bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dual Roles of IL-15 in Maintaining IL-7RαlowCCR7− Memory CD8+ T Cells in Humans via Recovering the Phosphatidylinositol 3-Kinase/AKT Pathway
Authors: Kim Hang-Rae , Hwang Kyung-A , Kang Insoo 
Published: April 2014

Abstract
Recently, we identified two subsets of CCR7− memory CD8+ T cells expressing high and low levels of the IL-7R α-chain (IL-7Rα) that is essential for memory T cell survival in human peripheral blood. IL-7RαlowCCR7− memory CD8+ T cells that produce effector cytokines and perforin have impaired proliferation and survival in response to TCR triggering and IL-7, respectively. These findings raise a question of how such cells are sustained at significant numbers, &gt;20% of peripheral CD8+ T cells, despite impaired IL-7- and TCR-mediated cell maintenance. In this study, we demonstrate that IL-7RαlowCCR7− memory CD8+ T cells have increased expression of IL-2/15R β-chain (IL-2/15Rβ), which is critical for IL-15 signaling, with enhanced gene expression of T box expressed in T cells (T-bet) and eomesodermin (eomes), transcriptional factors involved in IL-2/15Rβ expression compared with IL-7RαhighCCR7− memory CD8+ T cells. Such a cytokine chain is functional as IL-7RαlowCCR7− memory CD8+ T cells proliferate considerably in response to IL-15. Furthermore, adding IL-15 to TCR triggering recovers impaired TCR-mediated proliferation of IL-7Rαlow memory CD8+ T cells via restoring the activation of the PI3K/AKT pathway. These findings indicate that IL-15 has dual roles in maintaining IL-7RαlowCCR7− memory CD8+ T cells via TCR-dependent and -independent mechanisms. Moreover, IL-15 can be useful in reviving impaired proliferative function of such memory CD8+ T cells with effector functions against infections and tumors via rescuing the PI3K/AKT pathway.
Shaping of the Autoreactive Regulatory T Cell Repertoire by Thymic Cortical Positive Selection
Authors: Ribot Julie , Enault Geneviève , Pilipenko Sylvie , Huchenq Anne , Calise Maryline , Hudrisier Denis , Romagnoli Paola , van Meerwijk Joost P. M. 
Published: April 2014

Abstract
The main function of regulatory T lymphocytes is to keep autoimmune responses at bay. Accordingly, it has been firmly established that the repertoire of CD4+CD25+Foxp3+ regulatory T cells (Tregs) is enriched in autospecific cells. Differences in thymic-positive and/or -negative selection may account for selection of the qualitatively distinct regulatory and conventional T cell (Tconv) repertoires. It has previously been shown that precursors for Tregs are less sensitive to negative selection than Tconv precursors. Studies with TCR/ligand doubly transgenic mice suggested that an agonist ligand might induce positive selection of Treg (but not Tconv) cells. However, massive deletion of Tconv (but not Treg) cell precursors observed in these mice renders interpretation of such data problematic and a potential role for positive selection in generation of the autospecific Treg repertoire has remained therefore incompletely understood. To study this important unresolved issue and circumvent use of TCR/ligand-transgenic mice, we have developed transgenic mice expressing a single MHC class II/peptide ligand on positively selecting thymic cortical epithelial cells. We found that functional Treg (but not Tconv) cells specific for the single ligand were preferentially selected from the naturally diverse repertoire of immature precursors. Our data therefore demonstrate that thymic cortical positive selection of regulatory and Tconv precursors is governed by distinct rules and that it plays an important role in shaping the autoreactive Treg repertoire.
Sulfated Glycosphingolipid as Mediator of Phagocytosis: SM4s Enhances Apoptotic Cell Clearance and Modulates Macrophage Activity
Authors: Popovic Zoran V. , Sandhoff Roger , Sijmonsma Tjeerd P. , Kaden Sylvia , Jennemann Richard , Kiss Eva , Tone Edgar , Autschbach Frank , Platt Nick , Malle Ernst , Gröne Hermann-Josef 
Published: April 2014

Abstract
Sulfoglycolipids are present on the surface of a variety of cells. The sulfatide SM4s is increased in lung, renal, and colon cancer and is associated with an adverse prognosis, possibly due to a low immunoreactivity of the tumor. As macrophages significantly contribute to the inflammatory infiltrate in malignancies, we postulated that SM4s may modulate macrophage function. We have investigated the effect of SM4s on the uptake of apoptotic tumor cells, macrophage cytokine profile, and receptor expression. Using flow cytometry and microscopic analyses, we found that coating apoptotic murine carcinoma cells from the colon and kidney with SM4s promoted their phagocytosis by murine macrophages up to 3-fold ex vivo and in vivo. This increased capacity was specifically inhibited by preincubation of macrophages with oxidized or acetylated low density lipoprotein and maleylated albumin, indicating involvement of scavenger receptors in this interaction. The uptake of SM4s-coated apoptotic cells significantly enhanced macrophage production of TGF-β1, expression of P-selectin, and secretion of IL-6. These data suggest that SM4s within tumors may promote apoptotic cell removal and alter the phenotype of tumor-associated macrophages.
Localization and Differential Expression of Activation-Induced Cytidine Deaminase in the Amphibian Xenopus upon Antigen Stimulation and during Early Development
Authors: Marr Shauna , Morales Heidi , Bottaro Andrea , Cooper Michelle , Flajnik Martin , Robert Jacques 
Published: April 2014

Abstract
As in mammals, B cell maturation in the amphibian Xenopus involves somatic hypermutation (SHM) and class switch recombination to diversify the B cell receptor repertoire in response to Ag stimulation. Unlike mammals, however, the resulting increase in Ab affinity is poor in Xenopus, which is possibly related to the absence of germinal centers and a suboptimal selection mechanism of SHM. In mammals, both SHM and class switch recombination are mediated by the activation-induced cytidine deaminase enzyme and under Ag-dependent regulation. Given its evolutionary conservation in jawed vertebrates, we used activation-induced cytidine deaminase as a marker to monitor and localize B cell maturation in Xenopus upon immune responses and during early development. In adult, Xenopus laevis AID (XlAID) was detected mainly in the spleen, where cells expressing XlAID were preferentially distributed in follicular B cell zones, although some XlAID+ cells were also found in the red pulp. XlAID was markedly up-regulated in the spleen with different kinetics upon bacterial stimulation and viral infection. However, during secondary anti-viral response XlAID was also noticeably expressed by PBLs, suggesting that XlAID remains active in a subset of circulating B cells. During ontogeny, XlAID expression was detected as early as 5 days postfertilization in liver before the first fully differentiated B cells appear. Concomitant with appearance of mature B cells XlAID was up-regulated upon bacterial stimulation or viral infection at later larval stages. This study highlights the conserved involvement of XlAID during Ag-dependent B cell responses in Xenopus but also suggests another role in B cell differentiation earlier in ontogeny.
IL-6 Contributes to the Expression of RAGs in Human Mature B Cells
Authors: Hillion Sophie , Dueymes Maryvonne , Youinou Pierre , Jamin Christophe 
Published: April 2014

Abstract
Mature B cells acquire the capacity to revise rearranged Ig V region genes in secondary lymphoid organs. In previous studies, we demonstrated that cross-linking the BCR and the CD40 induces the expression of the RAG1 and RAG2 enzymes and, thereby, secondary rearrangements. We examine herein the mechanism that underpins RAG1 and RAG2 expression in peripheral and tonsil B cells. Coordinated engagement of the BCR and CD40 promoted the synthesis of IL-6 and, thereby, up-regulation of its receptor on activated B lymphocytes. Furthermore, we provide evidence that IL-6 initiates the expression of RAGs in circulating B cells, and extends those in tonsil B cells. Thus, neutralization of IL-6 or blocking of its receptor inhibits RAG expression. Moreover, we demonstrate that IL-6 impedes BCR-mediated termination of RAG gene expression in both population of B cells. The recovered inhibition of RAG gene transcription by IL-6 receptor blockade supports the notion that once recombination is launched, its termination is also regulated by IL-6. Taken together, these studies provide new insight into the dual role of IL-6 in inducing and terminating expression of the recombinase machinery for secondary rearrangements in mature human B cells.
Developmental Stage-Dependent Collaboration between the TNF Receptor-Associated Factor 6 and Lymphotoxin Pathways for B Cell Follicle Organization in Secondary Lymphoid Organs
Authors: Qin Junwen , Konno Hiroyasu , Ohshima Daisuke , Yanai Hiromi , Motegi Hidehiko , Shimo Yusuke , Hirota Fumiko , Matsumoto Mitsuru , Takaki Satoshi , Inoue Jun-ichiro , Akiyama Taishin 
Published: April 2014

Abstract
Signal transduction pathways regulating NF-κB activation essential for microenvironment formation in secondary lymphoid organs remain to be determined. We investigated the effect of a deficiency of TNFR-associated factor 6 (TRAF6), which activates the classical NF-κB pathway, in splenic microenvironment formation. Two-week-old TRAF6-deficient mice showed severe defects in B cell follicle and marginal zone formation, similar to mutant mice defective in lymphotoxin (Lt) β receptor (LtβR) signal induction of nonclassical NF-κB activation. However, analysis revealed a TRAF6 role in architecture formation distinct from its role in the early neonatal Lt signaling pathway. LtβR signal was essential for primary B cell cluster formation with initial differentiation of follicular dendritic cells (FDCs) in neonatal mice. In contrast, TRAF6 was dispensable for progression to this stage but was required for converting B cell clusters to B cell follicles and maintaining FDCs through to later stages. Fetal liver transfer experiments suggested that TRAF6 in radiation-resistant cells is responsible for follicle formation. Despite FDC-specific surface marker expression, FDCs in neonatal TRAF6-deficient mice had lost the capability to express CXCL13. These data suggest that developmentally regulated activation of TRAF6 in FDCs is required for inducing CXCL13 expression to maintain B cell follicles.
PTEN Down-Regulates IL-17 Expression in a Murine Model of Toluene Diisocyanate-Induced Airway Disease
Authors: Kim So Ri , Lee Kyung Sun , Park Seoung Ju , Min Kyung Hoon , Lee Ka Young , Choe Yeong Hun , Lee Young Rae , Kim Jong Suk , Hong Soo Jong , Lee Yong Chul 
Published: April 2014

AbstractToluene diisocyanate (TDI)-induced airway disease is a disorder characterized by chronic airway inflammation and airway remodeling. A recently discovered group of cytokines is the IL-17 family, which has been introduced as an important regulator of immune and inflammatory responses, including airway inflammation. Recently, we have reported that phosphatase and tensin homologue deleted on chromosome 10 (PTEN) plays a pivotal role in the pathogenesis of bronchial asthma. However, there are no available data for the effects of PTEN or IL-17 on TDI-induced airway disease and the relationship between PTEN and IL-17. We used a murine model to determine the role of PTEN in the pathogenesis of TDI-induced airway disease and the regulation of IL-17 production. These mice developed the typical pathophysiological features of TDI-induced airway disease and increased IL-17 expression in the lungs. Administration of phosphoinositide 3-kinase inhibitors or adenoviruses carrying PTEN cDNA (AdPTEN) reduced the pathophysiological features of TDI-induced airway disease and decreased the increased levels of IL-17 expression. Our results also showed that PI3K inhibitors or AdPTEN down-regulated a transcription factor, NF-κB activity, and BAY 11-7085 substantially reduced the increased levels of IL-17 after TDI inhalation. We also found that inhibition of IL-17 activity with an anti-IL-17 Ab reduced airway inflammation and airway hyperresponsiveness. These results suggest that PTEN plays a protective role in the pathogenesis of TDI-induced airway disease, at least in part through the regulation of IL-17 expression. Thus, PTEN may be a useful target for treating TDI-induced airway disease by modulating IL-17 expression.
Raf Signaling but not the ERK Effector SAP-1 Is Required for Regulatory T Cell Development
Authors: Willoughby Jane E. , Costello Patrick S. , Nicolas Robert H. , Robinson Nicholas J. , Stamp Gordon , Powrie Fiona , Treisman Richard 
Published: April 2014

Abstract
Regulatory T cells (Treg) play an important role in immune regulation. Their development in the thymus requires TCR activation and recognition of peptide-MHC, although the downstream signals controlling commitment to the lineage are unclear. To compare the requirements for positive selection and Treg development, we studied knockout and transgenic mice defective in Raf signaling and the ERK effector SRF accessory protein 1 (SAP-1), a member of the ternary complex factor family of Ets domain transcription factors. Although SAP-1 deficient mice display a severe defect in thymocyte positive selection, Treg development was unimpaired as assessed by expression of Foxp3 and the activation markers CD25, GITR, CTLA4, and CD103 in the CD4+ cell population. In contrast, inhibition of Raf signaling by the interfering dominant negative Raf derivative reduced both Foxp3+ and Foxp3− CD4+ populations. In SAP-1-deficient CD4+CD25+ Treg cells, TCR crosslinking efficiently induced ERK activation, but transcriptional induction of the immediate early gene Egr-1 was impaired. Nevertheless, neither deletion of SAP-1 nor expression of a dominant negative Raf derivative affected the ability of CD4+CD25+ Treg cells to suppress CD4+CD25− cell proliferation in vitro. Finally the suppressive activity of CD4+CD25+ Treg cells lacking SAP-1 in an in vivo colitis model was not significantly impaired. The signaling requirements for development of Treg cells in the thymus are thus distinct from those required for “conventional” T cell positive selection, and ERK signaling to SAP-1 is not required for the suppressive activity of Treg cells.
Trans-Sialidase Recombinant Protein Mixed with CpG Motif-Containing Oligodeoxynucleotide Induces Protective Mucosal and Systemic Trypanosoma cruzi Immunity Involving CD8+ CTL and B Cell-Mediated Cross-Priming
Authors: Hoft Daniel F. , Eickhoff Christopher S. , Giddings Olivia K. , Vasconcelos José R. C. , Rodrigues Maurício M. 
Published: April 2014

Abstract
The Trypanosoma cruzi trans-sialidase (TS) is a unique enzyme with neuraminidase and sialic acid transfer activities important for parasite infectivity. The T. cruzi genome contains a large family of TS homologous genes, and it has been suggested that TS homologues provide a mechanism of immune escape important for chronic infection. We have investigated whether the consensus TS enzymatic domain could induce immunity protective against acute and chronic, as well as mucosal and systemic, T. cruzi infection. We have shown that: 1) TS-specific immunity can protect against acute T. cruzi infection; 2) effective TS-specific immunity is maintained during chronic T. cruzi infection despite the expression of numerous related TS superfamily genes encoding altered peptide ligands that in theory could promote immune tolerization; and 3) the practical intranasal delivery of recombinant TS protein combined with a ssDNA oligodeoxynucleotide (ODN) adjuvant containing unmethylated CpG motifs can induce both mucosal and systemic protective immunity. We have further demonstrated that the intranasal delivery of soluble TS recombinant Ag combined with CpG ODN induces both TS-specific CD4+ and CD8+ T cells associated with vaccine-induced protective immunity. In addition, optimal protection induced by intranasal TS Ag combined with CpG ODN requires B cells, which, after treatment with CpG ODN, have the ability to induce TS-specific CD8+ T cell cross-priming. Our results support the development of TS vaccines for human use, suggest surrogate markers for use in future human vaccine trials, and mechanistically identify B cells as important APC targets for vaccines designed to induce CD8+ CTL responses.
CCAAT/Enhancer-Binding Protein β and δ Binding to CIITA Promoters Is Associated with the Inhibition of CIITA Expression in Response toMycobacterium tuberculosis19-kDa Lipoprotein
Authors: Pennini Meghan E. , Liu Yi , Yang Jianqi , Croniger Colleen M. , Boom W. Henry , Harding Clifford V. 
Published: April 2014

AbstractTLR2 signaling by Mycobacterium tuberculosis 19-kDa lipoprotein (LpqH) inhibits IFN-γ-induced expression of CIITA by macrophages. Microarray analysis, quantitative RT-PCR, and Western blots showed that LpqH induced C/EBPβ and C/EBPδ in kinetic correlation with inhibition of CIITA expression. Of the C/EBPβ isoforms, liver inhibitory protein (LIP) was notably induced and liver-activating protein was increased by LpqH. Putative C/EBP binding sites were identified in CIITA promoters I and IV (pI and pIV). LpqH induced binding of C/EBPβ (LIP and liver-activating protein) to biotinylated oligodeoxynucleotide containing the pI or pIV binding sites, and chromatin immunoprecipitation showed that LpqH induced binding of C/EBPβ and C/EBPδ to endogenous CIITA pI and pIV. Constitutive expression of C/EBPβ LIP inhibited IFN-γ-induced CIITA expression in transfected cells. In summary, LpqH induced expression of C/EBPβ and C/EBPδ, and their binding to CIITA pI and pIV, in correlation with inhibition of IFN-γ-induced expression of CIITA in macrophages, suggesting a role for C/EBP as a novel regulator of CIITA expression.
Inflammasome-Mediated Production of IL-1β Is Required for Neutrophil Recruitment against Staphylococcus aureus In Vivo
Authors: Miller Lloyd S. , Pietras Eric M. , Uricchio Lawrence H. , Hirano Kathleen , Rao Shyam , Lin Heping , O’Connell Ryan M. , Iwakura Yoichiro , Cheung Ambrose L. , Cheng Genhong , Modlin Robert L. 
Published: April 2014

Abstract
IL-1R activation is required for neutrophil recruitment in an effective innate immune response against Staphylococcus aureus infection. In this study, we investigated the mechanism of IL-1R activation in vivo in a model of S. aureus infection. In response to a S. aureus cutaneous challenge, mice deficient in IL-1β, IL-1α/IL-1β, but not IL-1α, developed larger lesions with higher bacterial counts and had decreased neutrophil recruitment compared with wild-type mice. Neutrophil recruitment and bacterial clearance required IL-1β expression by bone marrow (BM)-derived cells and not by non-BM-derived resident cells. In addition, mice deficient in the inflammasome component apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) had the same defects in neutrophil recruitment and host defense as IL-1β-deficient mice, demonstrating an essential role for the inflammasome in mediating the production of active IL-1β to promote neutrophil recruitment in host defense against S. aureus. This finding was further supported by the ability of recombinant active IL-1β to control the infection and promote bacterial clearance in IL-1β-deficient mice. These studies define a key host defense circuit where inflammasome-mediated IL-1β production by BM-derived cells signals IL-1R on non-BM-derived resident cells to activate neutrophil recruitment in the innate immune response against S. aureus in vivo.
Noduler, A Novel Immune Up-Regulated Protein Mediates Nodulation Response in Insects
Authors: Gandhe Archana S. , John Serene H. , Nagaraju Javaregowda 
Published: April 2014

Abstract
Insect immune system comprises of both humoral and cellular defenses. Nodulation is one of the major, yet very poorly understood cellular responses against microbial infections in insects. Through screening for novel immune genes from an Indian saturniid silkmoth Antheraea mylitta, we identified a protein up-regulated in hemolymph within minutes upon bacterial challenge. We have shown here, for first time, the involvement of this novel protein in mediating nodulation response against bacteria and hence designated it as Noduler. Noduler possessed a characteristic reeler domain found in several extracellular matrix vertebrate proteins. Noduler was shown in vitro to bind a wide range of bacteria, yeast, and also insect hemocytes. Furthermore, Noduler specifically bound LPS, lipotechoic acid, and β-1, 3 glucan components of microbial cell walls. RNA-interference mediated knock-down of the Noduler resulted in significant reduction in the number of nodules and consequent increase in bacterial load in larval hemolymph. The results suggest that the Noduler is widely conserved and is involved in very early clearance of bacteria by forming nodules of hemocytes and bacterial complexes in insects. The results would promote further studies for understanding of the crucial but hitherto overlooked nodulation mechanism in insects and also provide cues for the study of similar mammalian proteins whose function is not understood.
Altered Inflammatory Responses in TLR5-Deficient Mice Infected with Legionella pneumophila
Authors: Hawn Thomas R. , Berrington William R. , Smith Ian A. , Uematsu Satoshi , Akira Shizuo , Aderem Alan , Smith Kelly D. , Skerrett Shawn J. 
Published: April 2014

Abstract
Legionella pneumophila (Lp), an important cause of morbidity and mortality from pneumonia, infects alveolar macrophages (AMs) and is recognized by several TLRs as well as Birc1e (NAIP5) and IL-1 converting enzyme-protease activating factor. We examined the role of TLR5 during the murine response to aerosolized Lp infection. At 4 h after infection, Tlr5−/− mice had lower numbers of polymorphonuclear neutrophils (PMNs) in their broncho-alveolar lavage fluid in comparison to wild-type (WT) mice. At 24 and 72 h, the PMN recruitment was similar. WT mice infected with a flagellin-deficient strain (LpFlaA−) also showed an impaired early PMN response at 4 h compared with those infected with the WT strain. There was no consistent difference in bacterial counts at any of the time points when comparing the Tlr5−/− and WT mice. However, at 6 days after infection, the Tlr5−/− mice had increased leukocytic infiltrates in the alveolar and peribronchial interstitial spaces that were consistent with organizing pneumonia. We also examined the role of TLR5 during macrophage infection. In contrast to bone marrow-derived macrophages, AMs secreted TNF-α after stimulation with purified flagellin. In addition, WT, but not Tlr5−/−, AMs produced TNF-α after stimulation with Lp. Live LpFlaA− did not induce TNF-α secretion in AM. These results suggested that AMs recognize Lp flagellin and that a majority of the Lp-induced TNF-α response is TLR5-mediated. Thus, TLR5 mediates recognition of Lp in AMs and performs a distinct role during the in vivo pulmonary immune response through regulation of early PMN recruitment and subsequent later development of pneumonia.