bluuebunny/crossref_metadata_2025_split huggingface dataset:
CpG Oligonucleotides Can Prophylactically Immunize Against Th2-Mediated Schistosome Egg-Induced Pathology by an IL-12-Independent Mechanism
Authors: Chiaramonte Mónica G. , Hesse Matthias , Cheever Allen W. , Wynn Thomas A. 
Published: April 2014

AbstractUsing a Schistosoma mansoni egg-induced granuloma model, we examined the ability of CpG oligodeoxynucleotides (ODN) to suppress Th2-type cytokine expression and to prophylactically immunize against Th2-dependent pulmonary pathology. The mechanism was examined by studying Th2 response regulation in cytokine-deficient mice. Surprisingly, our findings revealed several functions of CpG DNA that were completely IL-12 independent. Most striking was the marked suppression in Th2 cytokine expression and granulomatous inflammation observed in egg/CpG-sensitized IL-12-deficient mice. Immune deviation was not dependent on NK or B cells. However, a role for IL-10, B7.1, and CD40 expression in Th2 response inhibition was suggested. Indeed, CpG ODN up-regulated all three elements in both wild-type and IL-12-deficient mice. The role of IL-10 was demonstrated in mice exhibiting combined deficiencies in IL-12 and IL-10. Here, a marked increase in egg-specific IL-4/IL-5-producing cells confirmed a role for both cytokines in Th2 response inhibition. Nevertheless, the frequency of Th2-producing cells was again reduced by CpG ODN. However, in marked contrast to IL-12-deficient animals, a significant increase in IFN-γ-producing cells likely explains the reduced Th2 response in IL-10/IL-12-deficient mice. Thus, a novel IL-12-independent type 1-inducing pathway was revealed in the combined absence of IL-12 and IL-10. Together, these data demonstrate 1) that the Th1-promoting activity of CpG DNA is controlled by IL-12 and IL-10, and 2) that Th2 response inhibition by CpG ODN involves IL-12-independent changes in IL-10 and costimulatory molecule expression. These findings illustrate the utility of CpG DNA as adjuvants for vaccines designed to prevent Th2-dependent immunopathology.
Characterization of CD4+ T Cell Responses During Natural Infection with Salmonella typhimurium
Authors: McSorley Stephen J. , Cookson Brad T. , Jenkins Marc K. 
Published: April 2014

Abstract
CD4+ T cells are important for resistance to infection with Salmonella typhimurium. However, the Ag specificity of this T cell response is unknown. Here, we demonstrate that a significant fraction of Salmonella-specific CD4+ T cells respond to the flagellar filament protein, FliC, and that this Ag has the capacity to protect naive mice from lethal Salmonella infection. To characterize this Ag-specific response further, we generated FliC-specific CD4+ T cell clones from mice that had resolved infection with an attenuated strain of Salmonella. These clones were found to respond to an epitope from a constant region of FliC, enabling them to cross-react with flagellar proteins expressed by a number of distinct Salmonella serovars.
Compartmental Differences in NK Cell Responsiveness to IL-12 During Lymphocytic Choriomeningitis Virus Infection
Authors: Pien Gary C. , Biron Christine A. 
Published: April 2014

Abstract
Some, but not all, viral infections induce endogenous IL-12 to drive NK cell IFN-γ production and downstream antiviral defenses during innate immune responses. Even though lymphocytic choriomeningitis virus (LCMV) can be sensitive to IFN-γ-mediated antiviral effects, infections with this agent do not elicit IL-12 or early IFN-γ in immunocompetent hosts. Studies presented here demonstrate that LCMV infections of mice not only fail to induce IL-12, but also modify responsiveness to exogenous IL-12 for IFN-γ production. IFN-γ responses induced by IL-12 administration were greatly diminished in splenic populations, but significantly increased in serum and hepatic leukocytes, during the early course of LCMV infections. The IFN-γ production was NK cell dependent, and the compartmental dichotomy between spleen and liver was also demonstrated in response to in vitro IL-12 stimulation. Although infections did increase proportions and numbers of liver NK cells, changes in responsiveness for IFN-γ expression could not be explained by cell redistribution. Corroborating changes in proportions of NK cells induced to express intracellular IFN-γ protein within the compartments were observed. The reduction in ability of splenic populations to produce IL-12-induced IFN-γ after infection by LCMV was associated with decreased efficacy of administered IL-12 for promoting IFN-γ-dependent antiviral effects in the spleen. Concomitantly, the maintenance of hepatic population IFN-γ production was associated with preserved efficacy of administered IL-12 to elicit IFN-γ-dependent antiviral effects in the liver. Taken together, these results demonstrate modifications of compartmental responses to IL-12 by viral infections and the consequences of these changes for efficacy of cytokine therapy.
Disruption of T Cell Tolerance to Self-Immunoglobulin Causes Polyclonal B Cell Stimulation Followed by Inactivation of Responding Autoreactive T Cells
Authors: Choudhury Arpita , Mukherjee Paushali , Basu Sandip K. , George Anna , Rath Satyajit , Bal Vineeta 
Published: April 2014

Abstract
Scavenger receptor (SR)-specific delivery by maleylation of a ubiquitous self-protein, Ig, to SR-bearing APCs results in self-limiting induction of autoimmune effects in vivo. Immunization with maleyl-Ig breaks T cell tolerance to self-Ig and causes hypergammaglobulinemia, with increases in spleen weight and cellularity. The majority of splenic B cells show an activated phenotype upon maleyl-Ig immunization, leading to large-scale conversion to a CD138+ phenotype and to significant increases in CD138-expressing splenic plasma cells. The polyclonal B cell activation, hypergammaglobulinemia, and autoreactive Ig-specific T cell responses decline over a 2-mo period postimmunization. Following adoptive transfer, T cells from maleyl-Ig-immune mice taken at 2 wk postimmunization can induce hypergammaglobulinemia in the recipients, but those taken at 10 wk postimmunization cannot. Hypergammaglobulinemia in the adoptive transfer recipients is also transient and is followed by an inability to respond to fresh maleyl-Ig immunization, suggesting that the autoreactive Ig-specific T cells are inactivated peripherally following disruption of tolerance. Thus, although autoreactive T cell responses to a ubiquitous self-Ag, Ig, are induced by SR-mediated delivery to professional APCs in vivo resulting in autoimmune pathophysiological effects, they are effectively and rapidly turned off by inactivation of these activated Ig-specific T cells in vivo.
Inhibition of IL-12 Production in Human Monocyte-Derived Macrophages by TNF
Authors: Ma Xiaojing , Sun Junwei , Papasavvas Emmanouil , Riemann Helge , Robertson Susan , Marshall Jason , Bailer Robert T. , Moore Anne , Donnelly Raymond P. , Trinchieri Giorgio , Montaner Luis J. 
Published: April 2014

Abstract
IL-12 is a pivotal cytokine that links the innate and adaptive immune responses. TNF-α also plays a key role in orchestrating inflammation and immunity. The reciprocal influence of these two inflammatory mediators on each other may have significant impact on the cytokine balance that shapes the type and extent of immune responses. To investigate the relationship between TNF-α and IL-12 production, we analyzed the effects of exposure of human monocyte-derived macrophages to TNF-α on LPS- or Staphylococcus aureus-induced IL-12 production in the presence or absence of IFN-γ. TNF-α is a potent inhibitor of IL-12 p40 and p70 secretion from human macrophages induced by LPS or S. aureus. IL-10 is not responsible for the TNF-α-mediated inhibition of IL-12. TNF-α selectively inhibits IL-12 p40 steady-state mRNA, but not those of IL-12 p35, IL-1α, IL-1β, or IL-6. Nuclear run-on analysis identified this specific inhibitory effect at the transcriptional level for IL-12 p40 without down-regulation of the IL-12 p35 gene. The major transcriptional factors identified to be involved in the regulation of IL-12 p40 gene expression by LPS and IFN-γ, i.e., c-Rel, NF-κB p50 and p65, IFN regulatory factor-1, and ets-2, were not affected by TNF-α when examined by nuclear translocation and DNA binding. These data demonstrate a selective negative regulation on IL-12 by TNF-α, identifying a direct negative feedback mechanism for inflammation-induced suppression of IL-12 gene expression.
TCR-Independent Activation of Extrathymically Developed, Self Antigen-Specific T Cells by IL-2/IL-15
Authors: Yamada Hisakata , Nakamura Takahiko , Matsuzaki Goro , Iwamoto Yukihide , Nomoto Kikuo 
Published: April 2014

AbstractNaive intrathymically developed T cells, which express foreign Ag-specific TCR, do not express IL-2R. After antigenic stimulation, they express high affinity IL-2R, which enables IL-2 to be used as an autocrine growth factor. On the contrary, extrathymically developed T cells, which express self Ag-specific TCR but are unresponsive to antigenic stimulation, spontaneously express low affinity IL-2R. In this study, we compared the responses of these two subsets of T cells to IL-2R stimulation and examined the influences of TCR-mediated signaling on the responses. IL-2 or IL-15 augmented the proliferative response of Ag-stimulated, intrathymically developed T cells. On the other hand, extrathymically developed T cells proliferated in response to IL-2 or IL-15, independently of Ag stimulation. Furthermore, both IL-2 and IL-15 induced IFN-γ production of these T cells, which is strikingly augmented by the presence of IL-12. These results revealed functional differences between intrathymically developed, foreign Ag-specific T cells and extrathymically developed, self Ag-specific T cells. The latter can be activated by some inflammatory cytokines, in an Ag-independent manner, similar to NK cells.
Signals from the IL-9 Receptor Are Critical for the Early Stages of Human Intrathymic T Cell Development
Authors: De Smedt Magda , Verhasselt Bruno , Kerre Tessa , Vanhecke Dominique , Naessens Evelien , Leclercq Georges , Renauld Jean-Christophe , Van Snick Jacques , Plum Jean 
Published: April 2014

Abstract
Highly purified human CD34+ hemopoietic precursor cells differentiate into mature T cells when seeded in vitro in isolated fetal thymic lobes of SCID mice followed by fetal thymus organ culture (FTOC). Here, this chimeric human-mouse FTOC was used to address the role of IL-9 and of the α-chain of the IL-9 receptor (IL-9Rα) in early human T cell development. We report that addition of the mAb AH9R7, which recognizes and blocks selectively the human high affinity α-chain of the IL-9R, results in a profound reduction of the number of human thymocytes. Analysis of lymphoid subpopulations indicates that a highly reduced number of cells undergo maturation from CD34+ precursor cells toward CD4+CD3−CD8−CD1+ progenitor cells and subsequently toward CD4+CD8+ double positive (DP) thymocytes. Addition of IL-9 to the FTOC resulted in an increase in cell number, without disturbing the frequencies of the different subsets. These data suggest that IL-9Rα signaling is critical in early T lymphoid development.
Ly49I NK Cell Receptor Transgene Inhibition of Rejection of H2b Mouse Bone Marrow Transplants
Authors: Liu Jingxuan , Morris Margaret A. , Nguyen Paul , George Thaddeus C. , Koulich Elena , Lai Wayne C. , Schatzle John D. , Kumar Vinay , Bennett Michael 
Published: April 2014

Abstract
The Ly49 family of genes encode NK cell receptors that bind class I MHC Ags and transmit negative signals if the cytoplasmic domains have immunoregulatory tyrosine-based inhibitory motifs (ITIMs). 5E6 mAbs recognize Ly49C and Ly49I receptors and depletion of 5E6+ NK cells prevents rejection of allogeneic or parental-strain H2d bone marrow cell (BMC) grafts. To determine the function of the Ly49I gene in the rejection of BMC grafts, we transfected fertilized eggs of FVB mice with a vector containing DNA for B6 strain Ly49I (Ly49IB6). Ly49IB6 is ITIM+ and is recognized by 5E6 as well as Ly49I-specific 8H7 mAbs. Normal FVB H2q mice reject H2b but not H2d BMC allografts, and the rejection of H2b BMC was inhibited partially by anti-NK1.1 and completely by anti-asialo GM1, but not by anti-CD8, Abs. In FVB mice, NK1.1 is expressed on only 60% NK cells. FVB.Ly49IB6 hosts failed to reject H2d or H2b BMC, but did reject class I-deficient TAP-1−/− BMC, indicating that NK cells were functional. Nondepleting doses of anti-Ly49I Abs reversed the acceptance of H2b BMC by FVB.Ly49IB6 mice. FVB.Ly49IB6+/− mice were crossed and back-crossed with 129 mice—H2b, 5E6−, poor responders to H2d BMC grafts. While transgene-negative H2b/q F1 or first-generation back-crossed mice rejected H2b marrow grafts (hybrid resistance), transgene-positive mice did not. Thus B6 strain Ly49I receptors transmit inhibitory signals from H2b MHC class I molecules. Moreover, Ly49IB6 has no positive influence on the rejection of H2d allografts.
The Balance of Protein Kinase C and Calcium Signaling Directs T Cell Subset Development
Authors: Noble Alistair , Truman Jean Philip , Vyas Beejal , Vukmanovic-Stejic Milica , Hirst William J. , Michael Kemeny David 
Published: April 2014

AbstractDevelopment of naive T cells into type 1 (Th1, Tc1) or type 2 (Th2, Tc2) effector cells is thought to be under the control of cytokines. In this study, we show that when both IL-12 and IL-4 are present, murine and human T cell differentiation is regulated by the balance of protein kinase C (PKC) and calcium signaling within T cells. Although both biochemical signals were required for T cell activation via the TCR, altering the balance between them redirected type 1 cells to type 2 and vice versa. Stimulation of calcium signaling or inhibition of PKC favored type 1 differentiation, whereas stimulation of PKC or inhibition of calcineurin resulted in type 2 effectors. Altered peptide ligands induced distinct balances of PKC/calcium signaling and altered Tc1/Tc2 development in TCR-transgenic CD8 T cells. The data suggest novel strategies for manipulation of the immune response in vivo.
Abrogation of CTL Epitope Processing by Single Amino Acid Substitution Flanking the C-Terminal Proteasome Cleavage Site
Authors: Beekman Nico J. , van Veelen Peter A. , van Hall Thorbald , Neisig Anne , Sijts Alice , Camps Marcel , Kloetzel Peter-M. , Neefjes Jacques J. , Melief Cornelis J. , Ossendorp Ferry 
Published: April 2014

Abstract
CTL directed against the Moloney murine leukemia virus (MuLV) epitope SSWDFITV recognize Moloney MuLV-induced tumor cells, but do not recognize cells transformed by the closely related Friend MuLV. The potential Friend MuLV epitope has strong sequence homology with Moloney MuLV and only differs in one amino acid within the CTL epitope and one amino acid just outside the epitope. We now show that failure to recognize Friend MuLV-transformed tumor cells is based on a defect in proteasome-mediated processing of the Friend epitope which is due to a single amino acid substitution (N→D) immediately flanking the C-terminal anchor residue of the epitope. Proteasome-mediated digestion analysis of a synthetic 26-mer peptide derived from the Friend sequence shows that cleavage takes place predominantly C-terminal of D, instead of V as is the case for the Moloney MuLV sequence. Therefore, the C terminus of the epitope is not properly generated. Epitope-containing peptide fragments extended with an additional C-terminal D are not efficiently translocated by TAP and do not show significant binding affinity to MHC class I-Kb molecules. Thus, a potential CTL epitope present in the Friend virus sequence is not properly processed and presented because of a natural flanking aspartic acid that obliterates the correct C-terminal cleavage site. This constitutes a novel way to subvert proteasome-mediated generation of proper antigenic peptide fragments.
The Tumor Suppressor PTEN Regulates T Cell Survival and Antigen Receptor Signaling by Acting as a Phosphatidylinositol 3-Phosphatase
Authors: Wang Xiaodong , Gjörloff-Wingren Anette , Saxena Manju , Pathan Nuzhat , Reed John C. , Mustelin Tomas 
Published: April 2014

Abstract
The tumor suppressor gene PTEN encodes a 55-kDa enzyme that hydrolyzes both protein phosphotyrosyl and 3-phosphorylated inositol phospholipids in vitro. We have found that the latter activity is physiologically relevant in intact T cells. Expression of active PTEN lead to a 50% loss of transfected cells due to increased apoptosis, which was completely prevented by coexpression of a constitutively active, membrane-bound form of protein kinase B. A mutant of PTEN selectively lacking lipid phosphatase activity, but retaining protein phosphatase activity, had no effects on cell number. Active (but not mutant) PTEN also decreased TCR-induced activation of the mitogen-activated protein kinase ERK2 (extracellular signal-related kinase 2), as seen after inhibition of phosphatidylinositol 3-kinase. Our data indicate that PTEN is a phosphatidylinositol 3-phosphatase in T cells, and we suggest that PTEN may play a role in the regulation of T cell survival and TCR signaling by directly opposing phosphatidylinositol 3-kinase.
A Prominent Role for Sp1 During Lipopolysaccharide- Mediated Induction of the IL-10 Promoter in Macrophages
Authors: Brightbill Hans D. , Plevy Scott E. , Modlin Robert L. , Smale Stephen T. 
Published: April 2014

Abstract
IL-10 is an antiinflammatory cytokine secreted by activated macrophages and Th2 cells. IL-10 secretion promotes the down-regulation of proinflammatory cytokine synthesis and the development of Th2 responses. In macrophages, proinflammatory cytokines appear to be induced by similar mechanisms, but the IL-10 induction mechanisms have not been examined. We have analyzed the murine IL-10 promoter in the RAW264.7 macrophage line activated with LPS. A comprehensive mutant analysis revealed only one element upstream of the core promoter that was essential for promoter induction. A refined mutant analysis localized this element to nucleotides −89 to −78, and gel shift experiments revealed that it represents a nonconsensus binding site for Sp1. The functional relevance of Sp1 was supported by the high affinity of the interaction, the close correlation between the nucleotides required for Sp1 binding and promoter function, and the ability of an Sp1 consensus sequence to substitute for the −89/−78 promoter sequence. Evidence that Sp1 may be a target of signaling pathways involved in IL-10 induction was provided by the exclusive requirement for the Sp1 binding site, by the ability of the Sp1 site to confer induction to a heterologous promoter, and by the delineation of an Sp1 domain that can mediate induction. No relevant contribution from Rel, C/EBP (CCAAT/enhancer-binding protein), or AP-1 binding sites, which regulate most proinflammatory cytokine promoters, was observed. Together, these results demonstrate that IL-10 gene regulation is distinct from the regulation of proinflammatory cytokine genes, and suggest that Sp1 may be a central mediator of IL-10 induction.
Role of Tumor Cell Apoptosis in Tumor Antigen Migration to the Draining Lymph Nodes
Authors: Bonnotte Bernard , Favre Nathalie , Moutet Monique , Fromentin Annie , Solary Eric , Martin Monique , Martin François 
Published: April 2014

Abstract
Establishment of an immune response against cancer may depend on the capacity of dendritic cells to transfer tumor Ags into T cell-rich areas. To check this possibility, we used a colon cancer cell variant that yields tumors undergoing complete T cell-dependent rejection when injected into syngeneic rats. We previously demonstrated that immunogenicity of these tumors depended on the early apoptosis of a part of these tumor cells. In this paper we show that fluorescent tumor cell proteins are released from FITC-labeled tumor cells and undergo engulfment by tumor-infiltrating monocytes without a phenotype of mature dendritic cells or macrophages. Fluorescence-labeled mononuclear cells with a phenotype of MHC class II+ dendritic cells are also found in the T cell areas of the draining lymph nodes. Interestingly, no fluorescent cell can be found in lymph nodes after a s.c. injection of Bcl2-transfected apoptosis-resistant tumor cells that yielded progressive tumors. Proliferation of tumor-immune T lymphocytes was induced by dendritic cells isolated from the draining lymph nodes recovered after a s.c. injection of apoptosis-sensitive, but not apoptosis-resistant, tumor cells. These results show that tumor cell apoptosis releases proteins that are engulfed by inflammatory cells in the tumor, then transported to lymph node T cell areas where they can induce a specific immune response leading to tumor rejection.
TGF-β Mediates CTLA-4 Suppression of Cellular Immunity in Murine Kalaazar
Authors: Gomes Nitza A. , Gattass Cerli R. , Barreto-de-Souza Victor , Wilson Mary E. , DosReis George A. 
Published: April 2014

AbstractRecent studies indicate important roles for CTLA-4 engagement in T cells, and for TGF-β production in the immunopathogenesis of murine kalaazar or visceral leishmaniasis, but a functional link between these two pathways in helping intracellular parasite growth is unknown. Here we report that Ag or anti-CD3 activation of splenic CD4+ T cells from visceral leishmaniasis leads to intense CTLA-4-mediated TGF-β1 production, as assessed either by CTLA-4 blockade or by direct CTLA-4 cross-linkage. Production of TGF-β1 accounted for the reciprocal regulation of IFN-γ production by CTLA-4 engagement. Following CD4+ T cell activation, intracellular growth of Leishmania chagasi in cocultured splenic macrophages required both CTLA-4 function and TGF-β1 secretion. Cross-linkage of CTLA-4 markedly increased L. chagasi replication in cocultures of infected macrophages and activated CD4+ T cells, and parasite growth could be completely blocked with neutralizing anti-TGF-β1 Ab. Exogenous addition of rTGF-β1 restored parasite growth in cultures protected from parasitism by CTLA-4 blockade. These results indicate that the negative costimulatory receptor CTLA-4 is critically involved in TGF-β production and in intracellular parasite replication seen in murine kalaazar.
Lipopolysaccharide Induces Actin Reorganization and Tyrosine Phosphorylation of Pyk2 and Paxillin in Monocytes and Macrophages
Authors: Williams Lynn M. , Ridley Anne J. 
Published: April 2014

Abstract
The bacterial endotoxin LPS is a potent stimulator of monocyte and macrophage activation and induces adhesion of monocytes. Morphological changes in response to LPS have not been characterized in detail, however, nor have the signaling pathways mediating LPS-induced adhesion been elucidated. We have found that LPS rapidly induced adhesion and spreading of peripheral blood monocytes, and that this was inhibited by the Src family kinase inhibitor PP1 and the phosphatidylinositide 3-kinase inhibitor LY294002. LPS also stimulated actin reorganization, leading to the formation of filopodia, lamellipodia, and membrane ruffles in Bac1 mouse macrophages. Proline-rich tyrosine kinase 2 (Pyk2), a tyrosine kinase related to focal adhesion kinase, and paxillin, a cytoskeletal protein that interacts with Pyk2, were both tyrosine phosphorylated in response to LPS in monocytes and macrophages. Both tyrosine phosphorylation events were inhibited by PP1 and LY294002. Adhesion also stimulated tyrosine phosphorylation of Pyk2 and paxillin in monocytes, and this was further enhanced by LPS. Finally, Pyk2 and paxillin colocalized within membrane ruffles in LPS-stimulated cells. These results indicate that LPS stimulation of monocytes and macrophages results in rapid morphological changes and suggest that Pyk2 and/or paxillin play a role in this response.