bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cutting Edge: Regulation of T Cell Activation Threshold by CD28 Costimulation Through Targeting Cbl-b for Ubiquitination
Authors: Zhang Jian , Bárdos Tamás , Li Dongdong , Gál István , Vermes Csaba , Xu Jianye , Mikecz Katalin , Finnegan Alison , Lipkowitz Stan , Glant Tibor T. 
Published: April 2014

AbstractOptimal T cell activation requires signaling through the TCR and CD28 costimulatory receptor. CD28 costimulation is believed to set the threshold for T cell activation. Recently, Cbl-b, a ubiquitin ligase, has been shown to negatively regulate CD28-dependent T cell activation. In this report, we show that CD28 costimulation selectively induces greater ubiquitination and degradation of Cbl-b in wild-type T cells than CD3 stimulation alone, and TCR-induced Cbl-b ubiquitination and degradation are significantly reduced in CD28-deficient T cells. Stimulation of CD28-deficient T cells with higher doses of anti-CD3 results in increased ubiquitination of Cbl-b, which correlates with enhanced T cell responses. Our results demonstrate that CD28 costimulation regulates the threshold for T cell activation, at least in part, by promoting Cbl-b ubiquitination and degradation.
Granulocyte-Macrophage Colony-Stimulating Factor Induces an Expression Program in Neonatal Microglia That Primes Them for Antigen Presentation
Authors: Re Fabio , Belyanskaya Svetlana L. , Riese Richiard J. , Cipriani Barbara , Fischer Falko R. , Granucci Francesca , Ricciardi-Castagnoli Paola , Brosnan Celia , Stern Lawrence J. , Strominger Jack L. , Santambrogio Laura 
Published: April 2014

AbstractNeonatal microglial cells respond to GM-CSF and M-CSF by acquiring different morphologies and phenotypes. To investigate the extent and consequences of this process, a global gene expression analysis was performed, with significant changes in transcript levels confirmed by biochemical analyses. Primary murine microglial cells underwent substantial expression reprogramming after treatment with GM-CSF or M-CSF with many differentially expressed transcripts important in innate and adaptive immunity. In particular, many gene products involved in Ag presentation were induced by GM-CSF, but not M-CSF, thus potentially priming relatively quiescent microglia cells for Ag presentation. This function of GM-CSF is distinct from its primary function in cell proliferation and survival.
Quantitative Differences in Chemokine Receptor Engagement Generate Diversity in Integrin-Dependent Lymphocyte Adhesion
Authors: D’Ambrosio Daniele , Albanesi Cristina , Lang Rosmarie , Girolomoni Giampiero , Sinigaglia Francesco , Laudanna Carlo 
Published: April 2014

AbstractChemokines control the specificity of lymphocyte homing. Numerous chemokines have been identified but the significance of redundancy in chemokine networks is unexplained. Here we investigated the biological significance of distinct chemokines binding to the same receptor. Among CCR4 ligands, skin vessels endothelial cells present C-C chemokine ligand (CCL) 17 but not CCL22 consistent with CCL17 involvement in T lymphocyte arrest on endothelial cells. However, CCL22 is much more powerful than CCL17 in the induction of rapid integrin-dependent T cell adhesion on VCAM-1 under conditions of physiological flow. The dominance of CCL22 over CCL17 extends to other CCR4-mediated phenomena such as receptor desensitization and internalization and correlates with the peculiar kinetics of CCR4 engagement by the two ligands. A similar phenomenological pattern is also shown for CXC chemokine ligand 9 and CXC chemokine ligand 11, which share binding to CXCR3. Our analysis shows how quantitative variations in chemokine receptor expression level and ligand engagement may alter the selectivity of integrin-dependent lymphocyte adhesive responses, suggesting a mechanism by which chemokine networks may either generate or break the specificity of lymphocyte subset recruitment.
Enhancement of MHC Class II-Restricted Responses by Receptor-Mediated Uptake of Peptide Antigens
Authors: Zaliauskiene Lolita , Kang Sunghyun , Sparks Kerri , Zinn Kurt R. , Schwiebert Lisa M. , Weaver Casey T. , Collawn James F. 
Published: April 2014

AbstractPeptides, either as altered peptide ligands, competitors, or vaccines, offer an outstanding potential for regulating immune responses because of their exquisite specificity. However, a major problem associated with peptide therapies is that they are poorly taken up by APCs. Because of poor bioavailability, high concentrations and repeated treatments are required for peptide therapies in vivo. To circumvent this problem, we tested whether covalently coupling a peptide T cell determinant, OVA323–339, to transferrin (Tf) enhances APC uptake and presentation as monitored by Th cell activation. Functional analysis of the Tf-peptide conjugates revealed that the conjugates were presented 10,000- and 100-fold more effectively by B cells than intact Ag and free peptide, respectively. Furthermore, we demonstrate that the Tf-peptide conjugates are taken up by B cells through a receptor-mediated process and subsequently delivered to the lysosomal compartment. Using an adoptive transfer assay, we show that that the Tf-peptide complexes are 100-fold more effective in vivo than the free peptide in activating CD4+ T cells by following an early activation marker, CD69. Our results demonstrate that coupling peptides to Tf enhances peptide presentation, thereby making it possible to take full advantage of peptide-specific therapies in modulating T cell responses.
1,25 (OH)2 Vitamin D3-Stimulated Osteoclast Formation in Spleen-Osteoblast Cocultures Is Mediated in Part by Enhanced IL-1α and Receptor Activator of NF-κB Ligand Production in Osteoblasts
Authors: Lee Sun-Kyeong , Kalinowski Judy , Jastrzebski Sandra , Lorenzo Joseph A. 
Published: April 2014

Abstract
We examined the ability of 1,25 (OH)2 vitamin D3 (Vit D) to stimulate osteoclast-like cell (OCL) formation in cocultures of spleen cells and primary calvarial osteoblasts from wild-type (WT) and IL-1R type 1-deficient (knockout; KO) mice. Vit D dose dependently increased OCL in cocultures containing WT osteoblasts. In contrast, there was a 90% reduction in OCL numbers in cocultures containing KO osteoblasts. In cocultures with either WT or KO osteoblasts, treatment with Vit D increased receptor activator of NF-κB ligand mRNA by 17-, 19-, or 3.5-fold, respectively. Vit D decreased osteoprotegerin mRNA to undetectable in all groups. Intracellular IL-1α protein increased after Vit D treatment in cocultures containing WT, but not KO osteoblasts. We also examined direct effects of Vit D, IL-1α, and their combination on gene expression in primary osteoblasts. In WT cells, Vit D and IL-1 stimulated receptor activator of NF-κB ligand mRNA expression by 3- and 4-fold, respectively, and their combination produced a 7-fold increase. Inhibition of osteoprotegerin mRNA in WT cells was partial with either agent alone and greatest with their combination. In KO cells, only Vit D stimulated a response. IL-1 alone increased IL-1α protein expression in WT osteoblasts. However, in combination with Vit D, there was a synergistic response (100-fold increase). In KO cultures, there were no effects of IL-1, Vit D, or their combination on IL-1α protein. These results demonstrate interactions between IL-1 and Vit D in primary osteoblasts that appear important in both regulation of IL-1α production and the ability of Vit D to support osteoclastogenesis.
FDC-SP, a Novel Secreted Protein Expressed by Follicular Dendritic Cells
Authors: Marshall Aaron J. , Du Quijiang , Draves Kevin E. , Shikishima Yasufumi , HayGlass Kent T. , Clark Edward A. 
Published: April 2014

AbstractTo define better the molecular basis for follicular dendritic cell (FDC) function, we used PCR-based cDNA subtraction to identify genes specifically expressed in primary FDC isolated from human tonsils. In this work we report the discovery of a novel gene encoding a small secreted protein, which we term FDC-SP (FDC secreted protein). The FDC-SP gene lies on chromosome 4q13 adjacent to clusters of proline-rich salivary peptides and C-X-C chemokines. Human and mouse FDC-SP proteins are structurally unique and contain a conserved N-terminal charged region adjacent to the leader peptide. FDC-SP has a very restricted tissue distribution and is expressed by activated FDCs from tonsils and TNF-α-activated FDC-like cell lines, but not by B cell lines, primary germinal center B cells, or anti-CD40 plus IL-4-activated B cells. Strikingly, FDC-SP is highly expressed in germinal center light zone, a pattern consistent with expression by FDC. In addition, FDC-SP is expressed in leukocyte-infiltrated tonsil crypts and by LPS- or Staphylococcus aureus Cowan strain 1-activated leukocytes, suggesting that FDC-SP can also be produced in response to innate immunity signals. We provide evidence that FDC-SP is posttranslationally modified and secreted and can bind to the surface of B lymphoma cells, but not T lymphoma cells, consistent with a function as a secreted mediator acting upon B cells. Furthermore, we find that binding of FDC-SP to primary human B cells is markedly enhanced upon activation with the T-dependent activation signals such as anti-CD40 plus IL-4. Together our data identify FDC-SP as a unique secreted peptide with a distinctive expression pattern within the immune system and the ability to specifically bind to activated B cells.
Solid-Phase Epitope Recovery: A High Throughput Method for Antigen Identification and Epitope Optimization
Authors: Lawendowski Carla A. , Giurleo Gina M. , Huang Yin Yin , Franklin G. Joseph , Kaplan Johanne M. , Roberts Bruce L. , Nicolette Charles A. 
Published: April 2014

AbstractSelf tolerance to MHC class I-restricted nonmutated self Ags is a significant hurdle to effective cancer immunotherapy. Compelling evidence is emerging that altered peptide ligands can be far more immunogenic than their corresponding native epitopes; however, there is no way to reliably predict which modifications will lead to enhanced native epitope-specific immune responses. We reasoned that this limitation could be overcome by devising an empirical screen in which the nearly complete combinatorial spectrum of peptides of optimal length can be rapidly assayed for reactivity with a MHC class I-restricted cytotoxic T cell clone. This method, solid-phase epitope recovery, quantitatively ranks all reactive peptides in the library and allows selection of altered peptide ligands having desirable immunogenic properties of interest. In contrast to rationally designed MHC anchor-modified peptides, peptides identified by the present method are highly substituted in predicted TCR contact residues and can reliably activate and expand effector cell populations in vitro which lyse target cells presenting the wild-type epitope. We demonstrate that solid-phase epitope recovery peptides corresponding to a poorly immunogenic epitope of the melanoma Ag, gp100, can reliably induce wild-type peptide-specific CTL using normal donor T cells in vitro. Furthermore, these peptides can complement one another to induce these responses in an overwhelming majority of normal individuals in vitro. These data provide a rationale for the design of superior vaccines comprising a mixture of structurally diverse yet functionally convergent peptides.
The Subpopulation of CD4+CD25+ Splenocytes That Delays Adoptive Transfer of Diabetes Expresses L-Selectin and High Levels of CCR7
Authors: Szanya Veronika , Ermann Joerg , Taylor Cariel , Holness Claire , Fathman C. Garrison 
Published: April 2014

AbstractRecently, CD4+CD25+ T cells have been implicated in the control of diabetes, suggesting that the inflamed islets of Langerhans in prediabetic NOD mice are under peripheral immune surveillance. Here we show that CD4+CD25+ splenocytes inhibit diabetes in cotransfer with islet-infiltrating cells. Furthermore, CD62L expression is necessary for this disease-delaying effect of CD4+CD25+ cells in vivo, but not for their suppressor function in vitro. We demonstrate that the CD4+CD25+CD62L+ splenocytes express CCR7 at high levels and migrate toward secondary lymphoid tissue chemokine and ELC (macrophage-inflammatory protein-3β), lymphoid chemokines, whereas CD4+CD25+CD62L− splenocytes preferentially express CCR2, CCR4, and CXCR3 and migrate toward the corresponding inflammatory chemokines. These data demonstrate that CD4+CD25+CD62L+, but not CD4+CD25+CD62L−, splenocytes delay diabetes transfer, and that CD4+CD25+ suppressor T cells are comprised of at least two subpopulations that behave differently in cotransfer in vivo and express distinct chemokine receptor and chemotactic response profiles despite demonstrating equivalent suppressor functions in vitro.
Cytokine Coexpression During Human Th1/Th2 Cell Differentiation: Direct Evidence for Coordinated Expression of Th2 Cytokines
Authors: Cousins David J. , Lee Tak H. , Staynov Dontcho Z. 
Published: April 2014

Abstract
We have developed an in vitro differentiation assay in which human naive CD4+ cells are driven toward either the Th1 or Th2 phenotype. We have examined the interrelationships among the expression of IL-2, IL-4, IL-5, IL-10, IL-13, GM-CSF, and IFN-γ in individual cells using intracellular cytokine staining at various times during the differentiation process. We provide direct evidence that the Th2 cytokines IL-4, IL-5, and IL-13, unlike the other cytokines, are regulated by a coordinated mechanism. We also show that IL-10 is expressed by a different subset of cells that is prevalent at early stages of Th2 differentiation, but then diminishes. Additionally we demonstrate that while naive cells can express IL-2 upon activation, they cannot express GM-CSF. Commitment to GM-CSF expression occurs during differentiation in a Th1/Th2 subset-independent manner. Furthermore, we have examined the levels of GATA3, c-Maf, T-bet, and Ets-related molecule during human Th1/Th2 differentiation and suggest that differences in the levels of these critical transcription factors are responsible for commitment toward the Th1 or Th2 lineage.
Identification of Multiple Novel Epididymis-Specific β-Defensin Isoforms in Humans and Mice
Authors: Yamaguchi Yasuhiro , Nagase Takahide , Makita Ryosuke , Fukuhara Shigetomo , Tomita Tetsuji , Tominaga Takashi , Kurihara Hiroki , Ouchi Yasuyoshi 
Published: April 2014

AbstractDefensins comprise a family of cationic antimicrobial peptides that are characterized by the presence of six conserved cysteine residues. We identified two novel human β-defensin (hBD) isoforms by mining the public human genomic sequences. The predicted peptides conserve the six-cysteine motif identical with hBD-4, termed hBD-5 and hBD-6. We also evaluated the characteristics of the mouse homologs of hBD-5, hBD-6, and HE2β1, termed mouse β-defensin (mBD)-12, mBD-11, and mouse EP2e (mEP2e). The mBD-12 synthetic peptide showed salt-dependent antimicrobial activity. We demonstrate the epididymis-specific expression pattern of hBD-5, hBD-6, mBD-11, mBD-12, and mEP2e. In situ hybridization revealed mBD-11, mBD-12, and mEP2e expression in the columnar epithelium of the caput epididymis, contrasting with the predominant expression of mBD-3 in the capsule or septum of the whole epididymis. In addition, the regional specificity of mBD-11, mBD-12, and mEP2e was somewhat overlapping, but not identical, in the caput epididymis, suggesting that specific regulation may work for each member of the β-defensin family. Our findings indicated that multiple β-defensin isoforms specifically and cooperatively contribute to the innate immunity of the urogenital system.
IL-18 Regulates Intestinal Mastocytosis and Th2 Cytokine Production Independently of IFN-γ DuringTrichinella spiralisInfection
Authors: Helmby Helena , Grencis Richard K. 
Published: April 2014

AbstractExpulsion of the gastrointestinal nematode Trichinella spiralis is associated with pronounced mastocytosis mediated by a Th2-type response involving IL-4, IL-10, and IL-13. Here we demonstrate that IL-18 is a key negative regulator of protective immune responses against T. spiralis in vivo. IL-18 knockout mice are highly resistant to T. spiralis infection, expel the worms rapidly and subsequently develop low levels of encysted muscle larvae. The increased speed of expulsion is correlated with high numbers of mucosal mast cells and an increase in IL-13 and IL-10 secretion. When normal mice were treated with rIL-18 in vivo, worm expulsion was notably delayed, and the development of mastocytosis and Th2 cytokine production was significantly reduced. The treatment had no effect on intestinal eosinophilia or goblet cell hyperplasia but specifically inhibited the development of mastocytosis. Addition of rIL-18 to in vitro cultures of bone marrow-derived mast cells resulted in a significant reduction in cell yields as well as in the number of IL-4-secreting mast cells. In vivo treatment of T. spiralis-infected IFN-γ knockout mice with rIL-18 demonstrated that the inhibitory effect of IL-18 on mastocytosis and Th2 cytokine secretion is independent of IFN-γ. Hence, IL-18 plays a significant biological role as a negative regulator of intestinal mast cell responses and may promote the survival of intestinal parasites in vivo.
Subset-Specific Reductions in Lung Lymphocyte Accumulation Following Intratracheal Antigen Challenge in Endothelial Selectin-Deficient Mice
Authors: Curtis Jeffrey L. , Sonstein Joanne , Craig Ronald A. , Todt Jill C. , Knibbs Randall N. , Polak Timothy , Bullard Daniel C. , Stoolman Lloyd M. 
Published: April 2014

AbstractWe previously demonstrated induction and expression of CD62E and CD62P in the lungs of mice primed and then challenged with intratracheal (i.t.) SRBC. The current study examined accumulation of endogenous lymphocytes in the lungs of endothelial E- and P-selectin-deficient (E−P−) mice after i.t. SRBC challenge. Compared with syngeneic wild-type (wt) mice, E−P− mice showed an 85–95% decrease in CD8+ T cells and B cells in the lungs at both early and late time points. In contrast, CD4+ T cell accumulation was reduced by ∼60% early, but equivalent to wt levels later. Surprisingly, many γδ T cells were found in lungs and blood of E−P− mice but were undetectable in the lungs and blood of wt mice. Absolute numbers of peripheral blood CD4, CD8, and B lymphocytes in E−P− mice equaled or exceeded the levels in wt mice, particularly after challenge. Trafficking studies using αβ T lymphoblasts confirmed that the recruitment of circulating cells after challenge was markedly reduced in E−P− mice. Furthermore, Ag priming occurred normally in both the selectin-deficient and wt mice, because primed lymphocytes from both groups transferred Ag sensitivity into naive wt mice. Lung production of mRNA for six CC and two CXC chemokines after challenge was equivalent by RT-PCR analysis in wt and E−P− mice. Therefore, reduced lung accumulation of αβ T cells and B cells in E−P− mice did not result from reduced delivery of circulating lymphocytes to the lungs, unsuccessful Ag priming, or defective pulmonary chemokine production. Selectin-dependent lymphocyte recruitment into the lungs following i.t.-SRBC challenge is subset specific and time dependent.
Vitamin K-Dependent Protein S Localizing Complement Regulator C4b-Binding Protein to the Surface of Apoptotic Cells
Authors: Webb Joanna H. , Blom Anna M. , Dahlbäck Björn 
Published: April 2014

AbstractApoptosis is characterized by a lack of inflammatory reaction in surrounding tissues, suggesting local control of complement activation. During the initial stage of apoptosis, cells expose negatively charged phospholipid phosphatidylserine on their surfaces. The vitamin K-dependent protein S has a high affinity for this type of phospholipid. In human plasma, 60–70% of protein S circulates in complex with C4b-binding protein (C4BP). The reason why protein S and C4BP form a high-affinity complex in plasma is not known. However, C4BP is an important regulator of the classical pathway of the complement system where it acts as a cofactor in degradation of complement protein C4b. Using Jurkat cells as a model system for apoptosis, we now show protein S to bind to apoptotic cells. We further demonstrate protein S-mediated binding of C4BP to apoptotic cells. Binding of the C4BP-protein S complex to apoptotic cells was calcium-dependent and could be blocked with Abs directed against the phospholipid-binding domain in protein S. Annexin V, which binds to exposed phosphatidylserine on the apoptotic cell surface, could inhibit the binding of protein S. The C4BP that was bound via protein S to the apoptotic cells was able to interact with the complement protein C4b, supporting a physiological role of the C4BP/protein S complex in regulation of complement on the surface of apoptotic cells.
Complement Factor B Gene Regulation: Synergistic Effects of TNF-α and IFN-γ in Macrophages
Authors: Huang Yong , Krein Peter M. , Muruve Daniel A. , Winston Brent W. 
Published: April 2014

AbstractComplement factor B (Bf) plays an important role in activating the alternative complement pathway. The inflammatory cytokines, in particular TNF-α and IFN-γ, are critical in the regulation of Bf gene expression in macrophages. In this study, we investigated the mechanisms of Bf gene regulation by TNF-α and IFN-γ in murine macrophages. Northern analysis revealed that Bf mRNA expression was synergistically up-regulated by TNF-α and IFN-γ in MH-S cells. Truncations of the 5′ Bf promoter identified a region between −556 and −282 bp that mediated TNF-α responsiveness as well as the synergistic effect of TNF-α and IFN-γ on Bf expression. Site-directed mutagenesis of a NF-κB-binding element in this region (−433 to −423 bp) abrogated TNF-α responsiveness and decreased the synergistic effect of TNF-α and IFN-γ on Bf expression. EMSAs revealed nuclear protein binding to this NF-κB cis-binding element on TNF-α stimulation. Supershift analysis revealed that both p50 and p65 proteins contribute to induction of Bf by TNF-α. An I-κB dominant negative mutant blocked Bf induction by TNF-α and reduced the synergistic induction by TNF-α and IFN-γ. In addition, the proteasome inhibitor MG132, which blocks NF-κB induction, blocked TNF-α-induced Bf promoter activity and the synergistic induction of Bf promoter activity by TNF-α and IFN-γ. LPS was found to induce Bf promoter activity through the same NF-κB cis-binding site. These findings suggest that a NF-κB cis-binding site between −433 and −423 bp is required for TNF-α responsiveness and for TNF-α- and IFN-γ-stimulated synergistic responsiveness of the Bf gene.