bluuebunny/crossref_metadata_2025 huggingface dataset:
Fetal Exposure to Ethanol Has Long-Term Effects on the Severity of Influenza Virus Infections
Authors: McGill Jodi , Meyerholz David K. , Edsen-Moore Michelle , Young Betty , Coleman Ruth A. , Schlueter Annette J. , Waldschmidt Thomas J. , Cook Robert T. , Legge Kevin L.
Published: June 2009

Alcohol use by pregnant women is a significant public health issue despite well-described risks to the fetus including physical and intellectual growth retardation and malformations. Although clinical studies are limited, they suggest that in utero alcohol exposure also results in significant immune deficiencies in naive neonates. However, little is known about fetal alcohol exposure (FAE) effects on adult infections. Therefore, to determine the long-term effects of FAE on disease susceptibility and the adult immune system, we infected FAE adult mice with influenza virus. In this study, we demonstrate that mice exposed to ethanol during gestation and nursing exhibit enhanced disease severity as well as increased and sustained pulmonary viral titers following influenza virus infection. Secondary exposure to alcohol as an adult further exacerbates these effects. Moreover, we demonstrate that FAE mice have impaired adaptive immune responses, including decreased numbers of virus-specific pulmonary CD8 T cells, a decreased size and frequency of pulmonary B cell foci, and reduced production of influenza-specific Ab following influenza infection. Together, our results suggest that FAE induces significant and long-term defects in immunity and susceptibility to influenza virus infection and that FAE individuals could be at increased risk for severe and fatal respiratory infections.
New Insights into the Molecular Basis of T Cell Anergy: Anergy Factors, Avoidance Sensors, and Epigenetic Imprinting
Authors: Wells Andrew D.
Published: June 2009

The vertebrate immune system has evolved to deal with invasive pathogens, but this adaptation comes at the expense of immunopathology. Among a number of mechanisms that coevolved to control adaptive immunity is anergy, the functional inactivation of T lymphocytes that respond to Ag in the absence of inflammation. In this review, I highlight a series of intracellular proteins in quiescent T cells that function to integrate signals from Ag, costimulatory, and growth factor receptors. These factors ensure that cells that fail to engage all three pathways are shunted into an alternative transcriptional program designed to dissuade them from participating in subsequent immune responses. Recent studies indicate that anergy is the combined result of factors that negatively regulate proximal TCR-coupled signal transduction, together with a program of active transcriptional silencing that is reinforced through epigenetic mechanisms.
Heterogeneity in HIV Suppression by CD8 T Cells from HIV Controllers: Association with Gag-Specific CD8 T Cell Responses
Authors: Sáez-Cirión Asier , Sinet Martine , Shin So Youn , Urrutia Alejandra , Versmisse Pierre , Lacabaratz Christine , Boufassa Faroudy , Avettand-Fènoël Véronique , Rouzioux Christine , Delfraissy Jean-François , Barré-Sinoussi Françoise , Lambotte Olivier , Venet Alain , Pancino Gianfranco ,   for the ANRS EP36 HIV Controllers Study Group
Published: June 2009

“HIV controllers” (HICs) are rare individuals in whom HIV-1 plasma viral load remains undetectable without antiretroviral treatment. This spontaneous viral control in HICs is usually associated to strong functional HIV-specific CD8+ T cell responses. Accordingly, we have recently shown that CD8+ T cells from HICs strongly suppress ex vivo HIV-1 infection of autologous CD4+ T cells, suggesting a crucial role of this response in vivo. Knowledge of the mechanisms underlying the CD8+ T cell antiviral activity might help to develop effective T cell-based vaccines. In the present work, we further characterized the HIV-suppressive capacity of CD8+ T cells in 19 HICs. CD8+ T cells from 14 of the 19 HICs showed strong HIV-suppressive capacity ex vivo. This capacity was stable over time and was partially effective even on other primate lentiviruses. HIV-suppressive capacity of CD8+ T cells correlated strongly with the frequency of HIV-specific CD8+ T cells, and in particular of Gag-specific CD8+ T cells. We also identified five HICs who had weak HIV-suppressive CD8+ T cell capacities and HIV-specific CD8+ T cell responses. Among these five HICs, at least three had highly in vitro replicative viruses, suggesting that the control of viremia in these patients is not due to replication-defective viruses. These results, on the one hand, suggest the importance of Gag responses in the antiviral potency of CD8+ T cells from HICs and, on the other hand, propose that other host mechanisms may contribute to restraining HIV infection in HICs.
Crucial Role of TNF Receptors 1 and 2 in the Control of Polymicrobial Sepsis
Authors: Secher Thomas , Vasseur Virginie , Poisson Didier Marc , Mitchell Jane A. , Cunha Fernando Q. , Alves-Filho José Carlos , Ryffel Bernhard
Published: June 2009

Sepsis is still a major cause of mortality in the intensive critical care unit and results from an overwhelming immune response to the infection. TNF signaling pathway plays a central role in the activation of innate immunity in response to pathogens. Using a model of polymicrobial sepsis by i.p. injection of cecal microflora, we demonstrate a critical role of TNFR1 and R2 activation in the deregulated immune responses and death associated with sepsis. A large and persistent production of TNF was found in wild-type (B6) mice. TNFR1/R2-deficient mice, compared with B6 mice, survive lethal polymicrobial infection with enhanced neutrophil recruitment and bacterial clearance in the peritoneal cavity. Absence of TNFR signaling leads to a decreased local and systemic inflammatory response with diminished organ injury. Furthermore, using TNFR1/R2-deficient mice, TNF was found to be responsible for a decrease in CXCR2 expression, explaining reduced neutrophil extravasation and migration to the infectious site, and in neutrophil apoptosis. In line with the clinical experience, administration of Enbrel, a TNF-neutralizing protein, induced however only a partial protection in B6 mice, with no improvement of clinical settings, suggesting that future TNF immunomodulatory strategies should target TNFR1 and R2. In conclusion, the present data suggest that the endogenous TNFR1/R2 signaling pathway in polymicrobial sepsis reduces neutrophil recruitment contributing to mortality and as opposed to pan-TNF blockade is an important therapeutic target for the treatment of polymicrobial sepsis.
Cross-Presentation of Male Seminal Fluid Antigens Elicits T Cell Activation to Initiate the Female Immune Response to Pregnancy
Authors: Moldenhauer Lachlan M. , Diener Kerrilyn R. , Thring Dougal M. , Brown Michael P. , Hayball John D. , Robertson Sarah A.
Published: June 2009

The events that generate T cell-mediated immune tolerance in early pregnancy are ill-defined. To investigate the significance of seminal fluid Ags in activating maternal T cells, and define the underlying Ag presentation pathways, OVA-specific T cells were adoptively transferred to female mice inseminated by males ubiquitously expressing membrane-bound OVA. OVA-reactive CD8+ OT-I and CD4+ OT-II T cells transferred to mated recipients expressed activation markers CD25 and CD69 and proliferated vigorously in the para-aortic lymph nodes, but not in distal lymph nodes or spleen, and OT-I T cells expressed IFN-γ and IL-2. In contrast, OT-I T cells transferred later in pregnancy or up to 10 days postpartum expressed CD25 and CD69 and proliferated in all peripheral lymphoid tissues examined. OVA Ag was present predominantly in the plasma fraction of seminal fluid, and seminal plasma, but not sperm, was necessary for T cell proliferation. Female H-2Kb bone marrow-derived cells expressing TAP were essential for OT-I T cell proliferation, but responses were not elicited by OVA Ag presented by paternal MHC in seminal fluid or associated with placental cells. This study shows that at conception, seminal fluid drives activation and expansion of paternal Ag-reactive CD4+ and CD8+ T cell populations, and female APCs have an essential role in cross-presenting Ag to CD8+ T cells via a TAP-dependent pathway. Delivery of paternal Ags and immune-deviating cytokines by seminal fluid at conception may activate Ag-dependent CD4+ and CD8+ regulatory T cells mediating tolerance of pregnancy.
Novel Function of CRTH2 in Preventing Apoptosis of Human Th2 Cells through Activation of the Phosphatidylinositol 3-Kinase Pathway
Authors: Xue Luzheng , Barrow Anna , Pettipher Roy
Published: June 2009

It is now well established that interaction of PGD2 with chemoattractant receptor- homologous molecule expressed on Th2 cells (CRTH2) promotes chemotaxis and proinflammatory cytokine production by Th2 lymphocytes. In this study we show a novel function of CRTH2 in mediating an inhibitory effect of PGD2 on the apoptosis of human Th2 cells induced by cytokine deprivation. This effect was mimicked by the selective CRTH2 agonist 13,14-dihydro-15-keto-PGD2, inhibited by the CRTH2 antagonists ramatroban and TM30089, and not observed in CRTH2-negative T cells. D prostanoid receptor 1 (DP1) or the thromboxane-like prostanoid (TP) receptor did not play a role in mediating the effects of PGD2 on the apoptosis of Th2 cells because neither the DP1 antagonist BW868C nor the TP antagonist SQ29548 had any effect on the antiapoptotic effect of PGD2. Apoptosis of Th2 cells induced by Fas ligation was not suppressed by treatment with PGD2, illustrating that activation of CRTH2 only inhibits apoptosis induced by cytokine deprivation. Treatment with PGD2 induced phosphorylation of Akt and BAD, prevented release of cytochrome c from mitochondria, and suppressed cleavage of caspase-3 and poly(ADP-ribose) polymerase in Th2 cells deprived of IL-2. The PI3K inhibitor LY294002 blocked the effect of PGD2 both on the signaling events and on the apoptotic death of Th2 cells. These data suggest that in addition to promoting the recruitment and activation of Th2 cells, PGD2 may also impede the resolution of allergic inflammation through inhibiting apoptosis of Th2 cells.
Atherogenic Lipids Induce High-Density Lipoprotein Uptake and Cholesterol Efflux in Human Macrophages by Up-Regulating Transmembrane Chemokine CXCL16 without Engaging CXCL16-Dependent Cell Adhesion
Authors: Barlic Jana , Zhu Wenjia , Murphy Philip M.
Published: June 2009

Atherosclerosis is a complex pathologic process in which chemokine-mediated leukocyte accumulation in arterial walls is thought to be an important mechanism of pathogenesis. An interesting exception to this paradigm is the chemokine CXCL16, also known as the scavenger receptor for phosphatidylserine and oxidized low density lipoprotein, which is highly expressed in mouse and human atherosclerotic lesions, yet appears to be atheroprotective. In this study, we address potential mechanisms responsible for this activity. Consistent with its presence in atherosclerotic plaque, we found that atherogenic lipids up-regulated CXCL16 in primary human monocyte-derived macrophages. However, the same lipids down-regulated the CXCL16-targeted protease ADAM10, resulting in preferential expression of CXCL16 as the transmembrane form, not the shed form. Although transmembrane CXCL16 is known to mediate cell-cell adhesion by binding its receptor CXCR6, and atherogenic lipids are known to stimulate macrophage adhesion to coronary artery smooth muscle cells, we found that heterotypic adhesion of these cell types occurred in a CXCL16-independent manner. Instead we found that in macrophages, CXCL16 promoted internalization of both oxidized low density lipoprotein and high density lipoprotein, as well as release of cholesterol. Moreover, CXCL16 deficiency in macrophages interfered with oxidized low density lipoprotein-induced up-regulation of atheroprotective genes: adenosine triphosphate-binding cassette transporter A1 and G1 as well as apolipoprotein E. Thus, our findings support the hypothesis that CXCL16 mediates atheroprotection through its scavenger role in macrophages and not by cell-cell adhesion.
Modulation of p38 MAPK Activity in Regulatory T Cells after Tolerance with Anti-DNA Ig Peptide in (NZB × NZW)F1 Lupus Mice
Authors: Lourenço Elaine V. , Procaccini Claudio , Ferrera Francesca , Iikuni Noriko , Singh Ram P. , Filaci Gilberto , Matarese Giuseppe , Shi Fu-Dong , Brahn Ernest , Hahn Bevra H. , La Cava Antonio
Published: June 2009

Treatment of (NZB × NZW)F1 (NZB/W) lupus-prone mice with the anti-DNA Ig-based peptide pConsensus prolongs the survival of treated animals and effectively delays the appearance of autoantibodies and glomerulonephritis. We have previously shown that part of these protective effects associated with the induction of CD4+CD25+Foxp3+ regulatory T cells (Tregs) that suppressed autoantibody responses. Because the effects of pConsensus appeared secondary to qualitative rather than quantitative changes in Tregs, we investigated the molecular events induced by tolerance in Tregs and found that signaling pathways including ZAP70, p27, STAT1, STAT3, STAT6, SAPK, ERK, and JNK were not significantly affected. However, peptide tolerization affected in Tregs the activity of the MAPK p38, whose phosphorylation was reduced by tolerance. The pharmacologic inhibition of p38 with the pyridinyl imidazole inhibitor SB203580 in naive NZB/W mice reproduced in vivo the effects of peptide-induced tolerance and protected mice from lupus-like disease. Transfer experiments confirmed the role of p38 in Tregs on disease activity in the NZB/W mice. These data indicate that the modulation of p38 activity in lupus Tregs can significantly influence the disease activity.
Direct Stimulation of tlr5+/+ CD11c+ Cells Is Necessary for the Adjuvant Activity of Flagellin
Authors: Bates John T. , Uematsu Satoshi , Akira Shizuo , Mizel Steven B.
Published: June 2009

Flagellin is a highly effective adjuvant, but the cellular mechanism underlying this activity remains uncertain. More specifically, no consensus exists as to whether flagellin activates dendritic cells (DC) directly or indirectly. Intramuscular immunization with flagellin-OVA fusion protein resulted in enhanced in vivo T cell clustering in draining lymph nodes and IL-2 production by OVA-specific CD4+ T cells. Immunization with flagellin-OVA also triggered greater levels of Ag-specific CD4+ T cell proliferation than immunization with flagellin and OVA as separate proteins. To determine whether flagellin, in the context of a fusion protein with OVA, was acting directly on DC, we used a combination of CD4+ T cell adoptive transfers and bone marrow chimera mice in which the presence or absence of potential tlr5+/+ CD11c+ cells was controlled by injection of diphtheria toxin. The Ag-specific CD4+ T cell response in mice with CD11c+ cells from a tlr5−/− background and mixed populations of all other hematopoietic cells was dramatically reduced in comparison to mice that had DC from tlr5−/− and wild-type backgrounds. Immunization of MyD88−/−tlr5+/+ mice revealed that the enhanced response following immunization with flagellin-OVA is dependent on signaling via the TLR5-MyD88 pathway as well as enhanced Ag uptake and processing resulting from Ag targeting via TLR5. In summary, our data are consistent with the conclusion that direct stimulation of tlr5+/+ CD11c+ cells is necessary for the adjuvant activity of a flagellin fusion protein and that this adjuvant effect requires signaling through TLR5.
Wiskott-Aldrich Syndrome Protein Is Required for Homeostasis and Function of Invariant NKT Cells
Authors: Astrakhan Alexander , Ochs Hans D. , Rawlings David J.
Published: June 2009

NKT cells comprise a separate T lineage expressing semi-invariant T cell receptors. Canonical invariant NKT (iNKT) cells specifically recognize lipid Ags presented by CD1d, a MHC class I-like molecule. iNKT cells function, in part, as initial responders to bacterial infection and play a role in immune surveillance and tumor rejection. The Wiskott-Aldrich Syndrome protein (WASp) serves as a crucial link between cellular stimuli and cytoskeletal rearrangements. Although we and others have identified a key role for WASp in homeostasis of T-regulatory and marginal zone B cells, little data exist regarding the role for WASp within the iNKT lineage. Analysis of WASp-expressing cell populations in heterozygous female WASp mice revealed a substantial selective advantage for WASp+ vs WASp− iNKT cells. Although adult WASp-deficient (WASp−/−) mice had normal thymic and bone marrow iNKT numbers, we observed 2- to 3-fold reduction in the numbers of iNKT cells in the spleen and liver. This peripheral iNKT deficit is manifested, in part, due to defective iNKT homeostasis. WASp−/− iNKT cells exhibited reduced levels of integrin surface expression and decreased homing and/or retention within peripheral tissues in a competitive repopulation model. In addition, analysis of young mice showed that WASp is important for both maturation and egress of thymic iNKT cells. WASp−/− iNKT cells also exhibited a marked reduction in Ag-induced proliferation and cytokine production. Our findings highlight the crucial role for WASp in iNKT development, homeostasis, and activation, and identify iNKT dysfunction as an additional factor likely to contribute to the clinical features observed in WAS patients.
HSP90α and HSP90β Isoforms Selectively Modulate MHC Class II Antigen Presentation in B Cells
Authors: Houlihan Josetta L. , Metzler Jennifer J. , Blum Janice S.
Published: June 2009

Two isoforms of heat shock protein (HSP) 90, α and β, are abundantly expressed in the cytoplasm of cells, yet only HSP90α serves as a chaperone to potentiate epitope presentation in the context of MHC class I molecules. By contrast, the role of HSP90 isoforms in MHC class II presentation of exogenous and endogenous Ags remains less clear. Studies here using human B lymphoblasts demonstrate the importance of HSP90α and HSP90β isoforms in selectively regulating class II presentation of the diabetes autoantigen glutamic acid decarboxylase (GAD). Inactivation of HSP90 function using geldanamycin or radicicol inhibited MHC class II presentation of exogenous and endogenous GAD, but did not perturb the presentation of several other intra- and extracellular Ags. Treatment of human B cells with geldanamycin and radicicol did not alter cellular MHC class II expression, but did induce a stress response in these APCs. Yet, cell stress alone failed to perturb MHC class II presentation of GAD. HSP90 was found to associate with select Ags such as GAD in cells and ex vivo. Knockdown of HSP90α or HSP90β expression using small interfering RNA decreased the abundance of each isoform, respectively, but did not affect MHC class II expression or induce a stress response. Notably, disruption of HSP90α or HSP90β expression specifically inhibited class II presentation of the exogenous and endogenous GAD Ag. Precomplexing HSP90 with GAD Ag enhanced exogenous GAD Ag presentation. These results demonstrate a requirement for HSP90α and HSP90β in regulating class II presentation of select Ags.
Regulation of T Cell Activation by Notch Ligand, DLL4, Promotes IL-17 Production and Rorc Activation
Authors: Mukherjee Sumanta , Schaller Matthew A. , Neupane Rupak , Kunkel Steven L. , Lukacs Nicholas W.
Published: June 2009

The activation and differentiation of T cells are dependent upon numerous initiating events that are influenced by the immune environment, nature of the Ag, as well as the activation state of APCs. In the present studies we have investigated the role of a specific notch ligand, delta-like 4 (Dll4). In particular, our data have indicated that Dll4 is inducible by pathogen-associated signals through TLR activation on dendritic cells but not early response inflammatory cytokines, IL-1 and IL-18 that also activate cells via MyD88 adapter pathway. Our observations from in vitro cultures confirmed earlier reports demonstrating that Dll4 inhibits Th2 cytokine production. Furthermore, Dll4 influences the generation of IL-17-producing T cells in the presence of additional skewing cytokines, IL-6 and TGF-β. In the absence of notch signals, IL-17 production was significantly inhibited even under specific skewing conditions. These studies further demonstrate that Dll4 up-regulates Rorc expression in T cells and that both Rorc and Il17 gene promoters are direct transcriptional notch targets that further enhance the differentiation of Th17 cell populations. Thus, facilitation of efficient T cell differentiation may depend upon the activation of T cells via specific notch ligand stimulation.
The Immunoregulatory Enzyme IDO Paradoxically Drives B Cell-Mediated Autoimmunity
Authors: Scott Grant N. , DuHadaway James , Pigott Elizabeth , Ridge Natalie , Prendergast George C. , Muller Alexander J. , Mandik-Nayak Laura
Published: June 2009

Rheumatoid arthritis (RA) is a chronic and debilitating inflammatory autoimmune disease of unknown etiology. As with a variety of autoimmune disorders, evidence of elevated tryptophan catabolism has been detected in RA patients indicative of activation of the immunomodulatory enzyme IDO. However, the role that IDO plays in the disease process is not well understood. The conceptualization that IDO acts solely to suppress effector T cell activation has led to the general assumption that inhibition of IDO activity should exacerbate autoimmune disorders. Recent results in cancer models, however, suggest a more complex role for IDO as an integral component of the inflammatory microenvironment necessary for supporting tumor outgrowth. This has led us to investigate the involvement of IDO in the pathological inflammation associated with RA. Using the K/BxN murine RA model and IDO inhibitor 1-methyl-tryptophan, we found that inhibiting IDO activity had the unexpected consequence of ameliorating, rather than exacerbating arthritis symptoms. 1-Methyl tryptophan treatment led to decreased autoantibody titers, reduced levels of inflammatory cytokines, and an attenuated disease course. This alleviation of arthritis was not due to an altered T cell response, but rather resulted from a diminished autoreactive B cell response, thus demonstrating a previously unappreciated role for IDO in stimulating B cell responses. Our findings raise the question of how an immunosuppressive enzyme can paradoxically drive autoimmunity. We suggest that IDO is not simply immunosuppressive, but rather plays a more complex role in modulating inflammatory responses, in particular those that are driven by autoreactive B cells.
CD154-CD40 Interactions Are Essential for Thymus-Dependent Antibody Production in Zebrafish: Insights into the Origin of Costimulatory Pathway in Helper T Cell-Regulated Adaptive Immunity in Early Vertebrates
Authors: Gong Yong-Feng , Xiang Li-Xin , Shao Jian-Zhong
Published: June 2009

The CD154-CD40-mediated costimulatory pathway is critical for T-B cell cooperation in thymus-dependent (TD) immune response in mammals. However, little is known about its existence and occurrence in lower vertebrates. Here, we report on the identification and functional characterization of CD154 and CD40 homologs from the zebrafish (Danio rerio) model. Zebrafish CD154 is a type II membrane-bound protein with a TNF homology domain in its extracellular C-terminal region, whose tertiary structure is a sandwich containing two stacked sheets with “jelly roll” topology, just as the human TNF members do. The zebrafish CD40 is a type I membrane-bound protein with a sequence pattern of four cysteine-rich domains in its extracellular N-terminal region. The consensus TNFR-associated factor (TRAF)2- and TRAF6-binding motifs in mammalian CD40 are found in the cytoplasmic tail of zebrafish CD40, which indicates similar signal transduction mechanisms to higher vertebrates. Zebrafish CD154 and CD40 are widely distributed and can be up-regulated by thymus-dependent Ag. The production of IgM was dramatically decreased by anti-CD154 or soluble CD40, and it was enhanced by soluble CD154 or CD154-encoding plasmid in vivo. Thymus-dependent Ag-induced CD154 expression was inhibited by cyclosporin A, suggesting that CD154 functionally associates with T cells. Double immunofluorescence staining showed that CD40 and membrane IgM colocalized in B cells. CD154-CD40 binding assays showed that CD154 specifically binds to CD40 at homodimeric form. Our results provide the first evidence for the existence of the functional CD154-CD40-mediated costimulatory pathway and helper T cell regulatory mechanism underlying adaptive immunity in a fish species.
Chlamydia trachomatis Native Major Outer Membrane Protein Induces Partial Protection in Nonhuman Primates: Implication for a Trachoma Transmission-Blocking Vaccine
Authors: Kari Laszlo , Whitmire William M. , Crane Deborah D. , Reveneau Nathalie , Carlson John H. , Goheen Morgan M. , Peterson Ellena M. , Pal Sukumar , de la Maza Luis M. , Caldwell Harlan D.
Published: June 2009

A vaccine is likely the most effective strategy for controlling human chlamydial infections. Recent studies have shown immunization with Chlamydia muridarum major outer membrane protein (MOMP) can induce significant protection against infection and disease in mice if its native trimeric structure is preserved (nMOMP). The objective of this study was to investigate the immunogenicity and vaccine efficacy of Chlamydia trachomatis nMOMP in a nonhuman primate trachoma model. Cynomolgus monkeys (Macaca fascicularis) were immunized systemically with nMOMP, and monkeys were challenged ocularly. Immunization induced high serum IgG and IgA ELISA Ab titers, with Abs displaying high strain-specific neutralizing activity. The PBMCs of immunized monkeys produced a broadly cross-reactive, Ag-specific IFN-γ response equivalent to that induced by experimental infection. Immunized monkeys exhibited a significant decrease in infectious burden during the early peak shedding periods (days 3–14). However, at later time points, they exhibited no difference from control animals in either burden or duration of infection. Immunization had no effect on the progression of ocular disease. These results show that systemically administered nMOMP is highly immunogenic in nonhuman primates and elicits partially protective immunity against ocular chlamydial challenge. This is the first time a subunit vaccine has shown a significant reduction in ocular shedding in nonhuman primates. A partially protective vaccine, particularly one that reduces infectious burden after primary infection of children, could interrupt the natural trachoma reinfection cycle. This would have a beneficial effect on the transmission between children and sensitized adults which drives blinding inflammatory disease.
Cooperation between Mast Cells and Neurons Is Essential for Antigen-Mediated Bronchoconstriction
Authors: Cyphert Jaime M. , Kovarova Martina , Allen Irving C. , Hartney John M. , Murphy Dennis L. , Wess Jürgen , Koller Beverly H.
Published: June 2009

Mast cells are important sentinels guarding the interface between the environment and the body: a breach in the integrity of this interface can lead to the release of a plethora of mediators that engage the foreign agent, recruit leukocytes, and initiate adaptive physiological changes in the organism. While these capabilities make mast cells critical players in immune defense, it also makes them important contributors to the pathogenesis of diseases such as asthma. Mast cell mediators induce dramatic changes in smooth muscle physiology, and the expression of receptors for these factors by smooth muscle suggests that they act directly to initiate constriction. Contrary to this view, we show herein that mast cell-mediated bronchoconstriction is observed only in animals with intact innervation of the lung and that serotonin release alone is required for this action. While ablation of sensory neurons does not limit bronchoconstriction, constriction after Ag challenge is absent in mice in which the cholinergic pathways are compromised. Linking mast cell function to the cholinergic system likely provides an important means of modulating the function of these resident immune cells to physiology of the lung, but may also provide a safeguard against life-threatening anaphylaxis during mast cell degranulation.
Glutamine Protects Mice from Lethal Endotoxic Shock via a Rapid Induction of MAPK Phosphatase-1
Authors: Ko Hyun-Mi , Oh Sin-Hye , Bang Hwa-Suk , Kang Nam-In , Cho Baik-Hwan , Im Suhn-Young , Lee Hern-Ku
Published: June 2009

The nonessential amino acid l-glutamine (Gln) is the most abundant amino acid in plasma. Clinical trials have demonstrated that Gln therapy is safe and improves clinical outcomes in critically ill patients. We have previously shown that Gln protect animals from endotoxic shock through the inhibition of cytosolic phospholipase A2 activity. In this study, we investigated how Gln regulates MAPK activation, as the molecular mechanism underlying Gln-induced cytosolic phospholipase A2 inactivation. Gln rapidly (within 10 min) inactivated p38 and JNK, but not ERK, by dephosphorylating them only when these MAPKs were phosphorylated in response to LPS in vivo as well as in vitro. Western blot analysis revealed that Gln administration resulted in rapid (∼5 min) phosphorylation and protein induction of MAP kinase phosphatase-1 (MKP-1). MKP-1 siRNA abrogated the Gln-mediated 1) inactivation of p38 and JNK, 2) induction of MKP-1, and 3) protection against endotoxic shock. The ERK inhibitor U0126 blocked Gln-induced MKP-1 phosphorylation and protein induction, as well as Gln’s protective activity against endotoxic shock. These data suggest that Gln exerts a beneficial effect on endotoxic shock by inactivating p38 and JNK via a rapid induction of MKP-1 protein in an ERK-dependent way.
The Immunomodulatory Action of Sialostatin L on Dendritic Cells Reveals Its Potential to Interfere with Autoimmunity
Authors: Sá-Nunes Anderson , Bafica André , Antonelli Lis R. , Choi Eun Young , Francischetti Ivo M. B. , Andersen John F. , Shi Guo-Ping , Chavakis Triantafyllos , Ribeiro José M. , Kotsyfakis Michalis
Published: June 2009

Sialostatin L (SialoL) is a secreted cysteine protease inhibitor identified in the salivary glands of the Lyme disease vector Ixodes scapularis. In this study, we reveal the mechanisms of SialoL immunomodulatory actions on the vertebrate host. LPS-induced maturation of dendritic cells from C57BL/6 mice was significantly reduced in the presence of SialoL. Although OVA degradation was not affected by the presence of SialoL in dendritic cell cultures, cathepsin S activity was partially inhibited, leading to an accumulation of a 10-kDa invariant chain intermediate in these cells. As a consequence, in vitro Ag-specific CD4+ T cell proliferation was inhibited in a time-dependent manner by SialoL, and further studies engaging cathepsin S−/− or cathepsin L−/− dendritic cells confirmed that the immunomodulatory actions of SialoL are mediated by inhibition of cathepsin S. Moreover, mice treated with SialoL displayed decreased early T cell expansion and recall response upon antigenic stimulation. Finally, SialoL administration during the immunization phase of experimental autoimmune encephalomyelitis in mice significantly prevented disease symptoms, which was associated with impaired IFN-γ and IL-17 production and specific T cell proliferation. These results illuminate the dual mechanism by which a human disease vector protein modulates vertebrate host immunity and reveals its potential in prevention of an autoimmune disease.
Reduced Expression of the Mevalonate Pathway Enzyme Farnesyl Pyrophosphate Synthase Unveils Recognition of Tumor Cells by Vγ9Vδ2 T Cells
Authors: Li Jianqiang , Herold Marco J. , Kimmel Brigitte , Müller Ingrid , Rincon-Orozco Bladimiro , Kunzmann Volker , Herrmann Thomas
Published: June 2009

Human Vγ9Vδ2 T cells are characterized by a unique specificity for certain tumors (e.g., Daudi), cells presenting so-called phosphoantigens such as isopentenyl pyrophosphate (IPP), or cells treated with aminobisphosphonates. We now report conversion of hematopoietic and nonhematopoietic tumor cell lines into Vγ9Vδ2 T cell activators by means of short hairpin RNA-mediated knockdown of expression of the IPP-consuming enzyme, farnesyl pyrophosphate synthase (FPPS). FPPS knockdown cells activated Vγ9Vδ2 T cells, as measured by increased levels of CD69 and CD107a, killing of FPPS knockdown cells, and induction of IFN-γ secretion. The IPP-synthesis-inhibiting drug mevastatin reduced Vγ9Vδ2 T cell activation by FPPS knockdown cells but not activation by the phosphoantigen bromohydrin pyrophosphate. In conclusion, our data support the concept of Vγ9Vδ2 T cells as sensors of a dysregulated isoprenoid metabolism and suggest therapeutic down-modulation of FPPS expression as an additional tool to target tumor cells to Vγ9Vδ2 T cell-mediated immunosurveillance.
Glycolipids Injected into the Skin Are Presented to NKT Cells in the Draining Lymph Node Independently of Migratory Skin Dendritic Cells
Authors: Tripp Christoph H. , Sparber Florian , Hermans Ian F. , Romani Nikolaus , Stoitzner Patrizia
Published: June 2009

APCs, such as dendritic cells (DC), can present glycolipid Ags on CD1d molecules to NKT cells. This interaction activates DC and NKT cells, leading to release of cytokines and enhanced T cell responses. Thus, glycolipid Ags are currently being tested as adjuvants for immunotherapy. We were interested in the interaction of murine skin DC with NKT cells in skin-draining lymph nodes. We observed that all skin DC subsets expressed CD1d upon migration to the lymph nodes. Moreover, skin DC were able to present the synthetic glycolipid Ag α-galactosylceramide (α-GalCer) to the NKT cell hybridoma DN32.D3. Intradermally injected α-GalCer was presented by migratory skin DC and lymph node DC to NKT hybridoma cells in vitro. When we injected α-GalCer intradermally into the skin, the numbers of various leukocyte subsets in the draining lymph nodes did not change significantly. However, T and B cells as well as NKT cells up-regulated the activation marker CD69. Coapplication of α-GalCer with the tumor model Ag OVA induced strong cytolytic CD8+ T cell function that could inhibit the growth of B16 melanoma cells expressing OVA. However, mice that were devoid of migratory skin DC developed similar cytotoxic immune responses after intradermal immunization, indicating that skin DC are not required for the adjuvant properties of NKT cell activation and Ag presentation by this immunization route. In conclusion, migratory skin DC are able to interact with NKT cells; however, intradermally applied glycolipids are presented predominantly by lymph node DC to NKT cells.
A Single Nucleotide Polymorphism inTyk2Controls Susceptibility to Experimental Allergic Encephalomyelitis
Authors: Spach Karen M. , Noubade Rajkumar , McElvany Ben , Hickey William F. , Blankenhorn Elizabeth P. , Teuscher Cory
Published: June 2009

Genes controlling immunopathologic diseases of differing etiopathology may also influence susceptibility to autoimmune disease. B10.D1-H2q/SgJ mice with a 2538 G→A missense mutation in the tyrosine kinase-2 gene (Tyk2) are susceptible to Toxoplasma gondii yet resistant to autoimmune arthritis, unlike the wild-type B10.Q/Ai substrain. To understand whether Tyk2 is also important in a second autoimmune model, experimental allergic encephalomyelitis (EAE) was induced in B10.D1-H2q/SgJ (Tyk2A) and B10.Q/Ai (Tyk2G) mice with the myelin oligodendrocyte glycoprotein peptide 79–96. B10.D1-H2q/SgJ mice were resistant to EAE whereas B10.Q/Ai mice were susceptible, and a single copy of the Tyk2G allele conferred EAE susceptibility in F1 hybrids. Furthermore, EAE resistance in B10.D1-H2q/SgJ mice was overridden when pertussis toxin (PTX) was used to mimic the effects of environmental factors derived from infectious agents. Numerous cytokines and chemokines were increased when PTX was included in the immunization protocol. However, only RANTES, IL-6, and IFN-γ increased significantly with both genetic compensation and PTX treatment. These data indicate that Tyk2 is a shared autoimmune disease susceptibility gene whose genetic contribution to disease susceptibility can be modified by environmental factors. Single nucleotide polymorphisms like the one that distinguishes Tyk2 alleles are of considerable significance given the potential role of gene-by-environment interactions in autoimmune disease susceptibility.
Identification and Biochemical Characterization of Human Plasma Soluble IL-7R: Lower Concentrations in HIV-1-Infected Patients
Authors: Rose Thierry , Lambotte Olivier , Pallier Coralie , Delfraissy Jean-François , Colle Jean-Hervé
Published: June 2009

The IL-7R α-chain and the common γ-chain (γc) are both components of IL-7R. Human plasma harbors soluble forms of IL-7R (sIL-7Rα and sγc) that are detected and assayed by Western blotting, showing that the levels of sIL-7Rα are higher than the levels of sγc (47.5 ng/ml and 1.5 ng/ml, respectively). Gel electrophoresis and tandem mass spectrometry used to analyze deglycosylated, affinity-purified protein showed that sIL-7Rα is generated through differentially spliced mRNA, not by membrane receptor shedding. Plasma sIL-7Rα and sγc are present as heterocomplexes and sγc was found to be mainly associated with sIL-7Rα. The affinities of two IL-7 binding sites (Kd = 35 ± 8 pM and Kd = 3 ± 1 nM) were similar to that of the membrane receptor, suggesting that the sIL-7Rα/sγc complex retains high affinity for IL-7. sIL-7Rα mRNA is constitutively present among peripheral T lymphocytes and is down-modulated in vitro by IL-7. Chronically HIV-1-infected patients (n = 20) showed no significant (p > 0.714) variation in sγc levels and a significant (p < 0.0014) 2-fold decrease in plasma sIL-7Rα levels compared with those in control healthy individuals. Plasma IL-7 and sIL-7Rα levels did not show any obvious relationship.
Resistance to Celiac Disease in Humanized HLA-DR3-DQ2-Transgenic Mice Expressing Specific Anti-Gliadin CD4+ T Cells
Authors: de Kauwe Andrea L. , Chen Zhenjun , Anderson Robert P. , Keech Catherine L. , Price Jason D. , Wijburg Odilia , Jackson David C. , Ladhams Jodi , Allison Janette , McCluskey James
Published: June 2009

Celiac disease is a chronic inflammatory enteropathy caused by cellular immunity to dietary gluten. More than 90% of patients carry HLA-DQ2 encoded by HLA-DQA1*05 and DQB1*02, and gluten-specific CD4+ T cells from intestinal biopsies of these patients are HLA-DQ2-restricted, produce Th1 cytokines and preferentially recognize gluten peptides deamidated by tissue transglutaminase. We generated mice lacking murine MHC class II genes that are transgenic for human CD4 and the autoimmunity and celiac disease-associated HLA-DR3-DQ2 haplotype. Immunization with the α-gliadin 17-mer that incorporates the overlapping DQ2-α-I and DQ2-α-II epitopes immunodominant in human celiac disease generates peptide-specific HLA-DQ2-restricted CD4+ T cells. When exposed to dietary gluten, naive or gliadin-primed mice do not develop pathology. Coincident introduction of dietary gluten and intestinal inflammation resulted in low-penetrance enteropathy and tissue transglutaminase-specific IgA. Two further strains of transgenic mice expressing HLA-DR3-DQ2 and human CD4, one with a NOD background and another TCR transgenic having over 90% of CD4+ T cells specific for the DQ2-α-II epitope with a Th1 phenotype, were also healthy when consuming gluten. These humanized mouse models indicate that gluten ingestion can be tolerated without intestinal pathology even when HLA-DQ2-restricted CD4+ T cell immunity to gluten is established, thereby implicating additional factors in controlling the penetrance of celiac disease.
Selective Up-Regulation of Intact, but Not Defective env RNAs of Endogenous Modified Polytropic Retrovirus by the Sgp3 Locus of Lupus-Prone Mice
Authors: Yoshinobu Kumiko , Baudino Lucie , Santiago-Raber Marie-Laure , Morito Naoki , Dunand-Sauthier Isabelle , Morley Bernard J. , Evans Leonard H. , Izui Shozo
Published: June 2009

Endogenous retroviruses are implicated in the pathogenesis of systemic lupus erythematosus (SLE). Because four different classes of endogenous retroviruses, i.e., ecotropic, xenotropic, polytropic, or modified polytropic (mPT), are expressed in mice, we investigated the possibility that a particular class of endogenous retroviruses is associated with the development of murine SLE. We observed >15-fold increased expression of mPT env (envelope) RNA in livers of all four lupus-prone mice, as compared with those of nine nonautoimmune strains of mice. This was not the case for the three other classes of retroviruses. Furthermore, we found that in addition to intact mPT transcripts, many strains of mice expressed two defective mPT env transcripts which carry a deletion in the env sequence of the 3′ portion of the gp70 surface protein and the 5′ portion of the p15E transmembrane protein, respectively. Remarkably, in contrast to nonautoimmune strains of mice, all four lupus-prone mice expressed abundant levels of intact mPT env transcripts, but only low or nondetectable levels of the mutant env transcripts. The Sgp3 (serum gp70 production 3) locus derived from lupus-prone mice was responsible for the selective up-regulation of the intact mPT env RNA. Finally, we observed that single-stranded RNA-specific TLR7 played a critical role in the production of anti-gp70 autoantibodies. These data suggest that lupus-prone mice may possess a unique genetic mechanism responsible for the expression of mPT retroviruses, which could act as a triggering factor through activating TLR7 for the development of autoimmune responses in mice predisposed to SLE.
Suppression of IgE B Cells and IgE Binding to FcεRI by Gene Therapy with Single-Chain Anti-IgE
Authors: Ota Takayuki , Aoki-Ota Miyo , Duong Bao Hoa , Nemazee David
Published: June 2009

IgE plays a pivotal role in allergic reactions and asthma through its ability to bind to the mast cell FcR for IgE (FcεRI). Current therapies to suppress such reactions include passive treatment with neutralizing Abs to IgE that block its binding to FcεRI. In theory, induction of immune tolerance in the B lymphocytes that carry IgE Ag receptors and give rise to IgE-secreting cells should provide longer term efficacy. However, recent data have suggested that such memory cells may lack cell surface IgE. Using a gene therapy approach, we show that a recombinant single-chain neutralizing anti-IgE could not only neutralize circulating IgE, but also reduce IgE+ B cell numbers and H chain transcripts. Therapeutic anti-IgE stimulated a calcium response in primary B cells or in a B cell line expressing membrane IgE and suppressed IgE secretion in vitro, suggesting that active signaling through membrane IgE likely promoted tolerance. Interestingly, upon subsequent challenge of anti-IgE-treated mice with an IgE cross-linking reagent capable of inducing activation of IgE-decorated mast cells, an anaphylaxis reaction was induced, apparently via a FcγRIII pathway involving recognition of anti-IgE Ab itself. These studies have important implications for the optimal design of safe and effective anti-IgE therapies and suggest that the IgE memory B cells may be targeted by such genetic Ab therapies.
SP-A Preserves Airway Homeostasis During Mycoplasma pneumoniae Infection in Mice
Authors: Ledford Julie G. , Goto Hisatsugu , Potts Erin N. , Degan Simone , Chu Hong Wei , Voelker Dennis R. , Sunday Mary E. , Cianciolo George J. , Foster William M. , Kraft Monica , Wright Jo Rae
Published: June 2009

The lung is constantly challenged during normal breathing by a myriad of environmental irritants and infectious insults. Pulmonary host defense mechanisms maintain homeostasis between inhibition/clearance of pathogens and regulation of inflammatory responses that could injure the airway epithelium. One component of this defense mechanism, surfactant protein-A (SP-A), exerts multifunctional roles in mediating host responses to inflammatory and infectious agents. SP-A has a bacteriostatic effect on Mycoplasma pneumoniae (Mp), which occurs by binding surface disaturated phosphatidylglycerols. SP-A can also bind the Mp membrane protein, MPN372. In this study, we investigated the role of SP-A during acute phase pulmonary infection with Mp using mice deficient in SP-A. Biologic responses, inflammation, and cellular infiltration, were much greater in Mp infected SP-A−/− mice than wild-type mice. Likewise, physiologic responses (airway hyperresponsiveness and lung compliance) to Mp infection were more severely affected in SP-A−/− mice. Both Mp-induced biologic and physiologic changes were attenuated by pharmacologic inhibition of TNF-α. Our findings demonstrate that SP-A is vital to preserving lung homeostasis and host defense to this clinically relevant strain of Mp by curtailing inflammatory cell recruitment and limiting an overzealous TNF-α response.
The C-Type Lectin Clec12A Present on Mouse and Human Dendritic Cells Can Serve as a Target for Antigen Delivery and Enhancement of Antibody Responses
Authors: Lahoud Mireille H. , Proietto Anna I. , Ahmet Fatma , Kitsoulis Susie , Eidsmo Liv , Wu Li , Sathe Priyanka , Pietersz Suzanne , Chang Hsuen-Wen , Walker Ian D. , Maraskovsky Eugene , Braley Hal , Lew Andrew M. , Wright Mark D. , Heath William R. , Shortman Ken , Caminschi Irina
Published: June 2009

We have cloned the mouse and human C-type lectin Clec12A, expressed both, and produced mAb recognizing both. Mouse Clec12A is highly expressed on splenic CD8+ dendritic cells (DC) and plasmacytoid DC. A proportion of CD8−DC also expresses lower levels of Clec12A, as do monocytes, macrophages, and B cells. Human CLEC12A, like the mouse counterpart, is expressed on blood monocytes and DC, including pDC and BDCA-3+DC, the proposed equivalent of mouse CD8+DC. To determine whether Ag targeted to Clec12A could induce immune responses, mice were injected with a rat mAb recognizing Clec12A, or a control rat mAb, then production of anti-rat Ig was measured. Anti-Clec12A mAb alone produced only moderate responses, but these were amplified by coinjecting only small amounts of LPS as a DC activation agent. Furthermore, when OVA was conjugated to anti-Clec12A mAb, OVA-specific T cells were induced to proliferate. This Ag presentation to naive T cells was due to targeting conventional DC, because their ablation eliminated T cell activation. The potent Ab responses induced using microgram amounts of anti-Clec12A and minimal amounts of adjuvant demonstrate that this molecule can be used as an Ag-delivery target to enhance Ab responses to vaccines.
α9 Integrin and Its Ligands Constitute Critical Joint Microenvironments for Development of Autoimmune Arthritis
Authors: Kanayama Masashi , Kurotaki Daisuke , Morimoto Junko , Asano Tsuyoshi , Matsui Yutaka , Nakayama Yosuke , Saito Yoshinari , Ito Koyu , Kimura Chiemi , Iwasaki Norimasa , Suzuki Koji , Harada Tanenobu , Li Hong Mei , Uehara Jun , Miyazaki Tadaaki , Minami Akio , Kon Shigeyuki , Uede Toshimitsu
Published: June 2009

Osteopontin is critically involved in rheumatoid arthritis; however, the molecular cross-talk between osteopontin and joint cell components that leads to the inflammatory joint destruction is largely unknown. We found that not only osteopontin but also tenascin-C and their common receptor, α9 integrin, are expressed at arthritic joints. The local production of osteopontin and tenascin-C is mainly due to synovial fibroblasts and, to a lesser extent, synovial macrophages. Synovial fibroblasts and macrophages express α9 integrin, and autocrine and paracrine interactions of α9 integrin on synovial fibroblasts and macrophages and its ligands contribute differently to the production of proinflammatory cytokines and chemokines. α9 integrin is also involved in the recruitment and accumulation of inflammatory cells. Inhibition of α9 integrin function with an anti-α9 integrin Ab significantly reduces the production of arthrogenic cytokines and chemokines and ameliorates ongoing arthritis. Thus, we identified α9 integrin as a critical intrinsic regulator that controls the development of autoimmune arthritis.