bluuebunny/crossref_metadata_2025_split huggingface dataset:
Different Efficiency of Heat Shock Proteins (HSP) to Activate Human Monocytes and Dendritic Cells: Superiority of HSP60
Authors: Bethke Karen , Staib Frank , Distler Martin , Schmitt Ute , Jonuleit Helmut , Enk Alexander H. , Galle Peter R. , Heike Michael 
Published: April 2014

Abstract
One essential immunoregulatory function of heat shock protein (HSP) is activation of the innate immune system. We investigated the activation of human monocytes and monocyte-derived dendritic cells (DC) by recombinant human HSP60, human inducible HSP72, and preparations of human gp96 and HSP70 under stringent conditions, in the absence of serum and with highly purified monocytes. HSP60 induced human DC maturation and activated human DC to secrete proinflammatory cytokines. HSP72 induced DC maturation to a lesser extent, but activated human monocytes and immature DC as efficiently as HSP60 to release proinflammatory cytokines. The independence of the effects of HSP60 and HSP72 from endotoxin or another copurifying bacterial component was shown by the resistance of these effects to polymyxin B, their sensitivity to heat treatment, the inactivity of endotoxin controls at concentrations up to 100-fold above the endotoxin contents of the HSP, and the inactivity of a recombinant control protein. Preparations of HSP70, which consisted mainly of the constitutively expressed HSP73, induced only marginal cytokine release from monocytes. The gp96 preparations did not have significant effects on human monocytes and monocyte-derived DC, indicating that these human APC populations were not susceptible to gp96 signaling under the stringent conditions applied in this study. The biological activities of gp96 and HSP70 preparations were confirmed by their peptide binding activity. These findings show that HSP can differ considerably in the capacity to activate monocyte-derived APC under certain conditions and underline the potential of HSP60 and HSP72 as activation signals for the innate immune system.
Zwitterionic Polysaccharides Stimulate T Cells by MHC Class II-Dependent Interactions
Authors: Kalka-Moll Wiltrud M. , Tzianabos Arthur O. , Bryant Paula W. , Niemeyer Marcus , Ploegh Hidde L. , Kasper Dennis L. 
Published: April 2014

Abstract
Polysaccharides of pathogenic extracellular bacteria commonly have negatively charged groups or no charged groups at all. These molecules have been considered classic T cell-independent Ags that do not elicit cell-mediated immune responses in mice. However, bacterial polysaccharides with a zwitterionic charge motif (ZPSs), such as the capsular polysaccharides of many strains of Bacteroides fragilis, Staphylococcus aureus, and Streptococcus pneumoniae type 1 elicit potent CD4+ T cell responses in vivo and in vitro. The cell-mediated response to ZPS depends on the presence of both positively charged and negatively charged groups on each repeating unit of the polysaccharide. In this study, we define some of the requirements for the presentation of ZPS to CD4+ T cells. We provide evidence that direct interactions of T cells with APCs are essential for T cell activation by ZPS. Monocytes, dendritic cells, and B cells are all able to serve as APCs for ZPS-mediated T cell activation. APCs lacking MHC class II molecules do not support this activity. Furthermore, mAb to HLA-DR specifically blocks ZPS-mediated T cell activation, while mAbs to other MHC class II and class I molecules do not. Immunoprecipitation of lysates of MHC class II-expressing cells following incubation with ZPS shows binding of ZPS and HLA-DR. Electron microscopy reveals colocalization of ZPS with HLA-DR on the cell surface and in compartments of the endocytic pathway. These results indicate that MHC class II molecules expressing HLA-DR on professional APCs are required for ZPS-induced T cell activation. The implication is that binding of ZPS to HLA-DR may be required for T cell activation.
Mouse Vascular Endothelium Activates CD8+ T Lymphocytes in a B7-Dependent Fashion
Authors: Kreisel Daniel , Krupnick Alexander S. , Balsara Keki R. , Riha Markus , Gelman Andrew E. , Popma Sicco H. , Szeto Wilson Y. , Turka Laurence A. , Rosengard Bruce R. 
Published: April 2014

Abstract
Despite several studies examining the contribution of allorecognition pathways to acute and chronic rejection of vascularized murine allografts, little data describing activation of alloreactive T cells by mouse vascular endothelium exist. We have used primary cultures of resting or IFN-γ-activated C57BL/6 (H-2b) vascular endothelial cells as stimulators and CD8+ T lymphocytes isolated from CBA/J (H-2k) mice as responders. Resting endothelium expressed low levels of MHC class I, which was markedly up-regulated after activation with IFN-γ. It also expressed moderate levels of CD80 at a resting state and after activation. Both resting and activated endothelium were able to induce proliferation of unprimed CD8+ T lymphocytes, with proliferation noted at earlier time points after coculture with activated endothelium. Activated endothelium was also able to induce proliferation of CD44low naive CD8+ T lymphocytes. Activated CD8+ T lymphocytes had the ability to produce IFN-γ and IL-2, acquired an effector phenotype, and showed up-regulation of the antiapoptotic protein Bcl-xL. Treatment with CTLA4-Ig led to marked reduction of T cell proliferation and a decrease in expression of Bcl-xL. Moreover, we demonstrate that nonhemopoietic cells such as vascular endothelium induce proliferation of CD8+ T lymphocytes in a B7-dependent fashion in vivo. These results suggest that vascular endothelium can act as an APC for CD8+ direct allorecognition and may, therefore, play an important role in regulating immune processes of allograft rejection.
Acquisition of CD80 by Human T Cells at Early Stages of Activation: Functional Involvement of CD80 Acquisition in T Cell to T Cell Interaction
Authors: Tatari-Calderone Zohreh , Semnani Roshanak Tolouei , Nutman Thomas B. , Schlom Jeffrey , Sabzevari Helen 
Published: April 2014

Abstract
The interaction between CD28 on T cells and CD80 on APCs intensifies the linkage between TCR and MHC at the site of contact between T cells and APCs. In this study, we demonstrate that during human T cell/human APC interaction, the autologous or allogeneic human CD4+ T cells become positive for the detection of CD80 at an early stage of activation (24 h). This detection of CD80 is attributable to the acquisition of CD80 from APCs, as opposed to the up-regulation of endogenous CD80, as demonstrated by CD4+ T cells treated with cyclohexamide. Furthermore, no CD80 mRNA could be detected at 24 h in T cells that had acquired CD80 from APCs. CD80 acquisition by T cells from APCs was enhanced upon TCR engagement. The amount of CD80 acquisition by CD4+ T cells was shown to be related to the expression of CD80 on APCs. Using soluble fusion proteins (soluble CTLA-4, CD28, and CD80) to block either CD28 on the surface of T cells or CD80 on the surface of APCs, it was demonstrated that CD80 acquisition by T cells is mediated through its receptors, possibly CD28 interaction. Moreover, we demonstrate that T cells that have acquired CD80 have the ability to stimulate other T cells. These data thus suggest that CD80 acquisition by human T cells might play a role in the immunoregulation of T cell responses.
Kinetics of Gene Induction After FcεRI Ligation of Atopic Monocytes Identified by Suppression Subtractive Hybridization
Authors: von Bubnoff Dagmar , Matz Heike , Cazenave Jean-Pierre , Hanau Daniel , Bieber Thomas , de la Salle Henri 
Published: April 2014

Abstract
The high-affinity receptor for IgE, FcεRI, on APCs plays an important role in the initiation and chronicity of inflammatory atopic diseases. To understand the molecular regulation of FcεRI-mediated processes, differentially expressed genes are of great interest to be identified. Suppression subtractive cDNA hybridization has been used to identify genes induced after FcεRI stimulation on atopic monocytes. Overexpression of the identified genes was determined by semiquantitative RT-PCR analysis of transcripts from the tester (stimulated) and driver (unstimulated) monocytes. Results were confirmed and kinetics of the transcripts established using blood cells from additional atopics at 4 and 24 h of FcεRI induction. The following sequences were identified: monocyte chemoattractant protein 1, macrophage-inflammatory protein 1β, IL-6, βA subunit of inhibin/activin, IFN-stimulated gene of 54 kDa, IL-1R antagonist, and kynurenine 3-monooxygenase. Chemokines are highly expressed during the early and late phase after FcεRI cross-linking, whereas proinflammatory and differentiation stimuli rapidly decline after an initial overexpression. Kynurenine 3-monooxygenase, an enzyme involved in the degradation of the amino acid tryptophan, is significantly up-regulated during the late phase after 24 h of FcεRI induction. These results demonstrate that the analysis of the profile of gene induction following activation of FcεRI on atopic monocytes may reveal how these cells might participate in the regulation of atopic disorders.
Clonal Anergy Is Maintained Independently of T Cell Proliferation
Authors: Colombetti Sara , Benigni Fabio , Basso Veronica , Mondino Anna 
Published: April 2014

AbstractAg encounter in the absence of proliferation results in the establishment of T cell unresponsiveness, also known as T cell clonal anergy. Anergic T cells fail to proliferate upon restimulation because of the inability to produce IL-2 and to properly regulate the G1 cell cycle checkpoint. Because optimal TCR and CD28 engagement can elicit IL-2-independent cell cycle progression, we investigated whether CD3/CD28-mediated activation of anergic T cells could overcome G1 cell cycle block, drive T cell proliferation, and thus reverse clonal anergy. We show here that although antigenic stimulation fails to elicit G1-to-S transition, anti-CD3/CD28 mAbs allow proper cell cycle progression and proliferation of anergic T cells. However, CD3/CD28-mediated cell division does not restore Ag responsiveness. Our data instead indicate that reversal of clonal anergy specifically requires an IL-2-dependent, rapamycin-sensitive signal, which is delivered independently of cell proliferation. Thus, by tracing proliferation and Ag responsiveness of individual cells, we show that whereas both TCR/CD28 and IL-2-generated signals can drive T cell proliferation, only IL-2/IL-2R interaction regulates Ag responsiveness, indicating that proliferation and clonal anergy can be independently regulated.
Autocrine IL-15 Mediates Intestinal Epithelial Cell Death Via the Activation of Neighboring Intraepithelial NK Cells
Authors: Kinoshita Naotoshi , Hiroi Takachika , Ohta Noriyuki , Fukuyama Satoshi , Park Eun Jeong , Kiyono Hiroshi 
Published: April 2014

AbstractIntestinal intraepithelial lymphocytes (IELs), which reside between the basolateral faces of intestinal epithelial cells (IECs), provide a first-line defense against pathogens via their cytotoxic activity. Although IEC-derived IL-7 and IL-15 are key regulatory cytokines for the development and activation of IELs, we report here that IL-15 but not IL-7 mediates the reciprocal interaction between IELs and IECs, an important interaction for the regulation of appropriate mucosal immunohomeostasis. IL-15-treated IELs induced cell death in IECs via the cytotoxic activity in vitro. Among the different subsets of IL-15-treated IELs, CD4−CD8−TCR− IELs, which express NK marker (DX5 or NK1.1), showed the most potent syngenic IEC killing activity. These intraepithelial NK cells expressed Ly-49 molecules, NKG2 receptors, and perforin. These results suggest the possibility that the cell death program of IECs could be regulated by self-produced IL-15 through the activation of intraepithelial NK cells.
Bone Marrow B Cell Apoptosis During In Vivo Influenza Virus Infection Requires TNF-α and Lymphotoxin-α
Authors: Sedger Lisa M. , Hou Sam , Osvath Sarah R. , Glaccum Moira B. , Peschon Jacques J. , van Rooijen Nico , Hyland Lisa 
Published: April 2014

AbstractSuppression of bone marrow myeloid and erythroid progenitor cells occurs after infection with a variety of different viruses. In this study, we characterize the alterations in bone marrow (BM) lymphocytes after influenza virus infection in mice. We found a severe loss of BM B cells, particularly CD43low/−B220+ pre-B and immature B cells, in influenza virus-infected mice. Depletion of BM B lineage cells resulted primarily from cell cycle arrest and most likely apoptosis within the BM environment, rather than from increased trafficking of BM emigrants to peripheral lymphoid tissues. Use of gene-knockout mice indicates that depletion of BM B cells is dependent on TNF-α, lymphotoxin-α, and both TNF receptors, TNFR1-p55 and TNFR2-p75. Thus, TNF-α and lymphotoxin-α are required for loss of BM B lineage cells during respiratory infection with influenza virus.
CTLA-4 Differentially Regulates T Cell Responses to Endogenous Tissue Protein Versus Exogenous Immunogen
Authors: Walker Lucy S. K. , Ausubel Lara J. , Chodos Anna , Bekarian Nyree , Abbas Abul K. 
Published: April 2014

Abstract
CTLA-4 is critical to the regulation of CD4 T cell homeostasis in vivo. However, whether CTLA-4 regulates responses to both self and foreign proteins is not clear. We have directly compared the role of CTLA-4 in controlling T cell responses to the same protein presented as an endogenous tissue Ag vs a foreign immunizing Ag. We show that CTLA-4 only modestly reduces responses to Ag administered with adjuvant, but dramatically inhibits responses to the same Ag expressed transgenically as a tissue self protein. The critical consequence of CTLA-4 engagement is to inhibit T cell accumulation in the local lymph node draining the Ag-bearing tissue, and failure of this control leads to the onset of autoimmune tissue destruction. Thus, CTLA-4 may preferentially dampen pathologic immune responses to self proteins while permitting protective immunity to foreign agents.
Inhibition of Human CD4+CD25+high Regulatory T Cell Function
Authors: Baecher-Allan Clare , Viglietta Vissia , Hafler David A. 
Published: April 2014

Abstract
CD4+CD25+high T cells are potent regulators of autoreactive T cells. However, it is unclear how regulatory CD4+CD25+high cells discriminate between desirable inflammatory immune responses to microbial Ags and potentially pathologic responses by autoreactive T cells. In this study, an in vitro model was created that allowed differential activation of regulatory CD4+CD25+high and responder CD4+ T cells. If CD4+CD25+high regulatory cells were strongly activated, they maintained suppressive effector function for only 15 h, while stimulation with weaker TCR stimuli produced regulatory cells that were suppressive until 60 h after activation. In contrast, strongly activated CD4+ responder T cells were resistant to regulation at all time points, while weakly stimulated CD4+ cells were sensitive to suppression until 38 or 60 h after activation depending upon the strength of the stimulus. The extent of suppression mediated by CD4+CD25+high cells also depended on the strength of stimulation in an Ag-specific system. Thus, the stronger the TCR signal, the more rapidly and more completely the responder cells become refractory to suppression.
T Cell Receptor Ligation Triggers Novel Nonapoptotic Cell Death Pathways That Are Fas-Independent or Fas-Dependent
Authors: Davidson Wendy F. , Haudenschild Christian , Kwon Jaeyul , Williams Mark S. 
Published: April 2014

Abstract
Short-term culture of activated T cells with IL-2 renders them highly susceptible to apoptotic death triggered by TCR cross-linking. Activation-induced apoptosis is contingent upon caspase activation and this is mediated primarily by Fas/Fas ligand (FasL) interactions that, in turn, are optimized by p38 mitogen-activated protein kinase (MAPK)-regulated signals. Although T cells from mice bearing mutations in Fas (lpr) or FasL (gld) are more resistant to activation-induced cell death (AICD) than normal T cells, a significant proportion of CD8+ T cells and to a lesser extent CD4+ T cells from mutant mice die after TCR religation. Little is known about this Fas-independent death process. In this study, we demonstrate that AICD in lpr and gld CD4+ and CD8+ T cells occurs predominantly by a novel mechanism that is TNF-α-, caspase-, and p38 MAPK-independent and has morphologic features more consistent with oncosis/primary necrosis than apoptosis. A related Fas- and caspase-independent, nonapoptotic death process is revealed in wild-type (WT) CD8+ T cell blasts following TCR ligation and treatment with caspase inhibitors, the p38 MAPK inhibitor, SB203580, or neutralizing anti-FasL mAb. In parallel studies with WT CD4+ T cells, two minor pathways leading to nonapoptotic, caspase-independent AICD were identified, one contingent upon Fas ligation and p38 MAPK activation and the other Fas- and p38 MAPK-independent. These data indicate that TCR ligation can activate nonapoptotic death programs in WT CD8+ and CD8+ T blasts that normally are masked by Fas-mediated caspase activation. Selective use of potentially proinflammatory oncotic death programs by activated lpr and gld T cells may be an etiologic factor in autosensitization.
Cyclic Adenosine 5′-Monophosphate and Calcium Induce CD152 (CTLA-4) Up-Regulation in Resting CD4+ T Lymphocytes
Authors: Vendetti Silvia , Riccomi Antonella , Sacchi Alessandra , Gatta Lucia , Pioli Claudio , De Magistris Maria Teresa 
Published: April 2014

Abstract
The CTLA-4 (CD152) molecule is up-regulated upon T cell activation and proliferation, and plays a critical role in the inhibition of immune responses. We show in this study that cAMP induces up-regulation of CD152 in human CD4+ T lymphocytes. This effect occurs in the absence of the up-regulation of CD69 and CD25 activation markers and T cell proliferation. In addition, we found that the Ca2+ ionophore ionomycin also up-regulates CD152, and that the combination of a cAMP analog or cAMP inducers with ionomycin further enhances the expression of CD152 in resting CD4+ T lymphocytes. However, cyclosporin A, which inhibits Ca2+/calcineurin signaling pathway, fully prevented the ionomycin- but not the cAMP-induced up-regulation of CD152. The effects of cAMP and ionomycin involve increase of both CD152 mRNA transcripts, coding for the membrane and the soluble forms of CD152. Furthermore, we show that CD152 molecules are translocated to the membrane and are functional, as their engagement by specific mAbs prevented NF-κB activation by anti-CD3/CD28 stimulation. These findings demonstrate that at least two novel signal pathways regulate CTLA-4 gene expression and CD152 molecule up-regulation in human CD4+ T lymphocytes, in the absence of full T cell activation.
NF-κB Regulates the Expression of the Human Complement Receptor 2 Gene
Authors: Tolnay Mate , Vereshchagina Lyudmila A. , Tsokos George C. 
Published: April 2014

Abstract
CR2 is a key regulator of the B cell response to Ag. Here we show that NF-κB enhances the expression of the human CR2 gene. Promoter truncation, deletion, and mutagenesis studies indicated a functional role for a consensus NF-κB promoter element, as well as a heterogeneous nuclear ribonucleoprotein D element and an overlapping X box/E box. By supershift analysis, the first two elements bound NF-κB p50 and p65 and heterogeneous nuclear ribonucleoprotein RNP D, respectively. The X box/E box bound regulatory factor X5 and, surprisingly, NF-κB p50 and p65. Overexpression of NF-κB p50 enhanced the activity of the CR2 promoter in B cell lines and primary B cells, suggesting a direct role for NF-κB in regulating promoter activity. Importantly, mutation of the NF-κB element or the X box/E box rendered the promoter unresponsive to NF-κB p50. Using chromatin immunoprecipitation in live B cell lines and primary B cells, we found that NF-κB proteins p50, p65, and c-Rel bound to the genomic promoter at two locations that overlap with the consensus NF-κB element or the X box/E box. Finally, stimuli that activate NF-κB enhanced the activity of the CR2 promoter, and LPS rapidly increased the number of CR2 proteins on the surface of primary B cells. We propose that the NF-κB signaling pathway enhances the expression of the CR2 gene, as a result of NF-κB proteins binding to two CR2 promoter elements. Thus, at the onset of an infection, LPS could sensitize the B cell to Ag by enhancing the level of CR2-costimulatory molecules on the cell surface.
Primary Structure and Complementarity-Determining Region (CDR) 3 Spectratyping of Rainbow Trout TCRβ Transcripts Identify Ten Vβ Families with Vβ6 Displaying Unusual CDR2 and Differently Spliced Forms
Authors: Boudinot Pierre , Boubekeur Samira , Benmansour Abdenour 
Published: April 2014

Abstract
VDJ rearrangement at the teleost TCRβ locus leads to a highly diverse repertoire of junctions for each VβJβ combination. From a rainbow trout 5′ RACE library of TCRβ transcripts, 47 clones encompassing a full Vβ-Dβ-Jβ-Cβ sequence were selected and analyzed. A similarity analysis of the sequences evidenced 10 Vβ families, of which 6 were not previously described. Immunoscope and sequence analysis of the Vβ-Dβ-Jβ junctions of the new families confirmed that they create a polyclonal and diverse repertoire. Multiple alignments showed that rainbow trout Vβs possess most of the conserved residues typical of Vβ segments. However, this study revealed a high complementarity-determining region 2 (CDR2) and CDR1 length diversity among rainbow trout Vβ families, suggesting that the spatial orientation of the TCR could fluctuate in the TCR/peptide/MHC complex, depending on the Vβ expressed. Among the new Vβ families, Vβ6 displayed the strongest deviance from typical hypervariable CDR1 and CDR2 loops, with an unusually short CDR2. Moreover, the Vβ6 sequence is overall divergent from typical Vβ sequence, raising the question of its functional relevance. Immunoscope experiments identified a Vβ6-Jβ3 junction, which was amplified during the response against viral hemorrhagic septicemia virus, a fish rhabdovirus. Vβ6 seems therefore to be expressed functionally in a selected TCR. However, the shorter Vβ6 transcripts produced through an alternative splicing lack the C′, C″, D, and E strands of the Vβ domain and are probably nonfunctional.
Dominant TCR-α Requirements for a Self Antigen Recognition in Humans
Authors: Mantovani Stefania , Palermo Belinda , Garbelli Silvia , Campanelli Rita , Robustelli della Cuna Gioacchino , Gennari Roberto , Benvenuto Federica , Lantelme Erica , Giachino Claudia 
Published: April 2014

Abstract
TCR-α and -β chains are composed of somatically rearranged V, D, and J germline-encoded gene segments that confer Ag specificity. Recent crystallographic analyses revealed that TCR-α has more contacts with peptide than TCR-β, suggesting the possibility that peptide recognition predominantly relies on TCR-α. T cells specific for the self Ag Melan-A/MART-1 possess an exceptionally high precursor frequency in human histocompatibility leukocyte Ag-A2 individuals. This provided a unique situation for assessment of the structural relationship between TCR and peptide/MHC ligand at both the pre- and postimmune levels. Molecular and phenotypic analysis of many different Melan-A-specific T cell populations revealed that a structural constraint is imposed on the TCR for engagement with Melan-A peptides presented by HLA-A2, namely the highly preferential use of a particular TCRAV segment, AV2. Examination of CD8 single-positive thymocytes indicated that this preferential use in forming the Melan-A-specific TCR is mainly imposed by intrathymic positive selection. Our data demonstrate a dominant function of TCRAV2 segment in forming the TCR repertoire specific for the human self Ag Melan-A/MART-1 and support the view that Ag recognition is mediated predominantly by TCR-α.