bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteolysis of Human Monocyte CD14 by Cysteine Proteinases (Gingipains) fromPorphyromonas gingivalisLeading to Lipopolysaccharide Hyporesponsiveness
Authors: Sugawara Shunji , Nemoto Eiji , Tada Hiroyuki , Miyake Kensuke , Imamura Takahisa , Takada Haruhiko 
Published: April 2014

AbstractCysteine proteinases (gingipains) elaborated from Porphyromonas gingivalis exhibit enzymatic activities against a broad range of host proteins and are considered key virulence factors in the onset and development of adult periodontitis and host defense evasion. In this study, we examined the ability of arginine-specific gingipains (high molecular mass Arg-specific gingipain (HRGP) and Arg-specific gingipain 2) and lysine-specific gingipain (KGP) to cleave monocyte CD14, the main receptor for bacterial cell surface components such as LPS. Binding of anti-CD14 mAb MY4 to human monocytes was almost completely abolished by 0.3 μM HRGP and KGP treatments for 15 min, and 1 μM RGP2 for 30 min. In contrast, the expressions of Toll-like receptor 4, and CD18, CD54, CD59, and HLA-A, -B, -C on monocytes were slightly increased and decreased, respectively, by 0.3 μM HRGP and KGP. This down-regulation resulted from direct proteolysis, because 1) gingipains eliminated MY4 binding even to fixed monocytes, and 2) CD14 fragments were detected in the extracellular medium by immunoblot analysis. Human rCD14 was degraded by all three gingipains, which confirmed that CD14 was a substrate for gingipains. TNF-α production by monocytes after HRGP and KGP treatments was decreased at 1 ng/ml, but not at 20 μg/ml LPS, indicating that gingipains inhibited a CD14-dependent cell activation. These results suggest that gingipains preferentially cleave monocyte CD14, resulting in attenuation of the cellular recognition of bacteria, and as a consequence sustain chronic inflammation.
Group BStreptococcusInduces TNF-α Gene Expression and Activation of the Transcription Factors NF-κB and Activator Protein-1 in Human Cord Blood Monocytes
Authors: Vallejo Jesus G. , Knuefermann Pascal , Mann Douglas L. , Sivasubramanian Natarajan 
Published: April 2014

AbstractIt has been postulated that production of TNF-α is central to the pathogenesis of septic shock induced by group B Streptococcus (GBS). In vitro studies using human cord blood monocytes have demonstrated that GBS induces TNF-α secretion, but little is known about the intracellular signaling pathways of TNF-α induction. In this report we show that heat-killed serotype III GBS induces host cell signal transduction pathways that lead to activation of the transcription factors NF-κB and AP-1. Using adenoviral transfer of IκBα (IκBα overexpression), the production of TNF-α induced by whole GBS was inhibited by only 20%. We also show that the p38 mitogen-activated protein kinase (MAPK) pathway is involved in GBS-induced TNF-α secretion, because TNF-α protein and mRNA levels in the presence of a specific inhibitor of p38 MAPK, SB 202190, were dramatically diminished. EMSAs showed that SB 202190 inhibited GBS-induced AP-1 activation, but had no effect on NF-κB-DNA binding activity. These results indicate that both NF-κB and AP-1 (via p38 MAPK) are involved in the regulation of TNF-α production in GBS-stimulated neonatal monocytes. Therefore, disrupting the signal transduction pathways induced by GBS has the potential to attenuate the production of immune response mediators, thereby halting or possibly reversing the course of this potentially fatal disease.
The LFA-1 Integrin Supports Rolling Adhesions on ICAM-1 Under Physiological Shear Flow in a Permissive Cellular Environment
Authors: Sigal Alex , Bleijs Diederik A. , Grabovsky Valentin , van Vliet Sandra J. , Dwir Oren , Figdor Carl G. , van Kooyk Yvette , Alon Ronen 
Published: April 2014

AbstractThe LFA-1 integrin is crucial for the firm adhesion of circulating leukocytes to ICAM-1-expressing endothelial cells. In the present study, we demonstrate that LFA-1 can arrest unstimulated PBL subsets and lymphoblastoid Jurkat cells on immobilized ICAM-1 under subphysiological shear flow and mediate firm adhesion to ICAM-1 after short static contact. However, LFA-1 expressed in K562 cells failed to support firm adhesion to ICAM-1 but instead mediated K562 cell rolling on the endothelial ligand under physiological shear stress. LFA-1-mediated rolling required an intact LFA-1 I-domain, was enhanced by Mg2+, and was sharply dependent on ICAM-1 density. This is the first indication that LFA-1 can engage in rolling adhesions with ICAM-1 under physiological shear flow. The ability of LFA-1 to support rolling correlates with decreased avidity and impaired time-dependent adhesion strengthening. A β2 cytoplasmic domain-deletion mutant of LFA-1, with high avidity to immobilized ICAM-1, mediated firm arrests of K562 cells interacting with ICAM-1 under shear flow. Our results suggest that restrictions in LFA-1 clustering mediated by cytoskeletal attachments may lock the integrin into low-avidity states in particular cellular environments. Although low-avidity LFA-1 states fail to undergo adhesion strengthening upon contact with ICAM-1 at stasis, these states are permissive for leukocyte rolling on ICAM-1 under physiological shear flow. Rolling mediated by low-avidity LFA-1 interactions with ICAM-1 may stabilize rolling initiated by specialized vascular rolling receptors and allow the leukocyte to arrest on vascular endothelium upon exposure to stimulatory endothelial signals.
Polyethylene Glycol-Modified GM-CSF Expands CD11bhighCD11chigh But Not CD11blowCD11chigh Murine Dendritic Cells In Vivo: A Comparative Analysis with Flt3 Ligand
Authors: Daro Elizabeth , Pulendran Bali , Brasel Kenneth , Teepe Mark , Pettit Dean , Lynch David H. , Vremec David , Robb Lorraine , Shortman Ken , McKenna Hilary J. , Maliszewski Charles R. , Maraskovsky Eugene 
Published: April 2014

AbstractDendritic cells (DC) are potent APCs that can be characterized in the murine spleen as CD11bhighCD11chigh or CD11blowCD11chigh. Daily injection of mice of Flt3 ligand (FL) into mice transiently expands both subsets of DC in vivo, but the effect of administration of GM-CSF on the expansion of DC in vivo is not well defined. To gain further insight into the role of GM-CSF in DC development and function in vivo, we treated mice with polyethylene glycol-modified GM-CSF (pGM-CSF) which has an increased half-life in vivo. Administration of pGM-CSF to mice for 5 days led to a 5- to 10-fold expansion of CD11bhighCD11chigh but not CD11blowCD11chigh DC. DC from pGM-CSF-treated mice captured and processed Ag more efficiently than DC from FL-treated mice. Although both FL- and pGM-CSF-generated CD11bhighCD11chigh DC were CD8α−, a greater proportion of these DC from pGM-CSF-treated mice were 33D1+ than from FL-treated mice. CD11blowCD11chigh DC from FL-treated mice expressed high levels of intracellular MHC class II. DC from both pGM-CSF- and FL-treated mice expressed high levels of surface class II, low levels of the costimulatory molecules CD40, CD80, and CD86 and were equally efficient at stimulating allogeneic and Ag-specific T cell proliferation in vitro. The data demonstrate that treatment with pGM-CSF in vivo preferentially expands CD11bhighCD11chigh DC that share phenotypic and functional characteristics with FL-generated CD11bhighCD11chigh DC but can be distinguished from FL-generated DC on the basis of Ag capture and surface expression of 33D1.
Tetramer-Guided Analysis of TCR β-Chain Usage Reveals a Large Repertoire of Melan-A-Specific CD8+ T Cells in Melanoma Patients
Authors: Valmori Danila , Dutoit Valérie , Liénard Danielle , Lejeune Ferdy , Speiser Daniel , Rimoldi Donata , Cerundolo Vincenzo , Dietrich Pierre-Yves , Cerottini Jean-Charles , Romero Pedro 
Published: April 2014

Abstract
The assessment of the TCR repertoire expressed by tumor-specific CD8+ T lymphocytes has been hampered to date by the difficulty of targeting the analysis to lymphocytes directed against a single epitope. In the present study we have used fluorescent A2/Melan-A tetramers in conjunction with anti-CD8 and anti-TCR β-chain variable (BV) mAbs to analyze by flow cytometry the BV segment usage by Melan-A-specific CD8+ T cells in tumor-infiltrated lymph nodes (TILN) and tumor-infiltrating lymphocytes (TIL) from A2 melanoma patients. Analysis of TILN populations revealed small proportions of A2/Melan-A tetramer+ cells expressing many different BV together with over-representation of A2/Melan-A tetramer+ cells expressing certain BVs. The BV usage by A2/Melan-A tetramer+ lymphocytes in TIL was more restricted than that in TILN. Moreover, the predominant BV segments were quite distinct in populations derived from different patients. A2/Melan-A tetramer+ cells expressing the dominant BVs found in TILN could also be found in the corresponding peptide-stimulated autologous PBMC, although A2/Melan-A tetramer+ lymphocytes expressing additional BVs were also identified. Together, these results suggest that a large and diverse repertoire of Melan-A-specific T cells using different BV TCR segments is available in A2 melanoma patients.
IFN-β-1b Inhibits IL-12 Production in Peripheral Blood Mononuclear Cells in an IL-10-Dependent Mechanism: Relevance to IFN-β-1b Therapeutic Effects in Multiple Sclerosis
Authors: Wang Xin , Chen Man , Wandinger Klaus Peter , Williams Gary , Dhib-Jalbut Suhayl 
Published: April 2014

AbstractIL-12 is a proinflammatory cytokine secreted by dendritic cells in response to microbial Ags and mitogens. IL-12 is thought to contribute to the pathogenesis of autoimmune diseases such as multiple sclerosis (MS). This is based on studies in experimental allergic encephalomyelitis and the demonstration that PBMC IL-12 production correlates with disease progression in MS. IFN-β-1b is an effective treatment for MS, which is thought to involve in part inhibition of proinflammatory cytokines. In this study we examined the effect of in vitro treatment with IFN-β-1b, on mitogen-induced IL-12 production in human PBMC and myelin basic protein-specific T cell lines obtained from healthy donors and MS patients. We demonstrate that IFN-β-1b significantly inhibits inducible IL-12 p40 up to 80% and biologically active IL-12 p70 up to 70% beginning at a dose of 10 IU/ml. This inhibition is IL-10 dependent, as it could be blocked by anti-IL-10 but not anti-IL-4 or control Abs. Thus, endogenously produced IL-10 is a required cofactor for the IFN-β-1b inhibitory effect on IL-12 to occur. We conclude that IFN-β-1b has a profound inhibitory effect on PBMC IL-12 production in vitro, and that this effect is IL-10 dependent. These findings are potentially relevant to the therapeutic mechanism of IFN-β-1b in MS.
Positive Impact of Inhibitory Ly49 Receptor-MHC Class I Interaction on NK Cell Development
Authors: Lowin-Kropf Bente , Held Werner 
Published: April 2014

AbstractNK cells can kill MHC-different or MHC-deficient but not syngeneic MHC-expressing target cells. This MHC class I-specific tolerance is acquired during NK cell development. MHC recognition by murine NK cells largely depends on clonally distributed Ly49 family receptors, which inhibit NK cell function upon ligand engagement. We investigated whether these receptors play a role for the development of NK cells and provide evidence that the expression of a Ly49 receptor transgene on developing NK cells endowed these cells with a significant developmental advantage over NK cells lacking such a receptor, but only if the relevant MHC ligand was present in the environment. The data suggest that the transgenic Ly49 receptor accelerates and/or rescues the development of NK cells which would otherwise fail to acquire sufficient numbers of self-MHC-specific receptors. Interestingly, the positive effect on NK cell development is most prominent when the MHC ligand is simultaneously present on both hemopoietic and nonhemopoietic cells. These findings correlate with functional data showing that MHC class I ligand on all cells is required to generate functionally mature NK cells capable of reacting to cells lacking the respective MHC ligand. We conclude that the engagement of inhibitory MHC receptors during NK cell development provides signals that are important for further NK cell differentiation and/or maturation.
Evidence for Functional Relevance of CTLA-4 in Ultraviolet-Radiation-Induced Tolerance
Authors: Schwarz Agatha , Beissert Stefan , Grosse-Heitmeyer Karin , Gunzer Matthias , Bluestone Jeffrey A. , Grabbe Stephan , Schwarz Thomas 
Published: April 2014

Abstract
Hapten sensitization through UV-exposed skin induces hapten-specific tolerance that can be adoptively transferred by injecting T lymphocytes into naive recipients. The exact phenotype of T cells responsible for inhibiting the immune response and their mode of action remain unclear. Evidence exists that CTLA-4 negatively regulates T cell activation. We addressed whether CTLA-4 is involved in the transfer of UV-induced tolerance. Injection of lymph node cells from mice that were sensitized with dinitrofluo-robenzene (DNFB) through UV-irradiated skin inhibited induction of contact hypersensitivity against DNFB in the recipient animals. When CTLA-4+ cells were depleted, transfer of suppression was lost. Likewise, significantly fewer lymphocytes enriched for CTLA-4+ cells were necessary to transfer suppression than unfractionated cells. Expression of CTLA-4 appears to be functionally relevant, since in vivo injection of a blocking anti-CTLA-4 Ab was able to break UV-induced tolerance and inhibited transfer of suppression. Upon stimulation with dendritic cells in the presence of the water-soluble DNFB analogue, DNBS, CTLA-4+ T cells from DNFB-tolerized mice secreted high levels of IL-10, TGF-β, and IFN-γ; low levels of IL-2; and no IL-4, resembling the cytokine pattern of T regulatory 1 cells. Ab blocking of CTLA-4 resulted in inhibition of IL-10 release. Accordingly, transfer of tolerance was not observed when recipients were treated with an anti-IL-10 Ab. Hence we propose that T cells, possibly of the T regulatory 1 type, transfer UV-mediated suppression through the release of IL-10. Activation of CTLA-4 appears to be important in this process.
Normal Thymic Architecture and Negative Selection Are Associated with Aire Expression, the Gene Defective in the Autoimmune-Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED)
Authors: Zuklys Saulius , Balciunaite Gina , Agarwal Anni , Fasler-Kan Elizaveta , Palmer Ed , Holländer Georg A. 
Published: April 2014

Abstract
T cell development is tightly controlled by thymic stromal cells. Alterations in stromal architecture affect T cell maturation and the development of self-tolerance. The monogenic autoimmune syndrome APECED (autoimmune-polyendocrinopathy-candidiasis-ectodermal dystrophy) is characterized by the loss of self-tolerance to multiple organs. Although mutations in the autoimmune regulator (AIRE) gene are responsible for this disease, the function of AIRE is not known. Here we report on the spatial and temporal pattern of murine Aire expression during thymic ontogeny and T cell selection. Early during development, thymic Aire transcription is critically dependent on RelB and occurs in epithelial cells in response to lymphocyte-mediated signals. In adult tissue, Aire expression is confined to the medulla and the corticomedullary junction, where it is modulated by thymocytes undergoing negative selection. Aire may determine thymic stromal organization and with it the induction of self-tolerance.
Intestinal Microflora and Diversification of the Rabbit Antibody Repertoire
Authors: Lanning Dennis , Sethupathi Periannan , Rhee Ki-Jong , Zhai Shi-Kang , Knight Katherine L. 
Published: April 2014

AbstractThe rabbit establishes its primary Ab repertoire by somatically diversifying an initial repertoire that is limited by restricted VH gene segment usage during VDJ gene rearrangement. Somatic diversification occurs in gut-associated lymphoid tissue (GALT), and by about 1–2 mo of age nearly all Ig VDJ genes are somatically diversified. In other species that are known to establish their primary Ab repertoire by somatic diversification, such as chicken, sheep, and cattle, diversification appears to be developmentally regulated: it begins before birth and occurs independent of exogenous factors. Because somatic diversification in rabbit occurs well after birth in GALT, the diversification process may not be developmentally regulated, but may require interaction with exogenous factors derived from the gut. To test this hypothesis, we examined Ab repertoire diversification in rabbits in which the appendix was ligated shortly after birth to prevent microbial colonization and all other organized GALT was surgically removed. We found that by 12 wk of age nearly 90% of the Ig VDJ genes in PBL were undiversified, indicating that intestinal microflora are required for somatically diversifying the Ab repertoire. We also examined repertoire diversification in sterilely derived remote colony rabbits that were hand raised away from contact with conventional rabbits and thereby acquired a different gut microflora. In these remote colony rabbits, GALT was underdeveloped, and 70% of the Ig VDJ genes in PBL were undiversified. We conclude that specific, currently unidentified intestinal microflora are required for Ab repertoire diversification.
Differentiation of Monocytes to Macrophages Switches theMycobacterium tuberculosisEffect on HIV-1 Replication from Stimulation to Inhibition: Modulation of Interferon Response and CCAAT/Enhancer Binding Protein β Expression
Authors: Weiden Michael , Tanaka Naohiko , Qiao Yaming , Zhao Ben Yang , Honda Yoshihiro , Nakata Koh , Canova Antony , Levy David E. , Rom William N. , Pine Richard 
Published: April 2014

AbstractHIV-1 replication is inhibited in uninflamed lung macrophages and is stimulated during tuberculosis. Attempts to recapitulate activation of HIV-1 replication in primary monocytes and macrophages ex vivo and in the untreated and PMA-treated THP-1 cell line model in vitro have produced opposite results depending on the state of differentiation of the cells. After infection with Mycobacterium tuberculosis, monocytes enhanced HIV-1 replication and produced a stimulatory 37-kDa CCAAT/enhancer binding protein β (C/EBPβ) transcription factor, whereas macrophages suppressed HIV-1 replication and produced an inhibitory 16-kDa C/EBPβ transcription factor. IFN-β induced inhibitory 16-kDa C/EBPβ in macrophages, but had no effect on C/EBPβ expression in monocytes. Macrophages, but not monocytes, were able to activate IFN-stimulated gene factor-3 (ISGF-3), a transcription factor composed of STAT-1, STAT-2, and IFN regulatory factor (IRF)-9, after infection with M. tuberculosis or stimulation with type I IFN. Macrophages expressed IRF-9 DNA-binding activity, but monocytes did not, and addition of the IRF-9 component reconstituted ISGF-3 in extracts of IFN-treated monocytes. Modulation of IFN responsiveness upon differentiation occurred at least in part through a post-transcriptionally regulated increase in IRF-9 expression. Both monocytes and macrophages maintained IFN responsiveness, activating STAT-1 homodimer formation and transcription of the STAT-1 gene after IFN stimulation. In addition, both monocytes and macrophages were able to activate NF-κB upon infection with M. tuberculosis. These results show that induction of ISGF-3, expression of the inhibitory 16-kDa C/EBPβ, and suppression of HIV-1 replication via a transcriptional mechanism are macrophage-specific responses to infection with M. tuberculosis.
Impaired CTL Recognition of Cells Latently Infected with Kaposi’s Sarcoma-Associated Herpes Virus
Authors: Brander Christian , Suscovich Todd , Lee Yun , Nguyen Phuong Thi , O’Connor Paula , Seebach Joerg , Jones Norman G. , van Gorder Mark , Walker Bruce D. , Scadden David T. 
Published: April 2014

Abstract
Kaposi’s sarcoma-associated herpes virus (KSHV) is a recently identified human γ2-herpesvirus associated with Kaposi’s sarcoma, primary effusion lymphoma, and Castleman’s disease. We reasoned that CTL responses may provide host defense against this virus, and consequently, KSHV may have evolved strategies to evade the CTL-mediated immune surveillance. In this study six B cell lines latently infected with KSHV were found to express reduced levels of HLA class I surface molecules compared with B cell lines transformed by the related γ-herpesvirus EBV. KSHV-infected cells also required higher concentrations of soluble peptides to induce efficient CTL-mediated lysis than control cell lines and were unable to process and/or present intracellularly expressed Ag. Incubation of the KSHV-infected cell lines with high concentrations of soluble HLA class I binding peptides did not restore the deficient HLA class I surface expression. To assess the underlying mechanisms of these phenomena, TAP-1 and TAP-2 gene expression was analyzed. While no attenuation in TAP-2 expression was observed, TAP-1 expression was significantly reduced in all KSHV cell lines compared with that in controls. These results indicate that KSHV can modulate HLA class I-restricted Ag presentation to CTL, which may allow latently infected cells to escape CTL recognition and persist in the infected host.
Monocyte Tissue Factor Induction by Activation of β2-Glycoprotein-I-Specific T Lymphocytes Is Associated with Thrombosis and Fetal Loss in Patients with Antiphospholipid Antibodies
Authors: Visvanathan Sudha , Geczy Carolyn L. , Harmer Jason A. , McNeil H. Patrick 
Published: April 2014

AbstractAntiphospholipid (aPL) syndrome (APS) is characterized by thromboembolic events, thrombocytopenia, or recurrent miscarriage associated with aPL Abs with specificity for β2-glycoprotein-I (β2GPI). We recently reported that at least 44% of patients with the APS possess circulating type 1 (Th1) CD4+ T cells that proliferate and secrete IFN-γ when stimulated with β2GPI in vitro. In this study, we show that stimulation of PBMCs from 20 APS patients with β2GPI induced substantial monocyte tissue factor (TF) (80 ± 11 TF stimulation index (TF-SI)), whereas no induction was observed using PBMCs from 13 patients with aPL Abs without APS (6 ± 1 TF-SI) or 7 normal and 7 autoimmune controls (5 ± 1 and 3 ± 1 TF-SI, respectively) (p &lt; 0.0001). TF induction on monocytes by β2GPI was dose dependent and required CD4+ T lymphocytes and class II MHC molecules. Because monocyte TF induction by β2GPI was observed in all patients with APS, but not in any patient with aPL Abs without APS, this response is a potentially useful predictor for APS in patients with aPL Abs, as well as providing mechanistic insight into thrombosis and fetal loss in these patients.
Proteolytic Cleavage of a Self-Antigen Following Xenobiotic-Induced Cell Death Produces a Fragment with Novel Immunogenic Properties
Authors: Pollard K. Michael , Pearson Deborah L. , Blüthner Martin , Tan Eng M. 
Published: April 2014

AbstractThe heavy metal mercury elicits a genetically restricted autoantibody response in mice that targets the nucleolar autoantigen fibrillarin. HgCl2-induced cell death of macrophages resulted in the proteolytic cleavage of fibrillarin. A prominent feature of mercury-induced cell death was the generation of a 19-kDa fragment of fibrillarin that was not found following apoptotic or nonapoptotic cell death induced by stimuli other than mercury. Proteolysis of fibrillarin lacking cysteines, and therefore unable to bind mercury, also produced the 19-kDa fragment, suggesting that a mercury-fibrillarin interaction was not necessary for the unique cleavage pattern of this self-Ag. In contrast to immunization with full-length fibrillarin, the 19-kDa fragment produced anti-fibrillarin Abs with some of the properties of the HgCl2-induced anti-fibrillarin response. We propose that cell death following exposure to an autoimmunity-inducing xenobiotic can lead to the generation of novel protein fragments that may serve as sources of antigenic determinants for self-reactive T lymphocytes.