bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polycyclic Aromatic Hydrocarbons Affect Functional Differentiation and Maturation of Human Monocyte-Derived Dendritic Cells
Authors: Laupeze Béatrice , Amiot Laurence , Sparfel Lydie , Le Ferrec Eric , Fauchet Renée , Fardel Olivier 
Published: April 2014

Abstract
Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (BP) are environmental carcinogens exhibiting potent immunosuppressive properties. To determine the cellular bases of this immunotoxicity, we have studied the effects of PAHs on differentiation, maturation, and function of monocyte-derived dendritic cells (DC). Exposure to BP during monocyte differentiation into DC upon the action of GM-CSF and IL-4 markedly inhibited the up-regulation of markers found in DC such as CD1a, CD80, and CD40, without altering cell viability. Besides BP, PAHs such as dimethylbenz(a)anthracene and benzanthracene also strongly altered CD1a levels. Moreover, DC generated in the presence of BP displayed decreased endocytic activity. Features of LPS-mediated maturation of DC, such as CD83 up-regulation and IL-12 secretion, were also impaired in response to BP treatment. BP-exposed DC poorly stimulated T cell proliferation in mixed leukocyte reactions compared with their untreated counterparts. In contrast to BP, the halogenated arylhydrocarbon 2,3,7,8-tetrachlorodibenzo-p-dioxin, which shares some features with PAHs, including interaction with the arylhydrocarbon receptor, failed to phenotypically alter differentiation of monocytes into DC, suggesting that binding to the arylhydrocarbon receptor cannot mimic PAH effects on DC. Overall, these data demonstrate that exposure to PAHs inhibits in vitro functional differentiation and maturation of blood monocyte-derived DC. Such an effect may contribute to the immunotoxicity of these environmental contaminants due to the major role that DC play as potent APC in the development of the immune response.
BCR Engagement Induces Fas Resistance in Primary B Cells in the Absence of Functional Bruton’s Tyrosine Kinase
Authors: Tumang Joseph R. , Negm Robert S. , Solt Laura A. , Schneider Thomas J. , Colarusso Thomas P. , Hastings William D. , Woodland Robert T. , Rothstein Thomas L. 
Published: April 2014

AbstractB cell susceptibility to Fas-mediated apoptosis is regulated in a receptor-specific fashion. CD40 engagement produces marked sensitivity to Fas killing, whereas surface Ig (sIg) engagement blocks Fas signaling for cell death in otherwise sensitive, CD40-stimulated B cell targets, and thus, induces a state of Fas resistance. The signaling mediator, Bruton’s tyrosine kinase (Btk), is required for certain sIg-triggered responses, and Btk is reported to directly bind Fas and block Fas-mediated apoptosis. For these reasons, the role of Btk as a mediator of sIg-induced Fas resistance was examined. Dysfunction of Btk through mutation, and absence of Btk through deletion did not interfere with induction of Fas resistance by anti-Ig. This may be due, at least in part, to induction of Btk-dependent Bcl-2 family members by anti-Ig after CD40 ligand treatment. However, the susceptibility to Fas-mediated apoptosis of B cell targets stimulated by CD40 ligand alone was increased in the absence of Btk. These results indicate that Fas resistance produced by sIg triggering does not require Btk, but suggests that in certain situations Btk modulates B cell susceptibility to Fas killing.
Lipid Microdomain Clustering Induces a Redistribution of Antigen Recognition and Adhesion Molecules on Human T Lymphocytes
Authors: Mitchell Jason S. , Kanca Oguz , McIntyre Bradley W. 
Published: April 2014

Abstract
The study of lipid microdomains in the plasma membrane is a topic of recent interest in leukocyte biology. Many T cell activation and signaling molecules are found to be associated with lipid microdomains and have been implicated in normal T cell function. It has been proposed that lipid microdomains with their associated molecules move by lateral diffusion to areas of cellular interactions to initiate signaling pathways. Using sucrose density gradients we have found that human T cell β1 integrins are not normally associated with lipid microdomains. However, cross-linking of GM1 through cholera toxin B-subunit (CTB) causes an enrichment of β1 integrins in microdomain fractions, suggesting that cross-linking lipid microdomains causes a reorganization of molecular associations. Fluorescent microscopy was used to examine the localization of various lymphocyte surface molecules before and after lipid microdomain cross-linking. Lymphocytes treated with FITC-CTB reveal an endocytic vesicle that is enriched in TCR and CD59, while β1 integrin, CD43, and LFA-3 were not localized in the vesicle. However, when anti-CTB Abs are used to cross-link lipid microdomains, the microdomains are not internalized but are clustered on the cell surface. In this study, CD59, CD43, and β1 integrin are all seen to colocalize in a new lipid microdomain from which LFA-3 remains excluded and the TCR is now dissociated. These findings show that cross-linking lipid microdomains can cause a dynamic rearrangement of the normal order of T lymphocyte microdomains into an organization where novel associations are created and signaling pathways may be initiated.
HIV-1 Down-Modulates γ Signaling Chain of FcγR in Human Macrophages: A Possible Mechanism for Inhibition of Phagocytosis
Authors: Kedzierska Katherine , Ellery Philip , Mak Johnson , Lewin Sharon R. , Crowe Suzanne M. , Jaworowski Anthony 
Published: April 2014

AbstractHIV-1 infection impairs a number of macrophage effector functions, thereby contributing to development of opportunistic infections and the pathogenesis of AIDS. FcγR-mediated phagocytosis by human monocyte-derived macrophages (MDM) is inhibited by HIV-1 infection in vitro, and the underlying mechanism was investigated in this study. Inhibition of phagocytosis directly correlated with the multiplicity of HIV-1 infection. Expression of surface FcγRs was unaffected by HIV-1 infection, suggesting that inhibition of phagocytosis occurred during or after receptor binding. HIV-1 infection of MDM markedly inhibited tyrosine phosphorylation of the cellular proteins, which occurs following engagement of FcγRs, suggesting a defect downstream of initial receptor activation. FcγR-mediated phagocytosis in HIV-infected MDM was associated with inhibition of phosphorylation of tyrosine kinases from two different families, Hck and Syk, defective formation of Syk complexes with other tyrosine-phosphorylated proteins, and inhibition of paxillin activation. Down-modulation of protein expression but not mRNA of the γ signaling subunit of FcγR (a docking site for Syk) was observed in HIV-infected MDM. Infection of MDM with a construct of HIV-1 in which nef was replaced with the gene for the γ signaling subunit augmented FcγR-mediated phagocytosis, suggesting that down-modulation of γ-chain protein expression in HIV-infected MDM caused the defective FcγR-mediated signaling and impairment of phagocytosis. This study is the first to demonstrate a specific alteration in phagocytosis signal transduction pathway, which provides a mechanism for the observed impaired FcγR-mediated phagocytosis in HIV-infected macrophages and contributes to the understanding of how HIV-1 impairs cell-mediated immunity leading to HIV-1 disease progression.
A 320-Kilobase Artificial Chromosome Encoding the Human HLA DR3-DQ2 MHC Haplotype Confers HLA Restriction in Transgenic Mice
Authors: Chen Zhenjun , Dudek Nadine , Wijburg Odilia , Strugnell Richard , Brown Lorena , Deliyannis Georgia , Jackson David , Koentgen Frank , Gordon Tom , McCluskey James 
Published: April 2014

AbstractMHC class II haplotypes control the specificity of Th immune responses and susceptibility to many autoimmune diseases. Understanding the role of HLA class II haplotypes in immunity is hampered by the lack of animal models expressing these genes as authentic cis-haplotypes. In this study we describe transgenic expression of the autoimmune prone HLA DR3-DQ2 haplotype from a yeast artificial chromosome (YAC) containing an intact ∼320-kb region from HLA DRA to DQB2. In YAC-transgenic mice HLA DR and DQ gene products were expressed on B cells, macrophages, and dendritic cells, but not on T cells indicating cell-specific regulation. Positive selection of the CD4 compartment by human class II molecules was 67% efficient in YAC-homozygous mice lacking endogenous class II molecules (Aβnull/null) and expressing only murine CD4. A broad range of TCR Vβ families was used in the peripheral T cell repertoire, which was also purged of Vβ5-, Vβ11-, and Vβ12-bearing T cells by endogenous mouse mammary tumor virus-encoded superantigens. Expression of the HLA DR3-DQ2 haplotype on the Aβnull/null background was associated with normal CD8-dependent clearance of virus from influenza-infected mice and development of CD4-dependent protection from otherwise lethal infection with Salmonella typhimurium. HLA DR- and DQ-restricted T cell responses were also elicited following immunization with known T cell determinants presented by these molecules. These findings demonstrate the potential for human MHC class II haplotypes to function efficiently in transgenic mice and should provide valuable tools for developing humanized models of MHC-associated autoimmune diseases.
Cutting Edge: Differential Segregation of the Src Homology 2-Containing Protein Tyrosine Phosphatase-1 Within the Early NK Cell Immune Synapse Distinguishes Noncytolytic from Cytolytic Interactions
Authors: Vyas Yatin M. , Maniar Hina , Dupont Bo 
Published: April 2014

Abstract
Inhibitory NK receptors with ligand specificity for MHC class I recruit Src homology 2-containing protein tyrosine phosphatase-1 (SHP-1) phosphatase and prevent autocytotoxicity. Activation of SHP-1 depends upon Src kinase-mediated tyrosine phosphorylation of the cytoplasmic domain of the inhibitory receptor. In this study we demonstrate, by quantitative temporal analysis, that talin, Lck, and SHP-1 are recruited to the synapse within 1 min in both cytolytic and noncytolytic conjugates. Polarization of talin and Lck rapidly disappears in the noncytolytic interactions but persists in cytolytic interactions, where protein kinase C-θ, Src homology 2 domain-containing leukocyte protein of 76 kDa, and lysosomes are recruited within 5 min. At 1 min SHP-1 clusters in the periphery of the cytolytic synapse, whereas it clusters in the center of the noncytolytic synapse. Lck has multifocal distribution in both synapses consistent with the shared requirement for early tyrosine phosphorylation. Our studies indicate that the spatial location of SHP-1 in the synapse distinguishes noncytolytic from cytolytic interactions within the first minute.
Interaction Between Src Homology 2 Domain Bearing Protein Tyrosine Phosphatase Substrate-1 and CD47 Mediates the Adhesion of Human B Lymphocytes to Nonactivated Endothelial Cells
Authors: Yoshida Hitoshi , Tomiyama Yoshiaki , Oritani Kenji , Murayama Yoko , Ishikawa Jun , Kato Hisashi , Miyagawa Jun-ichiro , Honma Nakayuki , Nishiura Tetsuo , Matsuzawa Yuji 
Published: April 2014

Abstract
CD47 modulates a variety of cell functions such as adhesion, spreading, and migration. Using a fusion protein consisting of the extracellular region of Src homology 2 domain bearing protein tyrosine phosphatase substrate-1 (SHPS-1) and the Fc portion of human Ig (SHPS-1-Ig) we investigated the effects of SHPS-1 as a ligand for CD47 on B lymphocytes. Although SHPS-1-Ig binding to human B cell lines was solely mediated via CD47, their binding capacity for soluble and immobilized SHPS-1-Ig varied among cell lines irrespective of the similar expression levels of CD47, suggesting that distinctive affinity/avidity states exist during B cell maturation. Nalm6 cell line and tonsilar B lymphocytes adhered to immobilized SHPS-1-Ig and showed polarization-like morphology. These effects of SHPS-1-Ig were blocked by anti-CD47 mAbs (B6H12 and SE5A5). Wortmannin, a phosphatidylinositol-3 kinase inhibitor, but not pertussis toxin significantly inhibited the polarization induced by the immobilized SHPS-1-Ig. Thus, SHPS-1 acts as an adhesive substrate via CD47 in human B lymphocyte. Immunohistochemical analyses indicated that SHPS-1 is expressed on high endothelial venule as well as macrophages in human tonsils. HUVECs also express SHPS-1 in the absence of any stimuli, and the adhesion of tonsilar B lymphocytes to nonactivated HUVECs was significantly inhibited by SE5A5, indicating that SHPS-1/CD47 interaction is involved in the adhesion. Our findings suggest that SHPS-1/CD47 interaction may contribute to the recruitment of B lymphocytes via endothelial cells under steady state conditions.
Expression of Inhibitory Receptors Ly49E and CD94/NKG2 on Fetal Thymic and Adult Epidermal TCR Vγ3 Lymphocytes
Authors: Van Beneden Katrien , De Creus An , Stevenaert Frederik , Debacker Veronique , Plum Jean , Leclercq Georges 
Published: April 2014

AbstractLy49 and CD94/NKG2 inhibitory receptors are predominantly expressed on murine NK cells, but they are also expressed on a subpopulation of peripheral CD8 memory TCR αβ lymphocytes. In this study we demonstrate that Ly49E and CD94/NKG2 receptors are expressed on mature TCR Vγ3+ cells in the fetal thymus. Expression correlated with a memory phenotype, such as expression of CD44, 2B4, and IL-2Rβ (CD122), and absence of IL-2Rα (CD25) expression. No expression of Ly49A, C, D, G2, or I receptors was observed. This phenotype is similar to that of fetal thymic NK cells. Skin-located Vγ3 T cells, the progeny of fetal thymic Vγ3 cells, also expressed CD94/NKG2 and Ly49E but not the other members of the Ly49 family. The development and survival of Ly49E+ or CD94/NKG2+ Vγ3 T lymphocytes was not dependent upon expression of MHC class I molecules. The cytotoxicity of TCR Vγ3 cells was inhibited when Qdm, the ligand for CD94/NKG2, was presented by Qa1b-transfected target cells. Also, upon cross-linking of CD94/NKG2 with mAb 3S9, TCR Vγ3 thymocytes were prevented from killing FcγR+ P815 target cells. These effects were most pronounced in the CD94/NKG2high subpopulation as compared with the CD94/NKG2low subpopulation of Vγ3 cells. Our data demonstrate that Vγ3 T cells expressing inhibitory Ly49E and CD94/NKG2 receptors are mature and display a memory phenotype, and that CD94/NKG2 functions as an inhibitory receptor on these T lymphocytes.
The First Cytokine Sequence Within Cartilaginous Fish: IL-1β in the Small Spotted Catshark (Scyliorhinus canicula)
Authors: Bird Steve , Wang Tiehui , Zou Jun , Cunningham Charlie , Secombes Chris J. 
Published: April 2014

AbstractCartilaginous fish are considered the most primitive living jawed vertebrates with a complex immune system typical of all jawed vertebrates. Cytokine homologs are found within jawless and bony fish, although no cytokine or cytokine receptor genes have been sequenced in cartilaginous fish. In this study the complete coding sequence of the small spotted catshark (Scyliorhinus canicula) IL-1β gene is presented that contains a short 5′ untranslated region (54 bp), a 903-bp open reading frame, a 379-bp 3′ untranslated region, a polyadenylation signal, and eight mRNA instability motifs. The predicted translation (301 amino acids) has highest identity to trout IL-1β (31.7%), with greatest homology within the putative 12 β-sheets. The IL-1 family signature is also present, but there is no apparent signal peptide. As with other nonmammalian IL-1β sequences, the IL-1-converting enzyme cut site is absent. Expression of the IL-1β transcript is detectable by RT-PCR in the spleen and testes, induced in vivo with LPS. Furthermore, a 7-fold increase of transcript levels in splenocytes incubated for 5 h with LPS was seen. The genomic organization comprises six exons and five introns with highest homology seen in exons encoding the largest amount of secondary structure per amino acid. Southern blot analysis suggests at least two copies of the IL-1β gene or genes related to the 3′ end of the IL-1β sequence are present in the catshark. The cloning of IL-1β in S. canicula, the first cytokine sequenced within cartilaginous fish, verifies previous bioactivity evidence for the presence of inflammatory cytokines.
Functional Analysis of Iα Promoter Regions of Multiple IgA Heavy Chain Genes
Authors: Spieker-Polet Helga , Yam Pi-Chen , Knight Katherine L. 
Published: April 2014

AbstractThe 13 nonallelic IgA H chain genes of rabbit are differentially expressed in vivo. They can be grouped into those expressed at high levels (Cα4, Cα5, Cα6, Cα9, Cα10, Cα12, and Cα13), those expressed at low levels (Cα1, Cα2, Cα7, and Cα11), and those that are not expressed (Cα3 and Cα8). We tested whether the differential in vivo expression is due to differential responses of the Iα promoters to TGF-β stimulation. We stimulated the rabbit B cell line 55D1 with TGF-β and, using single-cell RT-PCR, found that expression of germline (GL) transcripts of α3 and α8 could not be induced. By luciferase reporter gene assay and EMSA we found that the promoters of the unexpressed isotypes Cα3 and Cα8 are defective, thereby explaining the absence of IgA3 and IgA8 in vivo. When comparing the promoter activities of the other isotypes we found that the activities did not reflect the degree of in vivo expression. Instead, the promoters of the isotypes expressed at high or low levels promoted expression of the luciferase gene to a similar degree, except for the Iα4 promoter, which had much higher activity. Also the degree to which TGF-β induced GL expression of the various isotypes in 55D1 B cells did not reflect in vivo expression. However, most of the TGF-β-stimulated cells expressed GL mRNA of multiple isotypes; no isotype was expressed preferentially. These results suggest that the final switch to a single isotype is regulated in a step subsequent to GL transcription, rather than by induction of GL transcripts by the Iα promoter.
Segregation of Bad from Lipid Rafts Is Implicated in the Induction of Apoptosis
Authors: Ayllón Verónica , Fleischer Aarne , Cayla Xavier , García Alphonse , Rebollo Angelita 
Published: April 2014

Abstract
Many molecules relocate subcellularly in cells undergoing apoptosis. Using coimmunoprecipitation experiments we demonstrate that Bad is not associated to 14-3-3 protein, suggesting a new mechanism for the control of the proapoptotic role of Bad. Here we show, by confocal microscopy and cellular fractionation, that Bad is attached to lipid rafts in IL-4-stimulated cells and thymocytes while associated with mitochondria in IL-4-deprived cells. Disruption of lipid rafts by methyl-β-cyclodextrin treatment induces segregation of Bad from rafts, which correlates with apoptosis. Our results suggest that the interaction of Bad with rafts is a dynamic process regulated by IL-4 and involved in the control of apoptosis.
Antibody Efficacy in Murine PulmonaryCryptococcus neoformansInfection: A Role for Nitric Oxide
Authors: Rivera Johanna , Mukherjee Jean , Weiss Louis M. , Casadevall Arturo 
Published: April 2014

AbstractWe investigated the pathogenesis of pulmonary Cryptococcus neoformans infection and passive Ab efficacy in mice deficient in inducible NO synthase (NOS2−/−) and the parental strain. Parental mice lived significantly longer than NOS2−/− mice after intratracheal infection, despite having a higher lung fungal burden. Administration of Ab reduced lung CFU in both NOS2−/− and parental mice, but prolonged survival and increased the inflammatory response only in parental mice. Ab administration was associated with increased serum nitrite and reduced polysaccharide levels in parental mice. Eosinophils were present in greater numbers in the lung of infected NOS2−/− mice than parental mice, irrespective of Ab administration. C. neoformans infection in NOS2−/− mice resulted in significantly higher levels of IFN-γ, monocyte chemoattractant protein-1, and macrophage-inflammatory protein-1α than parental mice. Ab administration had different effects on infected NOS2−/− and parental mice with respect to IFN-γ, monocoyte chemoattractant protein-1, and macrophage-inflammatory protein-1α levels. Ab administration increased lung levels of IFN-γ in parental mice and reduced levels in NOS2−/− mice. The results indicate that NO is involved in the regulation of cytokine expression in response to cryptococcal pneumonia and is necessary for Ab efficacy against C. neoformans in mice. Our findings indicate a complex relationship between Ab efficacy against C. neoformans and cytokine expression, underscoring the interdependency of cellular and humoral defense mechanisms.
The Proinflammatory CD14+CD16+DR++ Monocytes Are a Major Source of TNF
Authors: Belge Kai-Uwe , Dayyani Farshid , Horelt Alexia , Siedlar Maciej , Frankenberger Marion , Frankenberger Bernhard , Espevik Terje , Ziegler-Heitbrock Löms 
Published: April 2014

AbstractIn human blood two monocyte populations can be distinguished, i.e., the CD14++CD16−DR+ classical monocytes and the CD14+CD16+DR++ proinflammatory monocytes that account for only 10% of all monocytes. We have studied TNF production in these two types of cells using three-color immunofluorescence and flow cytometry on whole peripheral blood samples stimulated with either LPS or with the bacterial lipopeptide S-(2,3-bis(palmitoyloxy)-(2-RS)-propyl)-N-palmitoyl-(R)-Cys-(S)-Ser-(S)-Lys4-OH,trihydrochloride (Pam3Cys). After stimulation with LPS the median fluorescence intensity for TNF protein was 3-fold higher in the proinflammatory monocytes when compared with the classical monocytes. After stimulation with Pam3Cys they almost exclusively responded showing 10-fold-higher levels of median fluorescence intensity for TNF protein. The median fluorescence intensity for Toll-like receptor 2 cell surface protein was found 2-fold higher on CD14+CD16+DR++ monocytes, which may explain, in part, the higher Pam3Cys-induced TNF production by these cells. When analyzing secretion of TNF protein into the supernatant in PBMCs after depletion of CD16+ monocytes we found a reduction of LPS-induced TNF by 28% but Pam3Cys-induced TNF was reduced by 64%. This indicates that the minor population of CD14+CD16+ monocytes are major producers of TNF in human blood.
IL-18-Binding Protein Expression by Endothelial Cells and Macrophages Is Up-Regulated During Active Crohn’s Disease
Authors: Corbaz Anne , ten Hove Tessa , Herren Suzanne , Graber Pierre , Schwartsburd Boris , Belzer Ilana , Harrison Jillian , Plitz Thomas , Kosco-Vilbois Marie H. , Kim Soo-Hyun , Dinarello Charles A. , Novick Daniela , van Deventer Sander , Chvatchko Yolande 
Published: April 2014

AbstractThe pathogenesis of Crohn’s disease (CD) remains under intense investigation. Increasing evidence suggests a role for mature IL-18 in the induction of proinflammatory cytokines and Th1 polarization in CD lesions. The aim of this study was to investigate the contribution of the IL-18-neutralizing (a and c) and non-neutralizing (b and d) isoforms of IL-18-binding protein (IL-18BP) during active CD. Intestinal endothelial cells and macrophages were the major source of IL-18BP within the submucosa, and this IL-18BP production was also found to be relevant to other types of endothelial cells (HUVEC) and macrophages (peripheral monocytes). IL-18BP messenger transcript and protein were significantly increased in surgically resected specimens from active CD compared with control patients, correlating with an up-regulation of IL-18. Analysis of the expression of the four IL-18BP isoforms as well as being free or bound to IL-18 was reported and revealed that unbound IL-18BP isoforms a and c and inactive isoform d were present in specimens from active CD and control patients while isoform b was not detected. IL-18/IL-18BP complex was also detected. Interestingly, although most was complexed, free mature IL-18 could still be detected in active CD specimens even in the presence of the IL-18BP isoform a/c. These results demonstrate that the appropriate neutralizing isoforms are present in the intestinal tissue of patients with active CD and highlights the complexity of IL-18/IL-18BP biology.