bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Analysis of Birch Pollen Allergen Bet v 1-Specific Regulatory T Cells
Authors: Nagato Toshihiro , Kobayashi Hiroya , Yanai Mitsuru , Sato Keisuke , Aoki Naoko , Oikawa Kensuke , Kimura Shoji , Abe Yusuke , Celis Esteban , Harabuchi Yasuaki , Tateno Masatoshi 
Published: April 2014

Abstract
Allergen-specific immunotherapy using peptides is an efficient treatment for allergic diseases. Recent studies suggest that the induction of CD4+ regulatory T (Treg) cells might be associated with the suppression of allergic responses in patients after allergen-specific immunotherapy. Our aim was to identify MHC class II promiscuous T cell epitopes for the birch pollen allergen Bet v 1 capable of stimulating Treg cells with the purpose of inhibiting allergic responses. Ag-reactive CD4+ T cell clones were generated from patients with birch pollen allergy and healthy volunteers by in vitro vaccination of PBMC using Bet v 1 synthetic peptides. Several CD4+ T cell clones were induced by using 2 synthetic peptides (Bet v 1141–156 and Bet v 151–68). Peptide-reactive CD4+ T cells recognized recombinant Bet v 1 protein, indicating that these peptides are produced by the MHC class II Ag processing pathway. Peptide Bet v 1141–156 appears to be a highly MHC promiscuous epitope since T cell responses restricted by numerous MHC class II molecules (DR4, DR9, DR11, DR15, and DR53) were observed. Two of these clones functioned as typical Treg cells (expressed CD25, GITR, and Foxp3 and suppressed the proliferation and IL-2 secretion of other CD4+ T cells). Notably, the suppressive activity of these Treg cells required cell-cell contact and was not mediated through soluble IL-10 or TGF-β. The identified promiscuous MHC class II epitope capable of inducing suppressive Treg responses may have important implication for the development of peptide-based Ag-specific immunotherapy to birch pollen allergy.
TCR Activation Eliminates Glutamate Receptor GluR3 from the Cell Surface of Normal Human T Cells, via an Autocrine/Paracrine Granzyme B-Mediated Proteolytic Cleavage
Authors: Ganor Yonatan , Teichberg Vivian I. , Levite Mia 
Published: April 2014

Abstract
The majority of resting normal human T cells, like neuronal cells, express functional receptors for glutamate (the major excitatory neurotransmitter in the CNS) of the ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-receptor subtype 3 (GluR3). Glutamate by itself (∼10 nM) activates key T cell functions, including adhesion to fibronectin and laminin and chemotactic migration toward CXCL12/stromal cell-derived factor 1. In this study, we found by GluR3-specific immunostaining, flow cytometry, and Western blots that GluR3 cell surface expression decreases dramatically following TCR activation of human T cells. CXCR4, VLA-4, and VLA-6 also decrease substantially, whereas CD147 increases as expected, after TCR activation. Media of TCR-activated cells “eliminates” intact GluR3 (but not CXCR4 and VLA-6) from the cell surface of resting T cells, suggesting GluR3 cleavage by a soluble factor. We found that this factor is granzyme B (GB), a serine protease released by TCR-activated cells, because the extent of GluR3 elimination correlated with the active GB levels, and because three highly specific GB inhibitors blocked GluR3 down-regulation. Media of TCR-activated cells, presumably containing cleaved GluR3B peptide (GluR3 aa 372–388), inhibited the specific binding of anti-GluR3B mAb to synthetic GluR3B peptide. In parallel to losing intact GluR3, TCR-activated cells lost glutamate-induced adhesion to laminin. Taken together, our study shows that “classical immunological” TCR activation, via autocrine/paracrine GB, down-regulates substantially the expression of specific neurotransmitter receptors. Accordingly, glutamate T cell neuroimmune interactions are influenced by the T cell activation state, and glutamate, via AMPA-GluR3, may activate only resting, but not TCR-activated, T cells. Finally, the cleavage and release to the extracellular milieu of the GluR3B peptide may in principle increase its antigenicity, and thus the production, of anti-self GluR3B autoantibodies, which activate and kill neurons, found in patients with various types of epilepsy.
TLR9-Signaling Pathways Are Involved in Kilham Rat Virus-Induced Autoimmune Diabetes in the Biobreeding Diabetes-Resistant Rat
Authors: Zipris Danny , Lien Egil , Nair Anjali , Xie Jenny X. , Greiner Dale L. , Mordes John P. , Rossini Aldo A. 
Published: April 2014

Abstract
Viral infections are associated epidemiologically with the expression of type 1 diabetes in humans, but the mechanisms underlying this putative association are unknown. To investigate the role of viruses in diabetes, we used a model of viral induction of autoimmune diabetes in genetically susceptible biobreeding diabetes-resistant (BBDR) rats. BBDR rats do not develop diabetes in viral-Ab-free environments, but ∼25% of animals infected with the parvovirus Kilham rat virus (KRV) develop autoimmune diabetes via a mechanism that does not involve β cell infection. Using this model, we recently documented that TLR agonists synergize with KRV infection and increase disease penetrance. We now report that KRV itself activates innate immunity through TLR ligation. We show that KRV infection strongly stimulates BBDR splenocytes to produce the proinflammatory cytokines IL-6 and IL-12p40 but not TNF-α. KRV infection induces high levels of IL-12p40 by splenic B cells and Flt-3-ligand-induced bone marrow-derived dendritic cells (DCs) but only low levels of IL-12p40 production by thioglycolate-elicited peritoneal macrophages or GM-CSF plus IL-4-induced bone marrow-derived DCs. KRV-induced cytokine production is blocked by pharmacological inhibitors of protein kinase R and NF-κB. Genomic KRV DNA also induces BBDR splenocytes and Flt-3L-induced DCs from wild-type but not TLR9-deficient mice to produce IL-12p40; KRV-induced up-regulation of B lymphocytes can be blocked by TLR9 antagonists including inhibitory CpG and chloroquine. Administration of chloroquine to virus-infected BBDR rats decreases the incidence of diabetes and decreases blood levels of IL-12p40. Our data implicate the TLR9-signaling pathway in KRV-induced innate immune activation and autoimmune diabetes in the BBDR rat.
Two Groups of Porcine TCRγδ+ Thymocytes Behave and Diverge Differently
Authors: Šinkora Marek , Šinkorová Jana , Cimburek Zdeněk , Holtmeier Wolfgang 
Published: April 2014

Abstract
Developmental pathways of γδ T cells are still unknown, largely because of the absence of recognized lineage-specific surface markers other than the TCR. We have shown that porcine γδ thymocytes can be divided into 12 subsets of the following two major groups: 1) CD4− γδ thymocytes that can be further subdivided according to their CD2/CD8αα phenotype, and 2) CD4+ γδ thymocytes that are always CD1+CD2+CD8αβ+ and have no counterpart in the periphery. In this study, we have analyzed γδ thymocyte subsets with respect to behavior during cultivation, cell cycle status, and lymphocyte-specific transcripts. The group of CD4− γδ thymocytes gives rise to all γδ T cells found in the periphery. Proliferating CD2+CD8−CD1+CD45RC− γδ thymocytes are a common precursor of this group. These precursors differentiate into CD2+CD8αα+, CD2+CD8−, and CD2−CD8− γδ T cell subsets, which subsequently mature by loss of CD1 and by eventual gain of CD45RC expression. In contrast, the group of CD4+ γδ thymocytes represents transient and independent subsets that are never exported from thymus as TCRγδ+ T cells. In accordance with the following findings, we propose that CD4+CD8αβ+ γδ thymocytes extinguish their TCRγδ expression and differentiate along the αβ T cell lineage program: 1) CD4+ γδ thymocytes are actively dividing; 2) CD4+ γδ thymocytes do not die, although their numbers decreased with prolonged cultivation; 3) CD4+ γδ thymocytes express transcripts for RAG-1, TdT, and TCRβ; and 4) CD4+ γδ thymocytes are able to alter their phenotype to TCRαβ+ thymocytes under appropriate culture conditions.
B Cell Receptor Signaling Down-Regulates Forkhead Box Transcription Factor Class O 1 mRNA Expression via Phosphatidylinositol 3-Kinase and Bruton’s Tyrosine Kinase
Authors: Hinman Rochelle M. , Bushanam Jessica N. , Nichols Whitney A. , Satterthwaite Anne B. 
Published: April 2014

AbstractBCR cross-linking promotes mature B cell proliferation and survival. PI3K-mediated down-regulation of proapoptotic and antimitogenic genes such as forkhead box transcription factor class O 1 (FOXO1) is an important component of this process. Previously, BCR-induced phosphorylation of FOXO1 was shown to lead to a block in nuclear localization and subsequent protein degradation. We demonstrate that the BCR also signals through PI3K to down-regulate FOXO1 mRNA expression. Bruton’s tyrosine kinase (Btk), a downstream effector of PI3K, signals through B cell linker protein (BLNK) and phospholipase C (PLC)γ2 to mediate B cell proliferation and survival in response to BCR cross-linking. BCR-induced down-regulation of FOXO1 mRNA was impaired in murine knockouts of Btk, BLNK, and PLCγ2. Because B cells in these models are predominantly immature, experiments were also performed using mature B cells expressing low levels of Btk and BLNK. Similar results were obtained. Inhibitors of downstream components of the Btk/BLNK/PLCγ2 pathway were used to define the mechanism by which Btk signaling inhibits FOXO1 expression. The protein kinase Cβ inhibitor Gö6850 had minimal effects on BCR-mediated FOXO1 mRNA down-regulation. However, cyclosporin A, an inhibitor of the Ca2+-dependent phosphatase calcineurin, had similar effects on FOXO1 mRNA expression as the PI3K inhibitor LY294002. Neither Btk deficiency nor cyclosporin A prevented FOXO1 protein phosphorylation, indicating that PI3K down-regulates FOXO1 via two independent pathways. We show that the Btk/BLNK/PLCγ2 pathway mediates BCR-induced changes in expression of the FOXO1 target gene cyclin G2. These observations support the hypothesis that Btk mediates BCR-induced proliferation and survival in part via inhibition of FOXO expression.
The Duration of Exposure to HIV Modulates the Breadth and the Magnitude of HIV-Specific Memory CD4+ T Cells
Authors: Younes Souheil-Antoine , Trautmann Lydie , Yassine-Diab Bader , Kalfayan Lena H. , Kernaleguen Anne-Elen , Cameron Thomas O. , Boulassel Rachid , Stern Lawrence J. , Routy Jean-Pierre , Grossman Zvi , Dumont Alain R. , Sekaly Rafick-Pierre 
Published: April 2014

AbstractThe impact of exposure to Ag on the development and maintenance of human CD4+ memory T cells in general and HIV infection in particular is partially understood. In this study, we measured HIV-specific CD4+ T cell proliferative responses against HIV proteins and derived peptides one year after highly active antiretroviral therapy initiation in 39 HIV-infected patients who initiated therapy at different times following infection. We show that a brief exposure to HIV of &lt;1 month does not allow the generation of significant detectable frequencies of HIV-specific CD4+ memory T cells. Patients having prolonged cumulative exposure to high viral load due to therapy failures also demonstrated limited HIV-specific CD4+ T cell responses. In contrast, patients exposed to significant levels of virus for periods ranging from 3 to 18 mo showed brisk and broad HIV-specific CD4+ T cell responses 1 year following the onset of therapy intervention. We also demonstrate that the nadir CD4+ T cell count before therapy initiation correlated positively with the breadth and magnitude of these responses. Our findings indicate that the loss of proliferative HIV-specific CD4+ T cell responses is associated with the systemic progression of the disease and that a brief exposure to HIV does not allow the establishment of detectable frequencies of HIV-specific memory CD4+ T cells.
Donor CD8+ T Cells Mediate Graft-versus-Leukemia Activity without Clinical Signs of Graft-versus-Host Disease in Recipients Conditioned with Anti-CD3 Monoclonal Antibody
Authors: Zhang Chunyan , Lou Jingwei , Li Nainong , Todorov Ivan , Lin Chia-Lei , Cao Yu-An , Contag Christopher H. , Kandeel Fouad , Forman Stephen , Zeng Defu 
Published: April 2014

AbstractDonor CD8+ T cells play a critical role in mediating graft-vs-leukemia (GVL) activity, but also induce graft-vs-host disease (GVHD) in recipients conditioned with total body irradiation (TBI). In this study, we report that injections of donor C57BL/6 (H-2b) or FVB/N (H-2q) CD8+ T with bone marrow cells induced chimerism and eliminated BCL1 leukemia/lymphoma cells without clinical signs of GVHD in anti-CD3-conditioned BALB/c (H-2d) recipients, but induced lethal GVHD in TBI-conditioned recipients. Using in vivo and ex vivo bioluminescent imaging, we observed that donor CD8+ T cells expanded rapidly and infiltrated GVHD target tissues in TBI-conditioned recipients, but donor CD8+ T cell expansion in anti-CD3-conditioned recipients was confined to lymphohematological tissues. This confinement was associated with lack of up-regulated expression of α4β7 integrin and chemokine receptors (i.e., CXCR3) on donor CD8+ T cells. In addition, donor CD8+ T cells in anti-CD3-conditioned recipients were rendered unresponsive, anergic, Foxp3+, or type II cytotoxic T phenotype. Those donor CD8+ T cells showed strong suppressive activity in vitro and mediated GVL activity without clinical signs of GVHD in TBI-conditioned secondary recipients. These results indicate that anti-CD3 conditioning separates GVL activity from GVHD via confining donor CD8+ T cell expansion to host lymphohemological tissues as well as tolerizing them in the host.
Intercellular Adhesion Molecule-1 Expression Is Required on Multiple Cell Types for the Development of Experimental Autoimmune Encephalomyelitis
Authors: Bullard Daniel C. , Hu Xianzhen , Schoeb Trenton R. , Collins Robert G. , Beaudet Arthur L. , Barnum Scott R. 
Published: April 2014

AbstractMany members of the Ig superfamily of adhesion molecules, such as ICAM-1 and VCAM-1, have been implicated in the pathogenesis of multiple sclerosis. Although it is well-established that VCAM-1/VLA-4 interactions can play important roles in mediating CNS inflammatory events in multiple sclerosis patients and during the development of experimental allergic encephalomyelitis (EAE), the contributions of ICAM-1 are poorly understood. This is due in large part to conflicting results from Ab inhibition studies and the observation of exacerbated EAE in ICAM-1 mutant mice that express a restricted set of ICAM-1 isoforms. To determine ICAM-1-mediated mechanisms in EAE, we analyzed ICAM-1 null mutant mice (ICAM-1null), which express no ICAM-1 isoforms. ICAM-1null mice had significantly attenuated EAE characterized by markedly reduced spinal cord T cell infiltration and IFN-γ production by these cells. Adoptive transfer of Ag-restimulated T cells from wild-type to ICAM-1null mice or transfer of ICAM-1null Ag-restimulated T cells to control mice failed to induce EAE. ICAM-1null T cells also showed reduced proliferative capacity and substantially reduced levels of IFN-γ, TNF-α, IL-4, IL-10, and IL-12 compared with that of control T cells following myelin oligodendrocyte glycoprotein 35–55 restimulation in vitro. Our results indicate that ICAM-1 expression is critical on T cells and other cell types for the development of demyelinating disease and suggest that expression of VCAM-1 and other adhesion molecules cannot fully compensate for the loss of ICAM-1 during EAE development.
Bone Marrow-Derived Hemopoietic Precursors Commit to the T Cell Lineage Only after Arrival in the Thymic Microenvironment
Authors: Heinzel Kornelia , Benz Claudia , Martins Vera C. , Haidl Ian D. , Bleul Conrad C. 
Published: April 2014

Abstract
T lymphocytes develop in the thymus from hemopoietic precursors that commit to the T cell lineage under the influence of Notch signals. In this study, we show by single cell analyses that the most immature hemopoietic precursors in the adult mouse thymus are uncommitted and specify to the T cell lineage only after their arrival in the thymus. These precursors express high levels of surface Notch receptors and rapidly lose B cell potential upon the provision of Notch signals. Using a novel culture system with complexed, soluble Notch ligands that allows the titration of T cell lineage commitment, we find that these precursors are highly sensitive to both Delta and Jagged ligands. In contrast, their phenotypical and functional counterparts in the bone marrow are resistant to Notch signals that efficiently induce T cell lineage commitment in thymic precursors. Mechanistically, this is not due to differences in receptor expression, because early T lineage precursors, bone marrow lineage marker-negative, Sca-1-positive, c-Kit-positive and common lymphoid progenitor cells, express comparable amounts of surface Notch receptors. Our data demonstrate that the sensitivity to Notch-mediated T lineage commitment is stage-dependent and argue against the bone marrow as the site of T cell lineage commitment.
Cigarette Smoke Impairs NK Cell-Dependent Tumor Immune Surveillance
Authors: Lu Ling-Min , Zavitz Caleb C. J. , Chen Biao , Kianpour Sussan , Wan Yonghong , Stämpfli Martin R. 
Published: April 2014

Abstract
In this study, we investigated the impact of cigarette smoke on tumor immune surveillance and its consequences to lung tumor burden in a murine lung metastasis model. Cigarette smoke exposure significantly increased the numbers of lung metastases following B16-MO5 melanoma challenge. This effect was reversible; we observed significantly fewer tumor nodules following smoking cessation. Using RAG2−/− and RAG2−/−γc−/− mice, we provide strong evidence that increased tumor incidence was NK cell dependent. Furthermore, we show that cigarette smoke suppressed NK activation and attenuated NK CTL activity, without apparent effect on activating or inhibitory receptor expression. Finally, activation of NK cells through bone marrow-derived dendritic cells conferred protection against lung metastases in smoke-exposed mice; however, protection was not as efficacious as in sham-exposed mice. To our knowledge, this is the first experimental evidence showing that cigarette smoke impairs NK cell-dependent tumor immune surveillance and that altered immunity is associated with increased tumor burden. Our findings suggest that altered innate immunity may contribute to the increased risk of cancer in smokers.
The Neutrophil-Activating Protein of Helicobacter pylori Crosses Endothelia to Promote Neutrophil Adhesion In Vivo
Authors: Polenghi Alessandra , Bossi Fleur , Fischetti Fabio , Durigutto Paolo , Cabrelle Anna , Tamassia Nicola , Cassatella Marco A. , Montecucco Cesare , Tedesco Francesco , de Bernard Marina 
Published: April 2014

Abstract
Helicobacter pylori induces an acute inflammatory response followed by a chronic infection of the human gastric mucosa characterized by infiltration of neutrophils/polymorphonuclear cells (PMNs) and mononuclear cells. The H. pylori neutrophil-activating protein (HP-NAP) activates PMNs, monocytes, and mast cells, and promotes PMN adherence to the endothelium in vitro. By using intravital microscopy analysis of rat mesenteric venules exposed to HP-NAP, we demonstrated, for the first time in vivo, that HP-NAP efficiently crosses the endothelium and promotes a rapid PMN adhesion. This HP-NAP-induced adhesion depends on the acquisition of a high affinity state of β2 integrin on the plasma membrane of PMNs, and this conformational change requires a functional p38 MAPK. We also show that HP-NAP stimulates human PMNs to synthesize and release a number of chemokines, including CXCL8, CCL3, and CCL4. Collectively, these data strongly support a central role for HP-NAP in the inflammation process in vivo: indeed, HP-NAP not only recruits leukocytes from the vascular lumen, but also stimulates them to produce messengers that may contribute to the maintenance of the flogosis associated with the H. pylori infection.
IL-12 Rapidly Alters the Functional Profile of Tumor-Associated and Tumor-Infiltrating Macrophages In Vitro and In Vivo
Authors: Watkins Stephanie K. , Egilmez Nejat K. , Suttles Jill , Stout Robert D. 
Published: April 2014

Abstract
Tumor-associated macrophages (TAMs) play a major role in promoting tumor growth and metastasis and in suppressing the antitumor immune response. Despite the immunosuppressive environment created by the tumor and enforced by tumor-associated macrophages, treatment of tumor-bearing mice with IL-12 induces tumor regression associated with appearance of activated NK cells and activated tumor-specific CTLs. We therefore tested the hypothesis that IL-12 treatment could alter the function of these tumor-associated suppressor macrophages. Analysis of tumor-infiltrating macrophages and distal TAMs revealed that IL-12, both in vivo and in vitro, induced a rapid (&lt;90 min) reduction of tumor supportive macrophage activities (IL-10, MCP-1, migration inhibitory factor, and TGFβ production) and a concomitant increase in proinflammatory and proimmunogenic activities (TNF-α, IL-15, and IL-18 production). Similar shifts in functional phenotype were induced by IL-12 in tumor-infiltrating macrophages isolated from the primary tumor mass and in TAMs isolated from lung containing metastases, spleen, and peritoneal cavity. Therefore, although TAMs display a strongly polarized immunosuppressive functional profile, they retain the ability to change their functional profile to proinflammatory activities given the appropriate stimulus. The ability of IL-12 to initiate this functional conversion may contribute to early amplification of the subsequent destructive antitumor immune response.
Mitogenic CD28 Signals Require the Exchange Factor Vav1 to Enhance TCR Signaling at the SLP-76-Vav-Itk Signalosome
Authors: Dennehy Kevin M. , Elias Fernando , Na Shin-Young , Fischer Klaus-Dieter , Hünig Thomas , Lühder Fred 
Published: April 2014

Abstract
Almost all physiological T cell responses require costimulation—engagement of the clonotypic TCR with MHC/Ag and CD28 by its ligands CD80/86. Whether CD28 provides signals that are qualitatively unique or quantitatively amplify TCR signaling is poorly understood. In this study, we use superagonistic CD28 Abs, which induce T cell proliferation without TCR coligation, to determine how CD28 contributes to mitogenic responses. We show that mitogenic CD28 signals require but do not activate the proximal TCR components TCRζ and Zap-70 kinase. In cell lines lacking proximal TCR signaling, an early defect in the CD28 pathway is in phosphorylation of the adaptor molecule SLP-76, which we show is essential for recruitment of the exchange factor Vav leading to Ca2+ flux and IL-2 production. Point mutations in CD28 that result in diminished Vav phosphorylation also result in defective Ca2+ flux, IL-2 production, and Tec-kinase phosphorylation. Using Vav1-deficient mice, we further demonstrate the importance of Vav1 for efficient proliferation, IL-2 production, and Ca2+ flux. Our results indicate that CD28 signals feed into the TCR signaling pathway at the level of the SLP-76 signalosome.