3201
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Zhang Y, Bliska JB. Role of Toll-like receptor signaling in the apoptotic response of macrophages to Yersinia infection. Infect Immun 2003; 71:1513-9. [PMID: 12595470 PMCID: PMC148878 DOI: 10.1128/iai.71.3.1513-1519.2003] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Macrophages encode several Toll-like receptors (TLRs) that recognize bacterial components, such as lipoproteins (TLR2) or lipopolysaccharides (TLR4), and activate multiple signaling pathways. Activation of transcription factor NF-kappaB by TLR2 or TLR4 signaling promotes proinflammatory and cell survival responses. Alternatively, TLR2 or TLR4 signaling can promote apoptosis if the activation of NF-kappaB is blocked. The gram-negative bacterial pathogen Yersinia pseudotuberculosis secretes into macrophages a protease (YopJ) that inhibits the activation of NF-kappaB and promotes apoptosis. We show that primary macrophages expressing constitutively active inhibitor kappaB kinase beta (IKKbeta) are completely resistant to YopJ-dependent apoptosis, indicating that YopJ inhibits signaling upstream of IKKbeta. Apoptosis is reduced two- to threefold in TLR4(-/-) macrophages infected with Y. pseudotuberculosis, while the apoptotic response of TLR2(-/-) macrophages to Y. pseudotuberculosis infection is equivalent to that of wild-type macrophages. Therefore, TLR4 is the primary source of apoptotic signaling in Yersinia-infected macrophages. Our results also show that a small percentage of macrophages can die as a result of an apoptotic process that is YopJ dependent but does not require TLR2 or TLR4 signaling.
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Affiliation(s)
- Yue Zhang
- Center for Infectious Diseases, Department of Molecular Genetics and Microbiology, State University of New York at Stony Brook, Stony Brook, New York 11794-5120, USA
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3202
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Byl B, Libin M, Bauer J, Martin OR, De Wit D, Davies G, Goldman M, Willems F. OM197-MP-AC induces the maturation of human dendritic cells and promotes a primary T cell response. Int Immunopharmacol 2003; 3:417-25. [PMID: 12639819 DOI: 10.1016/s1567-5769(03)00008-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Dendritic cell (DC) maturation is critical for the induction of antigen-specific T lymphocyte responses and may be essential for the development of human vaccines relying on T cell immunity. We investigated the effects on human DC of OM-197, a synthetic pseudodipeptide derived from amino acids, linked to three fatty acid chains and devoid of endotoxin properties. OM-197 upregulated the expression of HLA-DR, CD80, CD86, CD83, CD40 and CD54 at the surface of myeloid DC naturally present in blood as well as of DC generated in vitro from monocytes using IL-4 and GM-CSF. OM-197 also induced the release of IL-12 and TNF-alpha from DC. Finally, DC incubated with OM-197 after pulsing with hepatitis B surface antigen (HBs Ag) induced in vitro expansion of IFN-gamma-secreting HBs Ag-specific CD4(+) T lymphocytes from naive individuals. Taken together, these data identify OM-197 as a potential vaccine adjuvant for the induction of Th1-type responses.
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Affiliation(s)
- B Byl
- Laboratoire d'Immunologie Expérimentale, Université Libre de Bruxelles, Brussels, Belgium
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3203
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Abstract
Toll receptors in insects, mammals and plants are key players that sense the invasion of pathogens. Toll-like receptors (TLRs) in mammals have been established to detect specific components of bacterial and fungal pathogens. Furthermore, recent evidence indicates that TLRs are involved in the recognition of viral invasion. Signalling pathways via TLRs originate from the conserved Toll/IL-1 receptor (TIR) domain. The TIR domain-containing MyD88 acts as a common adaptor that induces inflammatory cytokines; however, there exists a MyD88-independent pathway that induces type I IFNs in TLR4 and TLR3 signalling. Another TIR domain-containing adaptor, TIRAP/Mal has recently been shown to mediate the MyD88-dependent activation in the TLR4 and TLR2 signalling pathway. Thus, individual TLRs may have their own signalling systems that characterize their specific activities.
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Affiliation(s)
- Kiyoshi Takeda
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, and SORST of Japan Science and Technology Corporation, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
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3204
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Klinman D. Does activation of the innate immune system contribute to the development of rheumatoid arthritis? ARTHRITIS AND RHEUMATISM 2003; 48:590-3. [PMID: 12632408 DOI: 10.1002/art.10852] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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3205
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Caramalho I, Lopes-Carvalho T, Ostler D, Zelenay S, Haury M, Demengeot J. Regulatory T cells selectively express toll-like receptors and are activated by lipopolysaccharide. J Exp Med 2003; 197:403-11. [PMID: 12591899 PMCID: PMC2193858 DOI: 10.1084/jem.20021633] [Citation(s) in RCA: 761] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Regulatory CD4 T cells (Treg) control inflammatory reactions to commensal bacteria and opportunist pathogens. Activation of Treg functions during these processes might be mediated by host-derived proinflammatory molecules or directly by bacterial products. We tested the hypothesis that engagement of germline-encoded receptors expressed by Treg participate in the triggering of their function. We report that the subset of CD4 cells known to exert regulatory functions in vivo (CD45RB(low) CD25(+)) selectively express Toll-like receptors (TLR)-4, -5, -7, and -8. Exposure of CD4(+) CD25(+) cells to the TLR-4 ligand lipopolysaccharide (LPS) induces up-regulation of several activation markers and enhances their survival/proliferation. This proliferative response does not require antigen-presenting cells and is augmented by T cell receptor triggering and interleukin 2 stimulation. Most importantly, LPS treatment increases CD4(+) CD25(+) cell suppressor efficiency by 10-fold and reveals suppressive activity in the CD4(+) CD45RB(low) CD25(-) subset that when tested ex-vivo, scores negative. Moreover, LPS-activated Treg efficiently control naive CD4 T cell-dependent wasting disease. These findings provide the first evidence that Treg respond directly to proinflammatory bacterial products, a mechanism that likely contributes to the control of inflammatory responses.
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Affiliation(s)
- Iris Caramalho
- Instituto Gulbenkian de Ciência, 2781-901 Oeiras, Portugal
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3206
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Sakaguchi S. Control of immune responses by naturally arising CD4+ regulatory T cells that express toll-like receptors. J Exp Med 2003; 197:397-401. [PMID: 12591898 PMCID: PMC2193860 DOI: 10.1084/jem.20030012] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Shimon Sakaguchi
- Department of Experimental Pathology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
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3207
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Hagiwara K, Kikuchi T, Endo Y, Usui K, Takahashi M, Shibata N, Kusakabe T, Xin H, Hoshi S, Miki M, Inooka N, Tokue Y, Nukiwa T. Mouse SWAM1 and SWAM2 are antibacterial proteins composed of a single whey acidic protein motif. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1973-9. [PMID: 12574366 DOI: 10.4049/jimmunol.170.4.1973] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Antibacterial proteins are important participants in the innate immunity system. Elafin and SLPI are the whey acidic protein (WAP) motif proteins with both antibacterial activity and antiprotease activity, and their role in innate immunity is under intense investigation. We cloned two novel antibacterial WAP motif proteins from mice, SWAM1 and SWAM2. SWAM1 and SWAM2 are composed of a signal sequence and a single WAP motif that has high homologies with the WAP motifs of elafin and SLPI. SWAM1 is constitutively expressed in kidney and epididymis, and is induced in the pneumonic lung. SWAM2 is constitutively expressed in tongue. SWAM1 and SWAM2 inhibit the growth of both Escherichia coli and Staphylococcus aureus at a IC(90) (concentration that achieves 90% inhibition) of 10 microM. Human genes LOC149709 and huWAP2 are considered to be human SWAM1 and SWAM2, respectively. These and several WAP motif proteins (WAP1, elafin, SLPI, HE4, eppin, C20orf170, LOC164237, and WFDC3) form a gene cluster on human chromosome 20, suggesting that they may be derived from the same ancestral gene by gene duplication. Our results underscore the role of the WAP motif as a skeletal motif to form antibacterial proteins, and warrant the study of antibacterial activity in other WAP motif proteins.
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Affiliation(s)
- Koichi Hagiwara
- Department of Respiratory Oncology and Molecular Medicine, Division of Cancer Control, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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3208
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Lobell A, Weissert R, Eltayeb S, de Graaf KL, Wefer J, Storch MK, Lassmann H, Wigzell H, Olsson T. Suppressive DNA vaccination in myelin oligodendrocyte glycoprotein peptide-induced experimental autoimmune encephalomyelitis involves a T1-biased immune response. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1806-13. [PMID: 12574345 DOI: 10.4049/jimmunol.170.4.1806] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Vaccination with DNA encoding a myelin basic protein peptide suppresses Lewis rat experimental autoimmune encephalomyelitis (EAE) induced with the same peptide. Additional myelin proteins, such as myelin oligodendrocyte glycoprotein (MOG), may be important in multiple sclerosis. Here we demonstrate that DNA vaccination also suppresses MOG peptide-induced EAE. MOG(91-108) is encephalitogenic in DA rats and MHC-congenic LEW.1AV1 (RT1(av1)) and LEW.1N (RT1(n)) rats. We examined the effects of DNA vaccines encoding MOG(91-108) in tandem, with or without targeting of the hybrid gene product to IgG. In all investigated rat strains DNA vaccination suppressed clinical signs of EAE. There was no requirement for targeting the gene product to IgG, but T1-promoting CpG DNA motifs in the plasmid backbone of the construct were necessary for efficient DNA vaccination, similar to the case in DNA vaccination in myelin basic protein-induced EAE. We failed to detect any effects on ex vivo MOG-peptide-induced IFN-gamma, TNF-alpha, IL-6, IL-4, IL-10, and brain-derived neurotropic factor expression in splenocytes or CNS-derived lymphocytes. In CNS-derived lymphocytes, Fas ligand expression was down-regulated in DNA-vaccinated rats compared with controls. However, MOG-specific IgG2b responses were enhanced after DNA vaccination. The enhanced IgG2b responses together with the requirement for CpG DNA motifs in the vaccine suggest a protective mechanism involving induction of a T1-biased immune response.
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MESH Headings
- Amino Acid Sequence
- Animals
- B-Lymphocyte Subsets/immunology
- Cells, Cultured
- CpG Islands/immunology
- DNA, Bacterial/immunology
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/mortality
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/prevention & control
- Female
- Guinea Pigs
- Immunosuppressive Agents/administration & dosage
- Immunosuppressive Agents/immunology
- Injections, Intramuscular
- Mice
- Molecular Sequence Data
- Myelin-Associated Glycoprotein/administration & dosage
- Myelin-Associated Glycoprotein/genetics
- Myelin-Associated Glycoprotein/immunology
- Myelin-Oligodendrocyte Glycoprotein
- Peptide Fragments/administration & dosage
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Rats
- Rats, Inbred Lew
- T-Lymphocyte Subsets/immunology
- Th1 Cells/immunology
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
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Affiliation(s)
- Anna Lobell
- Neuroimmunology Unit, Center for Molecular Medicine, L8:04, Karolinska Hospital, 171 76 Stockholm, Sweden.
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3209
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McCurdy JD, Olynych TJ, Maher LH, Marshall JS. Cutting edge: distinct Toll-like receptor 2 activators selectively induce different classes of mediator production from human mast cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1625-9. [PMID: 12574323 DOI: 10.4049/jimmunol.170.4.1625] [Citation(s) in RCA: 270] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mast cells play a critical role in host defense against bacterial infection. Murine mast cells produce cytokines in response to bacterial peptidoglycan and LPS via Toll-like receptor (TLR) TLR2- and TLR4-dependent mechanisms. The expression of TLRs by human mast cells and responses to known TLR activators was examined. Human mast cells expressed mRNA for TLR1, TLR2, and TLR6 but not TLR4. Bacterial peptidoglycan and yeast zymosan were potent inducers of GM-CSF and IL-1beta and also induced substantial short-term cysteinyl leukotriene generation. In contrast, a synthetic triacylated lipopeptide induced short-term degranulation but failed to induce cysteinyl leukotriene production. The TLR4 activator Escherichia coli LPS did not induce a GM-CSF, IL-1beta leukotriene, or degranulation response. These data demonstrate highly selective production of different classes of mast cell mediators in response to distinct TLR activators of potential importance to the host response to bacterial or fungal pathogens.
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Affiliation(s)
- Jeffrey D McCurdy
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, B3H 4H7 Canada
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3210
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Yanagisawa K, Tago K, Hayakawa M, Ohki M, Iwahana H, Tominaga SI. A novel splice variant of mouse interleukin-1-receptor-associated kinase-1 (IRAK-1) activates nuclear factor-kappaB (NF-kappaB) and c-Jun N-terminal kinase (JNK). Biochem J 2003; 370:159-66. [PMID: 12418963 PMCID: PMC1223149 DOI: 10.1042/bj20021218] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2002] [Revised: 10/30/2002] [Accepted: 11/06/2002] [Indexed: 12/15/2022]
Abstract
Interleukin-1 (IL-1)-receptor-associated kinase (IRAK) is an indispensable signalling molecule for host-defence responses initiated by a variety of ligands that bind to members of the Toll/IL-1 receptor family. Here we report a novel splice variant of mouse IRAK-1, IRAK-1-S, which is generated by utilizing a new splicing acceptor site within exon 12. IRAK-1-S cDNA is shorter than the originally reported IRAK-1 (IRAK-1-W) cDNA by 271 nucleotides, and the subsequent frameshift causes a premature termination of translation after 23 amino acids, which are unique to the IRAK-1-S protein. To elucidate the physiological function of IRAK-1-S, we overexpressed it in 293T cells and studied the effects on the IL-1 signalling cascade. As it lacks the C-terminal region of IRAK-1-W that has been reported to contain the TRAF6 (tumour necrosis factor receptor-associated factor 6) binding domain, IRAK-1-S was unable to bind TRAF6 protein, which is a proposed downstream signalling molecule. However, IRAK-1-S overexpressed in 293T cells induced constitutive activation of nuclear factor-kappaB (NF-kappaB) and c-Jun N-terminal kinase (JNK) independent of stimulation by IL-1, as did IRAK-1-W. To clarify the mechanism of NF-kappaB activation by IRAK-1-S in the absence of binding to TRAF6, we demonstrated that IRAK-1-S binds to IRAK-1-W through its death domain; the findings suggested that overexpressed IRAK-1-S may bind endogenous IRAK-1-W and activate TRAF6 through IRAK-1-W. These results also indicate that this novel variant may play roles in the activation of NF-kappaB and JNK by IL-1 and other ligands whose signal transduction is dependent on IRAK-1 under physiological conditions.
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Affiliation(s)
- Ken Yanagisawa
- Department of Biochemistry, Jichi Medical School, 3311-1 Yakushiji, Minamikawachi-machi, Kawachi-gun, Tochigi, 329-0498, Japan.
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3211
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Pasare C, Medzhitov R. Toll pathway-dependent blockade of CD4+CD25+ T cell-mediated suppression by dendritic cells. Science 2003; 299:1033-6. [PMID: 12532024 DOI: 10.1126/science.1078231] [Citation(s) in RCA: 1558] [Impact Index Per Article: 74.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Toll-like receptors (TLRs) control activation of adaptive immune responses by antigen-presenting cells (APCs). However, initiation of adaptive immune responses is also controlled by regulatory T cells (TR cells), which act to prevent activation of autoreactive T cells. Here we describe a second mechanism of immune induction by TLRs, which is independent of effects on costimulation. Microbial induction of the Toll pathway blocked the suppressive effect of CD4+CD25+ TR cells, allowing activation of pathogen-specific adaptive immune responses. This block of suppressor activity was dependent in part on interleukin-6, which was induced by TLRs upon recognition of microbial products.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Animals
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation/metabolism
- Cells, Cultured
- Culture Media, Conditioned
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Dinucleoside Phosphates/immunology
- Drosophila Proteins
- Immune Tolerance
- Immunization
- Interleukin-6/metabolism
- Interleukin-6/physiology
- Lipopolysaccharides/immunology
- Lymphocyte Activation
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred C57BL
- Myeloid Differentiation Factor 88
- Ovalbumin/immunology
- Receptors, Cell Surface/physiology
- Receptors, Immunologic/metabolism
- Self Tolerance
- T-Lymphocytes/immunology
- T-Lymphocytes, Regulatory/immunology
- Toll-Like Receptors
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Affiliation(s)
- Chandrashekhar Pasare
- Howard Hughes Medical Institute and Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
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3212
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Cateni C, Paulesu L, Bigliardi E, Hamlett WC. The interleukin 1 (IL-1) system in the uteroplacental complex of a cartilaginous fish, the smoothhound shark, Mustelus canis. Reprod Biol Endocrinol 2003; 1:25. [PMID: 12646051 PMCID: PMC151797 DOI: 10.1186/1477-7827-1-25] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2003] [Accepted: 02/14/2003] [Indexed: 11/10/2022] Open
Abstract
Cartilaginous fish are the oldest extant jawed vertebrates and the oldest line to have placentae. Their pivotal evolutionary position makes them attractive models to investigate the mechanisms involved in the maternal-fetal interaction. This study describes the tissue expression of the cytokine interleukin-1 (IL-1) alpha, IL-1 beta and its specific membrane receptor, IL-1 receptor type I (IL-1R tI) in a placental cartilaginous fish, the smoothhound shark, Mustelus canis. The presence of this cytokine has been reported in many mammalian placentae, as well as in the placenta of a squamate reptile and this study extends these observations to the cartilaginous fishes. The uteroplacental complex in M. canis consists of a yolk sac modified into a functional yolk sac placenta and complimentary uterine attachment sites. Immunohistochemistry for IL-1 alpha, IL-1 beta and the receptor reveals leucocytes of both the mother and fetus to be positive, as well as the apical aspect of paraplacental cells and the apical vesicles in the umbilical cord epithelium. Yolk sac endoderm is also positive with all the stains while the ectoderm is positive only for IL-1 alpha. Immunoreactivity in the uterine epithelium was obtained for IL-1 alpha and the receptor. The egg envelope is always negative. In light of the recent finding of IL-1 beta gene in a cartilaginous fish and of the high level of conservation of proteins implicated in IL-1 action, our data suggest that IL-1 system is a key mediator of the materno-fetal interaction since the oldest extant placental vertebrates.
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Affiliation(s)
- Chiara Cateni
- Department of Physiology, University of Siena, Siena, Italy
| | - Luana Paulesu
- Department of Physiology, University of Siena, Siena, Italy
| | - Elisa Bigliardi
- Department of Evolutionary Biology, University of Siena, Siena, Italy
| | - William C Hamlett
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Notre Dame, Indiana, USA
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3213
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Affiliation(s)
- Fiona Powrie
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK. fiona.powrie@path. ox.ac.uk
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3214
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Harte MT, Haga IR, Maloney G, Gray P, Reading PC, Bartlett NW, Smith GL, Bowie A, O'Neill LAJ. The poxvirus protein A52R targets Toll-like receptor signaling complexes to suppress host defense. J Exp Med 2003; 197:343-51. [PMID: 12566418 PMCID: PMC2193841 DOI: 10.1084/jem.20021652] [Citation(s) in RCA: 282] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Toll-like receptors (TLRs) are crucial in the innate immune response to pathogens, in that they recognize and respond to pathogen associated molecular patterns, which leads to activation of intracellular signaling pathways and altered gene expression. Vaccinia virus (VV), the poxvirus used to vaccinate against smallpox, encodes proteins that antagonize important components of host antiviral defense. Here we show that the VV protein A52R blocks the activation of the transcription factor nuclear factor kappa B (NF-kappa B) by multiple TLRs, including TLR3, a recently identified receptor for viral RNA. A52R associates with both interleukin 1 receptor-associated kinase 2 (IRAK2) and tumor necrosis factor receptor-associated factor 6 (TRAF6), two key proteins important in TLR signal transduction. Further, A52R could disrupt signaling complexes containing these proteins. A virus deletion mutant lacking the A52R gene was attenuated compared with wild-type and revertant controls in a murine intranasal model of infection. This study reveals a novel mechanism used by VV to suppress the host immunity. We demonstrate viral disabling of TLRs, providing further evidence for an important role for this family of receptors in the antiviral response.
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Affiliation(s)
- Mary T Harte
- The Cytokine Research Group, Department of Biochemistry, Trinity College, Dublin 2, Ireland
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3215
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Hatakeyama J, Tamai R, Sugiyama A, Akashi S, Sugawara S, Takada H. Contrasting responses of human gingival and periodontal ligament fibroblasts to bacterial cell-surface components through the CD14/Toll-like receptor system. ORAL MICROBIOLOGY AND IMMUNOLOGY 2003; 18:14-23. [PMID: 12588454 DOI: 10.1034/j.1399-302x.2003.180103.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We compared human periodontal ligament fibroblasts with human gingival fibroblasts isolated from the same donor to examine interleukin-8 (IL-8) responses of the cells to Salmonella lipopolysaccharide, a water-soluble peptidoglycan from Staphylococcus epidermidis and the synthetic muramyldipeptide, with special reference to the possible involvement of the CD14/Toll-like receptor (TLR) system of the cells in the responses. Human gingival fibroblasts expressed CD14 on their surfaces and strongly expressed CD14 mRNA, while human periodontal ligament fibroblasts showed considerably lower levels of expression in both respects. Both cells expressed mRNA of TLR-related molecules, i.e. TLR2, TLR4, MD-2 and MyD88, although human periodontal ligament fibroblasts expressed TLR2 more strongly than human gingival fibroblasts. Human gingival fibroblasts exhibited a stronger IL-8 response than human periodontal ligament fibroblasts to lipopolysaccharide, while human periodontal ligament fibroblasts exhibited a response comparable to, or slightly stronger than, that of human gingival fibroblasts to S. epidermidis peptidoglycan and muramyldipeptide. The IL-8 responses of both cells to lipopolysaccharide and S. epidermidis peptidoglycan were completely inhibited by antihuman CD14 monoclonal antibody (MAb). The responses of both cells to lipopolysaccaride were significantly inhibited by antihuman TLR4 MAb, while those to S. epidermidis peptidoglycan were inhibited by antihuman TLR2 MAb. In contrast, muramyldipeptide activated both types of cells in a TLR2- and TLR4-independent manner, although the activities of muramyldipeptide on human gingival fibroblasts, but not human periodontal ligament fibroblasts, were significantly inhibited by anti-CD14 MAb.
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Affiliation(s)
- J Hatakeyama
- Department of Microbiology and Immunology,Tohoku University School of Dentistry, Sendai, Japan
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3216
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Tsujimura H, Tamura T, Gongora C, Aliberti J, Reis e Sousa C, Sher A, Ozato K. ICSBP/IRF-8 retrovirus transduction rescues dendritic cell development in vitro. Blood 2003; 101:961-9. [PMID: 12393459 DOI: 10.1182/blood-2002-05-1327] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dendritic cells (DCs) develop from bone marrow (BM) progenitor cells and mature in response to external signals to elicit functions important for innate and adaptive immunity. Interferon consensus sequence binding protein (ICSBP; also called interferon regulatory factor 8 [IRF-8]) is a hematopoietic cell-specific transcription factor expressed in BM progenitor cells that contributes to myeloid cell development. In light of our earlier observation that ICSBP(-/-) mice lack CD8alpha(+) DCs, we investigated the role of ICSBP in DC development in vitro in the presence of Flt3 ligand. Immature ICSBP(-/-) DCs developed from BM progenitor cells showed assorted defects, did not mature in response to activation signals, and failed to express CD8alpha and interleukin 12 (IL-12) p40, a feature consistent with ICSBP(-/-) DCs in vivo. We show that retroviral introduction of ICSBP restores the development of immature DCs that can fully mature on activation signals. All the defects seen with ICSBP(-/-) DCs were corrected after ICSBP transduction, including the expression of CD8alpha and IL-12 p40 as well as major histocompatability complex class II and other costimulatory molecules. ICSBP is known to regulate gene expression by interacting with partner proteins PU.1 and IRFs, thereby binding to target elements ISRE and EICE. Analysis of a series of ICSBP mutants showed that the intact DNA-binding activity as well as the ability to interact with partner proteins are required for the restoration of DC development/maturation, pointing to the transcriptional function of ICSBP as a basis of restoration. Taken together, this study identifies ICSBP as a factor critical for both early differentiation and final maturation of DCs.
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Affiliation(s)
- Hideki Tsujimura
- Laboratory of Molecular Growth Regulation, National Institute of Child Health and Human Development, National Institutes of Health (NIH), Bethesda, MD 20892, USA
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3217
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Affiliation(s)
- Shizuo Akira
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
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3218
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Melmed G, Thomas LS, Lee N, Tesfay SY, Lukasek K, Michelsen KS, Zhou Y, Hu B, Arditi M, Abreu MT. Human intestinal epithelial cells are broadly unresponsive to Toll-like receptor 2-dependent bacterial ligands: implications for host-microbial interactions in the gut. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1406-15. [PMID: 12538701 DOI: 10.4049/jimmunol.170.3.1406] [Citation(s) in RCA: 326] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Intestinal epithelial cells (IEC) interact with a high density of Gram-positive bacteria and are active participants in mucosal immune responses. Recognition of Gram-positive organisms by Toll-like receptor (TLR)2 induces proinflammatory gene expression by diverse cells. We hypothesized that IEC are unresponsive to Gram-positive pathogen-associated molecular patterns and sought to characterize the functional responses of IEC to TLR2-specific ligands. Human colonic epithelial cells isolated by laser capture microscopy and IEC lines (Caco-2, T84, HT-29) were analyzed for expression of TLR2, TLR6, TLR1, and Toll inhibitory protein (Tollip) mRNA by RT-PCR and quantitative real-time PCR. Response to Gram-positive bacterial ligands was measured by NF-kappa B reporter gene activation and IL-8 secretion. TLR2 protein expression was analyzed by immunofluorescence and flow cytometry. Colonic epithelial cells and lamina propria cells from both uninflamed and inflamed tissue demonstrate low expression of TLR2 mRNA compared with THP-1 monocytes. IECs were unresponsive to TLR2 ligands including the staphylococcal-derived Ags phenol soluble modulin, peptidoglycan, and lipotechoic acid and the mycobacterial-derived Ag soluble tuberculosis factor. Transgenic expression of TLR2 and TLR6 restored responsiveness to phenol soluble modulin and peptidoglycan in IEC. In addition to low levels of TLR2 protein expression, IEC also express high levels of the inhibitory molecule Tollip. We conclude that IEC are broadly unresponsive to TLR2 ligands secondary to deficient expression of TLR2 and TLR6. The relative absence of TLR2 protein expression by IEC and high level of Tollip expression may be important in preventing chronic proinflammatory cytokine secretion in response to commensal Gram-positive bacteria in the gut.
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Affiliation(s)
- Gil Melmed
- Inflammatory Bowel Disease Center, Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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3219
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Okahashi N, Sakurai A, Nakagawa I, Fujiwara T, Kawabata S, Amano A, Hamada S. Infection by Streptococcus pyogenes induces the receptor activator of NF-kappaB ligand expression in mouse osteoblastic cells. Infect Immun 2003; 71:948-55. [PMID: 12540577 PMCID: PMC145386 DOI: 10.1128/iai.71.2.948-955.2003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group A Streptococcus pyogenes is known to induce nongonococcal septic arthritis in addition to pharyngitis, scarlet fever, and poststreptococcal sequelae. However, little is known about the interaction between S. pyogenes and bone cells. We report here that S. pyogenes strain JRS4 (M6) attached to and invaded mouse primary osteoblasts. Reverse transcription-PCR demonstrated that S. pyogenes infection of osteoblasts stimulated expression of mRNA for the receptor activator of NF-kappaB ligand (RANKL). Western blot analysis followed by ligand precipitation with the receptor activator of NF-kappaB receptor showed that there was an increase in RANKL protein in infected osteoblasts. Production of interleukin-6 was also stimulated, but no production of interleukin-1beta or tumor necrosis factor alpha was observed. Stimulation of RANKL production was not observed in osteoblasts stimulated with heat-inactivated S. pyogenes, suggesting that an active interaction of S. pyogenes with osteoblasts is essential for this phenomenon. A Western blot analysis performed with antibodies specific for phosphorylated signal transduction proteins demonstrated that S. pyogenes infection induces phosphorylation of p38 mitogen-activated protein kinase. A specific inhibitor of this kinase, SB203580, inhibited RANKL production by infected osteoblasts. These results suggest that infection of osteoblasts by S. pyogenes stimulates RANKL production and may trigger bone destruction in infected bone tissue.
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Affiliation(s)
- Nobuo Okahashi
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Japan.
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3220
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3221
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3222
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Tsuji RF, Hoshino K, Noro Y, Tsuji NM, Kurokawa T, Masuda T, Akira S, Nowak B. Suppression of allergic reaction by lambda-carrageenan: toll-like receptor 4/MyD88-dependent and -independent modulation of immunity. Clin Exp Allergy 2003; 33:249-58. [PMID: 12580919 DOI: 10.1046/j.1365-2222.2003.01575.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Recognition of foreign substances by innate immunity through pattern recognition receptors (PRRs) regulates acquired immunity such as allergic reaction. Because PRRs recognize heterogeneous ligands, daily food intake can potentially regulate immune allergic reaction. OBJECTIVE Elucidation of the effect of lambda-carrageenan on allergic reactions was aimed. METHOD IFN-gamma and IL-4 was measured in in vitro T cell-stimulated culture. Cytokine production from macrophages in response to lambda-carrageenan was measured as indicator for innate immunity activation. Mice were immunized with OVA in alum to induce specific IgE, and then histamine release was induced by systemic injection of OVA. RESULTS Activation of innate immunity by lambda-carrageenan is dependent on Toll-like receptor-4 (TLR4) and MyD88, in which induction of pro-inflammatory cytokines such as TNF-alpha and IL-6 was largely impaired in macrophages from TLR4- and MyD88-deficient mice. Footpad oedema, a model for in vivo inflammatory reactions, was significantly reduced in these mice. Similar to recent evidence showing a preference for the stimulation of Th1 via TLR/MyD88 signalling, lambda-carrageenan showed enhanced IFN-gamma and decreased IL-4 in stimulated T cell cultures. Interestingly, increased IFN-gamma production was still seen in TLR4- and MyD88-deficient splenocytes. Oral administration of lambda-carrageenan to immunized mice successfully decreased OVA-specific IgE, and lambda-carrageenan was also effective in previously immunized mice. Further, serum histamine release upon systemic challenge of OVA was significantly inhibited. Neither OVA-specific IgG1/IgG2a nor cytokine secretion from in vitro cultures were altered, suggesting the involvement of multiple PRRs as demonstrated by TLR4/MyD88-independent IFN-gamma up-regulation. The simultaneous feeding of OVA with lipopolysaccharide abrogated oral tolerance, but lambda-carrageenan was not only devoid of such an effect but was also found to promote oral tolerance in the absence of TLR4. CONCLUSION lambda-Carrageenan was suggested to be a useful dietary supplement to ameliorate allergic reactions while maintaining oral tolerance-dependent intestinal homeostasis.
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Affiliation(s)
- R F Tsuji
- Noda Institute for Scientific Research, Noda City, Japan.
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3223
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Oshiumi H, Matsumoto M, Funami K, Akazawa T, Seya T. TICAM-1, an adaptor molecule that participates in Toll-like receptor 3-mediated interferon-beta induction. Nat Immunol 2003; 4:161-7. [PMID: 12539043 DOI: 10.1038/ni886] [Citation(s) in RCA: 910] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2002] [Accepted: 12/20/2002] [Indexed: 11/09/2022]
Abstract
Human Toll-like receptor (TLR) 3 recognizes double-stranded (ds) RNA and induces production of interferon (IFN)-beta independent of the adaptor molecules MyD88 and TIRAP. Thus, another adaptor must exist that preferentially mediates TLR3-dependent production of IFN-beta. We have identified an alternative adaptor, designated Toll-interleukin 1 receptor domain (TIR)-containing adaptor molecule (TICAM)-1, that can physically bind the TIR domain of TLR3 and activate the IFN-beta promoter in response to poly(I):poly(C). Thus, dsRNA-TLR3-dependent production of IFN-beta is mediated mainly by TICAM-1. This TICAM-1-dependent pathway may have a role in other TLR-IFN-beta pathways, which form part of the MyD88-independent cellular immune response.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adaptor Proteins, Vesicular Transport/genetics
- Adaptor Proteins, Vesicular Transport/immunology
- Adaptor Proteins, Vesicular Transport/metabolism
- Amino Acid Sequence
- Animals
- Antigens, Differentiation/metabolism
- Binding Sites
- Cell Line
- Cloning, Molecular
- DNA-Binding Proteins/metabolism
- Drosophila Proteins
- Female
- Gene Silencing
- Humans
- Immunity, Cellular
- Interferon Regulatory Factor-3
- Interferon-beta/biosynthesis
- Male
- Membrane Glycoproteins/chemistry
- Membrane Glycoproteins/metabolism
- Mice
- Molecular Sequence Data
- Myeloid Differentiation Factor 88
- NF-kappa B/metabolism
- Pregnancy
- Protein Structure, Tertiary
- RNA, Double-Stranded/metabolism
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/metabolism
- Receptors, Immunologic/metabolism
- Receptors, Interleukin-1/metabolism
- Sequence Homology, Amino Acid
- Signal Transduction
- Tissue Distribution
- Toll-Like Receptor 3
- Toll-Like Receptors
- Transcription Factor AP-1/metabolism
- Transcription Factors/metabolism
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Affiliation(s)
- Hiroyuki Oshiumi
- Department of Immunology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari-ku, Japan
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3224
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Affiliation(s)
- Michael Zasloff
- Georgetown University Medical Center, Department of Pediatrics, Washington, DC 20007, USA.
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3225
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Anders HJ, Vielhauer V, Schlöndorff D. Chemokines and chemokine receptors are involved in the resolution or progression of renal disease. Kidney Int 2003; 63:401-15. [PMID: 12631106 DOI: 10.1046/j.1523-1755.2003.00750.x] [Citation(s) in RCA: 202] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Locally secreted chemokines mediate leukocyte recruitment during the initiation and amplification phase of renal inflammation. In turn, the infiltrating leukocytes contribute to renal damage by releasing inflammatory and profibrotic factors. Rapid down modulation of the chemokine signal will support resolution of acute inflammation, whereas progression occurs if ongoing or repeated renal injury maintains continuous local chemokine secretion and leukocyte influx into the glomerulus or the interstitial space. In glomerular injury proteinuria itself as well as glomerular secreted cytokines stimulate downstream tubular epithelial cells to also secrete chemokines. During primary tubular injury, tubular epithelial cells directly become a major site of chemokine production. This in turn supports leukocyte infiltration and activation. Infiltrating leukocytes stimulate fibroblast proliferation and matrix synthesis, leading to widening of the interstitial space. The specific and intricate renal vascular architecture renders the organ susceptible to ischemic damage as interstitial volume increases. Ischemia in turn serves as a stimulus for chemokine and cytokine production and matrix synthesis. The mutual stimulation between fibroblasts and infiltrating leukocytes supports progressive tubular damage, renal fibrosis, and glomerulosclerosis. Potentially this vicious circle leading to progression of chronic nephropathies offers the opportunity for therapeutic intervention. Interfering with the chemokine network that mediates leukocyte recruitment may represent a promising therapeutic option for progressive renal disorders and renal fibrosis. This article summarizes the present data on the role of chemokines in acute and chronic renal disease with special emphasis on their potential role in mediating resolution or progression of renal disease as well as on therapeutic options.
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Affiliation(s)
- Hans-Joachim Anders
- Medizinische Poliklinik - Innenstadt, Klinikum der Universität München, Munich, Germany
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3226
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Abstract
PURPOSE OF REVIEW The frequency of allergic diseases is increasing worldwide. Experimental and clinical studies have linked a reduced number of early infections to this trend. The gastrointestinal system, which comprises the largest lymphoid tissue and microbial reservoir of the body, has received more attention during the last few years as a potential determiner in the development of atopic disease. RECENT FINDINGS Alterations in intestinal microbiota have been detected both in infants suffering from allergic disease and in those later developing the disorder. Delay in the compositional development of and in gut microflora was a general finding in allergic children. In a subsequent study, perinatal administration of lactobacilli halved the later development of atopic eczema during the first 2 years of life. Specific strains of the healthy gut microbiota have been shown to induce the production of IL-10 and transforming growth factor-beta, which possess an important regulative role in the development of allergic type immune response. Probiotics also strengthen gut defence barrier mechanisms and reduce antigen load in the gut. Pattern recognition receptors in intestinal epithelial and antigen-presenting cells have been demonstrated to mediate a continuing dialogue between host and gut microbiota. SUMMARY Despite several promising findings, the exact role of gut normal microbiota in the development of allergy remains to be elucidated. For successful interventions, more data concerning a communication between host and specific microbial species are needed.
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3227
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Anders HJ, Banas B, Linde Y, Weller L, Cohen CD, Kretzler M, Martin S, Vielhauer V, Schlöndorff D, Gröne HJ. Bacterial CpG-DNA aggravates immune complex glomerulonephritis: role of TLR9-mediated expression of chemokines and chemokine receptors. J Am Soc Nephrol 2003; 14:317-26. [PMID: 12538732 DOI: 10.1097/01.asn.0000042169.23931.73] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Immune complex glomerulonephritis (GN) often deteriorates during infection with viruses and bacteria that, in contrast to mammals, have DNA that contains many unmethylated CpG motifs. Balb/c mice with horse apoferritin-induced GN (HAF-GN) were treated with either saline, CpG-oligodeoxynucleotides (ODN), or control GpC-ODN. Only CpG-ODN exacerbated HAF-GN with an increase of glomerular macrophages, which was associated with massive albuminuria and increased renal MCP-1/CCL2, RANTES/CCL5, CCR1, CCR2, and CCR5 mRNA expression. CpG-ODN induced a Th1 response as indicated by serum anti-HAF IgG(2a) titers, mesangial IgG(2a) deposits, and splenocyte IFN-gamma secretion. Messenger RNA for the CpG-DNA receptor Toll-like reeptor 9 (TLR9) was present in kidneys with HAF-GN but not in normal kidneys. The source of TLR9 mRNA in HAF-GN could be infiltrating macrophages or intrinsic renal cells, e.g., mesangial cells; but, in vitro, only murine J774 macrophages expressed TLR9. In J774 cells, CpG-ODN induced the chemokines MCP-1/CCL2 and RANTES/CCL5 and the chemokine receptors CCR1 and CCR5. It is concluded that CpG-DNA can aggravate preexisting GN via a shift toward a Th1 response but also by a novel pathway involving TLR9-mediated chemokine and chemokine receptor expression by macrophages, which may contribute to the enhanced glomerular macrophage recruitment and activation. This mechanism may be relevant during infection-triggered exacerbation of human immune-complex GN and other immune-mediated diseases in general.
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Affiliation(s)
- Hans-Joachim Anders
- Nephrological Center, Medical Policlinic, University of Munich, Munich, Germany
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3228
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Abstract
Interleukin-18 (IL-18), a recently described member of the IL-1 cytokine superfamily, is now recognized as an important regulator of innate and acquired immune responses. IL-18 is expressed at sites of chronic inflammation, in autoimmune diseases, in a variety of cancers, and in the context of numerous infectious diseases. This short review will describe the basic biology of IL-18 and thereafter address its potential effector and regulatory role in several human disease states including autoimmunity and infection. IL-18, previously known as interferon-gamma (IFN-gamma)-inducing factor, was identified as an endotoxin-induced serum factor that stimulated IFN-gamma production by murine splenocytes [(1) ]. IL-18 was cloned from a murine liver cell cDNA library generated from animals primed with heat-killed Propionibacterium acnes and subsequently challenged with lipopolysaccharide [(2) ]. Nucleotide sequencing of murine IL-18 predicted a precursor polypeptide of 192 amino acids lacking a conventional signal peptide and a mature protein of 157 amino acids. Subsequent cloning of human IL-18 cDNA revealed 65% homology with murine IL-18 [(3) ] and showed that both contain an unusual leader sequence consisting of 35 amino acids at their N terminus.
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Affiliation(s)
- J Alastair Gracie
- Centre for Rheumatic Diseases, University of Glasgow, 10 Alexandra Parade, Glasgow G31 2ER, Scotland, UK
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3229
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Abstract
Dendritic cells (DCs) form a network of potent antigen-presenting cells that initiate and amplify immune responses. The detection and capture of microorganisms by DCs trigger stimulus-specific maturation programs that enable DCs to convey pathogen-associated signals to the adaptive branch of the immune system. The appropriate activation of DCs is critical for their ability to direct the development of either a Th1 or a Th2 response, thereby determining the outcome of microbial infections. Advances in the understanding of DC interactions with microbes provide new concepts for immune interventions. In different models of infectious disease, it has been demonstrated that DCs can serve as vaccine carriers, mediating protection against various types of pathogens. The studies of the requirements of ex vivo manipulations of DCs may lead to the design of vaccines that induce protective immunity to infections by appropriate targeting of DCs in vivo.
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Affiliation(s)
- Heidrun Moll
- Institute for Molecular Biology of Infectious Diseases, University of Würzburg, Röntgenring 11, 97070 Wurzburg, Germany.
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3230
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Abstract
Toll-like receptors (TLRs) are type I transmembrane proteins involved in innate immunity by recognizing microbial conserved structures. Recent studies have shown that TLR3 recognizes dsRNA, a viral product, whereas TLR9 recognizes unmethylated CpG motifs frequently found in the genome of bacteria and viruses, but not vertebrates. TLR7 recognizes small synthetic immune modifiers including imiquimod, R-848, loxoribine, and bropirimine, all of which are already applied or promising for clinical use against viral infections and cancers. Plasmacytoid dendritic cells express TLR7 and TLR9, and respond to TLR7 and TLR9 ligands by producing a large amount of interferon (IFN-alpha). These results indicate that TLR3, TLR7 and TLR9 may play an important role in detecting and combating viral infections.
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Affiliation(s)
- Shizuo Akira
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, SORST of Japan Science and Technology Corporation, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
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3231
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Yeo SJ, Yoon JG, Hong SC, Yi AK. CpG DNA induces self and cross-hyporesponsiveness of RAW264.7 cells in response to CpG DNA and lipopolysaccharide: alterations in IL-1 receptor-associated kinase expression. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1052-61. [PMID: 12517973 DOI: 10.4049/jimmunol.170.2.1052] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Exposure of macrophages to LPS induces a state of hyporesponsiveness to subsequent challenge with LPS. It has not been known whether previous exposure to CpG DNA induces a similar suppressive response to subsequent stimulation with CpG DNA. In the present study, we demonstrate that pretreatment with CpG DNA induces suppression of cytokine release in a murine macrophage-like cell RAW264.7 in response to subsequent challenge by CpG DNA. Additionally, CpG DNA-mediated activation of mitogen-activated protein kinases, including c-Jun NH(2)-terminal kinase, extracellular signal-regulated kinase, and p38, and activation of transcription factors AP-1, CREB, NF-kappaB, and STAT1 are greatly suppressed in the cells pre-exposed to CpG DNA. Pretreatment with CpG DNA also partially inhibited LPS-mediated production of cytokines and activation of mitogen-activated protein kinases and transcription factors. Neither LPS nor CpG DNA treatment inhibited Toll-like receptor 4, MD2, Toll-like receptor 9, myeloid differentiation factor 88, Toll/IL-1R domain-containing adaptor protein, Tollip, and TNF-alpha receptor-associated factor 6 expression. Interestingly, CpG DNA or LPS stimulation led to the inhibition of IL-1R-associated kinase expression. These results indicate that CpG DNA-induced refractory of RAW264.7 cells may be, at least in part, due to suppressed IL-1R-associated kinase expression.
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Affiliation(s)
- Seon-Ju Yeo
- Children's Foundation Research Center at Le Bonheur Children's Hospital, and Department of Pediatrics, University of Tennessee Health Science Center, Memphis 38103, USA
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3232
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Berrebi D, Bruscoli S, Cohen N, Foussat A, Migliorati G, Bouchet-Delbos L, Maillot MC, Portier A, Couderc J, Galanaud P, Peuchmaur M, Riccardi C, Emilie D. Synthesis of glucocorticoid-induced leucine zipper (GILZ) by macrophages: an anti-inflammatory and immunosuppressive mechanism shared by glucocorticoids and IL-10. Blood 2003; 101:729-38. [PMID: 12393603 DOI: 10.1182/blood-2002-02-0538] [Citation(s) in RCA: 214] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glucocorticoids and interleukin 10 (IL-10) prevent macrophage activation. In murine lymphocytes, glucocorticoids induce expression of glucocorticoid-induced leucine zipper (GILZ), which prevents the nuclear factor kappaB (NF-kappaB)-mediated activation of transcription. We investigated whether GILZ could account for the deactivation of macrophages by glucocorticoids and IL-10. We found that GILZ was constitutively produced by macrophages in nonlymphoid tissues of humans and mice. Glucocorticoids and IL-10 stimulated the production of GILZ by macrophages both in vitro and in vivo. Transfection of the macrophagelike cell line THP-1 with the GILZ gene inhibited the expression of CD80 and CD86 and the production of the proinflammatory chemokines regulated on activation normal T-cell expressed and secreted (CCL5) and macrophage inflammatory protein 1alpha (CCL3). It also prevented toll-like receptor 2 production induced by lipopolysaccharide, interferongamma, or an anti-CD40 mAb, as well as NF-kappaB function. In THP-1 cells treated with glucocorticoids or IL-10, GILZ was associated with the p65 subunit of NF-kappaB. Activated macrophages in the granulomas of patients with Crohn disease or tuberculosis do not produce GILZ. In contrast, GILZ production persists in tumor-infiltrating macrophages in Burkitt lymphomas. Therefore, GILZ appears to play a key role in the anti-inflammatory and immunosuppressive effects of glucocorticoids and IL-10. Glucocorticoid treatment stimulates GILZ production, reproducing an effect of IL-10, a natural anti-inflammatory agent. The development of delayed-type hypersensitivity reactions is associated with the down-regulation of GILZ gene expression within lesions. In contrast, the persistence of GILZ gene expression in macrophages infiltrating Burkitt lymphomas may contribute to the failure of the immune system to reject the tumor.
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Affiliation(s)
- Dominique Berrebi
- Institut National de la Santé et de la Recherche Médicale (INSERM) U131, Institut Paris-Sud sur les Cytokines, Clamart, France
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3233
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Cognet I, de Coignac AB, Magistrelli G, Jeannin P, Aubry JP, Maisnier-Patin K, Caron G, Chevalier S, Humbert F, Nguyen T, Beck A, Velin D, Delneste Y, Malissard M, Gauchat JF. Expression of recombinant proteins in a lipid A mutant of Escherichia coli BL21 with a strongly reduced capacity to induce dendritic cell activation and maturation. J Immunol Methods 2003; 272:199-210. [PMID: 12505724 DOI: 10.1016/s0022-1759(02)00506-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mutations in the Escherichia coli (E. coli) and Salmonella lpxM gene have been shown to result in strains which grow normally and which produce a non-myristoylated lipopolysaccharide (nmLPS) with strongly reduced endotoxicity. Using homologous recombination, we inactivated the lpxM gene in BL21 (DE3), a strain widely used for the production of recombinant proteins. This led to a derivative unaffected in its capacity to support the production of recombinant proteins. This new strain expresses non-myristoylated LPS that induces markedly less activation and maturation of monocyte-derived dendritic cells (DC), as assessed by nuclear translocation of nuclear factor kappa B (NF-kappaB), production of TNF-alpha and IL-8 or expression of CD86. Activation of the main signal transducing receptor for extracellular LPS, Toll like receptor (TLR) 4 in conjunction with the soluble accessory protein MD-2 was also markedly decreased. The modified BL21 strain represents a new application of lpxM inactivation for the expression of proteins to be tested on dendritic cells or other LPS sensitive cells/receptor complexes. It is likely to be useful for the identification of new proteins activating the innate immune response and to reducing the risk linked with low level of endotoxin contamination in therapeutic recombinant proteins.
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Affiliation(s)
- Isabelle Cognet
- Centre d'Immunologie Pierre-Fabre, 5 avenue Napoléon III, Saint-Julien en, Genevois, 74164, France
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3234
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Abstract
Invading pathogens are controlled by the innate and adaptive arms of the immune system. Adaptive immunity, which is mediated by B and T lymphocytes, recognises pathogens by rearranged high affinity receptors. However, the establishment of adaptive immunity is often not rapid enough to eradicate microorganisms as it involves cell proliferation, gene activation and protein synthesis. More rapid defense mechanisms are provided by innate immunity, which recognises invading pathogens by germ-line-encoded pattern recognition receptors (PRR). Recent evidence shows that this recognition can mainly be attributed to the family of TOLL-like receptors (TLR). Binding of pathogen-associated molecular patterns (PAMP) to TLR induces the production of reactive oxygen and nitrogen intermediates (ROI and RNI), pro-inflammatory cytokines, and up-regulates expression of co-stimulatory molecules, subsequently initiating the adaptive immunity. In this review, we will summarize the discovery and the critical roles of the TLR family in host defense, briefly allude to signaling mechanisms mediating the response to TLR ligands, and will provide an update on current knowledge regarding the ligand specificity of these receptors and their role in immunity of domestic animals, particularly cattle.
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Affiliation(s)
- Dirk Werling
- Institute of Veterinary Virology, University of Berne, Länggass-Str. 122, CH-3012 Bern, Switzerland
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3235
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Smith KD, Ozinsky A. Toll-like receptor-5 and the innate immune response to bacterial flagellin. Curr Top Microbiol Immunol 2003; 270:93-108. [PMID: 12467246 DOI: 10.1007/978-3-642-59430-4_6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The innate immune system identifies the presence of infection by detecting structures that are unique to microbes and that are not expressed in the host. The bacterial flagellum (Latin, a whip) confers motility, on a wide range of bacterial species. Vertebrates, plants, and invertebrates all have evolved flagellar recognition systems that are activated by flagellin, the major component of the bacterial flagellar filament. In mammals, flagellin is recognized by Toll-like receptor-5 and activates defense responses both systemically and at epithelial surfaces. Here, we review the role for Toll-like receptor-5 in mediating the mammalian innate immune response to flagellin, and how this provides for defense against infections caused by many different species of flagellated bacteria.
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Affiliation(s)
- K D Smith
- Department of Pathology, University of Washington, Box 35610, 1959 NE Pacific Street, Seattle, WA 98195, USA
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3236
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Abstract
Myeloid differentiation factor 88 (MyD88) is an adaptor molecule composed of an N-terminal death domain and a C-terminal Toll/interleukin (IL)-1R homology domain. Ligand binding to Toll-like receptor (TLR)/IL-1R family members results in the association of MyD88 to the cytoplasmic tail of receptors; this then initiates the signaling cascade that leads to the activation of nuclear factor-kappa B and mitogen-activated protein kinases. Analysis of MyD88-deficient mice revealed its essential role in TLR/IL-1R signaling as well as in both the innate and the adaptive immune response.
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Affiliation(s)
- O Takeuchi
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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3237
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Geijtenbeek TBH, Van Vliet SJ, Koppel EA, Sanchez-Hernandez M, Vandenbroucke-Grauls CMJE, Appelmelk B, Van Kooyk Y. Mycobacteria target DC-SIGN to suppress dendritic cell function. J Exp Med 2003; 197:7-17. [PMID: 12515809 PMCID: PMC2193797 DOI: 10.1084/jem.20021229] [Citation(s) in RCA: 782] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mycobacterium tuberculosis represents a world-wide health risk and immunosuppression is a particular problem in M. tuberculosis infections. Although macrophages are primarily infected, dendritic cells (DCs) are important in inducing cellular immune responses against M. tuberculosis. We hypothesized that DCs represent a target for M. tuberculosis and that the observed immuno-suppression results from modulation of DC functions. We demonstrate that the DC-specific C-type lectin DC-SIGN is an important receptor on DCs that captures and internalizes intact Mycobacterium bovis bacillus Calmette-Guérin (BCG) through the mycobacterial cell wall component ManLAM. Antibodies against DC-SIGN block M. bovis BCG infection of DCs. ManLAM is also secreted by M. tuberculosis-infected macrophages and has been implicated as a virulence factor. Strikingly, ManLAM binding to DC-SIGN prevents mycobacteria- or LPS-induced DC maturation. Both mycobacteria and LPS induce DC maturation through Toll-like receptor (TLR) signaling, suggesting that DC-SIGN, upon binding of ManLAM, interferes with TLR-mediated signals. Blocking antibodies against DC-SIGN reverse the ManLAM-mediated immunosuppressive effects. Our results suggest that M. tuberculosis targets DC-SIGN both to infect DCs and to down-regulate DC-mediated immune responses. Moreover, we demonstrate that DC-SIGN has a broader pathogen recognition profile than previously shown, suggesting that DC-SIGN may represent a molecular target for clinical intervention in infections other than HIV-1.
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Affiliation(s)
- Teunis B H Geijtenbeek
- Department of Molecular Cell Biology, Vrije Universiteit Medical Center Amsterdam, 1081 BT Amsterdam, Netherlands.
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3238
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Boonstra A, Asselin-Paturel C, Gilliet M, Crain C, Trinchieri G, Liu YJ, O'Garra A. Flexibility of mouse classical and plasmacytoid-derived dendritic cells in directing T helper type 1 and 2 cell development: dependency on antigen dose and differential toll-like receptor ligation. J Exp Med 2003; 197:101-9. [PMID: 12515817 PMCID: PMC2193804 DOI: 10.1084/jem.20021908] [Citation(s) in RCA: 439] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Distinct dendritic cell (DC) subsets have been suggested to be preprogrammed to direct either T helper cell (Th) type 1 or Th2 development, although more recently different pathogen products or stimuli have been shown to render these DCs more flexible. It is still unclear how distinct mouse DC subsets cultured from bone marrow precursors, blood, or their lymphoid tissue counterparts direct Th differentiation. We show that mouse myeloid and plasmacytoid precursor DCs (pDCs) cultured from bone marrow precursors and ex vivo splenic DC subsets can induce the development of both Th1 and Th2 effector cells depending on the dose of antigen. In general, high antigen doses induced Th1 cell development whereas low antigen doses induced Th2 cell development. Both cultured and ex vivo splenic plasmacytoid-derived DCs enhanced CD4(+) T cell proliferation and induced strong Th1 cell development when activated with the Toll-like receptor (TLR)9 ligand CpG, and not with the TLR4 ligand lipopolysaccharide (LPS). The responsiveness of plasmacytoid pDCs to CpG correlated with high TLR9 expression similarly to human plasmacytoid pDCs. Conversely, myeloid DCs generated with granulocyte/macrophage colony-stimulating factor enhanced Th1 cell development when stimulated with LPS as a result of their high level of TLR4 expression. Polarized Th1 responses resulting from high antigen dose were not additionally enhanced by stimulation of DCs by TLR ligands. Thus, the net effect of antigen dose, the state of maturation of the DCs together with the stimulation of DCs by pathogen-derived products, will determine whether a Th1 or Th2 response develops.
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Affiliation(s)
- André Boonstra
- Division of Immunoregulation, The National Institute for Medical Research (NIMR), NW7 1AA London, United Kingdom.
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3239
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Remer KA, Brcic M, Jungi TW. Toll-like receptor-4 is involved in eliciting an LPS-induced oxidative burst in neutrophils. Immunol Lett 2003; 85:75-80. [PMID: 12505201 DOI: 10.1016/s0165-2478(02)00210-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The lipopolysaccharide (LPS) receptor complex of mononuclear phagocytes is composed of Toll-like receptor-4 (TLR4), MD-2 and CD14. Other phagocyte populations may express similar LPS receptors. The transmembrane glycoprotein TLR4 was shown to induce or upregulate a variety of gene products, which collectively are the mediators of an LPS effect. In this study, an involvement of TLR4 in mediation of an oxidative burst was determined using murine peritoneal exsudate neutrophils and lucigenin-enhanced chemiluminescence (CL). The CL response was dependent on the LPS dose and the presence of serum, putatively a source of lipopolysaccharide-binding protein (LBP). In the absence of serum, a CL signal was elicited by 4 microg/ml LPS in peritoneal exsudate cells (PEC) from TLR4-sufficient (C3H/HeN) but not TLR4 deficient (C3H/HeJ) mice. The signal obtained in PEC from TLR4-sufficient mice was completely abrogated by superoxide dismutase (SOD), which indicated that the response depended on the formation of superoxide anion, and was also seen in purified neutrophils but not purified macrophages (Mphi). In the presence of serum, lower LPS concentrations (e.g. 40 ng/ml) elicited a strong CL response in PEC from TLR4-sufficient, and a weak signal in cells from TLR-4-deficient mice. This suggests that TLR4 engagement is involved in promoting an oxidative burst in murine neutrophils.
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Affiliation(s)
- Katharina A Remer
- Institute of Veterinary Virology, University of Berne, Laenggass-Strasse 122, CH-3012, Berne, Switzerland
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3240
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Fairweather D, Afanasyeva M, Rose NR. Cellular Immunity: A Role for Cytokines. HANDBOOK OF SYSTEMIC AUTOIMMUNE DISEASES 2003. [DOI: 10.1016/s1571-5078(03)01001-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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3241
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Reindl M, Lutterotti A, Ingram J, Schanda K, Gassner C, Deisenhammer F, Berger T, Lorenz E. Mutations in the gene for toll-like receptor 4 and multiple sclerosis. TISSUE ANTIGENS 2003; 61:85-8. [PMID: 12622779 DOI: 10.1034/j.1399-0039.2003.610108.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system with heterogeneous pathological features, disease courses and genetical backgrounds. In this study we determined whether genetic variants of toll-like receptor (TLR) 4, which confer substantial differences in the inflammation elicited by bacterial lipopolysaccharide, are related to the development of MS. We found no differences in the frequencies of the cosegregating TLR4 Asp299Gly and Thr399Ile polymorphisms between Austrian MS patients (11.6%) and age-matched controls (13.7%). Furthermore, we could not detect any influence of these mutations on clinical parameters and serum levels of soluble adhesion molecules of MS patients. Our data indicate that these TLR4 polymorphisms have no influence on the incidence, progression and inflammatory parameters of MS.
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Affiliation(s)
- M Reindl
- Department of Neurology, University of Innsbruck, Innsbruck, Austria.
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3242
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Dobrovolskaia MA, Medvedev AE, Thomas KE, Cuesta N, Toshchakov V, Ren T, Cody MJ, Michalek SM, Rice NR, Vogel SN. Induction of in vitro reprogramming by Toll-like receptor (TLR)2 and TLR4 agonists in murine macrophages: effects of TLR "homotolerance" versus "heterotolerance" on NF-kappa B signaling pathway components. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:508-19. [PMID: 12496438 DOI: 10.4049/jimmunol.170.1.508] [Citation(s) in RCA: 255] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this study, tolerance induction by preexposure of murine macrophages to Toll-like receptor (TLR)2 and TLR4 agonists was revisited, focusing on the major signaling components associated with NF-kappaB activation. Pretreatment of macrophages with a pure TLR4 agonist (protein-free Escherichia coli (Ec) LPS) or with TLR2 agonists (Porphyromonas gingivalis LPS or synthetic lipoprotein Pam3Cys) led to suppression of TNF-alpha secretion, IL-1R-associated kinase-1, and IkappaB kinase (IKK) kinase activities, c-jun N-terminal kinase, and extracellular signal-regulated kinase phosphorylation, and to suppression of NF-kappaB DNA binding and transactivation upon challenge with the same agonist (TLR4 or TLR2 "homotolerance," respectively). Despite inhibited NF-kappaB DNA binding, increased levels of nuclear NF-kappaB were detected in agonist-pretreated macrophages. For all the intermediate signaling elements, heterotolerance was weaker than TLR4 or TLR2 homotolerance with the exception of IKK kinase activity. IKK kinase activity was unperturbed in heterotolerance. TNF-alpha secretion was also suppressed in P. gingivalis LPS-pretreated, Ec LPS-challenged cells, but not vice versa, while Pam3Cys and Ec LPS did not induce a state of cross-tolerance at the level of TNF-alpha. Experiments designed to elucidate novel mechanisms of NF-kappaB inhibition in tolerized cells revealed the potential contribution of IkappaBepsilon and IkappaBxi inhibitory proteins and the necessity of TLR4 engagement for induction of tolerance to Toll receptor-IL-1R domain-containing adapter protein/MyD88-adapter-like-dependent gene expression. Collectively, these data demonstrate that induction of homotolerance affects a broader spectrum of signaling components than in heterotolerance, with selective modulation of specific elements within the NF-kappaB signaling pathway.
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MESH Headings
- Animals
- Cell Line
- Cells, Cultured
- DNA-Binding Proteins/antagonists & inhibitors
- DNA-Binding Proteins/metabolism
- Down-Regulation/genetics
- Down-Regulation/immunology
- Drosophila Proteins
- Enzyme Activation/immunology
- Female
- Host Cell Factor C1
- Humans
- I-kappa B Kinase
- Immune Tolerance/genetics
- Interferon-beta/antagonists & inhibitors
- Interferon-beta/biosynthesis
- Interferon-beta/genetics
- Interleukin-1 Receptor-Associated Kinases
- JNK Mitogen-Activated Protein Kinases
- Lipopolysaccharides/pharmacology
- Macrophages, Peritoneal/enzymology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Membrane Glycoproteins/agonists
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mitogen-Activated Protein Kinases/metabolism
- NF-kappa B/antagonists & inhibitors
- NF-kappa B/genetics
- NF-kappa B/metabolism
- NF-kappa B/physiology
- NF-kappa B p50 Subunit
- Octamer Transcription Factor-1
- Protein Kinase Inhibitors
- Protein Kinases/metabolism
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/biosynthesis
- Protein Serine-Threonine Kinases/metabolism
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/biosynthesis
- Receptors, Cell Surface/agonists
- Receptors, Cell Surface/physiology
- Sequence Deletion
- Signal Transduction/genetics
- Signal Transduction/immunology
- Toll-Like Receptor 2
- Toll-Like Receptor 4
- Toll-Like Receptors
- Trans-Activators/antagonists & inhibitors
- Trans-Activators/metabolism
- Transcription Factor AP-1/metabolism
- Transcription Factor RelA
- Transcription Factors/metabolism
- Tumor Necrosis Factor-alpha/antagonists & inhibitors
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Marina A Dobrovolskaia
- Department of Microbiology and Immunology, University of Maryland, Baltimore, MD 21201, USA
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3243
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Sieling PA, Chung W, Duong BT, Godowski PJ, Modlin RL. Toll-like receptor 2 ligands as adjuvants for human Th1 responses. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:194-200. [PMID: 12496400 DOI: 10.4049/jimmunol.170.1.194] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bacterial lipopeptides (bLPs) are increasingly used as adjuvants to activate cell-mediated immune responses to foreign Ags. To explore mechanisms whereby bLPs adjuvant T cell responses, we stimulated human PBMCs with bLPs. We found that bLPs stimulate T cells to proliferate and produce IFN-gamma in an accessory cell-dependent manner and in the absence of exogenous protein Ags. The ability of bLPs to stimulate T cell proliferation was Toll-like receptor 2 dependent and required IL-12, interaction with costimulatory molecules, and MHC proteins. Our data suggest that bLPs adjuvant adaptive Th1 responses by enhancing Ag presentation of endogenous peptides.
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Affiliation(s)
- Peter A Sieling
- Department of Medicine, Division of Dermatology, David Gefffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
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3244
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Abstract
Sepsis and resulting multiple system organ failure are the leading causes of mortality in intensive care units. Although it is generally appreciated that rampant, deregulated inflammatory pathways play a major role in sepsis, a comprehensive understanding based on the integrated response of multiple signal transduction pathways has remained elusive. Here we review the main signal transduction pathways involved in the progression from inflammation to sepsis and discuss emerging genomic, proteomic, and systems biology approaches to decipher how these signaling pathways converge to cause the septic state. We propose that an integrative approach involving functional proteomics will provide a quantitative and mechanistic description that unifies inflammatory signaling networks in sepsis and will identify critical regulatory nodes for therapeutic manipulation. These types of systems biology-based approaches may lead to more effective therapies than those currently available.
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Affiliation(s)
- Anhco Nguyen
- Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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3245
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Foley E, O'Farrell PH. Nitric oxide contributes to induction of innate immune responses to gram-negative bacteria in Drosophila. Genes Dev 2003; 17:115-25. [PMID: 12514104 PMCID: PMC195964 DOI: 10.1101/gad.1018503] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Studies in mammals uncovered important signaling roles of nitric oxide (NO), and contributions to innate immunity. Suggestions of conservation led us to explore the involvement of NO in Drosophila innate immunity. Inhibition of nitric oxide synthase (NOS) increased larval sensitivity to gram-negative bacterial infection, and abrogated induction of the antimicrobial peptide Diptericin. NOS was up-regulated after infection. Antimicrobial peptide reporters revealed that NO triggered an immune response in uninfected larvae. NO induction of Diptericin reporters in the fat body required immune deficiency (imd) and domino. These findings show that NOS activity is required for a robust innate immune response to gram-negative bacteria, NOS is induced by infection, and NO is sufficient to trigger response in the absence of infection. We propose that NO mediates an early step of the signal transduction pathway, inducing the innate immune response upon natural infection with gram-negative bacteria.
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Affiliation(s)
- Edan Foley
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California 94143, USA
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3246
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Abstract
Toll-like receptor 4 (TLR4) is a pattern recognition receptor involved in the innate immune response to various microorganisms and other exogenous and endogenous stress factors. Recently, evidence emerged that important inflammatory processes implicit in human atherogenesis are mediated in part via the TLR4/nuclear factor-kappaB pathway. Polymorphisms of TLR4, which attenuate receptor signalling, enhance the risk of acute severe infections but may have opposite effects on atherogenesis. The aim of this review is to critically discuss current experimental and epidemiological evidence for a role of TLR4 in atherogenesis and to highlight the main controversies and perspectives in this emerging field of vascular biology.
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Affiliation(s)
- Stefan Kiechl
- Department of Neurology, Innsbruck University Clinic, Innsbruck, Austria.
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3247
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Seitzer U, Gerdes J. Cytoplasmic bacterial lipopolysaccharide does not induce NFkappaB activation or NFkappaB mediated activation signals in human macrophages and an LPS reporter cell line. J Cell Physiol 2003; 194:20-9. [PMID: 12447986 DOI: 10.1002/jcp.10177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although many membrane components have been described to be involved in the activation of cells by bacterial lipopolysaccharide (LPS), the question remains whether LPS, once internalized by target cells, is also capable of interacting with cytoplasmic elements in such a way that activation of cells results independently of receptor engagement. This is an important aspect to consider with respect to the development of strategies aimed at attenuating adverse effects of LPS in the framework of bacterial infections. In this study, human monocyte derived macrophages as representatives of one of the primary target cells activated by LPS, were microinjected with LPS to circumvent exogenous LPS stimulation. Parameters correlating to cytoplasmic activation of the nuclear transcription factor NFkappaB (intracellular calcium mobilization), to nuclear translocation of the NFkappaB p65 subunit and to mRNA-transcription of inflammatory cytokines known to be expressed upon exogenous LPS-stimulation and to require NFkappaB activation (interleukin-1beta, interleukin-6, tumor necrosis factor alpha) were investigated. In addition, the LPS-reporter cell line 3E10, which contains a reporter gene under the control of an NFkappaB-inducible promoter was analyzed with respect to NFkappaB nuclear translocation and reporter gene expression. None of the cellular systems used and none of the parameters investigated led to the observation that intracellular LPS leads to activation of the cells in comparison to external LPS stimulation. These experiments allow the conclusion that LPS in the cytoplasmic compartment does not lead to NFkappaB translocation, cytokine mRNA transcription, and NFkappaB dependent protein expression and suggest that these activation parameters require the interaction of LPS with external membrane components.
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Affiliation(s)
- Ulrike Seitzer
- Department of Immunology and Cell Biology, Research Center Borstel, Germany.
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3248
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3249
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Abstract
Diseases caused by Chlamydia are based on intense and chronic inflammation elicited and maintained by reinfection or persistent infection. The traditional view in the field is that disease is mediated by antigen-dependent delayed-type hypersensitivity or autoimmunity. This immunological paradigm has served as the basis for years of chlamydial research but the mechanism or the antigen that causes pathology has yet to be unequivocally revealed. Recent research on responses elicited in Chlamydia-infected cells defines a new direction for our understanding of this microorganism-host interaction and provides the basis for a reassessment of disease mechanisms. Chlamydia-infected non-immune mammalian cells produce proinflammatory chemokines, cytokines, growth factors and other cellular modulators. This cellular response to infection supports an alternative hypothesis for chlamydial pathogenesis: the inflammatory processes of chlamydial pathogenesis are elicited by infected host cells and are necessary and sufficient to account for chronic and intense inflammation and the promotion of cellular proliferation, tissue remodeling and scarring, the ultimate cause of disease sequelae.
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Affiliation(s)
- Richard S Stephens
- Division of Infectious Diseases, School of Public Health, 140 Earl Warren Hall, University of California, Berkeley 94720, USA.
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3250
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Telepnev M, Golovliov I, Grundström T, Tärnvik A, Sjöstedt A. Francisella tularensis inhibits Toll-like receptor-mediated activation of intracellular signalling and secretion of TNF-alpha and IL-1 from murine macrophages. Cell Microbiol 2003; 5:41-51. [PMID: 12542469 DOI: 10.1046/j.1462-5822.2003.00251.x] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Microbial ligands, including lipopolysaccharide (LPS) and bacterial lipoproteins, activate Toll-like receptors (TLR) of mononuclear phagocytes, thereby inducing proinflammatory cytokines and antimicrobial activity. We show that Francisella tularensis, an intracellular pathogen, is capable of inhibiting this macrophage response. Infection with the live vaccine strain F. tularensis LVS rendered cells of the murine macrophage-like cell line J774A.1 incapable of secreting TNF-alpha or IL-1beta and mobilizing an antimicrobial activity in response to bacterial lipopeptide or Escherichia coli-derived LPS. Inhibition of TNF-alpha secretion occurred also when J774 cells were infected with F. tularensis LVS in the presence of chloramphenicol, but not when they were infected with a mutant of F. tularensis LVS defective in expression of a 23 kDa protein that is upregulated during intracellular infection. Purified F. tularensis LPS did not show an agonistic or antagonistic effect on the E. coli LPS-induced activation of the J774 cells. Francisella tularensis LVS suppressed the capability of the cells to respond to LPS or bacterial lipopeptide (BLP) with activation of nuclear factor kappa B (NF-kappaB), and degradation of the in-hibitor of NF-kappaB, IkappaB, was blocked during the infection. Also the LPS- or BLP-induced phosphorylation of the mitogen-activated protein kinase p38 and the transcription factor c-Jun was inhibited by F. tularensis LVS but not by the 23 kDa protein mutant. In conclusion, F. tularensis appears capable of abrogating the TNF-alpha and IL-1 responses of macrophages induced by E. coli LPS or BLP via a mechanism that involves suppression of several intracellular pathways and is dependent on expression of a bacterial 23 kDa protein.
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Affiliation(s)
- Max Telepnev
- Department of Clinical Microbiology, Clinical Bacteriology, Umeå University, Umeå, Sweden
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