bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Schistosome-Expressed Immunomodulatory Glycoconjugate Expands Peritoneal Gr1+ Macrophages That Suppress Naive CD4+ T Cell Proliferation Via an IFN-γ and Nitric Oxide-Dependent Mechanism
Authors: Atochina Olga , Daly-Engel Toby , Piskorska Danuta , McGuire Edward , Harn Donald A. 
Published: April 2014

Abstract
Lacto-N-fucopentaose III (LNFPIII) is found in human milk and on the Th2 driving helminth parasite Schistosoma mansoni. This pentasaccharide drives Th2-type responses in vivo and in vitro when conjugated to a carrier. In an attempt to further understand early events in Th1 to Th2 switching, we examined phenotypic and functional changes in peritoneal cell populations in BALB/c and SCID mice following LNFPIII-dextran injection. We found that i.p. injection with LNFPIII-dextran resulted in rapid (&lt;20 h) expansion of the Gr1+ subpopulation of F4/80+/CD11b+ peritoneal cells, comprising up to 75% of F4/80+/CD11b+ peritoneal cells compared with 18% in uninjected or dextran-injected mice. Functionally, these cells suppressed anti-CD3- and anti-CD28-induced proliferation of naive CD4+ T cells. LNFPIII-dextran also expanded functional Gr1+ suppressor macrophages in SCID mice, demonstrating that expansion and function of suppressor cells did not require T cells. Suppression in both BALB/c and SCID mice was NO and IFN-γ dependent, as addition of inhibitors of inducible NO synthase (NG-monomethyl-l-arginine), as well as anti-IFN-γ Abs, restored the ability of CD4+ T cells to proliferate in vitro. Depletion of the F4/80+ subset of Gr1+ cells eliminated the suppressive activity of peritoneal exudate cells showing that these cells were macrophages. Thus, LNFPIII-dextran rapidly expands the Gr1+ suppressor macrophage population in the peritoneal cavities of otherwise naive mice. These Gr1+ cells suppress proliferation of naive CD4+ T cells in an NO-dependent mechanism, and may play a regulatory role in the switching of Th1- to Th2-type responses.
βc Cytokine Receptor-Induced Stimulation of cAMP Response Element Binding Protein Phosphorylation Requires Protein Kinase C In Myeloid Cells: A Novel Cytokine Signal Transduction Cascade
Authors: Gubina Elaina , Luo Xu , Kwon E. , Sakamoto Kathleen , Shi Yu Fang , Mufson R. Allan 
Published: April 2014

Abstract
We have recently shown that IL-3R occupancy activates a phosphatidylcholine-specific phospholipase C, and the sustained diacylglycerol accumulation subsequently activates protein kinase C (PKC). In human IL-3-dependent myeloid cells (TF-1), the novel PKCε isoform regulates bcl-2 expression and cell survival. The report of a PKC activatable cAMP response element (CRE) in the bcl-2 promoter and a role for PKC in bcl-2 expression in B cells led us to the hypothesis that PKC phosphorylation activates transcription factor CREB after IL-3R engagement. We found that IL-3 and GM-CSF induced phosphorylation of CREB on Ser133 in TF-1 cells, and this phosphorylation was blocked by two structurally unrelated classes of PKC inhibitors. An inhibitor of cyclic nucleotide-dependent kinases did not block this phosphorylation. IL-4, which is biologically active in these cells but does not use the β common subunit, did not phosphorylate CREB on Ser133. Inhibition of mitogen-activated protein kinase kinase activity also inhibited IL3-induced CREB phosphorylation. The PKC inhibitors, but not a cyclic nucleotide-dependent kinase inhibitor, blocked IL-3 activation of CRE-dependent transcription from an egr-1 promoter/chloramphenicol acetyltransferase (CAT) reporter construction transiently transfected into TF-1 cells. Finally, TF-1 cells stably overexpressing PKCε, but not the δ isoform of PKC, enhanced CRE-dependent CAT expression from the promoter/reporter construction. Therefore, it is likely that a PKCε kinase cascade resulting in CREB phosphorylation represents a novel signal transduction cascade for regulating cellular gene expression through the β common cytokine receptor.
CD4 Promotes Breadth in the TCR Repertoire
Authors: Wang Qi , Malherbe Laurent , Zhang DongJi , Zingler Kurt , Glaichenhaus Nicolas , Killeen Nigel 
Published: April 2014

Abstract
A diverse population of MHC class II-restricted CD4 lineage T cells develops in mice that lack expression of the CD4 molecule. In this study, we show that the TCR repertoire selected in the absence of CD4 is distinct, but still overlapping in its properties with that selected in the presence of CD4. Immunization of mice lacking CD4 caused the clonal expansion of T cells that showed less breadth in the range of Ag-binding properties exhibited by their TCRs. Specifically, the CD4-deficient Ag-specific TCR repertoire was depleted of TCRs that demonstrated low-affinity binding to their ligands. The data thus suggest a key role for CD4 in broadening the TCR repertoire by potentiating productive TCR signaling and clonal expansion in response to the engagement of low-affinity antigenic ligands.
Enhanced Immune Responses in Transgenic Mice Expressing a Truncated Form of the Lymphocyte Semaphorin CD100
Authors: Watanabe Chie , Kumanogoh Atsushi , Shi Wei , Suzuki Kazuhiro , Yamada Shuichi , Okabe Masaru , Yoshida Kanji , Kikutani Hitoshi 
Published: April 2014

Abstract
CD100/Sema4D is a 150-kDa transmembrane protein that belongs to the semaphorin family. Binding of CD100 to CD72 enhances the immune response by turning off the negative signaling effects of CD72. To investigate the physiological functions of CD100 in vivo, we generated transgenic mice expressing a truncated form of CD100. A large amount of the soluble form of CD100 was detected in the sera of mice expressing a truncated form of CD100, although the amount of CD100 was only slightly elevated on the surface of B cells. In the mutant mice the development of conventional B and T cells appeared normal in terms of the surface marker phenotypes, while the number of CD5+ B-1 cells in the peritoneal cavity increased in comparison with wild-type mice. In vitro proliferation and Ig production of B cells in response to CD40 stimulation were considerably enhanced in mice expressing a truncated form of CD100. Additionally, in vivo both Ab responses against T cell-dependent Ags and generation of Ag-specific T cells were enhanced. Furthermore, introduction of the CD100-transgene could restore in vitro B cell responses as well as in vivo Ab production against T cell-dependent Ag in CD100-deficient mice. Collectively, these results not only indicate that CD100 has an important role in the immune system, but also that the soluble form of CD100 released from the cell surface can exert functions in vivo.
Overcoming the Signaling Defect of Lyn-Sequestering, Signal-Curtailing FcεRI Dimers: Aggregated Dimers Can Dissociate from Lyn and Form Signaling Complexes with Syk
Authors: Lara Martha , Ortega Enrique , Pecht Israel , Pfeiffer Janet R. , Martinez A. Marina , Lee Rebecca J. , Surviladze Zurab , Wilson Bridget S. , Oliver Janet M. 
Published: April 2014

AbstractClustering the tetrameric (αβγ2) IgE receptor, FcεRI, on basophils and mast cells activates the Src-family tyrosine kinase, Lyn, which phosphorylates FcεRI β and γ subunit tyrosines, creating binding sites for the recruitment and activation of Syk. We reported previously that FcεRI dimers formed by a particular anti-FcεRI α mAb (H10) initiate signaling through Lyn activation and FcεRI subunit phosphorylation, but cause only modest activation of Syk and little Ca2+ mobilization and secretion. Curtailed signaling was linked to the formation of unusual, detergent-resistant complexes between Lyn and phosphorylated receptor subunits. Here, we show that H10-FcεRI multimers, induced by adding F(ab′)2 of goat anti-mouse IgG to H10-treated cells, support strong Ca2+ mobilization and secretion. Accompanying the recovery of signaling, H10-FcεRI multimers do not form stable complexes with Lyn and do support the phosphorylation of Syk and phospholipase Cγ2. Immunogold electron microscopy showed that H10-FcεRI dimers colocalize preferentially with Lyn and are rarely within the osmiophilic “signaling domains” that accumulate FcεRI and Syk in Ag-treated cells. In contrast, H10-FcεRI multimers frequently colocalize with Syk within osmiophilic patches. In sucrose gradient centrifugation analyses of detergent-extracted cells, H10-treated cells show a more complete redistribution of FcεRI β from heavy (detergent-soluble) to light (Lyn-enriched, detergent-resistant) fractions than cells activated with FcεRI multimers. We hypothesize that restraints imposed by the particular orientation of H10-FcεRI dimers traps them in signal-initiating Lyn microdomains, and that converting the dimers to multimers permits receptors to dissociate from Lyn and redistribute to separate membrane domains that support Syk-dependent signal propagation.
Epitope Mapping of the Indirect T Cell Response to Allogeneic Class I MHC: Sequences Shared by Donor and Recipient MHC May Prime T Cells That Provide Help for Alloantibody Production
Authors: Lovegrove Emma , Pettigrew Gavin J. , Bolton Eleanor M. , Bradley J. Andrew 
Published: April 2014

AbstractIndirect allorecognition occurs when T cells recognize donor MHC presented as peptide epitopes by recipient APC, but the precise nature of the epitopes involved remains unclear. Rejection of rat MHC class I-disparate PVG.R8 (RT1.Aa) grafts by PVG.RT1u (RT1.Au) recipients is mediated by indirectly restricted CD4 T cells that provide help for the generation of alloantibody. In this study, epitope mapping was performed using a functionally relevant readout (alloantibody production) to identify key peptides that prime an indirect alloimmune response, leading to graft rejection. PVG.RT1u rats were immunized with a series of overlapping 15-mer peptides (peptides 1–18) that spanned the α1 and α2 domains of the RT1.Aa molecule. Several peptides were able to accelerate both the alloantibody response to the intact RT1.Aa Ag and PVG.R8 heart graft rejection. An immunodominant epitope was identified within the hypervariable region of the α1 domain. Fine mapping of this region with a second series of peptides overlapping by single amino acids confirmed the presence of an eight-amino acid core determinant. Additional “subdominant” epitopes were identified, two of which were located within regions of amino acid homology between the RT1.Aa and RT1.Au molecules and not, as had been expected, within other hypervariable regions. The contribution of self-epitopes to indirect allorecognition was emphasized by the demonstration that i.v. administration of a 15-mer peptide encompassing one of the subdominant self-determinants diminished the recipient’s ability to mount an alloantibody response on challenge with intact Aa alloantigen. Our findings suggest that cryptic self-epitopes recognized by autoreactive T cells may contribute to allograft rejection and should be considered when designing novel strategies for inducing tolerance to alloantigen.
Cytokines Regulate the Capacity of CD8α+ and CD8α− Dendritic Cells to Prime Th1/Th2 Cells In Vivo
Authors: Maldonado-López Roberto , Maliszewski Charlie , Urbain Jacques , Moser Muriel 
Published: April 2014

Abstract
Prior studies have shown that subclasses of dendritic cells (DC) direct the development of distinct Th populations in rodents and in humans. In the mouse, we have recently shown that administration of Ag-pulsed CD8α− DC induces a Th2-type response, whereas injection of CD8α+ DC leads to Th1 differentiation. To define the DC-derived factors involved in the polarization of Th responses, we injected either subset purified from mice genetically deficient for IFN-γ, IL-4, IL-12, or IL-10 into wild-type animals. In this work, we report that DC-derived IL-12 and IFN-γ are required for Th1 priming by CD8α+ DC, whereas IL-10 is required for optimal development of Th2 cells by CD8α− DC. The level of IL-12 produced by the DC appears to determine the Th1/Th2 balance in vivo. We further show that the function of DC subsets displays some flexibility. Treatment of DC with IL-10 in vitro induces a selective decrease in the viability of CD8α+ DC. Conversely, incubation with IFN-γ down-regulates the Th2-promoting capacities of CD8α− DC and increases the Th1-skewing properties of both subsets.
Impaired Activation of Islet-Reactive CD4 T Cells in Pancreatic Lymph Nodes of B Cell-Deficient Nonobese Diabetic Mice
Authors: Greeley Siri Atma W. , Moore Daniel J. , Noorchashm Hooman , Noto Lauren E. , Rostami Susan Y. , Schlachterman Alexander , Song Howard K. , Koeberlein Brigitte , Barker Clyde F. , Naji Ali 
Published: April 2014

Abstract
Despite the impressive protection of B cell-deficient (μMT−/−) nonobese diabetic (NOD) mice from spontaneous diabetes, existence of mild pancreatic islet inflammation in these mice indicates that initial autoimmune targeting of β cells has occurred. Furthermore, μMT−/− NOD mice are shown to harbor a latent repertoire of diabetogenic T cells, as evidenced by their susceptibility to cyclophosphamide-induced diabetes. The quiescence of this pool of islet-reactive T cells may be a consequence of impaired activation of T lymphocytes in B cell-deficient NOD mice. In this regard, in vitro anti-CD3-mediated stimulation demonstrates impaired activation of lymph node CD4 T cells in μMT−/− NOD mice as compared with that of wild-type counterparts, a deficiency that is correlated with an exaggerated CD4 T cell:APC ratio in lymph nodes of μMT−/− NOD mice. This feature points to an insufficient availability of APC costimulation on a per T cell basis, resulting in impaired CD4 T cell activation in lymph nodes of μMT−/− NOD mice. In accordance with these findings, an islet-reactive CD4 T cell clonotype undergoes suboptimal activation in pancreatic lymph nodes of μMT−/− NOD recipients. Overall, the present study indicates that B cells in the pancreatic lymph node microenvironment are critical in overcoming a checkpoint involving the provision of optimal costimulation to islet-reactive NOD CD4 T cells.
Spatial Organization of Signal Transduction Molecules in the NK Cell Immune Synapses During MHC Class I-Regulated Noncytolytic and Cytolytic Interactions
Authors: Vyas Yatin M. , Mehta Kamini M. , Morgan Margaret , Maniar Hina , Butros Linda , Jung Steffen , Burkhardt Janis K. , Dupont Bo 
Published: April 2014

Abstract
The cytolytic activity of NK cells is tightly regulated by inhibitory receptors specific for MHC class I Ags. We have investigated the composition of signal transduction molecules in the supramolecular activation clusters in the MHC class I-regulated cytolytic and noncytolytic NK cell immune synapses. KIR2DL3-positive NK clones that are specifically inhibited in their cytotoxicity by HLA-Cw*0304 and polyclonal human NK cells were used for conjugate formation with target cells that are either protected or are susceptible to NK cell-mediated cytotoxicity. Polarization of talin, microtubule-organizing center, and lysosomes occurred only during cytolytic interactions. The NK immune synapses were analyzed by three-dimensional immunofluorescence microscopy, which showed two distinctly different synaptic organizations in NK cells during cytolytic and noncytolytic interactions. The center of a cytolytic synapse with MHC class I-deficient target is comprised of a complex of signaling molecules including Src homology (SH)2-containing protein tyrosine phosphatase-1 (SHP-1). Closely related molecules with overlapping functions, such as the Syk kinases, SYK, and ZAP-70, and adaptor molecules, SH2 domain-containing leukocyte protein of 76 kDa and B cell linker protein, are expressed in activated NK cells and are all recruited to the center of the cytolytic synapse. In contrast, the noncytolytic synapse contains SHP-1, but is lacking other components of the central supramolecular activation cluster. These findings indicate a functional role for SHP-1 in both the cytolytic and noncytolytic interactions. We also demonstrate, in three-cell conjugates, that a single NK cell forms a cytolytic synapse with a susceptible target cell in the presence of both susceptible and nonsusceptible target cells.
Protection from Pulmonary Fibrosis in the Absence of CCR2 Signaling
Authors: Moore Bethany B. , Paine Robert , Christensen Paul J. , Moore Thomas A. , Sitterding Stephanie , Ngan Rose , Wilke Carol A. , Kuziel William A. , Toews Galen B. 
Published: April 2014

AbstractPulmonary fibrosis can be modeled in animals by intratracheal instillation of FITC, which results in acute lung injury, inflammation, and extracellular matrix deposition. We have previously shown that despite chronic inflammation, this model of pulmonary fibrosis is lymphocyte independent. The CC chemokine monocyte-chemoattractant protein-1 is induced following FITC deposition. Therefore, we have investigated the contribution of the main monocyte-chemoattractant protein-1 chemokine receptor, CCR2, to the fibrotic disease process. We demonstrate that CCR2−/− mice are protected from fibrosis in both the FITC and bleomycin pulmonary fibrosis models. The protection is specific for the absence of CCR2, as CCR5−/− mice are not protected. The protection is not explained by differences in acute lung injury, or the magnitude or composition of inflammatory cells. FITC-treated CCR2−/− mice display differential patterns of cellular activation as evidenced by the altered production of cytokines and growth factors following FITC inoculation compared with wild-type controls. CCR2−/− mice have increased levels of GM-CSF and reduced levels of TNF-α compared with FITC-treated CCR2+/+ mice. Thus, CCR2 signaling promotes a profibrotic cytokine cascade following FITC administration.
Endothelial Cell Costimulation of T Cell Activation Through CD58-CD2 Interactions Involves Lipid Raft Aggregation
Authors: Mestas Javier , Hughes Christopher C. W. 
Published: April 2014

Abstract
Human endothelial cells (EC) costimulate CD4+ memory T cell activation through CD58-CD2 interactions. In this study we tested the hypothesis that EC activate distinct costimulatory pathways in T cells that target specific transcription factors. AP-1, composed of fos and jun proteins, is a critical effector of TCR signaling and binds several sites in the IL-2 promoter. EC augment c-fos promoter activity in T cells; however, deletion analysis reveals no transcription factor binding sites in the promoter uniquely responsive to EC costimulation. Overexpression of AP-1 proteins in T cells augments the activity of an AP-1-luciferase reporter gene equally in the absence or the presence of EC costimulation. Interestingly, EC stimulate a similar 2- to 3-fold up-regulation of AP-1, NF-AT, NF-κB, and NF-IL-2-luciferase reporters. CD2 mAbs completely block EC effects on all of these pathways, as well as costimulation of IL-2 secretion. We conclude that EC costimulation through CD2 does not trigger a single distinct costimulatory pathway in T cells, but rather, it amplifies several pathways downstream of the TCR. Indeed, we find that early EC costimulation acts “upstream” of the TCR by promoting lipid raft aggregation, thus amplifying TCR signaling. Soluble CD2 mAbs block EC-induced raft aggregation, whereas cross-linking CD2 promotes aggregation. These data are consistent with the critical role of CD2 in organizing the T cell-APC contact zone.
Rudimentary TCR Signaling Triggers Default IL-10 Secretion by Human Th1 Cells
Authors: Burrows Gregory G. , Chou Yuan K. , Wang Chunhe , Chang Justin W. , Finn Thomas P. , Culbertson Nicole E. , Kim Joseph , Bourdette Dennis N. , Lewinsohn Deborah A. , Lewinsohn David M. , Ikeda Masayuki , Yoshioka Tohru , Allen Charles N. , Offner Halina , Vandenbark Arthur A. 
Published: April 2014

Abstract
Understanding the process of inducing T cell activation has been hampered by the complex interactions between APC and inflammatory Th1 cells. To dissociate Ag-specific signaling through the TCR from costimulatory signaling, rTCR ligands (RTL) containing the α1 and β1 domains of HLA-DR2b (DRA*0101:DRB1*1501) covalently linked with either the myelin basic protein peptide 85–99 (RTL303) or CABL-b3a2 (RTL311) peptides were constructed to provide a minimal ligand for peptide-specific TCRs. When incubated with peptide-specific Th1 cell clones in the absence of APC or costimulatory molecules, only the cognate RTL induced partial activation through the TCR. This partial activation included rapid TCR ζ-chain phosphorylation, calcium mobilization, and reduced extracellular signal-related kinase activity, as well as IL-10 production, but not proliferation or other obvious phenotypic changes. On restimulation with APC/peptide, the RTL-pretreated Th1 clones had reduced proliferation and secreted less IFN-γ; IL-10 production persisted. These findings reveal for the first time the rudimentary signaling pattern delivered by initial engagement of the external TCR interface, which is further supplemented by coactivation molecules. Activation with RTLs provides a novel strategy for generating autoantigen-specific bystander suppression useful for treatment of complex autoimmune diseases.
Immunobiological Analysis of TCR Single-Chain Transgenic Mice Reveals New Possibilities for Interaction between CDR3α and an Antigenic Peptide Bound to MHC Class I
Authors: Zhang Weijia , Honda Shinichiro , Wang Fuming , DiLorenzo Teresa P. , Kalergis Alexis M. , Ostrov David A. , Nathenson Stanley G. 
Published: April 2014

Abstract
The interaction between TCRs and peptides presented by MHC molecules determines the specificity of the T cell-mediated immune response. To elucidate the biologically important structural features of this interaction, we generated TCR β-chain transgenic mice using a TCR derived from a T cell clone specific for the immunodominant peptide of vesicular stomatitis virus (RGYVYQGL, VSV8) presented by H-2Kb. We immunized these mice with VSV8 or analogs substituted at TCR contact residues (positions 1, 4, and 6) and analyzed the CDR3α sequences of the elicited T cells. In VSV8-specific CTLs, we observed a highly conserved residue at position 93 of CDR3α and preferred Jα usage, indicating that multiple residues of CDR3α are critical for recognition of the peptide. Certain substitutions at peptide position 4 induced changes at position 93 and in Jα usage, suggesting a potential interaction between CDR3α and position 4. Cross-reactivity data revealed the foremost importance of the Jα region in determining Ag specificity. Surprisingly, substitution at position 6 of VSV8 to a negatively charged residue induced a change at position 93 of CDR3α to a positively charged residue, suggesting that CDR3α may interact with position 6 in certain circumstances. Analogous interactions between the TCR α-chain and residues in the C-terminal half of the peptide have not yet been revealed by the limited number of TCR/peptide-MHC crystal structures reported to date. The transgenic mouse approach allows hundreds of TCR/peptide-MHC interactions to be examined comparatively easily, thus permitting a wide-ranging analysis of the possibilities for Ag recognition in vivo.