bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Involvement of E-Cadherin in TGF-β1-Induced Cell Cluster Formation of In Vitro Developing Human Langerhans-Type Dendritic Cells
Authors: Riedl Elisabeth , Stöckl Johannes , Majdic Otto , Scheinecker Clemens , Rappersberger Klemens , Knapp Walter , Strobl Herbert 
Published: April 2014

AbstractEpithelial Langerhans cells (LC) represent immature dendritic cells that require TGF-β1 stimulation for their development. Little is known about the mechanisms regulating LC generation from their precursor cells. We demonstrate here that LC development from human CD34+ hemopoietic progenitor cells in response to TGF-β1 costimulation (basic cytokine combination GM-CSF plus TNF-α, stem cell factor, and Flt3 ligand) is associated with pronounced cell cluster formation of developing LC precursor cells. This cell-clustering phenomenon requires hemopoietic progenitor cell differentiation, since it is first seen on day 4 after culture initiation of CD34+ cells. Cell cluster formation morphologically indicates progenitor cell development along the LC pathway, because parallel cultures set up in the absence of exogenous TGF-β1 fail to form cell clusters and predominantly give rise to monocyte, but not LC, development (CD1a−, lysozyme+, CD14+). TGF-β1 costimulation of CD34+ cells induces neoexpression of the homophilic adhesion molecule E-cadherin in the absence of the E-cadherin heteroligand CD103. Addition of anti-E-cadherin mAb or mAbs to any of the constitutively expressed adhesion molecule (CD99, CD31, LFA-1, or CD18) to TGF-β1-supplemented progenitor cell cultures inhibits LC precursor cell cluster formation, and this effect is, with the exception of anti-E-cadherin mAb, associated with inhibition of LC generation. Addition of anti-E-cadherin mAb to the culture allows cell cluster-independent generation of LC from CD34+ cells. Thus, functional E-cadherin expression and homotypic cell cluster formation represent a regular response of LC precursor cells to TGF-β1 stimulation, and cytoadhesive interactions may modulate LC differentiation from hemopoietic progenitor cells.
Bone-Marrow Chimeras Reveal Hemopoietic and Nonhemopoietic Control of Resistance to Experimental Lyme Arthritis
Authors: Brown Charles R. , Reiner Steven L. 
Published: April 2014

AbstractBoth genetic resistance and susceptibility to development of experimental Lyme arthritis are mediated by the innate immune response. To determine whether this process is mainly controlled by hemopoietic or nonhemopoietic cells, we created bone marrow (BM) chimeric mice between arthritis-resistant DBA/2J (DBA) and arthritis-susceptible C3H/HeJ (C3H) mice and infected them with Borrelia burgdorferi. Both sets of BM chimeric mice, C3H donors into DBA recipients (C→D) and DBA donors into C3H recipients (D→C), as well as DBA sham chimeric mice (D→D) were resistant to the development of experimental Lyme arthritis as measured by ankle swelling and arthritis severity scores. Only the C3H sham chimeric mice (C→C) developed severe arthritis. These results indicate that independent and nonoverlapping mechanisms exist in hemopoietic and nonhemopoietic cellular compartments that can provide protection against arthritic pathology.
Pulmonary Mononuclear Cell Responses to Antigens ofMycobacterium tuberculosisin Healthy Household Contacts of Patients with Active Tuberculosis and Healthy Controls from the Community
Authors: Schwander Stephan K. , Torres Martha , Carranza C Claudia , Escobedo Dante , Tary-Lehmann Magdalena , Anderson Peter , Toossi Zahra , Ellner Jerrold J. , Rich Elizabeth A. , Sada Eduardo 
Published: April 2014

AbstractProtective immunity against Mycobacterium tuberculosis requires CD4+ lymphocyte-mediated immune responses and IFN-γ activity. As the primary portal of entry of M. tuberculosis is the lung, pulmonary immune responses against multiple M. tuberculosis Ags were compared between both M. tuberculosis-exposed tuberculin skin test-positive healthy household contacts (HHC) of patients with active sputum smear and culture-positive tuberculosis and tuberculin skin test-positive healthy control individuals from the community (CC). Frequencies of M. tuberculosis Ag-specific IFN-γ-producing cells, IFN-γ concentrations in culture supernatants, and DNA synthesis in bronchoalveolar cells (BAC) and PBMC were studied in HHC (n = 10) and CC (n = 15). Using enzyme-linked immunospot assay we found higher frequencies of IFN-γ-producing cells with specificity to M. tuberculosis-secreted Ag 85 (Ag 85) in BAC from HHC than in BAC from CC (p &lt; 0.022) and relative to autologous PBMC, indicating compartmentalization of Ag 85-specific cells to the lungs. Further, IFN-γ-producing cells with specificity to components A and B of Ag 85 were specifically compartmentalized to the lungs in HHC (p &lt; 0.05). IFN-γ concentrations in culture supernatants of BAC and Ag-specific DNA synthesis were low and comparable in the two subject groups. Increased immune responses to Ag 85 at the site of repeated exposure to M. tuberculosis (the lung) may represent an important component of protective immunity against M. tuberculosis. Correlates of protective immunity against M. tuberculosis are required for assessment of the efficiency of anti-tuberculous vaccines.
Urokinase Receptor-Deficient Mice Have Impaired Neutrophil Recruitment in Response to PulmonaryPseudomonas aeruginosaInfection
Authors: Gyetko Margaret R. , Sud Sudha , Kendall Tara , Fuller Jennifer A. , Newstead Michael W. , Standiford Theodore J. 
Published: April 2014

AbstractLeukocytes express both urokinase-type plasminogen activator (uPA) and the urokinase receptor (uPAR, CD87). Evidence in vitro has implicated uPAR as a modulator of β2 integrin function, particularly CR3 (CD11b/CD18, Mac-1). Pseudomonas aeruginosa infection has been demonstrated to recruit neutrophils to the pulmonary parenchyma by a β2 integrin-dependent mechanism. We demonstrate that mice deficient in uPAR (uPAR−/−) have profoundly diminished neutrophil recruitment in response to P. aeruginosa pneumonia compared with wild-type (WT) mice. The requirement for uPAR in neutrophil recruitment is independent of the serine protease uPA, as neutrophil recruitment in uPA−/− mice is indistinguishable from recruitment in WT mice. uPAR−/− mice have impaired clearance of P. aeruginosa compared with WT mice, as demonstrated by CFU and comparative histology. WT mice have diminished neutrophil recruitment to the lung when an anti-CD11b mAb is given before inoculation with the pathogen, while recruitment of uPAR−/− neutrophils is unaffected. We conclude that uPAR is required for the recruitment of neutrophils to the lung in response to P. aeruginosa pneumonia and that this requirement is independent of uPA. Further, we show that uPAR and CR3 act by a common mechanism during neutrophil recruitment to the lung in response to P. aeruginosa. This is the first report of a requirement for uPAR during cellular recruitment in vivo against a clinically relevant pathogen.
Chloroquine Interferes with Lipopolysaccharide-Induced TNF-α Gene Expression by a Nonlysosomotropic Mechanism
Authors: Weber Stephen M. , Levitz Stuart M. 
Published: April 2014

AbstractChloroquine (CQ) is a lysosomotropic weak base with over 60 years of clinical use for the treatment of malaria and rheumatologic disorders. Consistent with its anti-inflammatory properties, CQ has been shown to interfere with TNF-α release from mononuclear phagocytes. Because it is unclear how CQ mediates these immunomodulatory effects, we set out to elucidate its mechanism of action. CQ exhibited dose-dependent inhibition of LPS-induced TNF-α release from human PBMC at therapeutically attainable concentrations. Additional studies to determine the specificity of this effect showed that although CQ reduced IL-1β and IL-6 release, secretion of RANTES was unaffected. CQ acted by reducing TNF-α mRNA accumulation without destabilizing its mRNA or interfering with NF-κB nuclear translocation or p50/p65 isoform composition of DNA-binding complexes. Intracellular cytokine staining indicated that CQ reduced TNF-α production pretranslationally without interfering with TNF-α processing or release. We utilized bafilomycin A1 pretreatment to block the pH-dependent trapping of CQ in endosomes and lysosomes. Although bafilomycin A1 alone did not interfere with TNF-α expression, preincubation augmented the ability of CQ to reduce TNF-α mRNA levels, suggesting that CQ did not act by a lysosomotropic mechanism. Using confocal microscopy, we showed that bafilomycin A1 pretreatment resulted in a dramatic redistribution of quinacrine, a fluorescent congener of CQ, from cytoplasmic vacuoles to the nucleus. These data indicate that CQ inhibits TNF-α gene expression without altering translocation of NF-κB p50/p65 heterodimers. This dose-dependent effect occurs over a pharmacologically relevant concentration range and does not require pH-dependent lysosomotropic accumulation of CQ.
CXCR3 Expression and Activation of Eosinophils: Role of IFN-γ-Inducible Protein-10 and Monokine Induced by IFN-γ
Authors: Jinquan Tan , Jing Chen , Jacobi Henrik H. , Reimert Claus M. , Millner Anders , Quan Sha , Hansen Jens B. , Dissing Steen , Malling Hans-Jørgen , Skov Per S. , Poulsen Lars K. 
Published: April 2014

AbstractCXC chemokine receptor 3 (CXCR3), predominately expressed on memory/activated T lymphocytes, is a receptor for both IFN-γ-inducible protein-10 (γ IP-10) and monokine induced by IFN-γ (Mig). We report a novel finding that CXCR3 is also expressed on eosinophils. γ IP-10 and Mig induce eosinophil chemotaxis via CXCR3, as documented by the fact that anti-CXCR3 mAb blocks γ IP-10- and Mig-induced eosinophil chemotaxis. γ IP-10- and Mig-induced eosinophil chemotaxis are up- and down-regulated by IL-2 and IL-10, respectively. Correspondingly, CXCR3 protein and mRNA expressions in eosinophils are up- and down-regulated by IL-2 and IL-10, respectively, as detected using flow cytometry, immunocytochemical assay, and a real-time quantitative RT-PCR technique. γ IP-10 and Mig act eosinophils to induce chemotaxis via the cAMP-dependent protein kinase A signaling pathways. The fact that γ IP-10 and Mig induce an increase in intracellular calcium in eosinophils confirms that CXCR3 exists on eosinophils. Besides induction to chemotaxis, γ IP-10 and Mig also activate eosinophils to eosinophil cationic protein release. These results indicate that CXCR3-γ IP-10 and -Mig receptor-ligand pairs as well as the effects of IL-2 and IL-10 on them may be especially important in the cytokine/chemokine environment for the pathophysiologic events of allergic inflammation, including initiation, progression, and termination in the processes.
Heterogeneous Effects of IL-2 on Collagen-Induced Arthritis
Authors: Thornton Sherry , Boivin Gregory P. , Kim Kwang N. , Finkelman Fred D. , Hirsch Raphael 
Published: April 2014

AbstractIL-2 is generally considered a pro-inflammatory cytokine that exacerbates Th1-mediated disease states, such as autoimmune arthritis. Consistent with this role for IL-2, recent studies from our laboratory demonstrate that IL-2 mRNA is markedly increased during the acute stage of collagen-induced arthritis (CIA), an animal model of rheumatoid arthritis. To further define the role of IL-2 in CIA, the levels of IL-2 protein and its receptor and the effects of IL-2 administration were analyzed during CIA. IL-2 protein and IL-2R were preferentially expressed at disease onset, compared with later stages of disease. Administration of recombinant human IL-2 (rhIL-2) at, or just before, disease onset exacerbated disease; surprisingly, rhIL-2 given before disease onset inhibited CIA, associated with reduced cellular and humoral responses to type II collagen. Determination of in vivo serum levels of Th1 and Th2 cytokines in response to rhIL-2 treatment demonstrated that IFN-γ, but not IL-4, was markedly up-regulated in response to IL-2. In mice treated with anti-IFN-γ Ab, both early and late IL-2 administration exacerbated CIA. Thus, IL-2 can have two opposite effects on autoimmune arthritis, a direct stimulatory effect and an indirect suppressive effect that is mediated by IFN-γ.
Airway Remodeling Is Absent in CCR1−/− Mice During Chronic Fungal Allergic Airway Disease
Authors: Blease Kate , Mehrad Borna , Standiford Theodore J. , Lukacs Nicholas W. , Kunkel Steven L. , Chensue Stephen W. , Lu Bao , Gerard Craig J. , Hogaboam Cory M. 
Published: April 2014

AbstractAsthmatic-like reactions characterized by elevated IgE, Th2 cytokines, C-C chemokines, eosinophilic inflammation, and persistent airway hyperresponsiveness follow pulmonary exposure to the spores or conidia from Aspergillus fumigatus fungus in sensitized individuals. In addition to these features, subepithelial fibrosis and goblet cell hyperplasia characterizes fungal-induced allergic airway disease in mice. Because lung concentrations of macrophage inflammatory protein-1α and RANTES were significantly elevated after A. fumigatus-sensitized mice received an intrapulmonary challenge with A. fumigatus spores or conidia, the present study addressed the role of their receptor, C-C chemokine receptor 1 (CCR1), in this model. A. fumigatus-sensitized CCR1 wild-type (+/+) and CCR1 knockout (−/−) mice exhibited similar increases in serum IgE and polymorphonuclear leukocyte numbers in the bronchoalveolar lavage. Airway hyperresponsiveness was prominent in both groups of mice at 30 days after an intrapulmonary challenge with A. fumigatus spores or conidia. However, whole lung levels of IFN-γ were significantly higher whereas IL-4, IL-13, and Th2-inducible chemokines such as C10, eotaxin, and macrophage-derived chemokine were significantly lower in whole lung samples from CCR1−/− mice compared with CCR1+/+ mice at 30 days after the conidia challenge. Likewise, significantly fewer goblet cells and less subepithelial fibrosis were observed around large airways in CCR1−/− mice at the same time after the conidia challenge. Thus, these findings demonstrate that CCR1 is a major contributor to the airway remodeling responses that arise from A. fumigatus-induced allergic airway disease.
Early Local Generation of C5a Initiates the Elicitation of Contact Sensitivity by Leading to Early T Cell Recruitment
Authors: Tsuji Ryohei F. , Kawikova Ivana , Ramabhadran Rajani , Akahira-Azuma Moe , Taub Dennis , Hugli Tony E. , Gerard Craig , Askenase Philip W. 
Published: April 2014

AbstractWe have shown previously that an early complement C5-dependent cascade is required to recruit T cells to elicit 24-h contact sensitivity (CS) responses. In this paper, we have characterized molecular events of this early required cascade by biochemically analyzing extracts of mouse ears undergoing elicitation of CS. Chemotactic activity was found after local Ag challenge, in CS ear extracts early (by 1 h), in CS ear extracts late (through 24 h), in previously immunized mice, but not in ears of vehicle-immunized or non-immune-challenged mice. The early chemotactic activity at 2 h was likely caused by C5a, because it was neutralized in vitro by anti-C5a Ab, was inactive on C5aR-deficient (C5aR−/−) macrophages, and was absent in C5-deficient mice. The activity was present in T cell-deficient mice, but elaboration was Ag-specific. This T cell-independent, Ag-specific elaboration of C5a early in CS ear responses likely led to T cell recruitment, because subsequent local IFN-γ mRNA and protein expression, as markers of T cell arrival and activation, began by 4 h after Ag challenge. In contrast to early C5a chemotactic activity, late chemotactic activity 24 h after Ag challenge was unaffected by anti-C5, was active on C5aR−/− macrophages, was T cell-dependent, and by ELISA appeared largely due to chemokines (macrophage-inflammatory protein-1α and -1β, IFN-γ-inducible protein-10, and monocyte chemoattractant protein-1). Importantly, early generation of C5a was required for T cell recruitment because C5aR−/− mice had absent 24-h CS. Taken together, these findings indicate an important linkage of C5a as a component of early activated innate immunity that is required for later elicitation of acquired T cell immunity, probably by facilitating the initial recruitment of T cells into the Ag-challenged local site in CS responses.
Phenotypic and Functional Maturation of Dendritic Cells Mediated by Heparan Sulfate
Authors: Kodaira Yuzo , Nair Smita K. , Wrenshall Lucile E. , Gilboa Eli , Platt Jeffrey L. 
Published: April 2014

AbstractPrimary immune responses are thought to be induced by dendritic cells. To promote such responses, dendritic cells must be activated by exogenous agonists, such as LPS, or by products of activated leukocytes, such as TNF-α and IL-1. How dendritic cells might be activated in the absence of exogenous stimuli, or without the immediate presence of activated leukocytes, as might occur in immunity to tumor cells or transplants, is unknown. We postulated that heparan sulfate, an acidic, biologically active polysaccharide associated with cell membranes and extracellular matrices, which is rapidly released under conditions of inflammation and tissue damage, might provide such a stimulus. Incubation of immature murine dendritic cells with heparan sulfate induced phenotypic maturation evidenced by up-regulation of I-A, CD40, CD54 (ICAM-1), CD80 (B7-1), and CD86 (B7-2). Dendritic cells exposed to heparan sulfate exhibited a markedly lowered rate of Ag uptake and increased allostimulatory capacity. Stimulation of dendritic cells with heparan sulfate induced release of TNF-α, IL-1β, and IL-6, although the maturation of dendritic cells was independent of these cytokines. These results suggest that soluble heparan sulfate chains, as products of the degradation of heparan sulfate proteoglycan, might induce maturation of dendritic cells without exogenous stimuli, thus contributing to the generation and maintenance of primary immune responses.
Regulation of Expression of Granulocyte-Macrophage Colony-Stimulating Factor in Human Bronchial Epithelial Cells: Roles of Protein Kinase C and Mitogen-Activated Protein Kinases
Authors: Reibman Joan , Talbot Anita T. , Hsu Yanshen , Ou Guoming , Jover Javier , Nilsen Diana , Pillinger Michael H. 
Published: April 2014

AbstractGM-CSF has a major role in the immune and inflammatory milieu of the airway. Airway epithelial cells (AEC) are among the first targets of environmental stimuli and local cytokines, in response to which they can produce GM-CSF. The regulation of GM-CSF is only minimally understood in AEC. We hypothesized that GM-CSF expression in AEC would result from activation of protein kinase C (PKC) and subsequent activation of the extracellular signal-regulated kinase (MAPKerk1/2) pathway, so we investigated signal transduction pathways in human primary culture bronchial epithelial cells (HBECs). TNF-α, IL-1β, and PMA induced the release of GM-CSF in HBECs. The robust response to PMA was not detected in SV40 adenovirus-transformed normal human bronchial epithelial cells (BEAS-2B). PMA and TNF-α stimulation of GM-CSF required activation of PKC (inhibition by staurosporine and bisindolylmaleimide I). GM-CSF expression was up-regulated by a nonphorbol PKC activator, but not by an inactive PMA analogue. PMA-induced GM-CSF production in HBECs did not require a Ca2+ ionophore and was not inhibited by cyclosporin A. Activation of MAPKerk1/2 via PKC was associated with and was required for GM-CSF production induced by PMA and TNF-α. The data demonstrate regulation of GM-CSF in HBECs by PKC pathways converging on the MAPKerk1/2 pathway and further define cell-specific regulation critical for local airway responses.
Immune Complexes Present in the Sera of Autoimmune Mice Activate Rheumatoid Factor B Cells
Authors: Rifkin Ian R. , Leadbetter Elizabeth A. , Beaudette Britte C. , Kiani Cornelia , Monestier Marc , Shlomchik Mark J. , Marshak-Rothstein Ann 
Published: April 2014

AbstractThe fate of an autoreactive B cell is determined in part by the nature of the interaction of the B cell receptor with its autoantigen. In the lpr model of systemic autoimmunity, as well as in certain human diseases, autoreactive B cells expressing rheumatoid factor (RF) binding activity are prominent. A murine B cell transgenic model in which the B cell receptor is a RF that recognizes IgG2a of the j allotype (IgG2aj), but not the b allotype, was used in this study to investigate how the form of the autoantigen influences its ability to activate B cells. We found that sera from autoimmune mice, but not from nonautoimmune mice, were able to induce the proliferation of these RF+ B cells but did not stimulate B cells from RF− littermate controls. The stimulatory factor in serum was found to be IgG2aj, but the IgG2aj was stimulatory only when in the form of immune complexes. Monomeric IgG2aj failed to stimulate. Immune complexes containing lupus-associated nuclear and cytoplasmic autoantigens were particularly potent B cell activators in this system. Appropriate manipulation of such autoantibody/autoantigen complexes may eventually provide a means for therapeutic intervention in patients with certain systemic autoimmune disorders.
Expression of Human Complement Receptor 2 (CR2, CD21) inCr2−/− Mice Restores Humoral Immune Function
Authors: Marchbank Kevin J. , Watson Clay C. , Ritsema David F. , Holers V. Michael 
Published: April 2014

AbstractComplement receptor type 2 (CR2, CD21) is expressed by both human and murine B cells and has been demonstrated to play a pivotal role in the humoral immune response. We have reconstituted Cr2−/− mice with an 80-kb human genomic fragment (designated P1-5) containing the full-length human CR2 (hCR2) gene. Transfection of P1-5 into the mouse A20 B cell line confirmed that it would direct expression of the hCR2 protein in mouse B cells. Immunoprecipitation analysis in these cells revealed that hCR2 coassociates with mouse CD19. After creation of transgenic mice using P1-5, we found significant expression of hCR2 on peripheral blood and splenic B cells by flow cytometric analysis. RT-PCR analysis of tissues and purified cell populations from transgene-positive mice revealed that hCR2 expression was restricted to B cells and the spleen in a pattern that matches mouse CR2. To rigorously assess the functional capabilities of hCR2, the transgene was bred onto Cr2−/− mice, which have a notable defect in response to SRBC Ag. We found that Cr2−/− mice expressing hCR2 had a substantial restoration of the humoral immune response to SRBC as compared with nontransgenic Cr2−/− littermate controls. Overall, this study suggests that hCR2 is able to substitute for mouse CR2 in the murine immune system. Therefore, hCR2-transgenic mice offer a valuable model system to further examine immunologic roles as well as structure-function relationships important for hCR2 function in primary cells in vivo.
Stat-1 Is Not Essential for Inhibition of B Lymphopoiesis by Type I IFNs
Authors: Gongora Rafael , Stephan Robert P. , Schreiber Robert D. , Cooper Max D. 
Published: April 2014

AbstractType I IFNs, IFN-α, -β, and -ω, are cytokine family members with multiple immune response roles, including the promotion of cell growth and differentiation. Conversely, the type I IFNs are potent inhibitors of IL-7-dependent growth of early B lineage progenitors, effectively aborting further B lineage differentiation at the pro-B cell stage. Type I IFNs α and β function via receptor-mediated activation of a Jak/Stat signaling pathway in which Stat-1 is functionally important, because many IFN-induced responses are abrogated in Stat-1-deficient mice. To the contrary, we show here that the inhibition of IL-7-dependent B lymphopoiesis by IFN-αβ is unaffected in Stat-1-deficient mice. The present data indicate that the type I IFNs can activate an alternative signaling pathway in which neither Stat-1 nor phosphatidylinositol 3′-kinase are essential components.