bluuebunny/crossref_metadata_2025_split huggingface dataset:
Redox Equilibrium in Mucosal T Cells Tunes the Intestinal TCR Signaling Threshold
Authors: Reyes Brenda M. Rivera , Danese Silvio , Sans Miquel , Fiocchi Claudio , Levine Alan D. 
Published: April 2014

AbstractMucosal immune tolerance in the healthy intestine is typified by lamina propria T cell (LPT) functional hyporesponsiveness after TCR engagement when compared with peripheral blood T cell (PBT). When LPT from an inflamed intestine are activated through TCR cross-linking, their responsiveness is stronger. LPT are thus capable of switching from a tolerant to a reactive state, toggling between high and low thresholds of activation. We demonstrate that in normal LPT global tyrosine phosphorylation upon TCR cross-linking or an increase in intracellular H2O2, an inhibitor of protein tyrosine phosphatases, is muted. Thus, we propose that LPT have a greater reducing capacity than PBT, shifting the balance between kinases and protein tyrosine phosphatases in favor of the latter. Surface γ-glutamyl transpeptidase, an indirect indicator of redox potential, and glutathione are significantly elevated in LPT compared with PBT, suggesting that elevated glutathione detoxifies TCR-induced reactive oxygen species. When glutathione is depleted, TCR-induced LPT tyrosine phosphorylation rises to PBT levels. Conversely, increasing glutathione in PBT attenuates tyrosine phosphorylation. In LPT isolated from inflamed mucosa, TCR cross-linking induces greater phosphorylation, and γ-glutamyl transpeptidase levels are reduced compared with those from autologous noninflamed tissue. We conclude that the high TCR signaling threshold of mucosal T cells is tuned by intracellular redox equilibrium, whose dysregulation may mediate intestinal inflammation.
A Role for IL-27 in Early Regulation of Th1 Differentiation
Authors: Owaki Toshiyuki , Asakawa Masayuki , Morishima Noriko , Hata Kikumi , Fukai Fumio , Matsui Masanori , Mizuguchi Junichiro , Yoshimoto Takayuki 
Published: April 2014

Abstract
IL-27 is a novel IL-6/IL-12 family cytokine that is considered to play a role in Th1 differentiation, whereas the exact role of IL-27 in Th1 differentiation and its molecular mechanism remain unclear. In this study we demonstrate a role for IL-27 in the early regulation of Th1 differentiation and its possible molecular mechanism. The ability of IL-27 to induce Th1 differentiation was most prominent under Th1-polarizing conditions, but without IL-12 in a STAT4- and IFN-γ-independent manner, and was overruled by IL-12 dose dependently. IL-27 rapidly up-regulated the expression of ICAM-1 on naive CD4+ T cells, but not on APCs, and blocking Abs against ICAM-1 and LFA-1 inhibited the IL-27-induced Th1 differentiation. Although IL-27 augmented T-bet expression in naive CD4+ T cells as previously reported, T-bet was not necessary for the IL-27-induced rapid up-regulation of ICAM-1 expression and Th1 differentiation. In contrast, STAT1 was revealed to be required for the rapid up-regulation of ICAM-1 expression and Th1 differentiation by directly mediating the transcriptional enhancement of ICAM-1 gene expression. These results indicate that IL-27 efficiently induces Th1 differentiation under Th1-polarizing conditions, but without IL-12, and that the rapid up-regulation of ICAM-1 expression on naive CD4+ T cells is important for the IL-27-induced Th1 differentiation. Considering that IL-27 is produced from macrophages and DCs earlier than IL-12, the present results suggest that IL-27 may play a pivotal role in early efficient induction of Th1 differentiation until sufficient IL-12 is produced.
Lack of ICAM-1 on APCs during T Cell Priming Leads to Poor Generation of Central Memory Cells
Authors: Parameswaran Neetha , Suresh Radhakrishnan , Bal Vineeta , Rath Satyajit , George Anna 
Published: April 2014

Abstract
ICAM-1/LFA-1 interactions are known to enhance T cell/APC interactions and to promote T cell activation and cytokine secretion. We have analyzed the consequences of ICAM-1-mediated signaling on the generation of memory T cell subsets. We report that lack of ICAM-1 on APCs, but not on T cells, leads to poor T cell activation and proliferation in vitro and in vivo, and that the defect can be compensated by Ag dose, exogenous IL-2, additional costimulation, and by increasing responder T cell density on APCs. ICAM-1-null mice do not respond to immunization with OVA peptide, but immunization with OVA or with Salmonella typhimurium leads to good T cell proliferation 7–10 days later, and clearance of a challenge infection is equivalent to that of wild-type mice. However, when followed over time, recall proliferation and antibacterial immunity decay rapidly in ICAM-1-null mice, while recall cytokine responses are unaffected. The decline in immunity is not related to poor survival of T cells activated on ICAM-1-null APCs, or to poor generation of effectors in ICAM-1-null mice. Phenotypic analysis of T cells stimulated on ICAM-1-null APCs reveals preferential generation of CD44highCD62Llow effector memory cells (TEM) over CD44highCD62Lhigh central memory cells (TCM). Further, while the proportion of naive:memory T cells is similar in unmanipulated wild-type and ICAM-1-null mice, there is an accumulation of TEM cells, and a high TEM: TCM ratio in aging ICAM-1-null mice. Together, the data indicate that signaling through LFA-1 during T cell activation may be involved in commitment to a proliferation-competent memory pool.
Enhancement of Dendritic Cell Antigen Cross-Presentation by CpG DNA Involves Type I IFN and Stabilization of Class I MHC mRNA
Authors: Kuchtey John , Chefalo Peter J. , Gray Reginald C. , Ramachandra Lakshmi , Harding Clifford V. 
Published: April 2014

Abstract
Dendritic cells (DCs) internalize exogenous Ags and process them for cross-presentation by class I MHC (MHC-I) to CD8+ T cells. This processing can occur by transporter for Ag presentation (TAP)-dependent or TAP-independent mechanisms. We observed that CpG DNA enhanced cross-presentation of Ags by Flt-3L-cultured bone marrow-derived murine DCs by a type I IFN (IFN-αβ)-dependent mechanism. Myeloid DCs provided cross-presentation function in this system. Both TAP1 knockout and wild-type DCs showed enhanced cross-presentation when treated with CpG DNA at 26°C, demonstrating that TAP is not essential to this regulatory mechanism, although TAP is an important determinant of MHC-I expression. Enhancement of cross-processing by CpG DNA did not involve increased Ag uptake or proteolysis but did correlate with IFN-αβ-dependent increases in expression of MHC-I mRNA and protein. Increased MHC-I mRNA levels resulted in part from stabilization of MHC-I mRNA, a novel posttranscriptional mechanism for regulation of MHC-I expression. Thus, a major mechanism by which CpG oligodeoxynucleotide increase cross presentation by DCs appears to be an IFN-αβ-mediated increase in MHC-I synthesis.
Novel Ganglioside Antigen Identified by B Cells in Human Medullary Breast Carcinomas: The Proof of Principle Concerning the Tumor-Infiltrating B Lymphocytes
Authors: Kotlan Beatrix , Simsa Peter , Teillaud Jean-Luc , Fridman Wolf Herman , Toth Jozsef , McKnight Michael , Glassy Mark C. 
Published: April 2014

AbstractThe potential tumor-recognizing capacity of B cells infiltrating human breast carcinoma is an important aspect of breast cancer biology. As an experimental system, we used human medullary breast carcinoma because of its heavy B lymphocytic infiltration paralleled to a relatively better prognosis. Ig-rearranged V region VH-JH, Vκ-Jκ, and Vλ-Jλ genes, amplified by RT-PCR of the infiltrating B cells, were cloned, sequenced, and subjected to a comparative DNA analysis. A combinatorial single-chain variable fragment Ab minilibrary was constructed out of randomly selected VH and Vκ clones and tested for binding activity. Our data analysis revealed that some of the VH-JH, Vκ-Jκ, and Vλ-Jλ region sequences were being assigned to clusters with oligoclonal predominance, while other characteristics of the Ab repertoire were defined also. A tumor-restricted binder clone could be selected out of the single-chain variable fragment κ minilibrary tested against membrane fractions of primary breast tumor cells and tumor cell lines, the VH of which proved to be the overexpressed VH3-1 cluster. The specific binding was confirmed by FACS analysis with primary breast carcinoma cells and MDA-MB 231 cell line. ELISA and thin layer chromatography dot-blot experiments showed this target Ag to be a ganglioside D3 (GD3). Our results are a proof of principle about the capacity of B cells infiltrating breast carcinomas to reveal key cancer-related Ags, such as the GD3. GD3-specific Abs may influence tumor cell progression and could be used for further development of diagnostic and/or therapeutic purposes.
Specific Inhibition of c-Raf Activity by Semapimod Induces Clinical Remission in Severe Crohn’s Disease
Authors: Löwenberg Mark , Verhaar Auke , van den Blink Bernt , ten Kate Fibo , van Deventer Sander , Peppelenbosch Maikel , Hommes Daniel 
Published: April 2014

Abstract
There is a substantial need for novel treatment strategies in Crohn’s disease (CD), a chronic relapsing inflammatory disease of the gut. In an earlier study, we reported clinical efficacy of a 2-wk treatment with semapimod (CNI-1493) in 12 patients with therapy resistant CD. The aim of this study was to identify the cellular target underlying semapimod action. In vitro experiments with murine macrophages showed impaired MAPK signaling and decreased cytokine production due to semapimod treatment. In vitro kinase assays revealed c-Raf as a direct molecular target of semapimod, and semapimod did not affect b-Raf enzymatic activity. Immunohistochemistry performed on paired colon biopsies obtained from CD patients (n = 6) demonstrated increased expression of phospho-MEK, the substrate of Raf. Strikingly, phospho-MEK levels were significantly decreased in patients with a good clinical response to semapimod, but no decrease in phospho-MEK expression was observed in a clinically nonresponsive patient. In conclusion, this study identifies c-Raf as a molecular target of semapimod action and suggests that decreased c-Raf activity correlates with clinical benefit in CD. Our observations indicate that c-Raf inhibitors are prime candidates for the treatment of CD.
The Role of ICOS in the CXCR5+ Follicular B Helper T Cell Maintenance In Vivo
Authors: Akiba Hisaya , Takeda Kazuyoshi , Kojima Yuko , Usui Yoshihiko , Harada Norihiro , Yamazaki Tomohide , Ma Juan , Tezuka Katsunari , Yagita Hideo , Okumura Ko 
Published: April 2014

Abstract
ICOS is a new member of the CD28 family of costimulatory molecules that is expressed on activated T cells. Its ligand B7RP-1 is constitutively expressed on B cells. Although the blockade of ICOS/B7RP-1 interaction inhibits T cell-dependent Ab production and germinal center formation, the mechanism remains unclear. We examined the contribution of ICOS/B7RP-1 to the generation of CXCR5+ follicular B helper T (TFH) cells in vivo, which preferentially migrate to the B cell zone where they provide cognate help to B cells. In the spleen, anti-B7RP-1 mAb-treated or ICOS-deficient mice showed substantially impaired development of CXCR5+ TFH cells and peanut agglutinin+ germinal center B cells in response to primary or secondary immunization with SRBC. Expression of CXCR5 on CD4+ T cells was associated with ICOS expression. Adoptive transfer experiments showed that the development of CXCR5+ TFH cells was enhanced by interaction with B cells, which was abrogated by anti-B7RP-1 mAb treatment. The development of CXCR5+ TFH cells in the lymph nodes was also inhibited by the anti-B7RP-1 mAb treatment. These results indicated that the ICOS/B7RP-1 interaction plays an essential role in the development of CXCR5+ TFH cells in vivo.
CC Chemokine Ligand 19 Secreted by Mature Dendritic Cells Increases Naive T Cell Scanning Behavior and Their Response to Rare Cognate Antigen
Authors: Kaiser Andrew , Donnadieu Emmanuel , Abastado Jean-Pierre , Trautmann Alain , Nardin Alessandra 
Published: April 2014

Abstract
For immune responses to take place, naive T cells have to encounter, adhere to, and be stimulated by dendritic cells (DCs). In murine lymph nodes, T cells move randomly and scan the surface of multiple DCs. The factors controlling this motility as well as its consequences remain unclear. We have monitored by video-imaging the earliest steps of the interaction between human DCs and autologous naive CD4+ T cells in the absence of exogenous Ags. Mature, but not immature, DCs were able to elicit small calcium responses in naive T cells along with cell polarization and random motility, resulting in an efficient scanning of DC surfaces by T cells. We identified CCL19 as a key factor enabling all these early T cell responses, including the occurrence of calcium transients. Because this chemokine did not influence the strength of naive T cell adhesion to DCs, enhanced LFA-1 affinity for ICAM-1 was not the main mechanism by which CCL19 increased Ag-independent calcium transients. However, concomitantly to T cell motility, CCL19 augmented the frequency of T cell responses to rare anti-CD3/CD28-coated beads, used as surrogate APCs. We thus propose a new role for CCL19 in humans: by conditioning T cells into a motile DC-scanning state, this chemokine promotes Ag-independent responses and increases the probability of cognate MHC-peptide encounter.
Coordinate Analysis of Murine Immune Cell Surface Markers and Intracellular Phosphoproteins by Flow Cytometry
Authors: Krutzik Peter O. , Clutter Matthew R. , Nolan Garry P. 
Published: April 2014

Abstract
Recently, phosphospecific flow cytometry has emerged as a powerful tool to analyze intracellular signaling events in complex populations of cells because of its ability to simultaneously discriminate cell types based on surface marker expression and measure levels of intracellular phosphoproteins. This has provided novel insights into the cell- and pathway-specific nature of immune signaling. However, we and others have found that the fixation and permeabilization steps necessary for phosphoprotein analysis often negatively affect the resolution of cell types based on surface marker analysis and light scatter characteristics. Therefore, we performed a comprehensive profile of &gt;35 different murine surface marker Abs to understand the effects of fixation and permeabilization on surface Ag staining. Fortuitously, ∼80% of the Abs tested resolved cell populations of interest, although with decreased separation between positive and negative populations and at very different titers than those used on live cells. The other 20% showed either complete loss of separation between populations or loss of intermediately staining populations. We were able to rescue staining of several of these Ags by performing staining after fixation, but before permeabilization, although with limited fluorophore choices. Scatter characteristics of lymphocytes were well retained, but changed dramatically for monocyte and neutrophil populations. These results compile a comprehensive resource for researchers interested in applying phosphospecific flow cytometry to complex populations of cells while outlining steps necessary to successfully apply new surface marker Abs to this platform.
ERK1-Deficient Mice Show Normal T Cell Effector Function and Are Highly Susceptible to Experimental Autoimmune Encephalomyelitis
Authors: Nekrasova Tanya , Shive Carey , Gao Yuehua , Kawamura Kazuyuki , Guardia Rocio , Landreth Gary , Forsthuber Thomas G. 
Published: April 2014

AbstractT cell activation engages multiple intracellular signaling cascades, including the ERK1/2 (p44/p42) pathway. It has been suggested that ERKs integrate TCR signal strength, and are important for thymocyte development and positive selection. However, the requirement of ERKs for the effector functions of peripheral mature T cells and, specifically, for T cell-mediated autoimmunity has not been established. Moreover, the specific requirements for ERK1 vs ERK2 in T cells have not been resolved. Therefore, we investigated the role of ERK1 in T cell immunity to foreign and self Ags and in the induction of experimental autoimmune encephalomyelitis. The results show that in ERK1-deficient (ERK1−/−) mice, the priming, proliferation, and cytokine secretion of T cells to the self Ag myelin oligodendrocyte glycoprotein peptide 35–55 and to the prototypic foreign Ag OVA are not impaired as compared with wild-type mice. Furthermore, ERK1−/− mice are highly susceptible to experimental autoimmune encephalomyelitis induced with myelin oligodendrocyte glycoprotein peptide 35–55. Finally, thymocyte development and mitogen-induced proliferation were not impaired in ERK1−/− mice on the inbred 129 Sv and C57BL/6 backgrounds. Collectively, the data show that ERK1 is not critical for the function of peripheral T cells in the response to self and foreign Ags and in T cell-mediated autoimmunity, and suggest that its loss can be compensated by ERK2.
Systemic Autoimmune Disease Caused by Autoreactive B Cells That Receive Chronic Help from Ig V Region-Specific T Cells
Authors: Munthe Ludvig André , Corthay Alexandre , Os Audun , Zangani Michael , Bogen Bjarne 
Published: April 2014

Abstract
B cells present BCR V region-derived Id-peptides on their MHC class II molecules to Id-specific CD4+ T cells. Prolonged Id-driven T-B collaboration could cause autoimmune disease, but this possibility is difficult to test in normal individuals. We have investigated whether mice doubly transgenic for an Id+ Ig L chain and an Id-specific TCR develop autoimmune disease. Surprisingly, T cell tolerance was not complete in these mice because a low frequency of weakly Id-reactive CD4+ T cells accumulated with age. These escapee Id-specific T cells provided chronic help for Id+ B cells, resulting in a lethal systemic autoimmune disease including germinal center reactions, hypergammaglobulinemia, IgG autoantibodies, glomerulonephritis, arthritis, skin affection, and inflammatory bowel disease. Inflamed tissues contained foci of Id-driven T-B collaboration, with deposition of IgG and complement. The disease could be transferred with B and T cells. The results demonstrate a novel mechanism for development of autoimmune disease in which self-reactive Id+ B cells receive prolonged help from Id-specific T cells, thus bypassing the need for help from T cells recognizing conventional Ag.
Immature CD4−CD103+ Rat Dendritic Cells Induce Rapid Caspase-Independent Apoptosis-Like Cell Death in Various Tumor and Nontumor Cells and Phagocytose Their Victims
Authors: Trinité Benjamin , Chauvin Camille , Pêche Hélène , Voisine Cécile , Heslan Michèle , Josien Régis 
Published: April 2014

Abstract
We previously reported the characterization of a MHC class IIlowCD4−CD103+ (CD4−) subset of dendritic cells (DC) in rat spleen that exhibit a Ca2+-, Fas ligand-, TRAIL- and TNF-α-independent cytotoxic activity against specific targets in vitro. In this study, we demonstrate that this DC subset was also found in lymph nodes. Freshly extracted and, therefore, immature CD4− DC exhibited a potent cytotoxic activity against a large panel of tumor cell lines as well as primary endothelial cells. The cytotoxic activity of immature CD4− DC required cell-to-cell contact and de novo protein expression. CD4− DC-mediated cell death resembled apoptosis, as evidenced by outer membrane phosphatidylserine exposure and nuclear fragmentation in target cells, but was caspase as well as Fas-associated death domain and receptor-interacting protein independent. Bcl-2 overexpression in target cells did not protect them against DC-mediated cell death. Immature CD4− DC phagocytosed efficiently apoptotic cells in vitro and, therefore, rapidly and specifically engulfed their victims following death induction. Maturation induced a dramatic down-regulation of the killing and phagocytic activities of CD4− DC. In contrast, CD4+ DC were both unable to kill target cells and to phagocytose apoptotic cells in vitro. Taken together, these data indicate that rat immature CD4−CD103+ DC mediate an unusual cytotoxic activity and can use this function to efficiently acquire Ag from live cells.
Characterization of a C3a Receptor in Rainbow Trout and Xenopus: The First Identification of C3a Receptors in Nonmammalian Species
Authors: Boshra Hani , Wang Tiehui , Hove-Madsen Leif , Hansen John , Li Jun , Matlapudi Anjun , Secombes Christopher J. , Tort Lluis , Sunyer J. Oriol 
Published: April 2014

Abstract
Virtually nothing is known about the structure, function, and evolutionary origins of the C3aR in nonmammalian species. Because C3aR and C5aR are thought to have arisen from the same common ancestor, the recent characterization of a C5aR in teleost fish implied the presence of a C3aR in this animal group. In this study we report the cloning of a trout cDNA encoding a 364-aa molecule (TC3aR) that shows a high degree of sequence homology and a strong phylogenetic relationship with mammalian C3aRs. Northern blotting demonstrated that TC3aR was expressed primarily in blood leukocytes. Flow cytometric analysis and immunofluorescence microscopy showed that Abs raised against TC3aR stained to a high degree all blood B lymphocytes and, to a lesser extent, all granulocytes. More importantly, these Abs inhibited trout C3a-mediated intracellular calcium mobilization in trout leukocytes. A fascinating structural feature of TC3aR is the lack of a significant portion of the second extracellular loop (ECL2). In all C3aR molecules characterized to date, the ECL2 is exceptionally large when compared with the same region of C5aR. However, the exact function of the extra portion of ECL2 is unknown. The lack of this segment in TC3aR suggests that the extra piece of ECL2 was not necessary for the interaction of the ancestral C3aR with its ligand. Our findings represent the first C3aR characterized in nonmammalian species and support the hypothesis that if C3aR and C5aR diverged from a common ancestor, this event occurred before the emergence of teleost fish.
HLA-B27 Misfolding in Transgenic Rats Is Associated with Activation of the Unfolded Protein Response
Authors: Turner Matthew J. , Sowders Dawn P. , DeLay Monica L. , Mohapatra Rajashree , Bai Shuzhen , Smith Judith A. , Brandewie Jaclyn R. , Taurog Joel D. , Colbert Robert A. 
Published: April 2014

Abstract
The mechanism by which the MHC class I allele, HLA-B27, contributes to spondyloarthritis pathogenesis is unknown. In contrast to other alleles that have been examined, HLA-B27 has a tendency to form high m.w. disulfide-linked H chain complexes in the endoplasmic reticulum (ER), bind the ER chaperone BiP/Grp78, and undergo ER-associated degradation. These aberrant characteristics have provided biochemical evidence that HLA-B27 is prone to misfold. Recently, similar biochemical characteristics of HLA-B27 were reported in cells from HLA-B27/human β2-microglobulin transgenic (HLA-B27 transgenic) rats, an animal model of spondyloarthritis, and correlated with disease susceptibility. In this study, we demonstrate that the unfolded protein response (UPR) is activated in macrophages derived from the bone marrow of HLA-B27 transgenic rats with inflammatory disease. Microarray analysis of these cells also reveals an IFN response signature. In contrast, macrophages derived from premorbid rats do not exhibit a strong UPR or evidence of IFN exposure. Activation of macrophages from premorbid HLA-B27 transgenic rats with IFN-γ increases HLA-B27 expression and leads to UPR induction, while no UPR is seen in cells from nondisease-prone HLA-B7 transgenic or wild-type (nontransgenic) animals. This is the first demonstration, to our knowledge, that HLA-B27 misfolding is associated with ER stress that results in activation of the UPR. These observations link HLA-B27 expression with biological effects that are independent of immunological recognition, but nevertheless may play an important role in the pathogenesis of inflammatory diseases associated with this MHC class I allele.