bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reverse Signaling Through Transmembrane TNF Confers Resistance to Lipopolysaccharide in Human Monocytes and Macrophages
Authors: Eissner Günther , Kirchner Silvia , Lindner Heidrun , Kolch Walter , Janosch Petra , Grell Matthias , Scheurich Peter , Andreesen Reinhard , Holler Ernst 
Published: April 2014

AbstractWe have previously reported that the CD14+ monocytic subpopulation of human PBMC induces programmed cell death (apoptosis) in cocultured endothelial cells (EC) when stimulated by bacterial endotoxin (LPS). Apoptosis is mediated by two routes, first via transmembrane TNF-α (mTNF) expressed on PBMC and, in addition, by TNF-independent soluble factors that trigger apoptosis in EC. Neutralizing anti-TNF mAb completely blocked coculture-mediated apoptosis, despite the fact that there should have been additional soluble cell death factors. This led to the hypothesis that a reverse signal is transmitted from the TNF receptor on EC to monocytes (MO) via mTNF that prevents the production of soluble apoptotic factors. Here we have tested this hypothesis. The results support the idea of a bidirectional cross-talk between MO and EC. Peripheral blood MO, MO-derived macrophages (MΦ), or the monocytic cell line Mono Mac 6 were preincubated with human microvascular EC that constitutively express TNF receptor type I (TNF-R1) and subsequently stimulated with LPS. Cell-free supernatants of these preparations no longer induced EC apoptosis. The preincubation of MO/MΦ with TNF-reactive agents, such as mAb and soluble receptors, also blocked the production of death factors, providing further evidence for reverse signaling via mTNF. Finally, we show that reverse signaling through mTNF mediated LPS resistance in MO/MΦ as indicated by the down-regulation of LPS-induced soluble TNF and IL-6 as well as IL-1 and IL-10.
Transcription-Coupled and Global Genome Repair Differentially Influence UV-B-Induced Acute Skin Effects and Systemic Immunosuppression
Authors: Garssen Johan , van Steeg Harry , de Gruijl Frank , de Boer Jan , van der Horst Gijsbertus T. J. , van Kranen Henk , van Loveren Henk , van Dijk Mariska , Fluitman Angelique , Weeda Geert , Hoeijmakers Jan H. J. 
Published: April 2014

Abstract
Exposure to UV-B radiation impairs immune responses in mammals by inhibiting especially Th1-mediated contact hypersensitivity and delayed-type hypersensitivity. Immunomodulation is not restricted to the exposed skin, but is also observed at distant sites, indicating the existence of mediating factors such as products from exposed skin cells or photoactivated factors present in the superficial layers. DNA damage appears to play a key role, because enhanced nucleotide excision repair (NER) strongly counteracts immunosuppression. To determine the effects of the type and genomic location of UV-induced DNA damage on immunosuppression and acute skin reactions (edema and erythema) four congenic mouse strains carrying different defects in NER were compared: CSB and XPC mice lacking transcription-coupled or global genome NER, respectively, as well as XPA and TTD/XPD mice carrying complete or partial defects in both NER subpathways, respectively. The major conclusions are that 1) transcription-coupled DNA repair is the dominant determinant in protection against acute skin effects; 2) systemic immunomodulation is only affected when both NER subpathways are compromised; and 3) sunburn is not related to UV-B-induced immunosuppression.
Sustained Expression of CD154 (CD40L) and Proinflammatory Cytokine Production by Alloantigen-Stimulated Umbilical Cord Blood T Cells
Authors: Matthews Nick C. , Wadhwa Meenu , Bird Chris , Borras Francesc E. , Navarrete Cristina V. 
Published: April 2014

AbstractRecent data suggests that graft-versus-host disease (GVHD) is initiated by host APCs. Blockade of CD40:CD154 interactions between APCs and T cells in vivo induces T cell tolerance to host alloantigen and dramatically reduces GVHD. Because allogeneic cord blood (CB) transplantation results in a lower incidence and severity of acute GVHD compared with bone marrow transplantation, we have investigated whether CB T cells can express CD154 in response to stimulation by allogeneic monocyte-derived dendritic cells (MDDC) and have used 5- (and 6-)carboxyfluorescein diacetate succinimidyl ester (CFSE) labeling in combination with intracellular cytokine analysis to assess the proliferation and cytokine profiles of alloantigen-responsive cells. CB T cells stimulated with allogeneic MDDC showed stronger proliferation than adult blood T cells. Surface CD154 expression was detected in the actively dividing CFSElow populations of both the CD4+ and CD4− subsets and was brightest in cells that had divided the most. Assessment of supernatants from MDDC-stimulated CB and adult blood T cells showed no significant difference in the levels of either IFN-γ or TNF-α, but CB T cell supernatants did show a significant lack of detectable IL-2. Intracellular cytokine analysis revealed that dividing CB T cells had been primed to produce IFN-γ, TNF-α, and IL-2 on restimulation. Further phenotype analysis showed that 75% of CB T cells producing IFN-γ were CD8+. These data suggest that MDDC-stimulated CB T cells express functional CD154 and provide enough costimulation for dendritic cells to prime naive CD8+ CB T cells and induce type 1 cytokine production.
Glucocorticoids Regulate TCR-Induced Elevation of CD4: Functional Implications
Authors: Wiegers G. Jan , Stec Ilona E. M. , Klinkert Wolfgang E. F. , Reul Johannes M. H. M. 
Published: April 2014

AbstractCD4 serves as a coreceptor during Ag recognition by the TCR. This interaction results in a marked increase in the sensitivity of a T cell to Ag presented by MHC class II molecules. Here we report that activation of T cells either by plate-bound mAb (anti-TCR, anti-CD3) or soluble activators (staphylococcal enterotoxin A, Con A) is associated with an (up to 3-fold) increase in CD4 cell surface expression on CD25+ cells, which was maximal after 72–96 h. Incubation with the glucocorticoid hormone corticosterone (CORT) shifted the enhancement of CD4 expression to a point about 24 h earlier than that observed in control cultures. In parallel, the proliferative response of these CORT-treated cells was profoundly enhanced. An involvement of increased CD4 expression in this enhanced proliferative response was evidenced by the observation that T cell proliferation in CORT-treated cultures was much less sensitive to inhibition by an inhibitory, nondepleting anti-CD4 mAb than that in control cultures. TCR down-regulation was, however, not affected by CORT. Thus, based on this study and previous reports we propose that both TCR-mediated signals and glucocorticoids are important physiological regulators of CD4 expression. In addition, these findings may be of significance for the sensitivity of CD4+ cells to HIV infection upon T cell activation, as the efficacy of primary patient HIV entry depends on the level of surface CD4.
Analysis of the Diversity of a Sheep Antibody Repertoire as Revealed from a Bacteriophage Display Library
Authors: Charlton Keith A. , Moyle Sarah , Porter Andrew J. R. , Harris William J. 
Published: April 2014

AbstractWe have applied bacteriophage display technology to construct and analyze the diversity of an IgG library of &gt;1 × 108 clones from an adult sheep immunized against the hapten atrazine. We have identified eight new VH gene families (VH2–VH9) and five new Vκ gene families (VκV–VκIX). The heavy and κ light chain variable region gene loci were found to be far more diverse than previously thought.
IL-2 Activation of NK Cells: Involvement of MKK1/2/ERK But Not p38 Kinase Pathway
Authors: Yu Tse-Kuan , Caudell Eva G. , Smid Christine , Grimm Elizabeth A. 
Published: April 2014

AbstractIL-2 stimulates extracellular signal-regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) in various immune cell populations. The functional roles that these kinases play are still unclear. In this study, we examined whether MAPK kinase (MKK)/ERK and p38 MAPK pathways are necessary for IL-2 to activate NK cells. Using freshly isolated human NK cells, we established that an intact MKK/ERK pathway is necessary for IL-2 to activate NK cells to express at least four known biological responses: LAK generation, IFN-γ secretion, and CD25 and CD69 expression. IL-2 induced ERK activation within 5 min. Treatment of NK cells with a specific inhibitor of MKK1/2, PD98059, during the IL-2 stimulation blocked in a dose-dependent manner each of four sequelae, with inhibition of lymphokine-activated killing induction being least sensitive to MKK/ERK pathway blockade. Activation of p38 MAPK by IL-2 was not detected in NK cells. In contrast to what was observed by others in T lymphocytes, SB203850, a specific inhibitor of p38 MAPK, did not inhibit IL-2-activated NK functions. This data indicate that p38 MAPK activation was not required for IL-2 to activate NK cells for the four functions examined. These results reveal selective signaling differences between NK cells and T lymphocytes; in NK cells, the MKK/ERK pathway and not p38 MAPK plays a critical positive regulatory role during activation by IL-2.
The ADP-Ribosylating CTA1-DD Adjuvant Enhances T Cell-Dependent and Independent Responses by Direct Action on B Cells Involving Anti-Apoptotic Bcl-2- and Germinal Center-Promoting Effects
Authors: Ågren Lena , Sverremark Eva , Ekman Lena , Schön Karin , Löwenadler Björn , Fernandez Carmen , Lycke Nils 
Published: April 2014

AbstractWe recently developed a novel immunomodulating gene fusion protein, CTA1-DD, that combines the ADP-ribosylating ability of cholera toxin (CT) with a dimer of an Ig-binding fragment, D, of Staphylococcus aureus protein A. The CTA1-DD adjuvant was found to be nontoxic and greatly augmented T cell-dependent responses to soluble protein Ags after systemic as well as mucosal immunizations. Here we show that CTA1-DD does not appear to form immune complexes or bind to soluble Ig following injections, but, rather, it binds directly to B cells of all isotypes, including naive IgD+ cells. No binding was observed to macrophages or dendritic cells. Immunizations in FcεR (common FcRγ-chain)- and FcγRII-deficient mice demonstrated that CTA1-DD exerted unaltered enhancing effects, indicating that FcγR-expressing cells are not required for the adjuvant function. Whereas CT failed to augment Ab responses to high m.w. dextran B512 in athymic mice, CTA1-DD was highly efficient, demonstrating that T cell-independent responses were also enhanced by this adjuvant. In normal mice both CT and CTA1-DD, but not the enzymatically inactive CTA1-R7K-DD mutant, were efficient enhancers of T cell-dependent as well as T cell-independent responses, and both promoted germinal center formation following immunizations. Although CT augmented apoptosis in Ag receptor-activated B cells, CTA1-DD strongly counteracted apoptosis by inducing Bcl-2 in a dose-dependent manner, a mechanism that was independent of the CD19 coreceptor. However, in the presence of CD40 stimulation, apoptosis was low and unaffected by CT, suggesting that the adjuvant effect of CT is dependent on the presence of activated CD40 ligand-expressing T cells.
Vitamin D3 Up-Regulated Protein 1 Mediates Oxidative Stress Via Suppressing the Thioredoxin Function
Authors: Junn Eunsung , Han Seung Hyun , Im Joo Young , Yang Young , Cho Eun Wie , Um Hong Duck , Kim Do Kyun , Lee Kang Woo , Han Pyung Lim , Rhee Sue Goo , Choi Inpyo 
Published: April 2014

AbstractAs a result of identifying the regulatory proteins of thioredoxin (TRX), a murine homologue for human vitamin D3 up-regulated protein 1 (VDUP1) was identified from a yeast two-hybrid screen. Cotransfection into 293 cells and precipitation assays confirmed that mouse VDUP1 (mVDUP1) bound to TRX, but it failed to bind to a Cys32 and Cys35 mutant TRX, suggesting the redox-active site is critical for binding. mVDUP1 was ubiquitously expressed in various tissues and located in the cytoplasm. Biochemical analysis showed that mVDUP1 inhibited the insulin-reducing activity of TRX. When cells were treated with various stress stimuli such as H2O2 and heat shock, mVDUP1 was significantly induced. TRX is known to interact with other proteins such as proliferation-associated gene and apoptosis signal-regulating kinase 1. Coexpression of mVDUP1 interfered with the interaction between TRX and proliferation-associated gene or TRX and ASK-1, suggesting its roles in cell proliferation and oxidative stress. To investigate the roles of mVDUP1 in oxidative stress, mVDUP1 was overexpressed in NIH 3T3 cells. When cells were exposed to stress, cell proliferation was declined with elevated apoptotic cell death compared with control cells. In addition, c-Jun N-terminal kinase activation and IL-6 expression were elevated. Taken together, these results demonstrate that mVDUP1 functions as an oxidative stress mediator by inhibiting TRX activity.
Mice with a Selective Deletion of the CC Chemokine Receptors 5 or 2 Are Protected from Dextran Sodium Sulfate-Mediated Colitis: Lack of CC Chemokine Receptor 5 Expression Results in a NK1.1+ Lymphocyte-Associated Th2-Type Immune Response in the Intestine
Authors: Andres Pietro G. , Beck Paul L. , Mizoguchi Emiko , Mizoguchi Atsushi , Bhan Atul K. , Dawson Tracey , Kuziel William A. , Maeda Nobuyo , MacDermott Richard P. , Podolsky Daniel K. , Reinecker Hans-Christian 
Published: April 2014

AbstractThe chemokine receptors CCR2 and CCR5 and their respective ligands regulate leukocyte chemotaxis and activation. To determine the role of these chemokine receptors in the regulation of the intestinal immune response, we induced colitis in CCR2- and CCR5-deficient mice by continuous oral administration of dextran sodium sulfate (DSS). Both CCR2- and CCR5-deficient mice were susceptible to DSS-induced intestinal inflammation. The lack of CCR2 or CCR5 did not reduce the DSS-induced migration of macrophages into the colonic lamina propria. However, both CCR5-deficient mice and, to a lesser degree, CCR2-deficient mice were protected from DSS-induced intestinal adhesions and mucosal ulcerations. CCR5-deficient mice were characterized by a greater relative infiltration of CD4+ and NK1.1+ lymphocyte in the colonic lamina propria when compared to wild-type and CCR2-deficient mice. In CCR5-deficient mice, mucosal mRNA expression of IL-4, IL-5, and IL-10 was increased, whereas that of IFN-γ was decreased, corresponding to a Th2 pattern of T cell activation. In CCR2-deficient mice, the infiltration of Th2-type T cells in the lamina propria was absent, but increased levels of IL-10 and decreased levels of IFN-γ may have down regulated mucosal inflammation. Our data indicate that CCR5 may be critical for the promotion of intestinal Th1-type immune responses in mice.
Genetic Immunization with Lung-Targeting Macroaggregated Polyethyleneimine-Albumin Conjugates Elicits Combined Systemic and Mucosal Immune Responses
Authors: Orson Frank M. , Kinsey Berma M. , Hua Pascal J. , Bhogal Balbir S. , Densmore Charles L. , Barry Michael A. 
Published: April 2014

AbstractGenetic immunization is a novel form of vaccination in which transgenes are delivered into the host to produce the foreign protein within host cells. Although systemic immune responses have been relatively easy to induce by genetic immunization, the induction of regional and mucosal immunity has often been more challenging. To address the problem of eliciting mucosal immunity in the lung, we utilized macroaggregated albumin to target plasmid DNA to the lung. Macroaggregated albumin is trapped in the lung after i.v. injection, and it is routinely used in radiolabeled form as an imaging modality to evaluate pulmonary blood flow. To couple DNA to this targeting agent, polyethyleneimine (a polycation that binds DNA and enhances transfection) was conjugated to serum albumin, and the conjugate was aggregated by heating to produce particles of 25–100 μm. The resulting particles bound plasmid DNA avidly, and when injected i.v. in mice, the particles distributed in the peripheral lung tissue in the alveolar interstitium. Particle-bound luciferase plasmid transfected a variety of cell lines in vitro, and after i.v. injection, gene expression was detected exclusively in the lung. Using human growth hormone as the encoded foreign Ag for immunization, i.v. injection of the particle-bound plasmid elicited both pulmonary mucosal and systemic immune responses, whereas naked DNA injected either i.v. or i.m. elicited only systemic responses. Thus, particle-bound plasmid DNA may have utility for genetic immunization by intravascular delivery to the lung and potentially to other organs and tissues.
Functional Analysis of the Murine TCRβ-Chain Gene Enhancer
Authors: Carvajal Irvith M. , Sen Ranjan 
Published: April 2014

Abstract
The TCRβ-chain gene enhancer activates transcription and V(D)J recombination in immature thymocytes. In this paper we present a systematic analysis of the elements that contribute to the activity of the murine TCRβ enhancer in mature and immature T cell lines. We identified a region containing the βE4, βE5, and βE6 motifs as the essential core of the TCRβ enhancer in pro-T cells. In mature cells, the core enhancer had low activity and required, in addition, either 5′ or 3′ flanking sequences whose functions may be partially overlapping. Mutation of any of the six protein binding sites located within the βE4–βE6 elements essentially abolished enhancer activity, indicating that this core enhancer contained no redundant elements. The βE4 and βE6 elements contain binding sites for ETS-domain proteins and the core binding factor. The βE5 element bound two proteins that could be resolved chromatographically and that were both essential for enhancer activity.
Primary Structure and Functional Characterization of a Soluble, Alternatively Spliced Form of B7-1
Authors: Faas Susan J. , Giannoni Michelle A. , Mickle Angela P. , Kiesecker Cheri L. , Reed Deborah J. , Wu Dayang , Fodor William L. , Mueller John P. , Matis Louis A. , Rother Russell P. 
Published: April 2014

AbstractRecent studies have suggested that soluble forms of B7-1 and B7-2 may exist, but transcripts that code for these molecules have not been previously described. In this study, we report the cloning and characterization of an alternatively spliced soluble form of porcine B7-1 (sB7-1) that lacks exons coding for both the transmembrane and cytoplasmic domains. Northern blot analysis of RNA from alveolar macrophages revealed an approximate 3:1 ratio of the transmembrane form of B7-1 mRNA relative to sB7-1 mRNA. Porcine B7-1 was present on the surface of both B and T cells following stimulation with PMA/ionomycin. A histidine-tagged form of porcine sB7-1 (sB7-1-His) interacted with both CD28 and CTLA-4, and effectively blocked IL-2 production from human responder cells stimulated with PHA and either porcine or human stimulator cells. In addition, sB7–1-His inhibited human T cell proliferation in response to porcine or human peripheral blood leukocytes. This study is the first report of an alternatively spliced form of B7 that codes for a soluble protein. Furthermore, these data demonstrate that porcine B7-1 interacts with the human receptors CD28 and CTLA-4, suggesting a potential role for this molecule in pig to human xenotransplantation. Possible physiological functions for the soluble form of B7-1 are discussed.
Functional Analysis of the OCA-B Promoter
Authors: Stevens Sean , Wang Lu , Roeder Robert G. 
Published: April 2014

AbstractOCA-B was identified as a B cell-specific coactivator that functions with either Oct-1 or Oct-2 to mediate efficient cell type-specific transcription via the octamer site (ATGCAAAT) both in vivo and in vitro. Mice lacking OCA-B exhibit normal Ag-independent B cell maturation. In contrast, Ag-dependent functions, including production of secondary Ig isotypes and germinal center formation, are greatly affected. To better understand OCA-B expression and, ultimately, the defects observed in the OCA-B knockout mice, we have cloned the OCA-B promoter and examined its function in both transformed and primary B cells. We show here that the OCA-B promoter is developmentally regulated, with activity increasing throughout B cell differentiation. Through physical and functional assays, we have found an activating transcription factor/cAMP response element binding protein binding site (or cAMP response element) that is crucial for OCA-B promoter activity. Furthermore, we demonstrate that IL-4 and anti-CD40 induce both the OCA-B promoter and octamer-dependent promoters, thus implicating OCA-B in B cell signaling events in the nucleus.
Regulation of Germline Promoters by the Two Human Ig Heavy Chain 3′ α Enhancers
Authors: Hu Yanzhong , Pan Qiang , Pardali Evangelia , Mills Frederick C. , M. Bernstein Ralph , Max Edward E. , Sideras Paschalis , Hammarström Lennart 
Published: April 2014

AbstractThe human IgH 3′ enhancers, located downstream of each of the two Cα genes, modulate germline (GL) transcription of the IgH genes by influencing the activity of promoter-enhancer complexes upstream of the switch and intervening (I) regions. The regulation of GL α1 and α2 promoters by different human 3′ enhancer fragments was investigated in cell lines representing various developmental stages. Both α1HS1,2 and α2HS1,2 fragments show equally strong enhancer activity on the GL α1 and α2 promoters in both orientations when transiently transfected into a number of mature B cell line (DG75, CL-01, and HS Sultan). However, there is no activity in a human pre-B cell line (NALM-6) nor a human T cell line (Jurkat). HS3 shows no enhancer activity by itself in any of the cell lines, whereas a modest effect is noted using HS4 in the three mature B cell lines. However, the combination of the α2HS3-HS1,2-HS4 fragments, which together form a potential locus control region, displays a markedly stronger enhancer activity than the individual fragments with a differential effect on the α1 and α2 promoters as compared with the γ3 promoter. Our results suggest that the human GL α promoter may be regulated by two independent pathways. One pathway is induced by TGF-β1 which directs IgA isotype switch through activation of the GL α promoter and no TGF-β1-responsive elements are present in the different 3′ enhancer fragments. The other route is through the human 3′ enhancer regions that cis-up-regulate the GL α promoter activity in mature B cells.
Evidence That Terminal Deoxynucleotidyltransferase Expression Plays a Role in Ig Heavy Chain Gene Segment Utilization
Authors: Tuaillon Nadine , Capra J. Donald 
Published: April 2014

AbstractTdT is a nuclear enzyme that catalyzes the addition of random nucleotides at Ig and TCR V(D)J junctions. In this paper we analyze human IgH rearrangements generated from transgenic minilocus mice in the presence or absence of TdT. In the absence of TdT, the pseudo-VH gene segment present in the minilocus is rearranged dramatically more frequently. Additionally, JH6 gene segment utilization is increased as well as the number of rearrangements involving only VH and JH gene segments. Thus, the recombination of IgH gene segments that are flanked by 23-nt spacer recombination signal sequences may be influenced by TdT expression. Extensive analysis indicates that these changes are independent of antigenic selection and cannot be explained by homology-mediated recombination. Thus, the role played by TdT may be more extensive than previously thought.