bluuebunny/crossref_metadata_2025_split huggingface dataset:
TLR Activation Synergizes with Kilham Rat Virus Infection to Induce Diabetes in BBDR Rats
Authors: Zipris Danny , Lien Egil , Xie Jenny X. , Greiner Dale L. , Mordes John P. , Rossini Aldo A. 
Published: April 2014

Abstract
Virus infection is hypothesized to be an important environmental “trigger” of type 1 diabetes in humans. We used the BBDR rat model to investigate the relationship between viral infection and autoimmune diabetes. BBDR rats are diabetes-free in viral Ab-free housing, but the disease develops in ∼30% of BBDR rats infected with Kilham rat virus (KRV) through a process that does not involve infection of pancreatic β cells. Pretreatment with polyinosinic-polycytidylic (poly(I:C)), a ligand of TLR3, acts synergistically to induce diabetes in 100% of KRV-infected rats. The mechanisms by which KRV induces diabetes and TLR3 ligation facilitates this process are not clear. In this study, we demonstrate that activation of the innate immune system plays a crucial role in diabetes induction. We report that multiple TLR agonists synergize with KRV infection to induce diabetes in BBDR rats, as do heat-killed Escherichia coli or Staphylococcus aureus (natural TLR agonists). KRV infection increases serum IL-12 p40 in a strain-specific manner, and increases IL-12 p40, IFN-γ-inducible protein-10, and IFN-γ mRNA transcript levels, particularly in the pancreatic lymph nodes of BBDR rats. Infection with vaccinia virus or H-1 parvovirus induced less stimulation of the innate immune system and failed to induce diabetes in BBDR rats. Our results suggest that the degree to which the innate immune system is activated by TLRs is important for expression of virus-induced diabetes in genetically susceptible hosts.
Enhanced Tolerance to Autoimmune Uveitis in CD200-Deficient Mice Correlates with a Pronounced Th2 Switch in Response to Antigen Challenge
Authors: Taylor Neil , McConnachie Karen , Calder Claudia , Dawson Rosemary , Dick Andrew , Sedgwick Jonathon D. , Liversidge Janet 
Published: April 2014

Abstract
A single exposure to inhaled Ag 10 days before immunization leads to long term, Ag-specific tolerance. Respiratory tract myeloid APCs are implicated, but how regulation is invoked, and how tolerance is sustained are unclear. This study examines the in vivo function of the myeloid regulatory molecule CD200 in the process of tolerance induction. Despite earlier onset of experimental autoimmune uveitis in sham-tolerized, CD200-deficient mice, disease incidence and subsequent severity were actually reduced compared with those in wild-type mice. Protection was more effective and long term, lasting at least 28 days. Halting disease progression and tolerance in CD200−/− mice correlated with a marked increase in Th2-associated cytokine production by Ag-challenged splenocytes. Reduced overall disease and enhanced tolerance in the CD200-deficient mice in this model system were unexpected and may be related to altered populations of MHC class IIlow APC in the respiratory tract compared with wild-type mice together with associated activation of STAT6 in draining lymph nodes of tolerized mice. These data indicate that in the absence of default inhibitory CD200 receptor signaling, alternative, powerful regulatory mechanisms are invoked. This may represent either permissive dominant Th2 activation or an altered hierarchy of negative signaling by other myeloid cell-expressed regulatory molecules.
Uncoupling of IL-2 Signaling from Cell Cycle Progression in Naive CD4+ T Cells by Regulatory CD4+CD25+ T Lymphocytes
Authors: Duthoit Christine T. , Mekala Divya J. , Alli Rajshekkhar S. , Geiger Terrence L. 
Published: April 2014

Abstract
Prior reports have shown that CD4+CD25+ regulatory T cells suppress naive T cell responses by inhibiting IL-2 production. In this report, using an Ag-specific TCR transgenic system, we show that naive T cells stimulated with cognate Ag in the presence of preactivated CD4+CD25+ T cells also become refractory to the mitogenic effects of IL-2. T cells stimulated in the presence of regulatory T cells up-regulated high affinity IL-2R, but failed to produce IL-2, express cyclins or c-Myc, or exit G0-G1. Exogenous IL-2 failed to break the mitotic block, demonstrating that the IL-2 production failure was not wholly responsible for the proliferation defect. This IL-2 unresponsiveness did not require the continuous presence of CD4+CD25+ regulatory T cells. The majority of responder T cells reisolated after coculture with regulatory cells failed to proliferate in response to IL-2, but were not anergic and proliferated in response to Ag. The mitotic block was also dissociated from the antiapoptotic effects of IL-2, because IL-2 still promoted the survival of T cells that had been cocultured with CD4+CD25+ T cells. IL-2-induced STAT5 phosphorylation in the cocultured responder cells was intact, implying that the effects of the regulatory cells were downstream of receptor activation. Our results therefore show that T cell activation in the presence of CD4+CD25+ regulatory T cells can induce an alternative stimulation program characterized by up-regulation of high affinity IL-2R, but a failure to produce IL-2, and uncoupling of the mitogenic and antiapoptotic effects of IL-2.
CTLA-4 Signaling Regulates the Intensity of Hypersensitivity Responses to Food Antigens, but is Not Decisive in the Induction of Sensitization
Authors: van Wijk Femke , Hoeks Sanne , Nierkens Stefan , Koppelman Stef J. , van Kooten Peter , Boon Louis , Knippels Léon M. J. , Pieters Raymond 
Published: April 2014

Abstract
Although food allergy has emerged as a major health problem, the mechanisms that are decisive in the development of sensitization to dietary Ag remain largely unknown. CTLA-4 signaling negatively regulates immune activation, and may play a crucial role in preventing induction and/or progression of sensitization to food Ag. To elucidate the role of CTLA-4 signaling in responses to food allergens, a murine model of peanut allergy was used. During oral exposure to peanut protein extract (PPE) together with the mucosal adjuvant cholera toxin (CT), which induces peanut allergy, CTLA-4 ligation was prevented using a CTLA-4 mAb. Additionally, the effect of inhibition of the CTLA-4 pathway on oral exposure to PPE in the absence of CT, which leads to unresponsiveness to peanut Ag, was explored. During sensitization, anti-CTLA-4 treatment considerably enhanced IgE responses to PPE and the peanut allergens, Ara h 1, Ara h 3, and Ara h 6, resulting in elevated mast cell degranulation upon an oral challenge. Remarkably, antagonizing CTLA-4 during exposure to PPE in the absence of CT resulted in significant induction of Th2 cytokines and an elevation in total serum IgE levels, but failed to induce allergen-specific IgE responses and mast cell degranulation upon a PPE challenge. These results indicate that CTLA-4 signaling is not the crucial factor in preventing sensitization to food allergens, but plays a pivotal role in regulating the intensity of a food allergic sensitization response. Furthermore, these data indicate that a profoundly Th2-biased cytokine environment is insufficient to induce allergic responses against dietary Ag.
CD28 Regulates the Translation of Bcl-xL via the Phosphatidylinositol 3-Kinase/Mammalian Target of Rapamycin Pathway
Authors: Wu Linda X. , La Rose Jose , Chen Liane , Neale Chris , Mak Tak , Okkenhaug Klaus , Wange Ronald , Rottapel Robert 
Published: April 2014

Abstract
In concert with the TCR, CD28 promotes T cell survival by regulating the expression of the antiapoptotic protein Bcl-xL. The mechanism by which CD28 mediates the induction of Bcl-xL remains unknown. We show that although signaling through the TCR is sufficient to stimulate transcription of Bcl-xL mRNA, CD28, by activating PI3K and mammalian target of rapamycin, provides a critical signal that regulates the translation of Bcl-xL transcripts. We observe that CD28 induced 4E-binding protein-1 phosphorylation, an inhibitor of the translational machinery, and that CD28 costimulation directly augmented the translation of a Bcl-xL 5′-untranslated region reporter construct. Lastly, costimulation by CD28 shifted the distribution of Bcl-xL mRNA transcripts from the pretranslation complex to the translationally active polyribosomes. These results demonstrate that CD28 relieves the translational inhibition of Bcl-xL in a PI3K/mammalian target of rapamycin-dependent manner.
Generation of Murine CTL by a Hepatitis B Virus-Specific Peptide and Evaluation of the Adjuvant Effect of Heat Shock Protein Glycoprotein 96 and Its Terminal Fragments
Authors: Li Hongtao , Zhou Minghai , Han Jinle , Zhu Xiaodong , Dong Tao , Gao George F. , Tien Po 
Published: April 2014

AbstractPreviously, we reported that a 7-mer HLA-A11-restricted peptide (YVNTNMG) of hepatitis B virus (HBV) core Ag (HBcAg88–94) was associated with heat shock protein (HSP) gp96 in liver tissues of patients with HBV-induced hepatocellular carcinoma (HCC). This peptide is highly homologous to a human HLA-A11-restricted 9-mer peptide (YVNVNMGLK) and to a mouse H-2-Kd-restricted 9-mer peptide (SYVNTNMGL). To further characterize its immunogenicity, BALB/c mice were vaccinated with the HBV 7-mer peptide. It was found that a specific CTL response was induced by the 7-mer peptide, although the response was ∼50% of that induced by the mouse H-2-Kd-restricted 9-mer peptide, as detected by ELISPOT, tetramer, and 51Cr release assays. To evaluate the adjuvant effect of HSP gp96, mice were coimmunized with gp96 and the 9-mer peptide, and a significant adjuvant effect was observed with gp96. To further determine whether the immune effect of gp96 was dependent on peptide binding, the N- and C-terminal fragments of gp96, which are believed to contain the putative peptide-binding domain, were cloned and expressed in Escherichia coli. CTL assays indicated that only the N-terminal fragment, but not the C-terminal fragment, was able to produce the adjuvant effect. These results clearly demonstrated the potential of using gp96 or its N-terminal fragment as a possible adjuvant to augment CTL response against HBV infection and HCC.
Hyperthermia Enhances CD95-Ligand Gene Expression in T Lymphocytes
Authors: Cippitelli Marco , Fionda Cinzia , Di Bona Danilo , Piccoli Mario , Frati Luigi , Santoni Angela 
Published: April 2014

AbstractHyperthermia represents an interesting therapeutic strategy for the treatment of tumors. Moreover, it is able to regulate several aspects of the immune response. Fas (APO-1/CD95) and its ligand (FasL) are cell surface proteins whose interaction activates apoptosis of Fas-expressing targets. In T cells, the Fas-Fas-L system regulates activation-induced cell death, is implicated in diseases in which lymphocyte homeostasis is compromised, and plays an important role during cytotoxic and regulatory actions mediated by these cells. In this study we describe the effect of hyperthermia on activation of the fas-L gene in T lymphocytes. We show that hyperthermic treatment enhances Fas-L-mediated cytotoxicity, fas-L mRNA expression, and fas-L promoter activity in activated T cell lines. Our data indicate that hyperthermia enhances the transcriptional activity of AP-1 and NF-κB in activated T cells, and this correlates with an increased expression/nuclear translocation of these transcription factors. Moreover, we found that heat shock factor-1 is a transactivator of fas-L promoter in activated T cells, and the overexpression of a dominant negative form of heat shock factor-1 may attenuate the effect of hyperthermia on fas-L promoter activity. Furthermore, overexpression of dominant negative mutants of protein kinase Cε (PKCε) and PKCθ partially inhibited the promoter activation and, more importantly, could significantly reduce the enhancement mediated by hyperthermia, indicating that modulation of PKC activity may play an important role in this regulation. These results add novel information on the immunomodulatory action of heat, in particular in the context of its possible use as an adjuvant therapeutic strategy to consider for the treatment of cancer.
The Immunomodulatory Effects of Novel β-Oxa, β-Thia, and γ-Thia Polyunsaturated Fatty Acids on Human T Lymphocyte Proliferation, Cytokine Production, and Activation of Protein Kinase C and MAPKs
Authors: Costabile Maurizio , Hii Charles S. T. , Melino Michelle , Easton Christopher , Ferrante Antonio 
Published: April 2014

Abstract
We have recently demonstrated that a novel n-3 long chain polyunsaturated fatty acid (PUFA) (β-oxa 21:3n-3) was a more potent and more selective anti-inflammatory agent than n-3 PUFA. To gain further insights into this technology, we synthesized other novel PUFA consisting of β-oxa, β-thia, and γ-thia compounds. All three types displayed anti-inflammatory activity. Each of the unsaturated β-oxa fatty acids showed similar inhibition of PHA-PMA-induced T cell proliferation with a parallel inhibition of TNF-β production. However, β-oxa 25:6n-3 and β-oxa 21:4n-3 displayed lower inhibitory action on IFN-γ production. Surprisingly, β-oxa 23:4n-6 and β-oxa 21:3n-6 had marginal effect on IL-2 production. Thus, structural variation can generate selectivity for different immunological parameters. The β-thia compounds 23:4n-6, 21:3n-6, and 21:3n-3 were highly effective in inhibiting all immunological responses. Of the two γ-thia PUFA tested, γ-thia 24:4n-6 was a strong inhibitor of all responses apart from IL-2, but γ-thia 22:3n-6 had very little inhibitory effect. Two of the most active compounds, β-thia 23:4n-6 and β-thia 21:3n-6, were studied in more detail and shown to have an IC50 of 1–2 μM under optimal conditions. Thus, these PUFA retain the immunosuppressive properties of the n-3 PUFAs, 20:5n-3 and 22:6n-3, but not the neutrophil-stimulating properties. Their action on T lymphocytes is independent of cyclooxygenase or lipoxygenase activity, and they act at a postreceptor-binding level by inhibiting the activation of protein kinase C and ERK1/ERK2 kinases.
Role for CXCR6 in Recruitment of Activated CD8+ Lymphocytes to Inflamed Liver
Authors: Sato Tohru , Thorlacius Henrik , Johnston Brent , Staton Tracy L. , Xiang Wenkai , Littman Dan R. , Butcher Eugene C. 
Published: April 2014

Abstract
Hepatic infiltration of activated CD8 lymphocytes is a major feature of graft-vs-host disease (GvHD). Chemoattractant cytokines and their receptors are key regulators of lymphocyte trafficking, but the involvement of chemoattractant receptors in the physiologic recruitment of cells into the inflamed liver has not been defined. The present study examines the role of the chemokine receptor CXCR6, which is highly expressed by liver-infiltrating CD8 T cells. Hepatic accumulation of donor CD8, but not donor CD4, lymphocytes was significantly reduced in GvHD induced by transfer of CXCR6−/−, H-2Db lymphocytes into BDF1, H-2Dbxd recipients. To determine whether altered recruitment contributes to the reduced accumulation, CXCR6−/− or wild-type splenic lymphocytes participating in an active GvHD response were isolated and transferred i.v. into secondary recipients with active GvHD, and the short term (6-h) recruitment of transferred cells to the inflamed liver was assessed. CXCR6−/− CD8 (but not CD4) cells displayed a significant (33%) reduction in liver localization, whereas frequencies in blood of CXCR6−/− and wild-type CD8 cells were similar. Proliferation and apoptosis of liver-infiltrating donor CD8 cells were unaffected. We conclude that CXCR6 helps mediate the recruitment of activated CD8 lymphocytes in GvHD-induced hepatitis and may be a useful target to treat pathological inflammation in the liver.
Down-Regulation of Stromal Cell-Derived Factor-1α-Induced T Cell Chemotaxis by a Peptide Based on the Complementarity-Determining Region 1 of an Anti-DNA Autoantibody via Up-Regulation of TGF-β Secretion
Authors: Sela Uri , Hershkoviz Rami , Cahalon Liora , Lider Ofer , Mozes Edna 
Published: April 2014

Abstract
Systemic lupus erythematosus (SLE) can be induced in mice by immunizing them with a monoclonal human anti-DNA Ab that expresses a major Id, designated 16/6Id. In addition, a peptide based on the sequence of the CDR 1 (hCDR1) of the 16/6Id ameliorated the clinical manifestations of SLE in experimental models. In this study we examined the effects of treating mice with human complementary-determining region 1 (hCDR1) on the subsequent chemotaxis of T cells derived from 16/6Id-primed mice. First we demonstrated elevated levels of stromal cell-derived factor-1α (SDF-1α) in the sera of SLE-afflicted mice and in the sera and lymphoid tissues of 16/6Id-immunized BALB/c mice shortly after the immunization. We then found that administration of hCDR1 to 16/6Id-immunized mice specifically down-regulated SDF1α-induced T cell chemotaxis through fibronectin and collagen type I. This was accompanied by diminished SDF1-α-induced T cell adhesion and ERK phosphorylation. Treatment with hCDR1 up-regulated TGF-β secretion, which, in turn, inhibited the murine T cell adhesion to and chemotaxis through fibronectin as well as their ERK phosphorylation. Thus, the secretion of TGF-β after treatment of 16/6Id-immunized mice with hCDR1 plays an important role in the down-regulation of SDF-1α-mediated T cell activation and the interactions with extracellular matrix moieties observed in the present study.
JAK-Mediated Signaling Inhibits Fas Ligand-Induced Apoptosis Independent of De Novo Protein Synthesis
Authors: Cousens Leslie P. , Goulette Frederick A. , Darnowski James W. 
Published: April 2014

Abstract
There is a growing appreciation for how cells integrate and appropriately respond to competing signals for proliferation and apoptosis. The studies described in this report examined the effects of exposure to the cytokine IFN-α (IFN-α-2a) on sensitivity of the human cell lines H9 and SKW6.4 to Fas ligand (FasL)-induced apoptosis. In a concentration-dependent manner, FasL induced apoptosis, as shown by Western blot analysis of procaspase 8 and poly(ADP-ribose) polymerase cleavage after 3-h exposure and by cytofluorometric analysis of sub-G0-G1 cellular DNA content after 24-h exposure. H9 and SKW6.4 cell lines responded to 10,000 IU/ml IFN-α-2a, as evidenced by decreased cell proliferation and tyrosine phosphorylation of Stat1 and Stat3 proteins without significant cytotoxicity. The effects of cytokine exposure on apoptosis were examined; incubation in medium containing 10,000 IU/ml IFN-α-2a for 1 h before FasL treatment significantly reduced all above-mentioned hallmarks of apoptosis. Surprisingly, these antiapoptotic effects of IFN-α-2a were independent of de novo protein synthesis, because they occurred in both the absence and the presence of cycloheximide. However, chemical inhibitors of JAK completely abrogated the effects of IFN-α-2a on FasL-induced apoptosis, indicating a direct role for JAK-mediated protein phosphorylation in modulating sensitivity to apoptosis. Together, these data suggest a novel mechanism, independent of protein synthesis, by which cytokine signals through JAKs can interact with and attenuate this receptor-mediated apoptotic process.
Functional Role of C-Terminal Sequence Elements in the Transporter Associated with Antigen Processing
Authors: Ehses Sarah , Leonhardt Ralf M. , Hansen Guido , Knittler Michael R. 
Published: April 2014

AbstractTAP delivers antigenic peptides into the endoplasmic reticulum (ER) that are subsequently bound by MHC class I molecules. TAP consists of two subunits (TAP1 and TAP2), each with a transmembrane (TMD) and a nucleotide-binding (NBD) domain. The two TAP-NBDs have distinct biochemical properties and control different steps during the peptide translocation process. We noted previously that the nonhomologous C-terminal tails of rat TAP1 and TAP2 determine the distinct functions of TAP-NBD1 and -NBD2. To identify the sequence elements responsible for the asymmetrical NBD function, we constructed chimeric rat TAP variants in which we systematically exchanged sequence regions of different length between the two TAP-NBDs. Our fine-mapping studies demonstrate that a nonhomologous region containing the α6/β10-loop in conjunction with the downstream switch region is directly responsible for the functional separation of the TAP-NBDs. The α6/β10-loop determines the nonsynonymous nucleotide binding of NBD1 and NBD2, whereas the switch region seems to play a critical role in regulating the functional cross-talk between the structural domains of TAP. Based on our findings, we postulate that these two sequence elements build a minimal functional unit that controls the asymmetry of the two TAP-NBDs.
Complement C2 Receptor Inhibitor Trispanning: A Novel Human Complement Inhibitory Receptor
Authors: Inal Jameel M. , Hui Kwok-Min , Miot Sylvie , Lange Sigrun , Ramirez Marcel Ivan , Schneider Brigitte , Krueger Gerhard , Schifferli Jürg-A. 
Published: April 2014

AbstractThe complement system presents a powerful defense against infection and is tightly regulated to prevent damage to self by functionally equivalent soluble and membrane regulators. We describe complement C2 receptor inhibitor trispanning (CRIT), a novel human complement regulatory receptor, expressed on hemopoietic cells and a wide range of tissues throughout the body. CRIT is present in human parasites through horizontal transmission. Serum complement component C2 binds to the N-terminal extracellular domain 1 of CRIT, which, in peptide form, blocks C3 convertase formation and complement-mediated inflammation. Unlike C1 inhibitor, which inhibits the cleavage of C4 and C2, CRIT only blocks C2 cleavage but, in so doing, shares with C1 inhibitor the same functional effect, of preventing classical pathway C3 convertase formation. Ab blockage of cellular CRIT reduces inhibition of cytolysis, indicating that CRIT is a novel complement regulator protecting autologous cells.
Activation of CD40 in Cervical Carcinoma Cells Facilitates CTL Responses and Augments Chemotherapy-Induced Apoptosis
Authors: Hill Seran C. , Youde Sarah J. , Man Stephen , Teale Glyn R. , Baxendale Amanda J. , Hislop Andrew , Davies Clare C. , Luesley David M. , Blom Anna M. , Rickinson Alan B. , Young Lawrence S. , Eliopoulos Aristides G. 
Published: April 2014

Abstract
In this study, we describe the expression and function of CD40, a TNF receptor family member, in cervical carcinomas. CD40 was present at very low levels in normal cervical epithelium but was overexpressed in human papillomavirus-infected lesions and advanced squamous carcinomas of the cervix. The stimulation of CD40-positive cervical carcinoma cell lines with soluble CD40L (CD154) resulted in activation of the NF-κB and MAPK signaling pathways and up-regulation of cell surface markers and intracellular molecules associated with Ag processing and presentation. Concomitantly, the CD154-induced activation of CD40 in carcinoma cells was found to directly influence susceptibility to CTL-mediated killing. Thus, CD40 stimulation in cervical carcinoma cell lines expressing a TAP-dependent human papillomavirus 16 E6 Ag epitope resulted in their enhanced killing by specific CTLs. However, CD154 treatment of carcinoma cells expressing proteasome-dependent but TAP-independent Ags from the EBV-encoded BRLF1 and BMLF1 failed to increase tumor cell lysis by specific CTLs. Moreover, we demonstrate that chemotherapeutic agents that suppress protein synthesis and reverse the CD40-mediated dissociation of the translational repressor eukaryotic initiation factor 4E-binding protein from the initiation factor eukaryotic initiation factor 4E, such as 5-fluorouracil, etoposide, and quercetin, dramatically increase the susceptibility of cervical carcinoma cells to CD40L-induced apoptosis. Taken together, these observations demonstrate the functional expression of CD40 in epithelial tumors of the cervix and support the clinical exploitation of the CD40 pathway for the treatment of cervical cancer through its multiple effects on tumor cell growth, apoptosis, and immune recognition.