bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Abundant NK Cells in Human Secondary Lymphoid Tissues Require Activation to Express Killer Cell Ig-Like Receptors and Become Cytolytic
Authors: Ferlazzo Guido , Thomas Dolca , Lin Shao-Lee , Goodman Kiera , Morandi Barbara , Muller William A. , Moretta Alessandro , Münz Christian 
Published: April 2014

AbstractNatural killer cells are important cytolytic cells in innate immunity. We have characterized human NK cells of spleen, lymph nodes, and tonsils. More than 95% of peripheral blood and 85% of spleen NK cells are CD56dimCD16+ and express perforin, the natural cytotoxicity receptors (NCRs) NKp30 and NKp46, as well as in part killer cell Ig-like receptors (KIRs). In contrast, NK cells in lymph nodes have mainly a CD56brightCD16− phenotype and lack perforin. In addition, they lack KIRs and all NCR expression, except low levels of NKp46. The NK cells of tonsils also lack perforin, KIRs, NKp30, and CD16, but partially express NKp44 and NKp46. Upon IL-2 stimulation, however, lymph node and tonsilar NK cells up-regulate NCRs, express perforin, and acquire cytolytic activity for NK-sensitive target cells. In addition, they express CD16 and KIRs upon IL-2 activation, and therefore display a phenotype similar to peripheral blood NK cells. We hypothesize that IL-2 can mobilize the NK cells of secondary lymphoid tissues to mediate natural killing during immune responses. Because lymph nodes harbor 40% and peripheral blood only 2% of all lymphocytes in humans, this newly characterized perforin− NK cell compartment in lymph nodes and related tissues probably outnumbers perforin+ NK cells. These results also suggest secondary lymphoid organs as a possible site of NK cell differentiation and self-tolerance acquisition.
CpG-DNA Aided Cross-Priming by Cross-Presenting B Cells
Authors: Heit Antje , Huster Katharina M. , Schmitz Frank , Schiemann Matthias , Busch Dirk H. , Wagner Hermann 
Published: April 2014

Abstract
Covalent linkage of immunostimulatory CpG-DNA to OVA (CpG-OVA complex) results in CpG-DNA-aided cross-presentation of OVA by dendritic cells (DCs). In this study, we analyzed the thesis that CpG-OVA complexes may be cross-presented by B cells to route internalized Ag into the class I MHC presentation pathway. First, we describe that conjugation of CpG-DNA to OVA enhances up to 40-fold internalization of OVA by B cells, which in turn generate the CD8 T cell epitope SIINFEKL complexed to MHC class I, albeit less efficiently than DCs. Furthermore, upon internalization, CpG-DNA conjugated to OVA stimulates B cells to up-regulate costimulatory molecules and cytokines including IL-12. Adoptive transfer of CpG-OVA complex-loaded wild-type B cells cross-primes naive CD8 T cells both in wild-type mice and in MyD88-deficient mice. Overall, these findings disclose attributes of B cells, including cross-presentation of exogenous Ag and cross-priming of naive CD8 T cells that hitherto have been considered as hallmarks restricted to DCs.
Tumor-Infiltrating Lymphocyte Secretion of IL-6 Antagonizes Tumor-Derived TGF-β1 and Restores the Lymphokine-Activated Killing Activity
Authors: Hsiao Ya-Wen , Liao Kuang-Wen , Hung Shao-Wen , Chu Rea-Min 
Published: April 2014

AbstractIL-6 is a multifunctional cytokine that regulates cell growth, differentiation, and cell survival. Many tumor cells produce TGF-β1, which allows them to evade CTL-mediated immune responses. IL-6 antagonizes TGF-β1 inhibition of CD3 cell activation. However, whether IL-6 restores NK activity, which also is suppressed by TGF-β1, is not known. We used canine transmissible venereal tumor (CTVT), which produces TGF-β1, as a model to determine whether IL-6 restores lymphokine-activated killer (LAK) activity. During the progression phase, CTVT cells stop expressing MHC molecules. During the regression phase, the number of surface MHC molecules increases dramatically on about one-third of tumor cells. Tumor cells that stop expressing MHC should be targeted by NK cells. In this study, we found that TGF-β1 secreted by CTVT cells suppressed LAK cytotoxicity. Interestingly, tumor-infiltrating lymphocytes (TIL) isolated from regressing CTVT secrete high concentrations of IL-6 and antagonize the anti-LAK activity of tumor cell TGF-β1. TIL also produce IL-6 during progression phase, but the concentration is too low to block the anti-LAK activity of TGF-β1. There is probably a threshold concentration of IL-6 needed to reverse TGF-β1-inhibited LAK activity. In addition, in the absence of TGF-β1, IL-6 derived from TIL does not promote the activity of LAK. This new mechanism, in which TIL manufacture high concentrations of IL-6 to block tumor TGF-β1 anti-LAK activity, has potential applications in cancer immunotherapy and tumor prognosis.
Phosphatidylinositol 3-Kinase Is a Determinant of Responsiveness to B Cell Antigen Receptor-Mediated Epstein-Barr Virus Activation
Authors: Iwakiri Dai , Takada Kenzo 
Published: April 2014

Abstract
B cell Ag receptor (BCR) cross-linking with anti-Ig Abs efficiently induces activation of latently infected EBV in some B cell lines, but not in others. The present study was aimed at defining the molecular mechanisms that determine the response to BCR-mediated EBV activation. Comparison of Burkitt’s lymphoma-derived Akata, Mutu-I, and Daudi cells, which are representative responders and nonresponders to BCR-mediated EBV activation, respectively, indicated that three signaling pathways, phosphatidylinositol 3-kinase (PI3K), extracellular signal-regulated kinase (ERK), and p38 mitogen-activated protein kinase (MAPK), were activated in anti-Ig-treated Akata and Mutu-I cells. However, in anti-Ig-treated Daudi cells PI3K was not activated, ERK was faintly activated, and p38 MAPK was constitutively phosphorylated irrespective of anti-Ig treatment. Restoration of PI3K activity with insulin-like growth factor 1 restored ERK and p38 MAPK pathways, and was accompanied by EBV activation in anti-Ig-treated Daudi cells. In contrast, a specific inhibitor for PI3K, wortmannin, inhibited EBV activation by anti-Ig Abs in Akata and Mutu-I cells. Transfection assays in EBV-negative Daudi cells revealed that PI3K activated a promoter for BZLF1, which is a switch of EBV activation from a latent infection, in the absence of other EBV products suggesting that the BZLF promoter was a target of BCR signaling, and that PI3K was important for BCR-mediated BZLF1 activation. These results indicate that the absence of PI3K impedes the progression of signals through the BCR and becomes a determinant of unresponsiveness to BCR-mediated EBV activation.
E-Selectin, Thymus- and Activation-Regulated Chemokine/CCL17, and Intercellular Adhesion Molecule-1 Are Constitutively Coexpressed in Dermal Microvessels: A Foundation for a Cutaneous Immunosurveillance System
Authors: Chong Benjamin F. , Murphy Jo-Ellen , Kupper Thomas S. , Fuhlbrigge Robert C. 
Published: April 2014

Abstract
The success of the cutaneous immune system reflects its ability to rapidly and efficiently recruit leukocytes to areas of trauma and infection. Skin-homing memory T cells expressing cutaneous lymphocyte-associated Ag tether on the walls of postcapillary venules in inflamed skin via interaction with endothelial E-selectin and roll in response to the shear stress imparted by flowing blood. Rolling cells sample the vascular surface for chemoattractant compounds (e.g., thymus- and activation-regulated chemokine/CCL17 interacting with CCR4 on the leukocyte surface) and, if successfully stimulated, progress to firm arrest and transmigration mediated by LFA-1 and vascular ICAM-1. Although it is established that this sequence of events draws T cells into inflamed skin, the mechanisms directing trafficking of T cells to noninflamed skin are less well characterized. We hypothesized that basal expression and colocalization of E-selectin, chemokine (e.g., CCL17), and ICAM-1 in dermal vessels could serve to recruit T cells to noninflamed human skin. Immunohistochemical staining for E-selectin and CD31 demonstrated E-selectin expression in a restricted subset of dermal vessels in noninflamed human skin from three different sites. Confocal multicolor immunofluorescence imaging revealed a nonuniform distribution of E-selectin in dermal vessels as well as colocalization of E-selectin with CCL17 and ICAM-1. Coexpression of these molecules on blood vessels in noninflamed skin provides the basis for a model of cutaneous immunosurveillance system active in the absence of pathologic inflammation.
Escherichia coliExpressing Recombinant Antigen and Listeriolysin O Stimulate Class I-Restricted CD8+ T Cells following Uptake by Human APC
Authors: Hu Paul Q. , Tuma-Warrino Renee J. , Bryan Marianne A. , Mitchell Kathleen G. , Higgins Darren E. , Watkins Simon C. , Salter Russell D. 
Published: April 2014

AbstractVaccination against cancer or intracellular pathogens requires stimulation of class I-restricted CD8+ T cells. It is therefore important to develop Ag delivery vectors that will promote cross-presentation by APCs and stimulate appropriate inflammatory responses. Toward this goal, we tested the potential of Escherichia coli as an Ag delivery vector in in vitro human culture. Bacteria expressing enhanced green fluorescent protein were internalized efficiently by dendritic cells, as shown by flow cytometry and fluorescence microscopy. Phenotypic changes in DC were observed, including up-regulation of costimulatory molecules and IL-12p40 production. We tested whether bacteria expressing recombinant Ags could stimulate human T cells using the influenza matrix protein as a model Ag. Specific responses against an immunodominant epitope were seen using IFN-γ ELISPOT assays when the matrix protein was coexpressed with listeriolysin O, but not when expressed alone. THP-1 macrophages were also capable of stimulating T cells after uptake of bacteria, but showed slower kinetics and lower overall levels of T cell stimulation than dendritic cells. Increased phagocytosis of bacteria induced by differentiation of THP-1 increased their ability to stimulate T cells, as did opsonization. Presentation was blocked by proteasome inhibitors, but not by lysosomal protease inhibitors leupeptin and E64. These results demonstrate that recombinant E. coli can be engineered to direct Ags to the cytosol of human phagocytic APCs, and suggest possible vaccine strategies for generating CD8+ T cell responses against pathogens or tumors.
Regulation of c-Jun N-Terminal Kinase by MEKK-2 and Mitogen-Activated Protein Kinase Kinase Kinases in Rheumatoid Arthritis
Authors: Hammaker Deepa R. , Boyle David L. , Chabaud-Riou Martine , Firestein Gary S. 
Published: April 2014

Abstract
The mitogen-activated protein kinase (MAPK) c-Jun N-terminal kinase (JNK) is a critical regulator of collagenase-1 production in rheumatoid arthritis (RA). The MAPKs are regulated by upstream kinases, including MAPK kinases (MAPKKs) and MAPK kinase kinases (MAP3Ks). The present study was designed to evaluate the expression and regulation of the JNK pathway by MAP3K in arthritis. RT-PCR studies of MAP3K gene expression in RA and osteoarthritis synovial tissue demonstrated mitogen-activated protein kinase/ERK kinase kinase (MEKK) 1, MEKK2, apoptosis-signal regulating kinase-1, TGF-β activated kinase 1 (TAK1) gene expression while only trace amounts of MEKK3, MEKK4, and MLK3 mRNA were detected. Western blot analysis demonstrated immunoreactive MEKK2, TAK1, and trace amounts of MEKK3 but not MEKK1 or apoptosis-signal regulating kinase-1. Analysis of MAP3K mRNA in cultured fibroblast-like synoviocytes (FLS) showed that all of the MAP3Ks examined were expressed. Western blot analysis of FLS demonstrated that MEKK1, MEKK2, and TAK1 were readily detectable and were subsequently the focus of functional studies. In vitro kinase assays using MEKK2 immunoprecipitates demonstrated that IL-1 increased MEKK2-mediated phosphorylation of the key MAPKKs that activate JNK (MAPK kinase (MKK)4 and MKK7). Furthermore, MEKK2 immunoprecipitates activated c-Jun in an IL-1 dependent manner and this activity was inhibited by the selective JNK inhibitor SP600125. Of interest, MEKK1 immunoprecipitates from IL-1-stimulated FLS appeared to activate c-Jun through the JNK pathway and TAK1 activation of c-Jun was dependent on JNK, ERK, and p38. These data indicate that MEKK2 is a potent activator of the JNK pathway in FLS and that signal complexes including MEKK2, MKK4, MKK7, and/or JNK are potential therapeutic targets in RA.
The Role of TNF-Related Activation-Induced Cytokine–Receptor Activating NF-κB Interaction in Acute Allograft Rejection and CD40L-Independent Chronic Allograft Rejection
Authors: Guillonneau Carole , Louvet Cédric , Renaudin Karine , Heslan Jean-Marie , Heslan Michèle , Tesson Laurent , Vignes Caroline , Guillot Cécile , Choi Yongwon , Turka Lawrence A. , Cuturi Maria-Cristina , Anegon Ignacio , Josien Régis 
Published: April 2014

Abstract
We analyzed the role of TNF-related activation-induced cytokine (TRANCE), a member of the TNF family expressed on activated T cells that shares functional properties with CD40L, and its receptor-activating NF-κB (RANK) which is mostly expressed on mature dendritic cells, during allogenic responses in vivo using a rodent heart allograft model. TRANCE mRNA was strongly up-regulated in acutely rejected allografts on days 4 and 5 posttransplantation whereas RANK was detected as early as day 1 but did not show further up-regulation during the first week. Immunofluoresence analyses of heart allografts showed that 80 and 100% of TRANCE and RANK-expressing cells were T cells and APCs, respectively. We show for the first time that short-term TRANCE blockade using a mouse RANKIg fusion molecule can significantly prolong heart allograft survival in both rat and mouse models. Similarly, rat heart allografts transduced with a RANKIg encoding recombinant adenovirus exhibited a significant prolongation of survival (14.3 vs 7.6 days, p &lt; 0.0001). However, TRANCE blockade using RANKIg did not appear to inhibit allogeneic T and B cell priming humoral responses against RANKIg. Interestingly, TRANCE blockade induced strong up-regulation of CD40 ligand (CD40L) mRNA in allografts. Combined CD40L and TRANCE blockade resulted in significantly decreased chronic allograft rejection lesions as well as allogeneic humoral responses compared with CD40L blockade alone. We conclude that TRANCE-RANK interactions play an important role during acute allograft rejection and that CD40L-independent allogeneic immune responses can be, at least in part, dependent on the TRANCE pathway of costimulation.
Hypoxia Selectively Inhibits Monocyte Chemoattractant Protein-1 Production by Macrophages
Authors: Bosco Maria Carla , Puppo Maura , Pastorino Sandra , Mi Zenghui , Melillo Giovanni , Massazza Stefano , Rapisarda Annamaria , Varesio Luigi 
Published: April 2014

AbstractHypoxia, a local decrease in oxygen tension occurring in inflammatory and tumor lesions, modulates gene expression in macrophages. Because macrophages are important chemokine producers, we investigated the regulatory effects of hypoxia on macrophage-derived chemokines. We demonstrated that hypoxia inhibits the production of the macrophage and T lymphocyte chemotactic and activating factor, monocyte chemoattractant protein-1 (MCP-1). Exposure of mouse macrophages to low oxygen tension resulted in the down-regulation of constitutive MCP-1 mRNA expression and protein secretion. Hypoxia inhibitory effects were selective for MCP-1 because the chemokines macrophage inflammatory protein-1β (MIP-1β), RANTES, IFN-γ-inducible protein-10, and MIP-2 were not affected, and MIP-1α was induced. Hypoxia also inhibited, in a time-dependent fashion, MCP-1 up-regulation by IFN-γ and LPS. Moreover, the inhibitory action of hypoxia was exerted on human monocytic cells. MCP-1 down-regulation was associated with inhibition of gene transcription and mRNA destabilization, suggesting a dual molecular mechanism of control. Finally, we found that the triptophan catabolite picolinic acid and the iron chelator desferrioxamine, which mimic hypoxia in the induction of gene expression, differentially regulated the expression of MCP-1. This study characterizes a novel property of hypoxia as a selective inhibitor of MCP-1 production induced by different stimuli in macrophages and demonstrates that down-regulation of gene expression by hypoxia can be controlled at both transcriptional and posttranscriptional levels. Inhibition of MCP-1 may represent a negative regulatory mechanism to control macrophage-mediated leukocyte recruitment in pathological tissues.
HLA Class II Polymorphisms Determine Responses to Bacterial Superantigens
Authors: Llewelyn Martin , Sriskandan Shiranee , Peakman Mark , Ambrozak David R. , Douek Daniel C. , Kwok William W. , Cohen Jonathan , Altmann Daniel M. 
Published: April 2014

AbstractThe excessive immunological response triggered by microbial superantigens has been implicated in the etiology of a wide range of human diseases but has been most clearly defined for the staphylococcal and streptococcal toxic shock syndromes. Because MHC class II presentation of superantigens to T cells is not MHC-restricted, the possibility that HLA polymorphisms could influence superantigenicity, and thus clinical susceptibility to the toxicity of individual superantigens, has received little attention. In this study, we demonstrate that binding of streptococcal and staphylococcal superantigens to HLA class II is influenced by allelic differences in class II. For the superantigen streptococcal pyrogenic exotoxin A, class II binding is dependent on DQ α-chain polymorphisms such that HLA-DQA1*01 α-chains show greater binding than DQA1*03/05 α-chains. The functional implications of differential binding on T cell activation were investigated in various experimental systems using human T cells and murine Vβ8.2 transgenic cells as responders. These studies showed quantitative and qualitative differences resulting from differential HLA-DQ binding. We observed changes in T cell proliferation and cytokine production, and in the Vβ specific changes in T cell repertoire that have hitherto been regarded as a defining feature of an individual superantigen. Our observations reveal a mechanism for the different outcomes seen following infection by toxigenic bacteria.
Cysteinyl Leukotrienes Regulate Dendritic Cell Functions in a Murine Model of Asthma
Authors: Machida Ikuko , Matsuse Hiroto , Kondo Yuki , Kawano Tetsuya , Saeki Sachiko , Tomari Shinya , Obase Yasushi , Fukushima Chizu , Kohno Shigeru 
Published: April 2014

Abstract
Dendritic cells (DCs) act as APCs in the airway and play a critical role in allergy. Cysteinyl leukotrienes (cysLTs) synthesized from arachidonic acid are primary mediators of immediate asthmatic reaction. The aim of this study was to investigate the effects of cysLTs on Dermatophagoides farinae (Der f)-pulsed mouse myeloid DCs in inducing allergic airway inflammation in vitro and in vivo. Control DC (medium-pulsed), Der f-pulsed DC, cysLT-pulsed DC, Der f- and cysLT-pulsed DC, and Der f-pulsed and cysLT receptor antagonist (LTRA)-treated DC were prepared from murine bone marrow, and the production of cytokines ws compared. Subsequently, these DCs were intranasally instilled into another group of naive mice, followed by intranasal Der f challenge to induce allergic airway inflammation in vivo. Der f-pulsed DC produced significantly higher amounts of IL-10 and IL-12 compared with control DC. Der f- and cysLT-pulsed DC further increased IL-10 production compared with Der f-pulsed DC. In contrast, treatment of Der f-pulsed DC with LTRA increased IL-12 and decreased IL-10. Intranasal instillation of Der f-pulsed DC resulted in airway eosinophilia associated with a significant rise in IL-5 levels in the airway compared with control DC. Pulmonary eosinophilia and excess IL-5 were further enhanced in Der f- and cysLT-pulsed DC-harboring mice. In contrast, Der f-pulsed and LTRA-treated DC significantly inhibited airway eosinophilia, reduced IL-5, and increased IFN-γ in the airway. Our results suggest that cysLTs play an important role in the development of allergic airway inflammation by regulating the immunomodulatory functions of DCs.
TNF-α-Induced Apoptosis of Macrophages Following Inhibition of NF-κB: A Central Role for Disruption of Mitochondria
Authors: Liu Hongtao , Ma Yingyu , Pagliari Lisa J. , Perlman Harris , Yu Chenfei , Lin Anning , Pope Richard M. 
Published: April 2014

AbstractPreviously, we established that suppressing the constitutive activation of NF-κB in in vitro matured human macrophages resulted in apoptosis initiated by a decrease of the Bcl-2 family member, A1, and the loss of mitochondrial transmembrane potential (Δψm). This study was performed to characterize the mechanism of TNF-α-induced apoptosis in macrophages following the inhibition of NF-κB. The addition of TNF-α markedly enhanced the loss of Δψm and the induction of apoptotic cell death. Although caspase 8 was activated and contributed to DNA fragmentation, it was not necessary for the TNF-α-induced loss of Δψm. The inhibition of NF-κB alone resulted in the release of cytochrome c from the mitochondria, while both cytochrome c and second mitochondria-derived activator of caspase/direct inhibitor of apoptosis-binding protein with low pI were released following the addition of TNF-α. Furthermore, c-Jun N-terminal kinase activation, which was sustained following treatment with TNF-α when NF-κB was inhibited, contributed to DNA fragmentation. These observations demonstrate that cytochrome c and second mitochondria-derived activator of caspase/direct inhibitor of apoptosis-binding protein with low pI may be differentially released from the mitochondria, and that the sustained activation of c-Jun N-terminal kinase modulated the DNA fragmentation independent of the loss of Δψm.
Ets-1 Regulates TNF-α-Induced Matrix Metalloproteinase-9 and Tenascin Expression in Primary Bronchial Fibroblasts
Authors: Nakamura Yutaka , Esnault Stéphane , Maeda Takashi , Kelly Elizabeth A. B. , Malter James S. , Jarjour Nizar N. 
Published: April 2014

Abstract
Increased subepithelial deposition of extracellular matrix proteins is a key feature in bronchial asthma. Matrix metalloproteinase-9 (MMP-9) is a proteolytic enzyme that degrades the extracellular matrix. Tenascin is an extracellular matrix glycoprotein that is abundant in thickened asthmatic subbasement membrane. The expression of MMP-9 and tenascin reflects disease activity in asthma and airway remodeling. The molecular mechanisms regulating the expression of these proteins remain unknown. Both MMP-9 and tenascin promoters contain an Ets binding site, suggesting control by Ets-1. Thus, we hypothesized that Ets-1 expression is increased in asthma and that it contributed to enhanced MMP-9 and tenascin expression. To test this hypothesis, we determined the expression of Ets-1 in bronchial biopsies obtained from asthmatic subjects and determined the expression of Ets-1, MMP-9, and tenascin by bronchial fibroblasts activated ex vivo. We observed that nuclear extracts from TNF-α-activated fibroblasts showed increased Ets-binding activity. In addition, TNF-α-activated fibroblasts had increased expression of Ets-1 mRNA and protein, which preceded an increase in MMP-9 and tenascin mRNA. Furthermore, treatment of fibroblasts with Ets-1 antisense oligonucleotides down-regulated TNF-α-induced Ets-1, MMP-9, and, to a lesser extent, tenascin protein expression or activity. Taken together, these data demonstrate that TNF-α increases MMP-9 and tenascin expression in bronchial fibroblasts via the transcription factor Ets-1, and suggest a role for Ets-1 in airway remodeling in asthma.