bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cooperation Between Decay-Accelerating Factor and Membrane Cofactor Protein in Protecting Cells from Autologous Complement Attack
Authors: Brodbeck William G. , Mold Carolyn , Atkinson John P. , Medof M. Edward 
Published: April 2014

AbstractDecay-accelerating factor (DAF or CD55) and membrane cofactor protein (MCP or CD46) function intrinsically in the membranes of self cells to prevent activation of autologous complement on their surfaces. How these two regulatory proteins cooperate on self-cell surfaces to inhibit autologous complement attack is unknown. In this study, a GPI-anchored form of MCP was generated. The ability of this recombinant protein and that of naturally GPI-anchored DAF to incorporate into cell membranes then was exploited to examine the combined functions of DAF and MCP in regulating complement intermediates assembled from purified alternative pathway components on rabbit erythrocytes. Quantitative studies with complement-coated rabbit erythrocyte intermediates constituted with each protein individually or the two proteins together demonstrated that DAF and MCP synergize the actions of each other in preventing C3b deposition on the cell surface. Further analyses showed that MCP’s ability to catalyze the factor I-mediated cleavage of cell-bound C3b is inhibited in the presence of factors B and D and is restored when DAF is incorporated into the cells. Thus, the activities of DAF and MCP, when present together, are greater than the sum of the two proteins individually, and DAF is required for MCP to catalyze the cleavage of cell-bound C3b in the presence of excess factors B and D. These data are relevant to xenotransplantation, pharmacological inhibition of complement in inflammatory diseases, and evasion of tumor cells from humoral immune responses.
Redundant and Segregated Functions of Granule-Associated Heparin-Binding Group II Subfamily of Secretory Phospholipases A2 in the Regulation of Degranulation and Prostaglandin D2 Synthesis in Mast Cells
Authors: Enomoto Ayako , Murakami Makoto , Valentin Emmanuel , Lambeau Gerard , Gelb Michael H. , Kudo Ichiro 
Published: April 2014

AbstractWe herein demonstrate that mast cells express all known members of the group II subfamily of secretory phospholipase A2 (sPLA2) isozymes, and those having heparin affinity markedly enhance the exocytotic response. Rat mastocytoma RBL-2H3 cells transfected with heparin-binding (sPLA2-IIA, -V, and -IID), but not heparin-nonbinding (sPLA2-IIC), enzymes released more granule-associated markers (β-hexosaminidase and histamine) than mock- or cytosolic PLA2α (cPLA2α)-transfected cells after stimulation with IgE and Ag. Site-directed mutagenesis of sPLA2-IIA and -V revealed that both the catalytic and heparin-binding domains are essential for this function. Confocal laser and electron microscopic analyses revealed that sPLA2-IIA, which was stored in secretory granules in unstimulated cells, accumulated on the membranous sites where fusion between the plasma membrane and granule membranes occurred in activated cells. These results suggest that the heparin-binding sPLA2s bind to the perigranular membranes through their heparin-binding domain, and lysophospholipids produced in situ by their enzymatic action may facilitate the ongoing membrane fusion. In contrast to the redundant role of sPLA2-IIA, -IID, and -V in the regulation of degranulation, only sPLA2-V had the ability to markedly augment IgE/Ag-stimulated immediate PGD2 production, which reached a level comparable to that elicited by cPLA2α. The latter observation reveals an unexplored functional segregation among the three related isozymes expressed in the same cell population.
Eosinophilopoiesis in A Murine Model of Allergic Airway Eosinophilia: Involvement of Bone Marrow IL-5 and IL-5 Receptor α
Authors: Tomaki Masafumi , Zhao Lin-Ling , Lundahl Joachim , Sjöstrand Margareta , Jordana Manel , Lindén Anders , O’Byrne Paul , Lötvall Jan 
Published: April 2014

Abstract
The airway inflammation in asthma is dominated by eosinophils. The aim of this study was to elucidate the contribution of newly produced eosinophils in airway allergic inflammation and to determine mechanisms of any enhanced eosinophilopoiesis. OVA-sensitized BALB/c mice were repeatedly exposed to allergen via airway route. Newly produced cells were identified using a thymidine analog, 5-bromo-2′-deoxyuridine, which is incorporated into DNA during mitosis. Identification of IL-5-producing cells in the bone marrow was performed using FACS. Bone marrow CD3+ cells were enriched to evaluate IL-5-protein release in vitro. Anti-IL-5-treatment (TRFK-5) was given either systemically or directly to the airways. IL-5R-bearing cells were localized by immunocytochemistry. Repeated airway allergen exposure caused prominent airway eosinophilia after three to five exposures, and increased the number of immature eosinophils in the bone marrow. Up to 78% of bronchoalveolar lavage (BAL) granulocytes were 5-bromo-2′-deoxyuridine positive. After three allergen exposures, both CD3+ and non-CD3 cells acquired from the bone marrow expressed and released IL-5-protein. Anti-IL-5 given i.p. inhibited both bone marrow and airway eosinophilia. Intranasal administration of anti-IL-5 also reduced BAL eosinophilia, partly via local effects in the airways. Bone marrow cells, but not BAL eosinophils, displayed stainable amounts of the IL-5R α-chain. We conclude that the bone marrow is activated by airway allergen exposure, and that newly produced eosinophils contribute to a substantial degree to the airway eosinophilia induced by allergen. Airway allergen exposure increases the number of cells expressing IL-5-protein in the bone marrow. The bone marrow, as well as the lung, are possible targets for anti-IL-5-treatment.
Experimentally Induced Recruitment of Plasmacytoid (CD123high) Dendritic Cells in Human Nasal Allergy
Authors: Jahnsen Frode L. , Lund-Johansen Fridtjof , Dunne John F. , Farkas Lorant , Haye Rolf , Brandtzaeg Per 
Published: April 2014

AbstractRecent evidence suggests that the previously enigmatic cell type designated plasmacytoid monocytes can function as dendritic cells and contribute substantially to both innate and adaptive immunity. This cell type has previously been described only in bone marrow, blood, and organized lymphoid tissue, but not at effector sites with direct Ag exposure such as the mucosae. Plasmacytoid dendritic cells (P-DCs) matured in vitro can induce T cells to produce allergy-promoting Th2 cytokines; therefore, their possible occurrence in nasal mucosa during experimentally elicited allergic rhinitis was examined. Patients with silent nasal allergy were challenged topically with relevant allergen daily for 7 days. Biopsy specimens as well as blood samples were obtained before and during such provocation, and P-DCs were identified by their high expression of CD123 (IL-3R α-chain), together with CD45RA. Our results showed that P-DCs were present in low and variable numbers in normal nasal mucosa but increased dramatically during the allergic reaction. This accumulation concurred with the expression of the L-selectin ligand peripheral lymph node addressin on the mucosal vascular endothelium. The latter observation was particularly interesting in view of the high levels of L-selectin on circulating P-DC precursors and of previous reports suggesting that these cells can enter organized lymphoid tissue via high endothelial venules (which express peripheral lymph node addressin constitutively). Together, our findings suggested that P-DCs are involved in the triggering of airway allergy and that they are directed to allergic lesions by adhesion molecules that normally mediate leukocyte extravasation in organized lymphoid tissue.
Eosinophils Maintain Their Capacity to Signal and Release Eosinophil Cationic Protein Upon Repetitive Stimulation with the Same Agonist
Authors: Simon Hans-Uwe , Weber Martina , Becker Eva , Zilberman Yael , Blaser Kurt , Levi-Schaffer Francesca 
Published: April 2014

AbstractEosinophils contain in their granules eosinophil cationic protein (ECP) and other basic proteins that have been implicated in immunity to parasites and pathophysiology of chronic allergic responses. In a model of eosinophil degranulation, we show that eosinophils release ECP upon short-term GM-CSF priming and stimulation with either platelet-activating factor (PAF) or the anaphylatoxin C5a, but not eotaxin. Restimulation with the same agonist (PAF or C5a) was unsuccessful as assessed by monitoring intracellular calcium concentration and ECP release. In contrast, upon an intermediate washing step, eosinophils rapidly transduced PAF and C5a signals followed by significant ECP releases. Ligand-binding studies demonstrated that only a proportion of PAF receptors is internalized upon cell stimulation and that washing of the cells removes the agonist from the cell surface. Upon repetitive stimulation, eosinophils with less than 50% of the original ECP content were obtained. Such eosinophils did not increase cellular ECP levels even in the presence of the eosinophil survival factor GM-CSF in overnight cultures. In vivo studies revealed that eosinophils always express detectable amounts of ECP under chronic inflammatory conditions. In conclusion, we have shown that eosinophils maintain their capacity to degranulate upon repetitive stimulation with the same agonist as long as the receptor is not occupied from a previous stimulation. The cellular content of ECP appears to be a no limiting factor in the case of repetitive stimulation, implying that mature eosinophils may not require a significant ECP resynthesis.
Overexpression of CD1d by Keratinocytes in Psoriasis and CD1d-Dependent IFN-γ Production by NK-T Cells
Authors: Bonish Brian , Jullien Denis , Dutronc Yves , Huang Barbara Bei , Modlin Robert , Spada Franca M. , Porcelli Steven A. , Nickoloff Brian J. 
Published: April 2014

Abstract
The MHC class I-like protein CD1d is a nonpolymorphic molecule that plays a central role in development and activation of a subset of T cells that coexpress receptors used by NK cells (NK-T cells). Recently, T cells bearing NK receptors were identified in acute and chronic lesions of psoriasis. To determine whether NK-T cells could interact with epidermal cells, we examined the pattern of expression of CD1d in normal skin, psoriasis, and related skin disorders, using a panel of CD1d-specific mAbs. CD1d was expressed by keratinocytes in normal skin, although expression was at a relatively low level and was generally confined to upper level keratinocytes immediately beneath the lipid-rich stratum corneum. In contrast, there was overexpression of CD1d in chronic, active psoriatic plaques. CD1d could be rapidly induced on keratinocytes in normal skin by physical trauma that disrupted barrier function or by application of a potent contact-sensitizing agent. Keratinocytes displayed enhanced CD1d following exposure to IFN-γ. Combining CD1d-positive keratinocytes with human NK-T cell clones resulted in clustering of NK-T cells, and while no significant proliferation ensued, NK-T cells became activated to produce large amounts of IFN-γ. We conclude that CD1d can be expressed in a functionally active form by keratinocytes and is up-regulated in psoriasis and other inflammatory dermatoses. The ability of IFN-γ to enhance keratinocyte CD1d expression and the subsequent ability of CD1d-positive keratinocytes to activate NK-T cells to produce IFN-γ, could provide a mechanism that contributes to the pathogenesis of psoriasis and other skin disorders.
Cytokine Dysregulation Induced by Apoptotic Cells Is a Shared Characteristic of Murine Lupus
Authors: Koh Jason S. , Wang Zhiyong , Levine Jerrold S. 
Published: April 2014

AbstractOf the multiple murine models of autoimmunity, the three most closely resembling human systemic lupus erythematosus (SLE) are the MRL/lpr, New Zealand Black/White F1, and male BXSB. Although these strains share many disease characteristics, no common cellular defect has previously been found in prediseased mice from all these strains. We show in this study that macrophages from prediseased mice of all three SLE-prone strains, as well as macrophages from mice whose genomes contribute to the development of SLE (MRL/+, New Zealand White, New Zealand Black, female BXSB, and LG/J), have an identical and profound defect in cytokine expression that is triggered by apoptotic cells. Strikingly, none of 13 nonautoimmune strains tested exhibited this defect. Given that apoptotic Ags have been increasingly recognized as the target of autoantibodies, a defect in cytokine expression that is triggered by apoptotic cells has broad potential to upset the balance between tolerance and immunity.
The Effects of Prolonged Administration of 5-Bromodeoxyuridine on Cells of the Immune System
Authors: Reome Joyce B. , Johnston Darrin S. , Helmich Brian K. , Morgan Tammy M. , Dutton-Swain Nicholas , Dutton Richard W. 
Published: April 2014

AbstractWe have determined the in vivo effect of 5-bromodeoxyuridine (BrdU) administered to mice in the drinking water for various lengths of time on the performance of T and B lymphocytes in a number of experimental protocols. Young mice continuously exposed to BrdU fail to gain weight, and the lymphocytes recovered after a prolonged period of exposure are fewer in number than in control mice. The recovery of normal levels of T and B lymphocytes after irradiation is severely impaired. Ag-specific cells responding to Ag in an adoptive transfer model fail to expand as much in the presence of BrdU as in the absence, and the Ag-specific effectors produced in the presence of BrdU are less able to secrete cytokines upon restimulation in vitro. Polarized populations of Tc1 and Tc2 effectors generated in vitro proliferate less in the presence of BrdU, and the resulting effectors make less cytokines per cell upon restimulation. Thus, the incorporation of BrdU into T or B lymphocytes can, under some circumstances, seriously impair the performance of the labeled cells, and these findings raise a note of caution in the interpretation of studies that make use of long-term exposure to BrdU.
Immortalization of Human CD8+ T Cell Clones by Ectopic Expression of Telomerase Reverse Transcriptase
Authors: Hooijberg Erik , Ruizendaal Janneke J. , Snijders Peter J. F. , Kueter Esther W. M. , Walboomers Jan M. M. , Spits Hergen 
Published: April 2014

AbstractReplicative senescence of T cells is correlated with erosion of telomere ends. Telomerase plays a key role in maintaining telomere length. Therefore, it is thought that telomerase regulates the life span of T cells. To test this hypothesis, we have over-expressed human telomerase reverse transcriptase in human CD8+ T cells. Ectopic expression of human telomerase reverse transcriptase led to immortalization of these T cells, without altering the phenotype and without loss of specificity or functionality. As the T cells remained dependent on cytokines and Ag stimulation for their in vitro expansion, we conclude that immortalization was achieved without malignant transformation.
Divergent Response to LPS and Bacteria in CD14-Deficient Murine Macrophages
Authors: Moore Kathryn J. , Andersson Lorna P. , Ingalls Robin R. , Monks Brian G. , Li Rui , Arnaout M. Amin , Golenbock Douglas T. , Freeman Mason W. 
Published: April 2014

AbstractGram-negative bacteria and the LPS constituent of their outer membranes stimulate the release of inflammatory mediators believed to be responsible for the clinical manifestations of septic shock. The GPI-linked membrane protein, CD14, initiates the signaling cascade responsible for the induction of this inflammatory response by LPS. In this paper, we report the generation and characterization of CD14-null mice in which the entire coding region of CD14 was deleted. As expected, LPS failed to elicit TNF-α and IL-6 production in macrophages taken from these animals, and this loss in responsiveness is associated with impaired activation of both the NF-κB and the c-Jun N-terminal mitogen-activated protein kinase pathways. The binding and uptake of heat-killed Escherichia coli, measured by FACS analysis, did not differ between CD14-null and wild-type macrophages. However, in contrast to the findings with LPS, whole E. coli stimulated similar levels of TNF-α release from CD14-null and wild-type macrophages at a dose of 10 bioparticles per cell. This effect was dose dependent, and at lower bacterial concentrations CD14-deficient macrophages produced significantly less TNF-α than wild type. Approximately half of this CD14-independent response appeared to be mediated by CD11b/CD18, as demonstrated by receptor blockade using neutrophil inhibitory factor. An inhibitor of phagocytosis, cytochalasin B, abrogated the induction of TNF-α in CD14-deficient macrophages by E. coli. These data indicate that CD14 is essential for macrophage responses to free LPS, whereas other receptors, including CD11b/CD18, can compensate for the loss of CD14 in response to whole bacteria.
Selective Bystander Proliferation of Memory CD4+ and CD8+ T Cells Upon NK T or T Cell Activation
Authors: Eberl Gérard , Brawand Pierre , MacDonald H. Robson 
Published: April 2014

AbstractAg-experienced or memory T cells have increased reactivity to recall Ag, and can be distinguished from naive T cells by altered expression of surface markers such as CD44. Memory T cells have a high turnover rate, and CD8+ memory T cells proliferate upon viral infection, in the presence of IFN-αβ and/or IL-15. In this study, we extend these findings by showing that activated NKT cells and superantigen-activated T cells induce extensive bystander proliferation of both CD8+ and CD4+ memory T cells. Moreover, proliferation of memory T cells can be induced by an IFN-αβ-independent, but IFN-γ- or IL-12-dependent pathway. In these conditions of bystander activation, proliferating memory (CD44high) T cells do not derive from activation of naive (CD44low) T cells, but rather from bona fide memory CD44high T cells. Together, these data demonstrate that distinct pathways can induce bystander proliferation of memory T cells.
IL-15 and IL-15 Receptor Selectively Regulate Differentiation of Common Mucosal Immune System-Independent B-1 Cells for IgA Responses
Authors: Hiroi Takachika , Yanagita Manabu , Ohta Noriyuki , Sakaue Gaku , Kiyono Hiroshi 
Published: April 2014

AbstractWe show in this report a new regulatory role for IL-15 and IL-15R in the development of B-1 cells and their differentiation into IgA-producing cells. Mucosal IgA levels were found to be inhibited by anti-IL-15 mAb treatment in vivo, but enhanced by administration of rIL-15, while serum IgA levels remained unaffected. Mucosal B-1 cells preferentially proliferated in response to IL-15 in vitro. When mucosal B-1 and B-2 cells were separated into surface (s)IgM+sIgA− and sIgM−sIgA+ fractions, IL-15R-specific mRNA was found to be predominant in both sIgM+sIgA− and sIgM−sIgA+ B-1 cells at a much higher level than B-2 cells. Further, incubation of these different subsets of B-1 and B-2 cells with IL-15 resulted in greater enhancement of the corresponding receptor expression by B-1 subset when compared with B-2 fraction. Interestingly, de novo isolated sIgM+sIgA− B-1, but not sIgM+sIgA− B-2, cells were already class-switched cells because the germline Cα transcript was detected and was then further enhanced by IL-15. IL-15 also supported differentiation of both sIgM+sIgA− and sIgM−sIgA+ B-1 cells into IgA-producing cells. Taken together, these findings suggest that IL-15 is a critically important cytokine for the differentiation of both sIgM+,IgA− and sIgM−sIgA+ B-1 cells expressing IL-15R into IgA-producing cells in mucosal tissues.
Macrophage-Derived Dendritic Cells Have Strong Th1-Polarizing Potential Mediated by β-Chemokines Rather Than IL-12
Authors: Zou Weiping , Borvak Jozef , Marches Florentina , Wei Shuang , Galanaud Pierre , Emilie Dominique , Curiel Tyler J. 
Published: April 2014

AbstractMonocyte-derived dendritic cells (MDDCs) activate naive T lymphocytes to induce adaptive immunity, effecting Th1 polarization through IL-12. However, little is known about other potential DC Th1 polarizing mechanisms, or how T cell polarization may be affected by DCs differentiating in, or exposed to, a proinflammatory environment. Macrophages (MΦs) are DC precursors abundant in inflamed tissues, lymph nodes, and tumors. Thus we studied the T cell-activating and -polarizing properties of MΦ-derived DCs (ΦDCs). Monocytes were cultured in MΦ-CSF (M-CSF) to produce MΦs, which were then differentiated into DCs following culture with GM-CSF plus IL-4. ΦDCs activated a significant allogeneic MLR and were significantly better than MDDCs in activating T cells with superantigen. Most strikingly, ΦDCs elicited up to 9-fold more IFN-γ from naive or Ag-specific T cells compared with MDDCs (with equivalent IL-4 secretion), despite producing up to 9-fold less IL-12. Neutralization of MDDC, but not ΦDC IL-12 significantly inhibited T cell IFN-γ induction. ΦDCs produced up to 12-fold more β-chemokines (macrophage-inflammatory protein-1α, -1β, and RANTES) than MDDCs. Ab blockade of CCR5, but not CXC chemokine receptor 4, inhibited T cell IFN-γ induction by ΦDCs significantly greater than by MDDCs. Thus DCs differentiating from MΦs induce T cell IFN-γ through β-chemokines with little or no requirement for IL-12. Myeloid DCs arising from distinct precursor cells may have differing properties, including different mechanisms of Th1 polarization. These data are the first reports of IFN-γ induction through chemokines by DCs.
Reciprocal Expression of the TNF Family Receptor Herpes Virus Entry Mediator and Its Ligand LIGHT on Activated T Cells: LIGHT Down-Regulates Its Own Receptor
Authors: Morel Yannis , Schiano de Colella Jean-Marc , Harrop Jeremy , Deen Keith C. , Holmes Stephen D. , Wattam Trevor A. , Khandekar Sanjay S. , Truneh Alemseged , Sweet Raymond W. , Gastaut Jean-Albert , Olive Daniel , Costello Régis T. 
Published: April 2014

AbstractThe TNF receptor (TNFR) family plays a central role in the development of the immune response. Here we describe the reciprocal regulation of the recently identified TNFR superfamily member herpes virus entry mediator (HVEM) (TR2) and its ligand LIGHT (TL4) on T cells following activation and the mechanism of this process. T cell activation resulted in down-regulation of HVEM and up-regulation of LIGHT, which were both more pronounced in CD8+ than CD4+ T lymphocytes. The analysis of HVEM and LIGHT mRNA showed an increase in the steady state level of both mRNAs following stimulation. LIGHT, which was present in cytoplasm of resting T cells, was induced both in cytoplasm and at the cell surface. For HVEM, activation resulted in cellular redistribution, with its disappearance from cell surface. HVEM down-regulation did not rely on de novo protein synthesis, in contrast to the partial dependence of LIGHT induction. Matrix metalloproteinase inhibitors did not modify HVEM expression, but did enhance LIGHT accumulation at the cell surface. However, HVEM down-regulation was partially blocked by a neutralizing mAb to LIGHT or an HVEM-Fc fusion protein during activation. As a model, we propose that following stimulation, membrane or secreted LIGHT binds to HVEM and induces receptor down-regulation. Degradation or release of LIGHT by matrix metalloproteinases then contributes to the return to baseline levels for both LIGHT and HVEM. These results reveal a self-regulating ligand/receptor system that contributes to T cell activation through the interaction of T cells with each other and probably with other cells of the immune system.