bluuebunny/crossref_metadata_2025_split huggingface dataset:
BALB/c Mice Bearing a Transgenic IL-12 Receptor β2 Gene Exhibit a Nonhealing Phenotype toLeishmania majorInfection Despite Intact IL-12 Signaling
Authors: Nishikomori Ryuta , Gurunathan Sanjay , Nishikomori Kanako , Strober Warren 
Published: April 2014

AbstractIn BALB/c mice infected with Leishmania major, early secretion of IL-4 leads to a Th2-type response and nonhealing. We explored the role of IL-4-induced down-regulation of the IL-12Rβ2 chain in the establishment of this Th2 response. First, we showed that the draining lymph nodes of resistant C57BL/6 mice infected with L. major were enriched in CD4+/IL-12Rβ2 chain+ cells producing IFN-γ. Next, we demonstrated that BALB/c background mice bearing an IL-12Rβ2-chain transgene manifested a nonhealing phenotype similar to wild-type littermates despite the persistence of their ability to undergo STAT4 activation. Finally, we found that such transgenic mice display more severe infection than wild-type littermates when treated with IL-12 7 days after infection, and under this condition, the mice display increased Leishmania Ag-induced IL-4 secretion. These studies indicate that although CD4+/IL-12Rβ2 chain+ T cells are important components of the Th1 response, maintenance of IL-12Rβ2 chain expression is not sufficient to change a Th2 response to a Th1 response in vivo and thus to allow BALB/c mice to heal L. major infection.
IκB Kinase Is Critical for TNF-α-Induced VCAM1 Gene Expression in Renal Tubular Epithelial Cells
Authors: Tu Zheng , Kelley Vicki Rubin , Collins Tucker , Lee Frank S. 
Published: April 2014

Abstract
The expression of VCAM1 is up-regulated in renal proximal tubular epithelial cells (TEC) in a variety of inflammatory renal diseases, a prominent example of which is acute renal allograft rejection. VCAM1 may play an important role in these diseases because it binds to the integrins very late Ag-4 and α4β7 on lymphocytes and monocytes, thereby providing a potential mechanism to recruit these leukocytes to sites of inflammation. The molecular mechanisms underlying VCAM1 regulation in renal TEC are essentially unknown. We now report that VCAM1 mRNA is dramatically up-regulated in C1, a cell line derived from renal TEC, on exposure to TNF-α. Two NF-κB binding sites in the VCAM1 promoter are critical for the TNF-α-induced VCAM1 transcriptional up-regulation, and both sites bind to p65-p50 NF-κB complexes. TNF-α induces activation of inhibitor of NF-κB (IκB) kinase-β (IKK-β), a protein kinase that phosphorylates the NF-κB inhibitor IκB, and thereby targets the latter for degradation via the ubiquitin-proteasome pathway. Moreover, dominant negative versions of IKK inhibit TNF-α activation of a VCAM1 promoter reporter. We conclude that the IKK/NF-κB pathway is critical in the TNF-α-induced up-regulation of VCAM1 mRNA in renal TEC.
Activation of Human Macrophages by Amyloid-β Is Attenuated by Astrocytes
Authors: Smits Hessel A. , van Beelen Astrid J. , de Vos N. Machiel , Rijsmus Annemarie , van der Bruggen Tjomme , Verhoef Jan , van Muiswinkel Freek L. , Nottet Hans S. L. M. 
Published: April 2014

AbstractIn Alzheimer’s disease, neuritic amyloid-β plaques along with surrounding activated microglia and astrocytes are thought to play an important role in the inflammatory events leading to neurodegeneration. Studies have indicated that amyloid-β can be directly neurotoxic by activating these glial cells to produce oxygen radicals and proinflammatory cytokines. This report shows that, using primary human monocyte-derived macrophages as model cells for microglia, amyloid-β1–42 stimulate these macrophages to the production of superoxide anions and TNF-α. In contrast, astrocytes do not produce both inflammatory mediators when stimulated with amyloid-β1–42. In cocultures with astrocytes and amyloid-β1–42-stimulated macrophages, decreased levels of both superoxide anion and TNF-α were detected. These decreased levels of potential neurotoxins were due to binding of amyloid-β1–42 to astrocytes since FACScan analysis demonstrated binding of FITC-labeled amyloid-β1–42 to astrocytoma cells and pretreatment of astrocytes with amyloid-β1–16 prevented the decrease of superoxide anion in cocultures of human astrocytes and amyloid-β1–42-stimulated macrophages. To elucidate an intracellular pathway involved in TNF-α secretion, the activation state of NF-κB was investigated in macrophages and astrocytoma cells after amyloid-β1–42 treatment. Interestingly, although activation of NF-κB could not be detected in amyloid-β-stimulated macrophages, it was readily detected in astrocytoma cells. These results not only demonstrate that amyloid-β stimulation of astrocytes and macrophages result in different intracellular pathway activation but also indicate that astrocytes attenuate the immune response of macrophages to amyloid-β1–42 by interfering with amyloid-β1–42 binding to macrophages.
The p38 Mitogen-Activated Protein Kinase Mediates Cytoskeletal Remodeling in Pulmonary Microvascular Endothelial Cells Upon Intracellular Adhesion Molecule-1 Ligation
Authors: Wang Qin , Doerschuk Claire M. 
Published: April 2014

AbstractChanges in the cytoskeleton of endothelial cells (ECs) play important roles in mediating neutrophil migration during inflammation. Previous studies demonstrated that neutrophil adherence to TNF-α-treated pulmonary microvascular ECs induced cytoskeletal remodeling in ECs that required ICAM-1 ligation and oxidant production and was mimicked by cross-linking ICAM-1. In this study, we examined the role of ICAM-1-induced signaling pathways in mediating actin cytoskeletal remodeling. Cross-linking ICAM-1 induced alterations in ICAM-1 distribution, as well as the filamentous actin rearrangements and stiffening of ECs shown previously. ICAM-1 cross-linking induced phosphorylation of the p38 mitogen-activated protein kinase (MAPK) that was inhibited by allopurinol and also induced an increase in the activity of the p38 MAPK that was inhibited by SB203580. However, SB203580 had no effect on oxidant production in ECs or ICAM-1 clustering. ICAM-1 cross-linking also induced phosphorylation of heat shock protein 27, an actin-binding protein that may be involved in filamentous actin polymerization. The time course of heat shock protein 27 phosphorylation paralleled that of p38 MAPK phosphorylation and was completely inhibited by SB203580. In addition, SB203580 blocked the EC stiffening response induced by either neutrophil adherence or ICAM-1 cross-linking. Moreover, pretreatment of ECs with SB203580 reduced neutrophil migration toward EC junctions. Taken together, these data demonstrate that activation of p38 MAPK, mediated by xanthine oxidase-generated oxidant production, is required for cytoskeletal remodeling in ECs induced by ICAM-1 cross-linking or neutrophil adherence. These cytoskeletal changes in ECs may in turn modulate neutrophil migration toward EC junctions.
Gα16 Couples Chemoattractant Receptors to NF-κB Activation
Authors: Yang Ming , Sang Hairong , Rahman Arshad , Wu Dianqing , Malik Asrar B. , Ye Richard D. 
Published: April 2014

Abstract
The guanine nucleotide-binding regulatory protein α-subunit, Gα16, is primarily expressed in hemopoietic cells, and interacts with a large number of seven-membrane span receptors including chemoattractant receptors. We investigated the biological functions resulting from Gα16 coupling of chemoattractant receptors in a transfected cell model system. HeLa cells expressing a κB-driven luciferase reporter, Gα16, and the formyl peptide receptor responded to fMLP with a ∼7- to 10-fold increase in luciferase activity. This response was accompanied by phosphorylation of IκBα and elevation of nuclear κB-DNA binding activity, indicating activation of NF-κB. In contrast to Gα16, expression of Gαq, Gα13, and Gαi2 resulted in a marginal increase in κB luciferase activity. A GTPase-deficient, constitutively active Gα16 mutant (Q212L) could replace agonist stimulation for activation of NF-κB. Furthermore, expression of Gα16 (Q212L) markedly enhanced TNF-α-induced κB reporter activity. The Gα16-mediated NF-κB activation was paralleled by an increase in phospholipase C-β activity, and was blocked by pharmacological inhibitors of protein kinase C (PKC) and by buffering of intracellular Ca2+. The involvement of a conventional PKC isoform was confirmed by the finding that expression of PKCα enhanced the effect of Gα16, and a dominant negative PKCα partially blocked Gα16-mediated NF-κB activation. In addition to formyl peptide receptor, Gα16 also enhanced NF-κB activation by the C5a and C3a receptors, and by CXC chemokine receptor 2 and CCR8. These results suggest a potential role of Gα16 in transcriptional regulation downstream of chemoattractant receptors.
Chemokine Receptor CCR4 on CD4+ T Cells in Juvenile Rheumatoid Arthritis Synovial Fluid Defines a Subset of Cells with Increased IL-4:IFN-γ mRNA Ratios
Authors: Thompson Susan D. , Luyrink Lorie K. , Graham T. Brent , Tsoras Monica , Ryan Mary , Passo Murray H. , Glass David N. 
Published: April 2014

Abstract
To understand the mechanisms that promote recruitment and survival of T cells within the pediatric inflamed joint, we have studied the expression of CCR4 and CCR5 on synovial fluid T cells and matched peripheral blood samples from juvenile rheumatoid arthritis (JRA) patients using three-color flow cytometric analysis. Thymus- and activation-regulated chemokine and macrophage-derived chemokine, ligands for CCR4, were measured by ELISA in JRA synovial fluid, JRA plasma, adult rheumatoid arthritis synovial fluid, and normal plasma. IL-4 and IFN-γ mRNA production was assessed in CD4+/CCR4+ and CD4+/CCR4− cell subsets. We found accumulations of both CCR4+ and CCR5+ T cells in JRA synovial fluids and a correlation for increased numbers of CCR4+ T cells in samples collected early in the disease process. Thymus- and activation-regulated chemokine was detected in JRA synovial fluid and plasma samples, but not in adult rheumatoid arthritis synovial fluid or control plasma. Macrophage-derived chemokine was present in all samples. CD4+/CCR4+ synovial lymphocytes produced more IL-4 and less IFN-γ than CD4+/CCR4− cells. These findings suggest that CCR4+ T cells in the JRA joint may function early in disease in an anti-inflammatory capacity through the production of type 2 cytokines and may play a role in determining disease phenotype.
Thiopalmitoylation of Myelin Proteolipid Protein Epitopes Enhances Immunogenicity and Encephalitogenicity
Authors: Greer Judith M. , Denis Bérangère , Sobel Raymond A. , Trifilieff Elisabeth 
Published: April 2014

AbstractProteolipid protein (PLP) is the most abundant protein of CNS myelin, and is posttranslationally acylated by covalent attachment of long chain fatty acids to cysteine residues via a thioester linkage. Two of the acylation sites are within epitopes of PLP that are encephalitogenic in SJL/J mice (PLP104–117 and PLP139–151) and against which increased immune responses have been detected in some multiple sclerosis patients. It is known that attachment of certain types of lipid side chains to peptides can result in their enhanced immunogenicity. The aim of this study was to determine whether thioacylated PLP peptides, as occur in the native protein, are more immunogenic than their nonacylated counterparts, and whether thioacylation influences the development of autoreactivity and experimental autoimmune encephalomyelitis. The results show that in comparison with nonacylated peptides, thioacylated PLP lipopeptides can induce greater T cell and Ab responses to both the acylated and nonacylated peptides. They also enhanced the development and chronicity of experimental autoimmune encephalomyelitis. Synthetic peptides in which the fatty acid was attached via an amide linkage at the N terminus were not encephalitogenic, and they induced greater proportions of CD8+ cells in initial in vitro stimulation. Therefore, the lability and the site of the linkage between the peptide and fatty acid may be important for induction of encephalitogenic CD4+ T cells. These results suggest that immune responses induced by endogenous thioacylated lipopeptides may contribute to the immunopathogenesis of chronic experimental demyelinating diseases and multiple sclerosis.
IFN-γ-Inducible Protein-10 Is Essential for the Generation of a Protective Tumor-Specific CD8 T Cell Response Induced by Single-Chain IL-12 Gene Therapy
Authors: Pertl Ursula , Luster Andrew D. , Varki Nissi M. , Homann Dirk , Gaedicke Gerhard , Reisfeld Ralph A. , Lode Holger N. 
Published: April 2014

AbstractThe successful induction of T cell-mediated protective immunity against poorly immunogenic malignancies remains a major challenge for cancer immunotherapy. Here, we demonstrate that the induction of tumor-protective immunity by IL-12 in a murine neuroblastoma model depends entirely on the CXC chemokine IFN-γ-inducible protein 10 (IP-10). This was established by in vivo depletion of IP-10 with mAbs in mice vaccinated against NXS2 neuroblastoma by gene therapy with a linearized, single-chain (sc) version of the heterodimeric cytokine IL-12 (scIL-12). The efficacy of IP-10 depletion was indicated by the effective abrogation of scIL-12-mediated antiangiogenesis and T cell chemotaxis in mice receiving s.c. injections of scIL-12-producing NXS2 cells. These findings were extended by data demonstrating that IP-10 is directly involved in the generation of a tumor-protective CD8+ T cell-mediated immune response during the early immunization phase. Four lines of evidence support this contention: First, A/J mice vaccinated with NXS2 scIL-12 and depleted of IP-10 by two different anti-IP-10 mAbs revealed an abrogation of systemic-protective immunity against disseminated metastases. Second, CD8+ T cell-mediated MHC class I Ag-restricted tumor cell lysis was inhibited in such mice. Third, intracellular IFN-γ expressed by proliferating CD8+ T cells was substantially inhibited in IP-10-depleted, scIL-12 NXS2-vaccinated mice. Fourth, systemic tumor protective immunity was completely abrogated in mice depleted of IP-10 in the early immunization phase, but not if IP-10 was depleted only in the effector phase. These findings suggest that IP-10 plays a crucial role during the early immunization phase in the induction of immunity against neuroblastoma by scIL-12 gene therapy.
CD134L Expression on Dendritic Cells in the Mesenteric Lymph Nodes Drives Colitis in T Cell-Restored SCID Mice
Authors: Malmström Vivianne , Shipton Deborah , Singh Baljit , Al-Shamkhani Aymen , Puklavec Michael J. , Barclay A. Neil , Powrie Fiona 
Published: April 2014

AbstractTransfer of CD45RBhigh CD4+ T cells to immune-deficient mice in the absence of regulatory T cells leads to a Th1-mediated colitis. In this study, we show that intestinal inflammation is characterized by a 15-fold increase in the number of CD134L+ (OX40L+)-activated DC in the mesenteric lymph nodes (MLNs) compared with BALB/c mice. This was important functionally, as administration of an anti-CD134L mAb inhibited the proliferation of T cells in the MLNs as well as their expression of the gut-homing integrin α4β7. Most importantly, the anti-CD134L mAb completely blocked development of colitis. Surprisingly, CD134L was found to be expressed by a proportion of dendritic cells (DC) in the MLNs of unreconstituted SCID mice, suggesting that CD134L can be induced on DC in the absence of T cell-derived signals. These results indicate that some DC in the MLNs of SCID mice express an activated phenotype and that CD134L expression by these cells is involved in the development of colitis induced by T cell transfer. Accumulation of CD134L+ DC was inhibited by cotransfer of regulatory T cells, suggesting that inhibition of the accumulation of activated DC is one mechanism by which these cells prevent immune pathology.
Vasoactive Intestinal Peptide and Pituitary Adenylate Cyclase-Activating Polypeptide Inhibit Expression of Fas Ligand in Activated T Lymphocytes by Regulating c-Myc, NF-κB, NF-AT, and Early Growth Factors 2/3
Authors: Delgado Mario , Ganea Doina 
Published: April 2014

AbstractActivation-induced cell death in T cells, a major mechanism for limiting an ongoing immune response, is initiated by Ag reengagement and mediated through Fas/Fas ligand interactions. Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP), two multifunctional neuropeptides, modulate innate and adaptive immunity. We reported previously that VIP/PACAP protect T cells from activation-induced cell death through down-regulation of Fas ligand (FasL). In this study, we investigate the molecular mechanisms involved in the protective effect of VIP and PACAP. VIP/PACAP reduce in a dose-dependent manner anti-CD3-induced apoptosis in 2B4.11 T cell hybridomas. The protective effect is mediated through the specific type 2 VIP receptor, and the cAMP/protein kinase A pathway. A functional study demonstrates that VIP/PACAP inhibit activation-induced FasL expression. VIP/PACAP inhibit the expression and/or DNA-binding activity of several transcriptional factors involved in FasL expression, i.e., c-myc, NF-κB, NF-ATp, and early growth factors (Egr) 2/3. The inhibition of NF-κB binding is due to the stabilization of I-κB (inhibitory protein that dissociates from NF-κB), through the inhibition of I-κB kinase α activity. Subsequently, p65 nuclear translocation is significantly reduced. The inhibition in NF-ATp binding results from a calcineurin-independent reduction in NF-ATp nuclear translocation. VIP/PACAP inhibit the expression of Egr2 and 3, but not of Egr1. The effects on the transcriptional factors are mediated through type 2 VIP receptor with cAMP as secondary messenger.
Histoplasma capsulatumYeasts Are Phagocytosed Via Very Late Antigen-5, Killed, and Processed for Antigen Presentation by Human Dendritic Cells
Authors: Gildea Lucy A. , Morris Randal E. , Newman Simon L. 
Published: April 2014

AbstractHistoplasma capsulatum (Hc) is a facultative, intracellular parasite of world-wide importance. As the induction of cell-mediated immunity to Hc is of critical importance in host defense, we sought to determine whether dendritic cells (DC) could function as a primary APC for this pathogenic fungus. DC obtained by culture of human monocytes in the presence of GM-CSF and IL-4 phagocytosed Hc yeasts in a time-dependent manner. Upon ingestion, the intracellular growth of yeasts within DC was completely inhibited compared with rapid growth within human macrophages. Electron microscopy of DC with ingested Hc revealed that many of the yeasts were degraded as early as 2 h postingestion. In contrast to macrophages, human DC recognized Hc yeasts via the fibronectin receptor, very late Ag-5, and not via CD18 receptors. DC stimulated Hc-specific lymphocyte proliferation in a concentration-dependent manner after phagocytosis of viable and heat-killed Hc yeasts, but greater proliferation was achieved after ingestion of viable yeasts. These data demonstrate that human DC can phagocytose and degrade a fungal pathogen and subsequently process the appropriate Ags for stimulation of lymphocyte proliferation. In vivo, such interactions between DC and Hc may facilitate the induction of cell-mediated immunity.
Bispecific Monoclonal Antibodies Mediate Binding of Dengue Virus to Erythrocytes in a Monkey Model of Passive Viremia
Authors: Hahn Chang S. , French Olivia G. , Foley Patricia , Martin Edward N. , Taylor Ronald P. 
Published: April 2014

Abstract
Dengue viruses (DEN), causative agents of dengue fever (DF) and more severe dengue hemorrhagic fever (DHF)/dengue shock syndrome, infect over 100 million people every year. Among those infected, up to one-half million people develop DHF, which requires an extensive hospital stay. Recent reports indicate that there is a significant correlation between virus titer in the bloodstream of infected individuals and the severity of the disease, especially the development of DHF. This suggests that if there is a procedure to reduce viremia in infected subjects, then the severity of the disease may be controlled during the critical early stages of the disease before it progresses to DHF. We have generated bispecific mAb complexes (heteropolymer(s), HP), which contain a mAb specific for the DEN envelope glycoprotein cross-linked with a second mAb specific for the primate E complement receptor 1. These HP facilitate rapid binding of DEN to human and monkey E in vitro, with ∼90% bound within 5 min. Furthermore, in a passive viremia monkey model established by continuous steady state infusion of DEN, injection of HP during the steady state promoted rapid binding of DEN to the E, followed by subsequent clearance from the vascular system. Moreover, HP previously infused into the circulation is capable of efficiently capturing a subsequent challenge dose of DEN and binding it to E. These data suggest that HP potentially can be useful for alleviating DEN infection-associated symptoms by reducing titers of free virus in the vascular system.
Mucosal Delivery of a Respiratory Syncytial Virus CTL Peptide with Enterotoxin-Based Adjuvants Elicits Protective, Immunopathogenic, and Immunoregulatory Antiviral CD8+ T Cell Responses
Authors: Simmons Cameron P. , Hussell Tracy , Sparer Tim , Walzl Gerhard , Openshaw Peter , Dougan Gordon 
Published: April 2014

AbstractIn an effort to develop a safe and effective vaccine against respiratory syncytial virus (RSV), we used Escherichia coli heat-labile toxin (LT), and LTK63 (an LT mutant devoid of ADP-ribosyltransferase activity) to elicit murine CD8+ CTL responses to an intranasally codelivered CTL peptide from the second matrix protein (M2) of RSV. M282–90-specific CD8+ T cells were detected by IFN-γ enzyme-linked immunospot and 51Cr release assay in local and systemic lymph nodes, and their induction was dependent on the use of a mucosal adjuvant. CTL elicited by peptide immunization afforded protection against RSV challenge, but also enhanced weight loss. CTL-mediated viral clearance was not dependent on IFN-γ since depletion using specific mAb during RSV challenge did not affect cellular recruitment or viral clearance. Depletion of IFN-γ did, however, reduce the concentration of TNF detected in lung homogenates of challenged mice and largely prevented the weight loss associated with CTL-mediated viral clearance. Mice primed with the attachment glycoprotein (G) develop lung eosinophilia after intranasal RSV challenge. Mucosal peptide vaccination reduced pulmonary eosinophilia in mice subsequently immunized with G and challenged with RSV. These studies emphasize that protective and immunoregulatory CD8+ CTL responses can be mucosally elicited using enterotoxin-based mucosal adjuvants but that resistance against viral infection may be accompanied by enhanced disease.