bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Protein Made from a Common Allele of KIR3DL1 (3DL1*004) Is Poorly Expressed at Cell Surfaces due to Substitution at Positions 86 in Ig Domain 0 and 182 in Ig Domain 1
Authors: Pando Marcelo J. , Gardiner Clair M. , Gleimer Michael , McQueen Karina L. , Parham Peter 
Published: April 2014

Abstract
KIR3DL1 is an inhibitory HLA-B receptor of human NK and T cells that exhibits genetic and phenotypic polymorphism. KIR3DL1*004, a common allotype, cannot be detected on the surface of PBLs using the KIR3DL1-specific Ab DX9. The nature of this phenotype was investigated through comparison of 3DL1*004 with 3DL1*002, an allele giving high DX9 binding to cell surfaces. Analysis of Jurkat T cell transfectants with 3DL1*004 cDNA showed that 3DL1*004 is poorly expressed at the cell surface, but detectable intracellularly. Analysis of recombinant mutants made between 3DL1*004 and 3DL1*002 showed that polymorphism in Ig domains 0 and 1 (D0 and D1) causes the intracellular retention of 3DL1*004. Reciprocal point mutations were introduced into 3DL1*004 and 3DL1*002 at positions 44 and 86 of the D0 domain, where 3DL1*004 has unique residues, and at position 182 of the D1 domain, where 3DL1*004 resembles 3DL1*005, an allotype giving low DX9-binding phenotype. Leucine 86 in 3DL1*004 is the principal cause of its intracellular retention, with a secondary and additive contribution from serine 182. By contrast, glycine 44, which is naturally present in 3DL1*004, slightly increased cell surface expression when introduced into 3DL1*002. In 3DL1*004, the presence of leucine at position 86 corrupts the WSXPS motif implicated in proper folding of the KIR D0 Ig-like domain. This study demonstrates how a difference between KIR3DL1 allotypes in the D0 domain profoundly affects cell surface expression and function.
Homotypic Secretory Vesicle Fusion Induced by the Protein Tyrosine Phosphatase MEG2 Depends on Polyphosphoinositides in T Cells
Authors: Huynh Huong , Wang Xiaodong , Li Weizhong , Bottini Nunzio , Williams Scott , Nika Konstantina , Ishihara Hisamitsu , Godzik Adam , Mustelin Tomas 
Published: April 2014

Abstract
Sec14p homology domains are found in a large number of proteins from plants, yeast, invertebrates, and higher eukaryotes. We report that the N-terminal Sec14p homology domain of the human protein tyrosine phosphatase PTP-MEG2 binds phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) in vitro and colocalizes with this lipid on secretory vesicle membranes in intact cells. Point mutations that prevented PtdIns(3,4,5)P3 binding abrogated the capacity of PTP-MEG2 to induce homotypic secretory vesicle fusion in cells. Inhibition of cellular PtdIns(3,4,5)P3 synthesis also rapidly reversed the effect of PTP-MEG2 on secretory vesicles. Finally, we show that several different phosphoinositide kinases colocalize with PTP-MEG2, thus allowing for local synthesis of PtdIns(3,4,5)P3 in secretory vesicle membranes. We suggest that PTP-MEG2 through its Sec14p homology domain couples inositide phosphorylation to tyrosine dephosphorylation and the regulation of intracellular traffic of the secretory pathway in T cells.
Basal Chromatin Modification at the IL-4 Gene in Helper T Cells
Authors: Grogan Jane L. , Wang Zhi-En , Stanley Sarah , Harmon Brian , Loots Gaby G. , Rubin Edward M. , Locksley Richard M. 
Published: April 2014

Abstract
Chromatin immunoprecipitations in naive CD4, but not CD8, T cells, demonstrated association of the IL-4 promoter with acetylated histone. Histone modifications and rapid IL-4 transcription were absent in conserved noncoding sequence 1 (CNS-1)−/− cells lacking an 8-kb-distant enhancer in the IL-4/IL-13 intergenic region, but also in CD4−/− and Itk−/− cells, which have similar Th2 deficiencies. Histones associated with the IL-13 promoter were not similarly acetylated in naive T cells, but became acetylated in differentiated Th2 cells. Conversely, Th1 differentiation induced histone methylation at the type 2 cytokine locus. Like CD4−/− and Itk−/− mice, CNS-1−/− BALB/c mice were highly resistant to the Th2-inducing protozoan, Leishmania major. CNS-1 deficiency led to failure of IL-4 gene repositioning to heterochromatin after Th1 polarization, possibly related to the presence of reiterative Ikaros binding sites in the intergenic element. Hyperacetylation of nonexpressed genes may serve to mark lineage-specific loci for rapid expression and further modification.
CTL Are Inactivated by Herpes Simplex Virus-Infected Cells Expressing a Viral Protein Kinase
Authors: Sloan Derek D. , Zahariadis George , Posavad Christine M. , Pate Nichlos T. , Kussick Steven J. , Jerome Keith R. 
Published: April 2014

Abstract
Numerous cell-to-cell signals tightly regulate CTL function. Human fibroblasts infected with HSV type 1 or 2 can generate such a signal and inactivate human CTL. Inactivated CTL lose their ability to release cytotoxic granules and synthesize cytokines when triggered through the TCR. Inactivation requires cell-to-cell contact between CTL and HSV-infected cells. However, inactivated CTL are not infected with HSV. The inactivation of CTL is sustainable, as CTL function remains impaired when the CTL are removed from the HSV-infected cells. IL-2 treatment does not alter inactivation, and the inactivated phenotype is not transferable between CTL, distinguishing this phenotype from traditional anergy and T regulatory cell models. CTL inactivated by HSV-infected cells are not apoptotic, and the inactivated state can be overcome by phorbol ester stimulation, suggesting that inactivated CTL are viable and that the signaling block is specific to the TCR. HSV-infected cells require the expression of US3, a viral protein kinase, to transmit the inactivating signal. Elucidation of the molecular nature of this signaling pathway may allow targeted manipulation of CTL function.
Human Cytomegalovirus-Encoded US2 Differentially Affects Surface Expression of MHC Class I Locus Products and Targets Membrane-Bound, but Not Soluble HLA-G1 for Degradation
Authors: Barel Martine T. , Ressing Maaike , Pizzato Nathalie , van Leeuwen Daphne , Le Bouteiller Philippe , Lenfant Francoise , Wiertz Emmanuel J. H. J. 
Published: April 2014

AbstractHuman CMV (HCMV) can elude CTL as well as NK cells by modulating surface expression of MHC class I molecules. This strategy would be most efficient if the virus would selectively down-regulate viral Ag-presenting alleles, while at the same time preserving other alleles to act as inhibitors of NK cell activation. We focused on the HCMV unique short (US) region encoded protein US2, which binds to newly synthesized MHC class I H chains and supports their dislocation to the cytosol for subsequent degradation by proteasomes. We studied the effect of US2 on surface expression of individual class I locus products using flow cytometry. Our results were combined with crystal structure data of complexed US2/HLA-A2/β2-microglobulin and alignments of 948 HLA class I database sequences of the endoplasmic reticulum lumenal region inplicated in US2 binding. This study suggests that surface expression of all HLA-A and -G and most HLA-B alleles will be affected by US2. Several HLA-B alleles and all HLA-C and -E alleles are likely to be insensitive to US2-mediated degradation. We also found that the MHC class I endoplasmic reticulum-lumenal domain alone is not sufficient for degradation by US2, as illustrated by the stability of soluble HLA-G1 in the presence of US2. Furthermore, we showed that the membrane-bound HLA-G1 isoform, but also tailless HLA-A2, are targeted for degradation. This indicates that the cytoplasmic tail of the MHC class I H chain is not required for its dislocation to the cytosol by US2.
Differential Activation of Formyl Peptide Receptor-Like 1 by Peptide Ligands
Authors: Bae Yoe-Sik , Yi Hee Jeong , Lee Ha-Young , Jo Eun Jin , Kim Jung Im , Lee Taehoon G. , Ye Richard D. , Kwak Jong-Young , Ryu Sung Ho 
Published: April 2014

Abstract
Formyl peptide receptor-like 1 (FPRL1) plays a key role in the regulation of immune responses. The activation of FPRL1 induces a complicated pattern of cellular signaling, which results in the regulation of several immune responses, such as chemotactic migration and the production of reactive oxygen species (ROS). Because some of these cellular responses are not beneficial to the host, ligands that selectively modulate these cellular responses are useful. His-Phe-Tyr-Leu-Pro-Met (HFYLPM) is a synthetic peptide that binds to FPRL1. In this study, we generated various HFYLPM analogues and examined their effects on cellular responses via FPRL1 in FPRL1-expressing rat basophilic leukemia-2H3 cells or in primary human neutrophils. Among the HXYLPM analogues, His-Arg-Tyr-Leu-Pro-Met (HRYLPM) activated a broad spectrum of cellular signaling events, including an intracellular Ca2+ concentration increase, phosphoinositide 3-kinase, extracellular signal-regulated kinase, and Akt activation, however, His-Glu-Tyr-Leu-Pro-Met (HEYLPM) activated only intracellular Ca2+ concentration and Akt but did not increase Ca2+. In addition, HRYLPM was found to stimulate chemotaxis and ROS generation via phosphoinositide 3-kinase and an intracellular Ca2+ concentration increase, respectively, whereas HEYLPM stimulated chemotaxis but not ROS generation. With respect to the molecular mechanisms involved in the differential action of HRYLPM and HEYLPM, we found that HRYLPM but not HEYLPM competitively inhibited the binding of 125I-labeled Trp-Lys-Tyr-Met-Val-d-Met-NH2 (WKYMVm, a FPRL1 ligand) to FPRL1. This study demonstrates that the important chemoattractant receptor, FPRL1, may be differentially modulated by distinct peptide ligands. We also suggest that HRYLPM and HEYLPM may be used to selectively modulate FPRL1.
Activation of Toll-Like Receptor 2 on Human Tracheobronchial Epithelial Cells Induces the Antimicrobial Peptide Human β Defensin-2
Authors: Hertz Cheryl J. , Wu Qi , Porter Edith Martin , Zhang Yan J. , Weismüller Karl-Heinz , Godowski Paul J. , Ganz Tomas , Randell Scott H. , Modlin Robert L. 
Published: April 2014

Abstract
As pattern recognition receptors capable of eliciting responses to a diverse array of microbial products, Toll-like receptors (TLRs) participate in the activation of host defense mechanisms that protect against infectious pathogens. Given that epithelial cells lie at the interface between the host and its environment, we designed experiments to determine whether human airway epithelial cells express TLRs and respond to TLR agonists. Immunohistochemical labeling of TLR2 in normal human airways revealed TLR2 expression throughout the epithelium, with an apparently higher level of expression on noncolumnar basal epithelial cells. Two-color immunofluorescent labeling of TLR2 and cytokeratins 8 and 15 revealed that TLR2 is coexpressed with the epithelial cell markers. In addition, airway epithelial cells grown at air-liquid interface responded to bacterial lipopeptide in a TLR2-dependent manner with induction of mRNA and protein of the antimicrobial peptide human β defensin-2. Stimulation of epithelial cell cultures with lipopeptide resulted in a small and variable reduction of bacteria on the apical surface. Together, these data suggest that TLRs monitor epithelial surfaces to enhance host defense by inducing the production of an antimicrobial peptide.
Reduced Inflammation and Tissue Damage in Transgenic Rabbits Overexpressing 15-Lipoxygenase and Endogenous Anti-inflammatory Lipid Mediators
Authors: Serhan Charles N. , Jain Ashish , Marleau Sylvie , Clish Clary , Kantarci Alpdogan , Behbehani Balsam , Colgan Sean P. , Stahl Gregory L. , Merched Aksam , Petasis Nicos A. , Chan Lawrence , Van Dyke Thomas E. 
Published: April 2014

Abstract
PGs and leukotrienes (LTs) mediate cardinal signs of inflammation; hence, their enzymes are targets of current anti-inflammatory therapies. Products of arachidonate 15-lipoxygenases (LO) types I and II display both beneficial roles, such as lipoxins (LXs) that stereoselectively signal counterregulation, as well as potential deleterious actions (i.e., nonspecific phospholipid degradation). In this study, we examined transgenic (TG) rabbits overexpressing 15-LO type I and their response to inflammatory challenge. Skin challenges with either LTB4 or IL-8 showed that 15-LO TG rabbits give markedly reduced neutrophil (PMN) recruitment and plasma leakage at dermal sites with LTB4. PMN from TG rabbits also exhibited a dramatic reduction in LTB4-stimulated granular mobilization that was not evident with peptide chemoattractants. Leukocytes from 15-LO TG rabbits gave enhanced LX production, underscoring differences in lipid mediator profiles compared with non-TG rabbits. Microbe-associated inflammation and leukocyte-mediated bone destruction were assessed by initiating acute periodontitis. 15-LO TG rabbits exhibited markedly reduced bone loss and local inflammation. Because enhanced LX production was associated with an increased anti-inflammatory status of 15-LO TG rabbits, a stable analog of 5S,6R,15S-trihydroxyeicosa-7E,9E,11Z,13E-tetraenoic acid (LXA4) was applied to the gingival crevice subject to periodontitis. Topical application with the 15-epi-16-phenoxy-para-fluoro-LXA4 stable analog (ATLa) dramatically reduced leukocyte infiltration, ensuing bone loss as well as inflammation. These results indicate that overexpression of 15-LO type I and LXA4 is associated with dampened PMN-mediated tissue degradation and bone loss, suggesting that enhanced anti-inflammation status is an active process. Moreover, they suggest that LXs can be targets for novel approaches to diseases, e.g., periodontitis and arthritis, where inflammation and bone destruction are features.
IL-12 p40 Homodimer-Dependent Macrophage Chemotaxis and Respiratory Viral Inflammation Are Mediated through IL-12 Receptor β1
Authors: Russell Tonya D. , Yan Qingyun , Fan Guangshun , Khalifah Anthony P. , Bishop D. Keith , Brody Steven L. , Walter Michael J. 
Published: April 2014

Abstract
Leukocyte recruitment to the airway lumen is a central feature of inflammatory conditions such as asthma and respiratory viral infection. Characterization of mediators that regulate leukocyte recruitment in these conditions revealed increased IL-12 p40 homodimer (p80) levels were associated with enhanced airway macrophage accumulation. To examine this association, we used in vivo and in vitro assays to demonstrate p80, but not IL-12 or p40, provided a macrophage chemoattractant signal. Macrophages from genetically deficient mice indicated p80-dependent chemotaxis was independent of IL-12 and required IL-12Rβ1 (Rβ1) expression. Furthermore, analysis of murine cell lines and primary culture macrophages revealed Rβ1 expression, with an intact cytoplasmic tail, was necessary and sufficient to mediate p80-dependent chemotaxis. To examine the role for Rβ1 in mediating macrophage accumulation in vivo, we contrasted Sendai virus-driven airway inflammation in wild-type and Rβ1-deficient mice. Despite similar viral burden and production of the macrophage chemoattractant p80, the Rβ1-deficient mice displayed a selective decrease in airway macrophage accumulation and resistance to viral-dependent mortality. Thus, Rβ1 mediates p80-dependent macrophage chemotaxis and inhibition of the p80-Rβ1 interaction may provide a novel anti-inflammatory strategy to manipulate the inflammation associated with asthma and respiratory viral infection.
Blocking the Monocyte Chemoattractant Protein-1/CCR2 Chemokine Pathway Induces Permanent Survival of Islet Allografts through a Programmed Death-1 Ligand-1-Dependent Mechanism
Authors: Lee Iris , Wang Liqing , Wells Andrew D. , Ye Qunrui , Han Rongxiang , Dorf Martin E. , Kuziel William A. , Rollins Barrett J. , Chen Lieping , Hancock Wayne W. 
Published: April 2014

Abstract
Islet allografts are subject to rapid rejection through host cellular immune responses involving mononuclear cell recruitment and tissue injury. Interruption of leukocyte recruitment through chemokine receptor targeting is of therapeutic benefit in various experimental models, but little is known about the contribution of chemokine pathways to islet allograft rejection. We found that murine islets produce monocyte chemoattractant protein-1 (MCP-1; CCL2) in vitro and that islet allograft rejection was associated with intragraft expression of MCP-1 and its receptor, CCR2. We therefore investigated whether MCP-1 and CCR2 are required for the rejection of fully MHC-disparate islet allografts. Wild-type mice treated with blocking anti-MCP-1 mAb plus a brief, subtherapeutic course of rapamycin had long-term islet allograft survival, in contrast to the effect of treatment with either mAb or rapamycin alone. CCR2−/− mice treated with rapamycin also maintained islet allografts long-term. Both MCP/CCR2- and rapamycin-sensitive signals were required for maximal proliferation of alloreactive T cells, suggesting that MCP-1/CCR2 induce rejection by promoting alloreactive T cell clonal expansion and homing and migration. Prolonged islet allograft survival achieved by blockade of the MCP-1/CCR2 pathway plus rapamycin therapy was accompanied by a mononuclear cell infiltrate expressing the inhibitory receptor, programmed death-1 (PD-1), and its ligand (PD-L1, B7-H1), and prolongation of islet allograft survival was abrogated by anti-PD-L1 mAb therapy. These data show that the blockade of MCP-1 binding to CCR2 in conjunction with subtherapeutic immunosuppression can have profound effects on islet allograft survival and implicate the expression of the PD-1/PD-L1 pathway in the regulation of physiologic responses in vivo.
Macrophages of the Splenic Marginal Zone Are Essential for Trapping of Blood-Borne Particulate Antigen but Dispensable for Induction of Specific T Cell Responses
Authors: Aichele Peter , Zinke Jana , Grode Leander , Schwendener Reto A. , Kaufmann Stefan H. E. , Seiler Peter 
Published: April 2014

AbstractRapid removal of pathogens from the circulation by secondary lymphoid organs is prerequisite for successful control of infection. Blood-borne Ags are trapped mainly in the splenic marginal zone. To identify the cell populations responsible for Ag trapping in the marginal zone, mice were selectively depleted of marginal zone macrophages and marginal metallophilic macrophages. In the absence of these cells, trapping of microspheres and Listeria monocytogenes organisms was lost, and early control of infection was impaired. Depletion of marginal zone macrophages and marginal metallophilic macrophages, however, did not limit Ag presentation because Listeria-specific protective T cell immunity was induced. Therefore, marginal zone macrophages and marginal metallophilic macrophages are crucial for trapping of particulate Ag but dispensable for Ag presentation.
IL-18 Binding Protein Protects Against Contact Hypersensitivity
Authors: Plitz Thomas , Saint-Mézard Pierre , Satho Masataka , Herren Susanne , Waltzinger Caroline , de Carvalho Bittencourt Marcelo , Kosco-Vilbois Marie H. , Chvatchko Yolande 
Published: April 2014

AbstractAllergic contact dermatitis, the clinical manifestation of contact hypersensitivity, is one of the most common disorders of the skin. It is elicited upon multiple cutaneous re-exposure of sensitized individuals to the sensitizing agent. In this study, we demonstrate that using IL-18 binding protein (IL-18BP) to neutralize IL-18 significantly reduced clinical symptoms in a murine model of contact hypersensitivity. Furthermore, IL-18BP alleviated the relapses during established disease, as indicated by significant protection during re-exposure of mice that had previously undergone a contact hypersensitivity response without treatment. Although edema was not influenced, IL-18BP reduced the number of T cells homing to sites of inflammation, resulting in diminished local production of IFN-γ. Thus, by preventing the accumulation of effector T cells to the target tissue, IL-18BP appears to be a potent protective mediator to counter skin inflammation during contact hypersensitivity. Taken together with the evidence that IL-18 is present in tissue samples of the human disease, our data reinforces IL-18BP as a candidate for this therapeutic indication.
Constitutive Caspase Activation and Impaired Death-Inducing Signaling Complex Formation in CD95-Resistant, Long-Term Activated, Antigen-Specific T Cells
Authors: Strauss Gudrun , Knape Ingrid , Melzner Ingo , Debatin Klaus-Michael 
Published: April 2014

AbstractElimination of T cells during an immune response is mediated by activation-induced cell death (AICD) and CD95-mediated apoptosis. Chronic graft-vs-host disease and T cell-mediated autoimmune diseases are caused by the persistence of activated T cells that escaped tolerance induction by deletion or silencing. To mimic the in vivo situation of long-term activated T cells, we generated an in vitro system using HLA-A1-specific T cells, weekly restimulated by Ag. While short-term activated T cells (two to five rounds of stimulation) were CD95 sensitive and susceptible to AICD, T cells stimulated more than eight times acquired constitutive CD95 resistance and exhibited reduced AICD. Phenotypically, these long-term activated T cells could be identified as effector/memory T cells. The expression of the proforms of the CD95 receptor initiator caspases, caspase-8 and -10, and the effector caspase-3 was strongly decreased in these cells, and only active caspase fragments were detected. In contrast to short-term activated T cells, constitutive CD95 receptor clustering was observed on the cell surface, and caspase-8 was bound to the CD95 receptor in the absence of receptor triggering. After further cross-linking of CD95, additional formation of the death-inducing signaling complex (DISC) was strongly impaired. Reduced DISC formation in long-term activated T cells was associated with the loss of PTEN expression and the increased phosphorylation of protein kinase B. Inhibitors of phosphoinositol 3-kinase restored CD95 sensitivity and DISC formation in long-term activated T cells. These data suggest that defective CD95 signaling in effector/memory T cells may contribute to the apoptosis resistance toward physiological stimuli in T cells mediating tissue destruction in vivo.
Fas Ligand on Tumor Cells Mediates Inactivation of Neutrophils
Authors: Chen Yi-Ling , Chen Shun-Hua , Wang Jiu-Yao , Yang Bei-Chang 
Published: April 2014

AbstractThe expression of Fas ligand (FasL) on tumor cells (tumor FasL) has been implicated in their evasion of immune surveillance. In this study, we investigated the cellular mechanism for FasL-associated immune escape using melanoma B16F10-derived cells as a model. Transfectants carrying FasL-specific ribozymes expressed low levels of FasL (FasLlow tumor cells) as compared with those carrying enhanced green fluorescent protein-N1 plasmids (FasLhigh tumor cells). When injected s.c. into C57BL/6 mice, FasLlow tumor cells grew more slowly than did FasLhigh melanoma cells. FasLhigh tumor cells showed more intensive neutrophilic infiltration accompanied by multiple necrotizing areas than did FasLlow tumor cells. The average size of FasLlow tumors, but not of FasLhigh tumors, was significantly enhanced in mice depleted of neutrophils. Consistently, a local injection of LPS to recruit/activate neutrophils significantly delayed tumor formation by FasLlow tumor cells, and slightly retarded that of FasLhigh tumor cells in both C57BL/6 and nonobese diabetic/SCID mice. Neutrophils killed FasLlow melanoma cells more effectively than FasLhigh melanoma cells in vitro. The resistance of FasLhigh melanoma cells to being killed by neutrophils was correlated with impaired neutrophil activation, as demonstrated by reductions in gelatinase B secretion, reactive oxygen species production, and the surface expression of CD11b and the transcription of FasL. Local transfer of casein-enriched or PMA-treated neutrophils delayed tumor formation by melanoma cells. Taken together, inactivation of neutrophils by tumor FasL is an important mechanism by which tumor cells escape immune attack.