bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monocyte-Derived Dendritic Cells Generated After a Short-Term Culture with IFN-α and Granulocyte-Macrophage Colony-Stimulating Factor Stimulate a Potent Epstein-Barr Virus-Specific CD8+ T Cell Response
Authors: Santodonato Laura , D’Agostino Giuseppina , Nisini Roberto , Mariotti Sabrina , Monque Domenica M. , Spada Massimo , Lattanzi Laura , Perrone Maria Paola , Andreotti Mauro , Belardelli Filippo , Ferrantini Maria 
Published: April 2014

Abstract
Cellular immune responses are crucial for the control of EBV-associated lymphoproliferative diseases. To induce an anti-EBV cell-mediated immunity, we have used dendritic cells (DCs) generated by a 3-day culture of human CD14+ monocytes in the presence of GM-CSF and type I IFN (IFN-DCs) and pulsed with peptides corresponding to CTL EBV epitopes. The functional activity of IFN-DCs was compared with that of APCs differentiated by culturing monocytes for 3 days with GM-CSF and IL-4 and indicated as IL-4-DCs. Stimulation of PBLs from EBV-seropositive donors with EBV peptide-pulsed autologous IFN-DCs resulted in a stronger expansion of specific T lymphocytes producing IFN-γ with respect to stimulation with peptide-loaded IL-4-DCs, as assessed by ELISPOT assays. When purified CD8+ T cells were cocultured with EBV peptide-pulsed IFN-DCs or IL-4-DCs, significantly higher levels of specific cytotoxic activity were observed in CD8+ T cell cultures stimulated with IFN-DCs. Injection of peptide-pulsed IFN-DCs into SCID mice transplanted with autologous PBLs led to the recovery of a significantly greater number of EBV-specific human CD8+ T cells from the spleen and the peritoneal cavity with respect to that recovered from mice injected with peptide-pulsed IL-4-DCs. Moreover, a significant delay in lymphoma development was observed when peptide-pulsed IFN-DCs were injected into SCID mice reconstituted with PBMCs endowed with a high capability of lymphoma induction, whereas injection of unpulsed IFN-DCs was ineffective. Our results indicate that IFN-DCs efficiently promote in vitro and in vivo the expansion of CD8+ T lymphocytes acting as cytotoxic effectors against EBV-transformed cells.
Cumulative Toll-Like Receptor Activation in Human Macrophages Treated with Whole Bacteria
Authors: Nau Gerard J. , Schlesinger Ann , Richmond Joan F. L. , Young Richard A. 
Published: April 2014

AbstractPurified components from bacteria selectively activate Toll-like receptors (TLR), leading to shared and unique responses in innate immune cells. Whole bacteria contain agonists for multiple TLR and induce a common macrophage activation program of transcription. It is not known, however, whether the stimulation of specific TLR by whole bacteria results in differential activation of the innate immune system. We evaluated gene expression data from human macrophages and found a unique gene expression profile induced by Gram-negative bacteria. In contrast, Gram-positive bacteria evoked few specific alterations in gene expression. LPS, a TLR4-specific ligand, was sufficient to elicit the distinct expression profile observed with Gram-negative bacteria. TLR4 activation regulated gene expression by both an IFN-dependent and an IFN-independent mechanism, illustrated by I-TAC and IL-12 p70, respectively. IL-12 p70 was produced by cells in whole blood exposed to Gram-negative bacteria, demonstrating faithful reproduction of the macrophage response in mixed populations of cells and identifying a potential diagnostic marker of infection. Our results show that the macrophage response to bacteria is dominated by the accumulated input from multiple TLR. For macrophages exposed to Gram-negative bacteria, gene expression changes encompass those induced by Gram-positive bacteria plus a distinct TLR4 response. This distinct TLR4 response may provide the basis to diagnose clinical Gram-negative infections.
The Lymphotoxin β Receptor Is Critically Involved in Controlling Infections with the Intracellular Pathogens Mycobacterium tuberculosis and Listeria monocytogenes
Authors: Ehlers Stefan , Hölscher Christoph , Scheu Stefanie , Tertilt Christine , Hehlgans Thomas , Suwinski Johanna , Endres Robert , Pfeffer Klaus 
Published: April 2014

Abstract
Containment of intracellularly viable microorganisms requires an intricate cooperation between macrophages and T cells, the most potent mediators known to date being IFN-γ and TNF. To identify novel mechanisms involved in combating intracellular infections, experiments were performed in mice with selective defects in the lymphotoxin (LT)/LTβR pathway. When mice deficient in LTα or LTβ were challenged intranasally with Mycobacterium tuberculosis, they showed a significant increase in bacterial loads in lungs and livers compared with wild-type mice, suggesting a role for LTαβ heterotrimers in resistance to infection. Indeed, mice deficient in the receptor for LTα1β2 heterotrimers (LTβR-knockout (KO) mice) also had significantly higher numbers of M. tuberculosis in infected lungs and exhibited widespread pulmonary necrosis already by day 35 after intranasal infection. Furthermore, LTβR-KO mice were dramatically more susceptible than wild-type mice to i.p. infection with Listeria monocytogenes. Compared with wild-type mice, LTβR-KO mice had similar transcript levels of TNF and IFN-γ and recruited similar numbers of CD3+ T cells inside granulomatous lesions in M. tuberculosis-infected lungs. Flow cytometry revealed that the LTβR is expressed on pulmonary macrophages obtained after digestion of M. tuberculosis-infected lungs. LTβR-KO mice showed delayed expression of inducible NO synthase protein in granuloma macrophages, implicating deficient macrophage activation as the most likely cause for enhanced susceptibility of these mice to intracellular infections. Since LIGHT-KO mice proved to be equally resistant to M. tuberculosis infection as wild-type mice, these data demonstrate that signaling of LTα1β2 heterotrimers via the LTβR is an essential prerequisite for containment of intracellular pathogens.
Macrophages RestrictPseudomonas aeruginosaGrowth, Regulate Polymorphonuclear Neutrophil Influx, and Balance Pro- and Anti-Inflammatory Cytokines in BALB/c Mice
Authors: McClellan Sharon A. , Huang Xi , Barrett Ronald P. , van Rooijen Nico , Hazlett Linda D. 
Published: April 2014

AbstractThe role of macrophages in Pseudomonas aeruginosa corneal infection in susceptible (cornea perforates), C57BL/6 (B6) vs resistant (cornea heals), BALB/c mice was tested by depleting macrophages using subconjunctival injections of clodronate-containing liposomes before corneal infection. Both groups of inbred mice treated with clodronate-liposomes compared with PBS-liposomes (controls) exhibited more severe disease. In B6 mice, the cornea perforated and the eye became extremely shrunken, whereas in BALB/c mice, the cornea perforated rather than healed. The myeloperoxidase assay detected significantly more PMN in the cornea of both groups of mice treated with clodronate-liposomes vs PBS-liposomes. In independent experiments, ELISA analysis showed that protein levels for IL-1β, macrophage-inflammatory protein 2, and macrophage-inflammatory protein 1α, all regulators of PMN chemotaxis, also were elevated in both groups of mice treated with clodronate-liposomes. Bacterial plate counts in B6 mice treated with clodronate-liposomes were unchanged at 3 days and were higher in control-treated mice at 5 days postinfection (p.i.), whereas in BALB/c mice, bacterial load was significantly elevated in the cornea of mice treated with clodronate-liposomes at both 3 and 5 days p.i. mRNA expression levels for pro (IFN-γ and TNF-α)- and anti (IL-4 and IL-10)-inflammatory cytokines also were determined in BALB/c mice treated with clodronate-liposomes vs control-treated mice. Expression levels for IFN-γ were significantly elevated in mice treated with clodronate-liposomes at 3 and 5 days p.i., while IL-10 levels (mRNA and protein) were reduced. These data provide evidence that macrophages control resistance to P. aeruginosa corneal infection through regulation of PMN number, bacterial killing and balancing pro- and anti-inflammatory cytokine levels.
Neutrophilia in LFA-1-Deficient Mice Confers Resistance to Listeriosis: Possible Contribution of Granulocyte-Colony-Stimulating Factor and IL-17
Authors: Miyamoto Mamiko , Emoto Masashi , Emoto Yoshiko , Brinkmann Volker , Yoshizawa Izumi , Seiler Peter , Aichele Peter , Kita Eiji , Kaufmann Stefan H. E. 
Published: April 2014

AbstractLFA-1 (CD11a/CD18) plays a crucial role in various inflammatory responses. In this study, we show that LFA-1−/− mice are far more resistant to Listeria monocytogenes infection than LFA-1+/− mice. Consistent with this, we found the following: 1) the numbers of granulocytes infiltrating the liver were markedly higher in LFA-1−/− mice than in LFA-1+/− mice, 2) increased antilisterial resistance in LFA-1−/− mice was abrogated by depletion of granulocytes, and 3) the numbers of granulocytes in peripheral blood, and the serum levels of both G-CSF and IL-17 were higher in LFA-1−/− mice than in LFA-1+/− mice. Neither spontaneous apoptosis nor survival of granulocytes from LFA-1−/− mice were affected by physiological concentrations of G-CSF. Our data suggest regulatory effects of LFA-1 on G-CSF and IL-17 secretion, and as a corollary on neutrophilia. Consequently, we conclude that increased resistance of LFA-1−/− mice to listeriosis is due to neutrophilia facilitating liver infiltration by granulocytes promptly after L. monocytogenes infection, although it is LFA-1 independent.
Chemotactic Factor-Induced Recruitment and Activation of Tec Family Kinases in Human Neutrophils. II. Effects of LFM-A13, a Specific Btk Inhibitor
Authors: Gilbert Caroline , Levasseur Sylvain , Desaulniers Philippe , Dusseault Andrée-Anne , Thibault Nathalie , Bourgoin Sylvain G. , Naccache Paul H. 
Published: April 2014

AbstractTyrosine phosphorylation events play major roles in the initiation and regulation of several functional responses of human neutrophils stimulated by chemotactic factors such as the bacterially derived tripeptide formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe). However, the links between the G protein-coupled receptors, the activation of the tyrosine kinases, and the initiation of neutrophil functional responses remain unclear. In the present study we assessed the effects of a Btk inhibitor, leflunomide metabolite analog (LFM-A13), on neutrophils. LFM-A13 decreased the tyrosine phosphorylation induced by fMet-Leu-Phe and inhibited the production of superoxide anions and the stimulation of adhesion, chemotaxis, and phospholipase D activity. We observed a decreased accumulation of phosphatidylinositol-3,4,5-trisphosphate in response to fMet-Leu-Phe in LFM-A13-pretreated cells even though the inhibitor had no direct effect on the lipid kinase activity of the p110γ or p85/p110 phosphatidylinositol 3-kinases or on the activation of p110γ by fMet-Leu-Phe. The phosphorylation of Akt and of extracellular signal-regulated kinases 1/2 and p38 were similarly inhibited by LFM-A13. LFM-A13 also negatively affected the translocation of Rac-2, RhoA, ADP ribosylation factor-1, Tec, Bmx, and Btk induced by fMet-Leu-Phe. The results of this study provide evidence for an involvement of Btk and possibly other Tec kinase family members in the regulation of the functional responsiveness of human neutrophils and link these events, in part at least, to the modulation of levels of phosphatidylinositol-3,4,5-trisphosphate.
Duffy Antigen Facilitates Movement of Chemokine Across the Endothelium In Vitro and Promotes Neutrophil Transmigration In Vitro and In Vivo
Authors: Lee Janet S. , Frevert Charles W. , Wurfel Mark M. , Peiper Stephen C. , Wong Venus A. , Ballman Kimberley K. , Ruzinski John T. , Rhim Johng S. , Martin Thomas R. , Goodman Richard B. 
Published: April 2014

Abstract
The Duffy Ag expressed on RBCs, capillaries, and postcapillary venular endothelial cells binds selective CXC and CC chemokines with high affinity. Cells transfected with the Duffy Ag internalize but do not degrade chemokine ligand. It has been proposed that Duffy Ag transports chemokines across the endothelium. We hypothesized that Duffy Ag participates in the movement of chemokines across the endothelium and, by doing so, modifies neutrophil transmigration. We found that the Duffy Ag transfected into human endothelial cells facilitates movement of the radiolabeled CXC chemokine, growth related oncogene-α/CXC chemokine ligand 1 (GRO-α/CXCL1), across an endothelial monolayer. In addition, neutrophil migration toward GRO-α/CXCL1 and IL-8 (IL-8/CXCL8) was enhanced across an endothelial monolayer expressing the Duffy Ag. Furthermore, GRO-α/CXCL1 stimulation of endothelial cells expressing the Duffy Ag did not affect gene expression by oligonucleotide microarray analysis. These in vitro observations are supported by the finding that IL-8/CXCL8-driven neutrophil recruitment into the lungs was markedly attenuated in transgenic mice lacking the Duffy Ag. We conclude that Duffy Ag has a role in enhancing leukocyte recruitment to sites of inflammation by facilitating movement of chemokines across the endothelium.
C-C Chemokine Ligand 2/Monocyte Chemoattractant Protein-1 Directly Inhibits NKT Cell IL-4 Production and Is Hepatoprotective in T Cell-Mediated Hepatitis in the Mouse
Authors: Ajuebor Maureen N. , Hogaboam Cory M. , Le Tai , Swain Mark G. 
Published: April 2014

AbstractT cell-mediated liver diseases are associated with elevated serum levels of C-C chemokine ligand 2 (CCL2)/monocyte chemoattractant protein-1 (MCP-1). However, the extent to which the actions of CCL2/MCP-1 contribute to the pathogenesis of T cell-mediated hepatitis remains incompletely understood. Con A-induced hepatitis is a liver-specific inflammation mediated by activated T cells and is driven by an up-regulation of the hepatic expression of TNF-α, IFN-γ, and IL-4. The present study examined the role of CCL2/MCP-1 in the pathogenesis of T cell-mediated hepatitis induced by Con A administration in the mouse. We demonstrate a novel hepatoprotective role for CCL2/MCP-1 during Con A-induced hepatitis, because CCL2/MCP-1 neutralization strikingly enhanced hepatic injury, both biochemically and histologically, after Con A administration. Furthermore, CCL2/MCP-1 neutralization was associated with a significant reduction in the hepatic levels of TNF-α and IFN-γ, but with a significant increase in hepatic IL-4 levels. Moreover, IL-4 production and CCR2 expression by Con A-stimulated CD3+NK1.1+ T cells was significantly reduced by rMCP-1 treatment in vitro. In summary, we propose that CCL2/MCP-1 fulfills a novel anti-inflammatory role in T cell-mediated hepatitis by inhibiting CD3+NK1.1+ T cell-derived IL-4 production through direct stimulation of its specific receptor CCR2. These findings may have direct clinical relevance to T cell-mediated hepatitis.
Different Modes of IL-10 and TGF-β to Inhibit Cytokine-Dependent IFN-γ Production: Consequences for Reversal of Lipopolysaccharide Desensitization
Authors: Schröder Martina , Meisel Christian , Buhl Katharina , Profanter Nina , Sievert Nadine , Volk Hans-Dieter , Grütz Gerald 
Published: April 2014

AbstractLPS hyporesponsiveness is characterized by a diminished production of proinflammatory cytokines which can be caused by pretreatment with either LPS (=LPS desensitization) or the combination of the anti-inflammatory cytokines IL-10 and TGF-β. However, the resulting hyporesponsive states differ regarding their reversibility by the IFN-γ-inducing cytokine IL-12. Therefore, we aimed at studying the reasons for this differential IL-12 responsiveness of IFN-γ-producing cells and its consequences for LPS hyporesponsiveness in more detail. In an in vitro IL-12/IL-18 responsiveness model, we demonstrated that IL-10, if permanently present, does not directly inhibit IL-12/IL-18 responsiveness in T/NK cells but indirectly interferes with IFN-γ production in the presence of monocytes. In contrast, TGF-β acted directly on IFN-γ-producing cells by interfering with IL-12/IL-18 responsiveness. After removal of IL-10 but not of TGF-β, LPS hyporesponsiveness can be reverted by IL-12/IL-18. Consequently, the addition of recombinant TGF-β during LPS desensitization rendered PBMCs hyporesponsive to a reversal by IL-12/IL-18. Our data suggest that the persistence of IL-10 and the presence of TGF-β determine the level of IFN-γ inhibition and may result in different functional phenotypes of LPS desensitization and LPS hyporesponsiveness in vitro and in vivo.
Selective Roles for Toll-Like Receptor (TLR)2 and TLR4 in the Regulation of Neutrophil Activation and Life Span
Authors: Sabroe Ian , Prince Lynne R. , Jones Elizabeth C. , Horsburgh Malcolm J. , Foster Simon J. , Vogel Stefanie N. , Dower Steven K. , Whyte Moira K. B. 
Published: April 2014

Abstract
Neutrophil responses to commercial LPS, a dual Toll-like receptor (TLR)2 and TLR4 activator, are regulated by TLR expression, but are amplified by contaminating monocytes in routine cell preparations. Therefore, we investigated the individual roles of TLR2 and TLR4 in highly purified, monocyte-depleted neutrophil preparations, using selective ligands (TLR2, Pam3CysSerLys4 and Staphylococcus aureus peptidoglycan; TLR4, purified LPS). Activation of either TLR2 or TLR4 caused changes in adhesion molecule expression, respiratory burst (alone, and synergistically with fMLP), and IL-8 generation, which was, in part, dependent upon p38 mitogen-activated protein kinase signaling. Neutrophils also responded to Pam3CysSerLys4 and purified LPS with down-regulation of the chemokine receptor CXCR2 and, to a lesser extent, down-regulation of CXCR1. TLR4 was the principal regulator of neutrophil survival, and TLR2 signals showed relatively less efficacy in preventing constitutive apoptosis over short time courses. TLR4-mediated neutrophil survival depended upon signaling via NF-κB and mitogen-activated protein kinase cascades. Prolonged neutrophil survival required both TLR4 activation and the presence of monocytes. TLR4 activation of monocytes was associated with the release of neutrophil survival factors, which was not evident with TLR2 activation, and TLR2 activation in monocyte/neutrophil cocultures did not prevent late neutrophil apoptosis. Thus, TLRs are important regulators of neutrophil activation and survival, with distinct and separate roles for TLR2 and TLR4 in neutrophil responses. TLR4 signaling presents itself as a pharmacological target that may allow therapeutic modulation of neutrophil survival by direct and indirect mechanisms at sites of inflammation.
Calcium-Independent Phospholipase A2 Is Required for Lysozyme Secretion in U937 Promonocytes
Authors: Balboa María A. , Sáez Yolanda , Balsinde Jesús 
Published: April 2014

Abstract
As a part of their surveillance functions in the immune system, monocytes/macrophages secrete large amounts of the bactericidal enzyme lysozyme to the extracellular medium. We report here that lysozyme secretion in activated U937 promonocytes depends on a functional calcium-independent phospholipase A2 (iPLA2). Inhibition of the enzyme by bromoenol lactone or by treatment with a specific antisense oligonucleotide results in a diminished capacity of the cells to secrete lysozyme to the extracellular medium. Calcium-independent PLA2 is largely responsible for the maintenance of the steady state of lysophosphatidylcholine (lysoPC) levels within the cells, as manifested by the marked decrease in the levels of this metabolite in cells deficient in iPLA2 activity. Reconstitution experiments reveal that lysoPC efficiently restores lysozyme secretion in iPLA2-deficient cells, whereas other lysophospholipids, including lysophosphatidic acid, lysophosphatidylserine, and lysophosphatidylethanolamine, are without effect. Arachidonic acid mobilization in activated U937 cells is under control of cytosolic phospholipase A2 (cPLA2). Selective inhibition of cPLA2 results in a complete abrogation of the arachidonate mobilization response, but has no effect on lysozyme secretion. These results identify iPLA2-mediated lysoPC production as a necessary component of the molecular machinery leading to lysozyme secretion in U937 cells and rule out a role for cPLA2 in the response. Collectively, the results demonstrate distinct roles in inflammatory cell signaling for these two intracellular phospholipases.
Amyloid Peptide-Induced Cytokine and Chemokine Expression in THP-1 Monocytes Is Blocked by Small Inhibitory RNA Duplexes for Early Growth Response-1 Messenger RNA
Authors: Giri Ranjit K. , Selvaraj Suresh K. , Kalra Vijay K. 
Published: April 2014

Abstract
In Alzheimer’s disease (AD) one finds increased deposition of Aβ and also an increased presence of monocytes/macrophages in the vessel wall and activated microglial cells in the brain. AD patients show increased levels of proinflammatory cytokines by activated microglia. Here we used a human monocytic THP-1 cell line as a model for microglia to delineate the cellular signaling mechanism involved in amyloid peptides (Aβ1–40 and Aβ1–42)-induced expression of inflammatory cytokines and chemokines. We observed that Aβ peptides at physiological concentrations (125 nM) increased mRNA expression of cytokines (TNF-α, and IL-1β) and chemokines (monocyte chemoattractant protein-1 (MCP-1), IL-8, and macrophage inflammatory protein-1β (MIP-1β)). The cellular signaling involved activation of c-Raf, extracellular signal-regulated kinase-1 (ERK-1)/ERK-2, and c-Jun N-terminal kinase, but not p38 mitogen-activated protein kinase. This is further supported by the data showing that Aβ causes phosphorylation of ERK-1/ERK-2, which, in turn, activates Elk-1. Furthermore, Aβ mediated a time-dependent increase in DNA binding activity of early growth response-1 (Egr-1) and AP-1, but not of NF-κB and CREB. Moreover, Aβ-induced Egr-1 DNA binding activity was reduced &gt;60% in THP-1 cells transfected with small interfering RNA duplexes for Egr-1 mRNA. We show that Aβ-induced expression of TNF-α, IL-1β, MCP-1, IL-8, and MIP-1β was abrogated in Egr-1 small inhibitory RNA-transfected cells. Our results indicate that Aβ-induced expression of cytokines (TNF-α and IL-1β) and chemokines (MCP-1, IL-8, and MIP-1β) in THP-1 monocytes involves activation of ERK-1/ERK-2 and downstream activation of Egr-1. The inhibition of Egr-1 by Egr-1 small inhibitory RNA may represent a potential therapeutic target to ameliorate the inflammation and progression of AD.
Peroxisome Proliferator-Activated Receptor γ Inhibits the Migration of Dendritic Cells: Consequences for the Immune Response
Authors: Angeli Véronique , Hammad Hamida , Staels Bart , Capron Monique , Lambrecht Bart N. , Trottein François 
Published: April 2014

AbstractThe migration of dendritic cells (DCs) from the epithelia to the lymphoid organs represents a tightly regulated multistep event involved in the induction of the immune response. In this process fatty acid derivatives positively and negatively regulate DC emigration. In the present study we investigated whether activation of peroxisome proliferator-activated receptors (PPARs), a family of nuclear receptors activated by naturally occurring derivatives of arachidonic acid, could control DC migration from the peripheral sites of Ag capture to the draining lymph nodes (DLNs). First, we show that murine epidermal Langerhans cells (LCs) express PPARγ, but not PPARα, mRNA, and protein. Using an experimental murine model of LC migration induced by TNF-α, we show that the highly potent PPARγ agonist rosiglitazone specifically impairs the departure of LCs from the epidermis. In a model of contact allergen-induced LC migration, PPARγ activation not only impedes LC emigration, and their subsequent accumulation as DCs in the DLNs, but also dramatically prevents the contact hypersensitivity responses after challenge. Finally, after intratracheal sensitization with an FITC-conjugated Ag, PPARγ activation inhibits the migration of DCs from the airway mucosa to the thoracic LNs and also profoundly reduces the priming of Ag-specific T lymphocytes in the DLNs. Our results suggest a novel regulatory pathway via PPARγ for DC migration from epithelia that could contribute to the initiation of immune responses.