonal Antibody Agonists to CD200R2 in Development of Dendritic Cells That Preferentially Induce Populations of CD4+CD25+ T Regulatory Cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:5946-55. [DOI: 10.4049/jimmunol.180.9.5946] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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68
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Gorczynski R, Boudakov I, Khatri I. Peptides of CD200 Modulate LPS-Induced TNF-α Induction and Mortality In Vivo. J Surg Res 2008; 145:87-96. [DOI: 10.1016/j.jss.2007.04.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Revised: 04/19/2007] [Accepted: 04/25/2007] [Indexed: 10/22/2022]
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