bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD4 Cell Priming and Tolerization Are Differentially Programmed by APCs upon Initial Engagement
Authors: Higgins Amy D. , Mihalyo Marianne A. , McGary Patrick W. , Adler Adam J. 
Published: April 2014

AbstractBone marrow-derived APCs present both parenchymal-self and pathogen-derived Ags in a manner that elicits either T cell tolerization or immunity, respectively. To study the parameters that confer tolerogenic vs immunogenic APC function we used an adoptive transfer system in which naive TCR transgenic hemagglutinin (HA)-specific CD4+ T cells are either tolerized upon encountering HA expressed constitutively as a parenchymal self-Ag (self-HA) or primed to express effector function upon encountering transiently expressed vaccinia-derived HA (viral-HA). When the duration of viral-HA presentation was extended for the period required to elicit tolerization toward self-HA, CD4 cell tolerization to viral-HA did not occur. Furthermore, CD4 cells exhibited both phenotypic as well as functional differences during early stages of tolerization and priming, suggesting that these divergent differentiation processes are programmed soon after the initial APC-CD4 cell interaction. When mice expressing self-HA were infected with an irrelevant vaccinia, CD4 cell tolerization still occurred, indicating that priming vs tolerization cannot be explained by pathogen-induced third parties (i.e., non-APCs) that act directly on CD4 cells. Taken together, these results suggest that CD4 cell tolerization to parenchymal self-Ags and priming to pathogen-derived Ags are initiated by functionally distinct APCs.
Uptake of Apoptotic Antigen-Coupled Cells by Lymphoid Dendritic Cells and Cross-Priming of CD8+ T Cells Produce Active Immune Unresponsiveness
Authors: Ferguson Thomas A. , Herndon John , Elzey Bennett , Griffith Thomas S. , Schoenberger Steve , Green Douglas R. 
Published: April 2014

AbstractThe induction of immunologic unresponsiveness by i.v. administration of Ag-coupled lymphoid cells has been studied extensively, but the mechanisms remain unclear. We have further explored this model by examining the role of Fas/Fas ligand (FasL)-mediated apoptosis. Using i.v. injection of trinitrophenyl-coupled splenocytes (TNP-spl) as tolerogen, we found that Fas signaling for apoptosis in the spleen cells delivered by FasL in the recipient is the critical event. The requirement for Fas and FasL was overcome by prior induction of apoptosis in TNP-spl, making the tolerogen 100 times more potent. Prevention of apoptosis by a caspase inhibitor blocks tolerance. Interestingly, while blocking CD40/CD40 ligand interaction does not prevent tolerance induction, an agonist anti-CD40 Ab turns tolerogenic TNP-spl into an immunizing Ag. Studies further showed that tolerance is induced through cross-presentation of Ag in a class I MHC-dependent manner by CD8+CD11c+ lymphoid-derived dendritic cells to regulatory T cells. The results provide a mechanism for a well-established method of inducing immunologic unresponsiveness.
Impaired Light Chain Allelic Exclusion and Lack of Positive Selection in Immature B Cells Expressing Incompetent Receptor Deficient of CD19
Authors: Shivtiel Shoham , Leider Nira , Sadeh Orit , Kraiem Zaki , Melamed Doron 
Published: April 2014

AbstractPositive signaling is now thought to be important for B cell maturation, although the nature of such signals has not yet been defined. We are studying the regulatory role of B cell Ag receptor (BCR) signaling in mediating positive selection of immature B cells. To do so, we use Ig transgenic mice (3-83Tg) that are deficient in CD19, thus generating a monoclonal immature B cell population expressing signaling-incompetent BCR. Immature 3-83Tg CD19−/− B cells undergo developmental arrest in the bone marrow, allowing maturation only to cells that effectively compensate for the compromised receptor by elevated levels of BCR. We find that developmentally arrested 3-83Tg CD19−/− B cells fail to impose L chain allelic exclusion and undergo intensive V(D)J recombination to edit their BCR. Furthermore, immature 3-83Tg CD19−/− B cells, which were grown in vitro, failed to undergo positive selection and to survive when adoptively transferred into normal recipients. However, elevation of BCR expression levels, obtained by transgene homozygosity, effectively compensated for the compromised BCR and completely restored BCR-mediated Ca2+ influx, allelic exclusion, and positive selection. Our results suggest that the BCR signaling threshold mediates positive selection of developing B cells, and that a receptor-editing mechanism has an important role in rescuing cells that fail positive selection because of incompetent receptors.
CD9 Is a Unique Marker for Marginal Zone B Cells, B1 Cells, and Plasma Cells in Mice
Authors: Won Woong-Jai , Kearney John F. 
Published: April 2014

AbstractMarginal zone (MZ), follicular (FO), and B1 B cells form the long-lived naive B cell compartment. To identify surface markers that define MZ B cells in mice, we generated a panel of mAbs reactive with MZ but not FO B cells. One of these mAbs, MZ3, was found to recognize the tetraspanin CD9. CD9 expression not only distinguishes MZ B cells from FO B cells but also divided peritoneal cavity B1 cells into smaller subsets. After short-term in vitro stimulation with various mitogens, FO B cells failed to induce CD9 protein, while MZ B cells up-regulated the level of CD9 protein. However, after prolonged culture of FO B cells with LPS, surface CD9 was induced, together with syndecan 1, indicative of plasma cell differentiation. Following immunization with a T-independent-2 Ag, R36A, or a T-dependent Ag, SRBC, we found that CD9 is not expressed by germinal center B cells but is eventually expressed on plasma cells in response to both T-independent-2 and T-dependent Ags. Collectively, these results suggest that MZ B cells and B1 cell subsets are the immediate precursors of plasma cells in the primary response and that CD9 is acquired by T-dependent plasma cells.
AP2 Adaptor Complex-Dependent Internalization of CD5: Differential Regulation in T and B Cells
Authors: Lu Xianghuai , Axtell Robert C. , Collawn James F. , Gibson Andrew , Justement Louis B. , Raman Chander 
Published: April 2014

AbstractCD5 is a key regulator of Ag receptor-mediated activation, selection, and differentiation in both T and B cells. Accumulating evidence indicates that lymphocyte activation and selection are sensitive to variations in levels of CD5 on the cell surface. We now show that CD5 expression on the surface of B and T cells is regulated posttranslationally by direct interaction with the μ2 subunit of the AP2 adaptor complex that links transmembrane proteins to clathrin-coated pits. CD5 is rapidly internalized from the cell surface in lymphoid cell lines, mature splenic T and B cells, and peritoneal CD5+ B cells following monovalent or bivalent ligation of the receptor. We mapped the μ2 subunit binding site on CD5 to Y429 and determined that the integrity of this site was necessary for CD5 internalization. Cross-linking of the Ag receptor with intact Abs inhibited CD5 internalization in B cells, but had the opposite effect in T cells. However, if F(ab′)2 Abs were used to stimulate the Ag receptor in B cells, the effect on CD5 internalization was now similar to that observed in T cells, indicating that signals through the Ag receptor and FcR regulate CD5 endocytosis in B cells. This was confirmed using an FcγRIIB1-deficient B cell line. The ability to differentially alter posttranslational CD5 expression in T and B cells is likely to be key in regulation of Ag receptor signaling and generation of tolerance in T and B lymphocytes.
Transcriptional Regulation of the HumanToll-Like Receptor 2Gene in Monocytes and Macrophages
Authors: Haehnel Viola , Schwarzfischer Lucia , Fenton Matthew J. , Rehli Michael 
Published: April 2014

AbstractThis report investigates the molecular basis for tissue-restricted and regulated expression of the pattern recognition receptor Toll-like receptor (TLR)2 in human monocytes and macrophages. To define the proximal promoter, the full 5′-sequence and transcriptional start sites of TLR2 mRNA were determined. The human TLR2 gene was found to consist of two 5′ noncoding exons followed by a third coding exon. Alternative splicing of exon II was detected primarily in human blood monocytes. The proximal promoter, exon I, and part of intron I were found to be located in a CpG island. Although CpG methylation of the proximal human TLR2 promoter in cell lines correlated with TLR2 repression, the promoter was unmethylated in primary cells, indicating that CpG methylation does not contribute to the cell-type specific expression of human TLR2 in normal tissues. The promoter sequence contains putative binding sites for several transcription factors, including Sp1 and Ets family members. Reporter gene analysis revealed a minimal promoter of 220 bp that was found to be regulated by Sp1, Sp3, and possibly PU.1. Interestingly, no sequence homology was detected between human and murine TLR2 promoter regions. In contrast to murine TLR2, expression of human TLR2 in monocytes/macrophages is not induced by the proinflammatory stimuli LPS or macrophage-activating lipopeptide-2, and reporter activity of the promoter was not enhanced by stimuli-induced NF-κB activation in THP-1 or MonoMac-6 cells. Our findings provide an initial definition of the human TLR2 promoter and reveal profound differences in the regulation of an important pattern recognition molecule in humans and mice.
Cloning and Characterization of the Homolog of Mammalian Lipopolysaccharide-Binding Protein and Bactericidal Permeability-Increasing Protein in Rainbow TroutOncorhynchus mykiss
Authors: Inagawa Hiroyuki , Honda Teruko , Kohchi Chie , Nishizawa Takashi , Yoshiura Yasutoshi , Nakanishi Teruyuki , Yokomizo Yuichi , Soma Gen-Ichiro 
Published: April 2014

AbstractWe cloned two cDNAs denoted as RT-LBP/BPI-1 and RT-LBP/BPI-2, respectively, which were derived from the mRNA of head kidney from rainbow trout. They showed structural homology with LPS-binding protein (LBP) and bactericidal/permeability-increasing protein (BPI) in mammals. The full-length cDNA of RT-LBP/BPI-1 and RT-LBP/BPI-2 is 1666 and 1741 bp, respectively. Both cDNAs encoded 473 aa residues, including the amino acids conserved in mammalian LBP and BPI proteins that were assumed to be involved in LPS binding. The overall coding sequence of RT-LBP/BPI-1 has 33% amino acid homology to human LBP and 34% to human BPI, and RT-LBP/BPI-2 has 32% amino acid homology to human LBP and 33% to human BPI. Three-dimensional structure analysis by three-dimensional/one-dimensional (3D-1D) methods also demonstrated that RT-LBP/BPI-1 and RT-LBP/BPI-2 proteins showed significant similarity to human BPI, having a boomerang shape with N-terminal and C-terminal barrels. Phylogenetic analysis showed that the LBP and BPI genes seemed to be established after the divergence of mammals from teleosts. These results suggested that RT-LBP/BPI-1 and RT-LBP/BPI-2 may be a putative ortholog for mammalian LBP and/or BPI genes. This is the first study to identify the LBP family genes from nonmammalian vertebrates.
Characterization of a De Novo Conversion in Human Complement C4 Gene Producing a C4B5-Like Protein
Authors: Jaatinen Taina , Eholuoto Miia , Laitinen Tarja , Lokki Marja-Liisa 
Published: April 2014

AbstractComplement C4 is a highly polymorphic protein essential for the activation of the classical complement pathway. Most of the allelic variation of C4 resides in the C4d region. Four polymorphic amino acid residues specify the isotype and an additional four specify the Rodgers and Chido determinants of the protein. Rare C4 allotypes have been postulated to originate from recombination between highly homologous C4 genes through gene conversions. Here we describe the development of a de novo C4 hybrid protein with allotypic and antigenic diversity resulting from nonhomologous intra or interchromosomal recombination of the maternal chromosomes. A conversion was observed between maternal C4A3a and C4B1b genes producing a functional hybrid gene in one of the children. The codons determining the isotype, Asp1054, Leu1101, Ser1102, Ile1105 and His1106, were characteristic of C4B gene, whereas the polymorphic sites in exon and intron 28 were indicative of C4A3a sequence. The protein produced by this hybrid gene was electrophoretically similar to C4B5 allotype. It also possesses reversed antigenicity being Rodgers 1, 2, 3 and Chido-1, -2, -3, 4, -5, and -6. Our case describes the development of a rare bimodular C4B-C4B haplotype containing a functional de novo C4 hybrid gene arisen through gene conversion from C4A to C4B. Overall the data supports the hypothesis of gene conversions as an ongoing process increasing allelic diversity in the C4 locus.
IFN Regulatory Factor 4 Participates in the Human T Cell Lymphotropic Virus Type I-Mediated Activation of the IL-15 Receptor α Promoter
Authors: Mariner Jennifer M. , Mamane Yael , Hiscott John , Waldmann Thomas A. , Azimi Nazli 
Published: April 2014

AbstractIL-15Rα mRNA and protein levels are increased in human T cell lymphotropic virus type-I (HTLV-I)-associated adult T cell leukemia. Previously, we demonstrated that IL-15Rα expression was activated by HTLV-I Tax, in part, through the action of NF-κB. However, there appeared to be additional motifs within the IL-15Rα promoter that were responsive to HTLV-I Tax. In this study, we demonstrated that IL-15Rα mRNA expression was activated in human monocytes by IFN treatment, suggesting a role for IFN regulatory factors (IRFs) in IL-15Rα transcription. In addition, an IRF element within the Tax-responsive element of the IL-15Rα promoter was necessary for maximal Tax-induced activation of this promoter. Furthermore, we demonstrated that IRF-4, a transcription factor known to be elevated in HTLV-I-infected cells, activated the IL-15Rα promoter. Inhibition of IRF-4 action lead to reduced Tax-induced activation of the IL-15Rα promoter, while inhibition of both IRF-4 and NF-κB severely inhibited the Tax-induced activation of this promoter. These findings suggest a role for both NF-κB and IRF-4 in the transcriptional regulation of IL-15Rα by HTLV-I Tax. It is possible that the HTLV-I Tax-mediated induction of IL-15Rα and IL-15 may lead to an autocrine cytokine-mediated stimulatory loop leading to the proliferation of HTLV-I infected cells. This loop of proliferation may facilitate viral propagation and play a role in HTLV-I-mediated disease progression.
A Receptor for the Heterodimeric Cytokine IL-23 Is Composed of IL-12Rβ1 and a Novel Cytokine Receptor Subunit, IL-23R
Authors: Parham Christi , Chirica Madaline , Timans Jacqueline , Vaisberg Elena , Travis Marilyn , Cheung Jeanne , Pflanz Stefan , Zhang Rebecca , Singh Komal P. , Vega Felix , To Wayne , Wagner Janet , O’Farrell Anne-Marie , McClanahan Terrill , Zurawski Sandra , Hannum Charles , Gorman Daniel , Rennick Donna M. , Kastelein Robert A. , de Waal Malefyt Rene , Moore Kevin W. 
Published: April 2014

AbstractIL-23 is a heterodimeric cytokine composed of the IL-12p40 “soluble receptor” subunit and a novel cytokine-like subunit related to IL-12p35, termed p19. Human and mouse IL-23 exhibit some activities similar to IL-12, but differ in their capacities to stimulate particular populations of memory T cells. Like IL-12, IL-23 binds to the IL-12R subunit IL-12Rβ1. However, it does not use IL-12Rβ2. In this study, we identify a novel member of the hemopoietin receptor family as a subunit of the receptor for IL-23, “IL-23R.” IL-23R pairs with IL-12Rβ1 to confer IL-23 responsiveness on cells expressing both subunits. Human IL-23, but not IL-12, exhibits detectable affinity for human IL-23R. Anti-IL-12Rβ1 and anti-IL-23R Abs block IL-23 responses of an NK cell line and Ba/F3 cells expressing the two receptor chains. IL-23 activates the same Jak-stat signaling molecules as IL-12: Jak2, Tyk2, and stat1, -3, -4, and -5, but stat4 activation is substantially weaker and different DNA-binding stat complexes form in response to IL-23 compared with IL-12. IL-23R associates constitutively with Jak2 and in a ligand-dependent manner with stat3. The ability of cells to respond to IL-23 or IL-12 correlates with expression of IL-23R or IL-12Rβ2, respectively. The human IL-23R gene is on human chromosome 1 within 150 kb of IL-12Rβ2.
BAD1, an Essential Virulence Factor ofBlastomyces dermatitidis, Suppresses Host TNF-α Production Through TGF-β-Dependent and -Independent Mechanisms
Authors: Finkel-Jimenez Beatriz , Wüthrich Marcel , Klein Bruce S. 
Published: April 2014

AbstractWe investigated how BAD1, an adhesin and virulence factor of Blastomyces dermatitidis, suppresses phagocyte proinflammatory responses. Wild-type yeast cocultured with murine neutrophils or macrophages prompted release of a soluble factor into conditioned supernatant that abolished TNF-α production in response to the fungus; isogenic, attenuated BAD1 knockout yeast did not have this effect. Phagocytes released 4- to 5-fold more TGF-β in vitro in response to wild-type yeast vs BAD1 knockout yeast. Treatment of inhibitory, conditioned supernatant with anti-TGF-β mAb neutralized detectable TGF-β and restored phagocyte TNF-α production. Similarly, addition of anti-TGF-β mAb into cultures of phagocytes and wild-type yeast reversed BAD1 inhibition of TNF-α production. Conversely, TGF-β treatment of phagocytes cultured with knockout yeast suppressed TNF-α production. Hence, TGF-β mediates BAD1 suppression of TNF-α by wild-type B. dermatitidis cultured in vitro with phagocytes. In contrast to these findings, neutralization of elevated TGF-β levels during experimental pulmonary blastomycosis did not restore BAD1-suppressed TNF-α levels in the lung or ameliorate disease. Soluble BAD1 was found to accumulate in the alveoli of infected mice at levels that suppressed TNF-α production by phagocytes. However, in contrast to yeast cell surface BAD1, which induced TGF-β, soluble BAD1 failed to do so and TNF-α suppression mediated by soluble BAD1 was unaffected by neutralization of TGF-β. Thus, BAD1 of B. dermatitidis induces suppression of TNF-α and progressive infection by both TGF-β-dependent and -independent mechanisms.
Sustained Impairment of IFN-γ Secretion in Suppressed HIV-Infected Patients Despite Mature NK Cell Recovery: Evidence for a Defective Reconstitution of Innate Immunity
Authors: Azzoni Livio , Papasavvas Emmanouil , Chehimi Jihed , Kostman Jay R. , Mounzer Karam , Ondercin Joe , Perussia Bice , Montaner Luis J. 
Published: April 2014

AbstractThe impairment of NK cell functions in the course of HIV infection contributes to a decreased resistance against HIV and other pathogens. We analyzed the proportion of mature and immature NK cell subsets, and measured subsets of IFN-γ and TNF-α-producing NK and T cells in viremic or therapy-suppressed HIV-infected subjects, and noninfected control donors. Viremic HIV+ individuals had significantly lower proportions of mature CD3−/CD161+/CD56+ NK cells and of IFN-γ-producing NK cells compared with noninfected donors, independent of CD4+ T cell counts. HIV-infected subjects with undetectable viral load recovered mature CD3−/CD161+/CD56+ NK cells and cytotoxicity against tumor (K562) and HSV-infected target cells to percentages comparable with those of uninfected individuals, but their NK cells remained impaired in their ability to produce IFN-γ. In parallel to these ex vivo findings, in vitro NK cell differentiation of CD34-positive cord blood precursors in the presence of R5 or X4 HIV-1 resulted in the production of NK cells with a normal mature phenotype, but lacking the ability to produce IFN-γ, whereas coculture of uninfected PBMC with HIV failed to affect mature NK cell properties or IFN-γ secretion. Altogether, our findings support the hypothesis that mature NK cell phenotype may be uncoupled from some mature functions following highly active antiretroviral therapy-mediated suppression of HIV-1, and indicate that relevant innate immune functions of NK cell subsets may remain altered despite effective viral suppression following antiretroviral treatment.
Treatment with α-Galactosylceramide BeforeTrypanosoma cruziInfection Provides Protection or Induces Failure to Thrive
Authors: Duthie Malcolm S. , Kahn Stuart J. 
Published: April 2014

AbstractTrypanosoma cruzi, a protozoan parasite, chronically infects many mammalian species and triggers a chronic inflammatory disease. Invariant Vα14 NK T (iNKT) cells are a regulatory subset of T cells that can contribute to protection against pathogens and to control of chronic inflammatory diseases. α-Galactosylceramide (α-GalCer) is an iNKT cell-specific glycolipid Ag: a single immunization with α-GalCer stimulates robust IFN-γ and IL-4 production by iNKT cells, while multiple immunizations stimulate IL-4 production, but limited IFN-γ production. We recently demonstrated that iNKT cells help control T. cruzi infection and affect the chronic Ab response. Therefore, α-GalCer treatment might be used to increase protection or decrease chronic inflammation during T. cruzi infection. In this report, we show that a single dose of α-GalCer before T. cruzi infection decreases parasitemia. This protection is independent of IL-12, but dependent upon iNKT cell IFN-γ. In addition, α-GalCer treatment of the IFN-γ−/− mice exacerbates parasitemia through IL-4 production. Furthermore, a multiple dose regimen of α-GalCer before T. cruzi infection does not lower parasitemia and, surprisingly, after parasitemia has resolved, causes poor weight gain. These data demonstrate that during T. cruzi infection glycolipids can be used to manipulate iNKT cell responses and suggest the possibility of developing glycolipid treatments that can increase protection and possibly decrease the chronic inflammatory pathology.
Generation of Biologically Active Angiostatin Kringle 1–3 by Activated Human Neutrophils
Authors: Scapini Patrizia , Nesi Lorella , Morini Monica , Tanghetti Elena , Belleri Mirella , Noonan Douglas , Presta Marco , Albini Adriana , Cassatella Marco A. 
Published: April 2014

AbstractThe contribution of polymorphonuclear neutrophils (PMN) to host defense and natural immunity extends well beyond their traditional role as professional phagocytes. In this study, we demonstrate that upon stimulation with proinflammatory stimuli, human PMN release enzymatic activities that, in vitro, generate bioactive angiostatin fragments from purified plasminogen. We also provide evidence that these angiostatin-like fragments, comprising kringle domain 1 to kringle domain 3 (kringle 1–3) of plasminogen, are generated as a byproduct of the selective proteolytic activity of neutrophil-secreted elastase. Remarkably, affinity-purified angiostatin kringle 1–3 fragments generated by neutrophils inhibited basic fibroblast growth factor plus vascular endothelial growth factor-induced endothelial cell proliferation in vitro, and both vascular endothelial growth factor-induced angiogenesis in the matrigel plug assay and fibroblast growth factor-induced angiogenesis in the chick embryo chorioallantoic membrane assay, in vivo. These results represent the first demonstration that biologically active angiostatin-like fragments can be generated by inflammatory human neutrophils. Because angiostatin is a potent inhibitor of angiogenesis, tumor growth, and metastasis, the data suggest that activated PMN not only act as potent effectors of inflammation, but might also play a critical role in the inhibition of angiogenesis in inflammatory diseases and tumors, by generation of a potent anti-angiogenic molecule.