bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conserved NontypeableHaemophilus influenzae-Derived TLR2-Binding Lipopeptides Synergize with IFN-β to Increase Cytokine Production by Resident Murine and Human Alveolar Macrophages
Authors: Punturieri Antonello , Copper Phil , Polak Timothy , Christensen Paul J. , Curtis Jeffrey L. 
Published: April 2014

AbstractNontypeable Haemophilus influenzae (NTHi) is strongly associated with exacerbations of chronic obstructive pulmonary disease, which often coincide with viral respiratory infections. TLR2 contributes importantly to innate immunity to NTHi, but whether this pathway is affected by simultaneous antiviral responses is unknown. To analyze potential interactions, resident murine and human alveolar macrophages (AMφ) were exposed, in the presence or absence of the appropriate rIFN-β, to synthetic lipopeptides corresponding to the triacylated N-terminal fragments of three outer membrane proteins (OMP) (PCP, P4, and P6) that are highly conserved among different NTHi strains. Synthetic OMP elicited strong release of IL-6, the principal inducer of airway mucin genes, and induced CCL5 and CXCL10 from murine AMφ only when IFN-β was also present. Surprisingly, combined stimulation by OMPs and IFN-β also markedly enhanced TNF-α release by murine AMφ. Stimulation with PCP plus IFN-β induced IFN-regulatory factor 1 expression and sustained STAT1 activation, but did not alter the activation of MAPKs or NF-κB. AMφ derived from STAT1-deficient mice did not demonstrate increased production of TNF-α in response to PCP plus IFN-β. Analysis of wild-type and STAT1-deficient AMφ using real-time PCR showed that increased TNF-α production depended on transcriptional up-regulation, but not on mRNA stabilization. The synergistic effect of synthetic OMP and IFN-β was conserved between murine AMφ and human AMφ for IL-6, but not for TNF-α. Thus, IFN-β, which is produced by virally infected respiratory epithelial cells, converts normally innocuous NTHi OMP into potent inflammatory stimulants, but does so via different mechanisms in mice and humans.
Peptidoglycan-Induced IL-6 Production in RAW 264.7 Macrophages Is Mediated by Cyclooxygenase-2, PGE2/PGE4 Receptors, Protein Kinase A, IκB Kinase, and NF-κB
Authors: Chen Bing-Chang , Liao Chiao-Chun , Hsu Ming-Jen , Liao Yi-Ting , Lin Chia-Chin , Sheu Joen-Rong , Lin Chien-Huang 
Published: April 2014

Abstract
In this study, we investigated the signaling pathway involved in IL-6 production caused by peptidoglycan (PGN), a cell wall component of the Gram-positive bacterium, Staphylococcus aureus, in RAW 264.7 macrophages. PGN caused concentration- and time-dependent increases in IL-6, PGE2, and cAMP production. PGN-mediated IL-6 production was inhibited by a nonselective cyclooxygenase (COX) inhibitor (indomethacin), a selective COX-2 inhibitor (NS398), a PGE2 (EP2) antagonist (AH6809), a PGE4 (EP4) antagonist (AH23848), and a protein kinase A (PKA) inhibitor (KT5720), but not by a nonselective NO synthase inhibitor (NG-nitro-l-arginine methyl ester). Furthermore, PGE2, an EP2 agonist (butaprost), an EP2/PGE3 (EP3)/EP4 agonist (misoprostol), and misoprostol in the presence of AH6809 all induced IL-6 production, whereas an EP1/EP3 agonist (sulprostone) did not. PGN caused time-dependent activations of IκB kinase αβ (IKKdβ) and p65 phosphorylation at Ser276, and these effects were inhibited by NS398 and KT5720. Both PGE2 and 8-bromo-cAMP also caused IKKdβ kinase αβ phosphorylation. PGN resulted in two waves of the formation of NF-κB-specific DNA-protein complexes. The first wave of NF-κB activation occurred at 10–60 min of treatment, whereas the later wave occurred at 2–12 h of treatment. The PGN-induced increase in κB luciferase activity was inhibited by NS398, AH6809, AH23848, KT5720, a protein kinase C inhibitor (Ro31-8220), and a p38 MAPK inhibitor (SB203580). These results suggest that PGN-induced IL-6 production involves COX-2-generated PGE2, activation of the EP2 and EP4 receptors, cAMP formation, and the activation of PKA, protein kinase C, p38 MAPK, IKKdβ, kinase αβ, p65 phosphorylation, and NF-κB. However, PGN-induced NO release is not involved in the signaling pathway of PGN-induced IL-6 production.
ERK and p38 MAPK Signaling Pathways Negatively Regulate CIITA Gene Expression in Dendritic Cells and Macrophages
Authors: Yao Yongxue , Xu Qi , Kwon Myung-Ja , Matta Ranyia , Liu Yusen , Hong Soon-Cheol , Chang Cheong-Hee 
Published: April 2014

Abstract
The CIITA is a master regulator for MHC class II expression, but the signaling events that control CIITA expression remain poorly understood. In this study, we report that both constitutive and IFN-γ-inducible expression of CIITA in mouse bone marrow-derived dendritic cells (DC) and macrophages, respectively, are regulated by MAPK signals. In DC, the inhibitory effect of LPS on CIITA expression was prevented by MyD88 deficiency or pharmacological MAPK inhibitors specific for MEK (U0126) and p38 (SB203580), but not JNK (SP600125). In macrophages, LPS inhibited IFN-γ-inducible CIITA and MHC class II expression without affecting expression of IFN regulatory factor-1 and MHC class I. Blocking ERK and p38 by MAPK inhibitors not only rescued LPS-mediated inhibition, but also augmented IFN-γ induction of CIITA. Moreover, the induction of CIITA by IFN-γ was enhanced by overexpressing MAPK phosphatase-1 that inactivates MAPK. Conversely, CIITA expression was attenuated in the absence of MAPK phosphatase-1. The down-regulation of CIITA gene expression by ERK and p38 was at least partly due to decreased histone acetylation of the CIITA promoter. Our study indicates that both MAPK and phosphatase play an important role for CIITA regulation in DC and macrophages.
Inhibition of Mixed Lineage Kinase 3 Prevents HIV-1 Tat-Mediated Neurotoxicity and Monocyte Activation
Authors: Sui Ziye , Fan Shongshan , Sniderhan Lynn , Reisinger Elizabeth , Litzburg Angela , Schifitto Giovanni , Gelbard Harris A. , Dewhurst Stephen , Maggirwar Sanjay B. 
Published: April 2014

Abstract
The HIV-1 gene products Tat and gp120 are toxic to neurons and can activate cells of myeloid origin, properties that are thought to contribute to the clinical manifestations of HIV-1-associated dementia (HAD). To investigate the intracellular signaling mechanisms involved in these events, the effect of Tat and gp120 on mixed lineage kinase (MLK) 3 activation was examined. Tat and gp120 were shown to induce autophosphorylation of MLK3 in primary rat neurons; this was abolished by the addition of an inhibitor of MLK3 (CEP1347). CEP1347 also enhanced survival of both rat and human neurons and inhibited the activation of human monocytes after exposure to Tat and gp120. Furthermore, overexpression of wild-type MLK3 led to the induction of neuronal death, whereas expression of a dominant negative MLK3 mutant protected neurons from the toxic effects of Tat. MLK3-dependent downstream signaling events were implicated in the neuroprotective and monocyte-deactivating pathways triggered by CEP1347. Thus, the inhibition of p38 MAPK and JNK protected neurons from Tat-induced apoptosis, whereas the inhibition of p38 MAPK, but not of JNK, was sufficient to prevent Tat- and gp120-mediated activation of monocytes. These results suggest that the normal function of MLK3 is compromised by HIV-1 neurotoxins (Tat, gp120), resulting in the activation of downstream signaling events that result in neuronal death and monocyte activation (with release of inflammatory cytokines). In aggregate, our data define MLK3 as a promising therapeutic target for intervention in HAD.
Circulating and Liver Resident CD4+CD25+ Regulatory T Cells Actively Influence the Antiviral Immune Response and Disease Progression in Patients with Hepatitis B
Authors: Xu Dongping , Fu Junliang , Jin Lei , Zhang Hui , Zhou Chunbao , Zou Zhengsheng , Zhao Jing-Min , Zhang Bin , Shi Ming , Ding Xilai , Tang Zirong , Fu Yang-Xin , Wang Fu-Sheng 
Published: April 2014

Abstract
CD4+CD25+ regulatory T cells (Treg) have been shown to maintain immune tolerance against self and foreign Ags, but their role in persistent viral infection has not been well-defined. In this study, we investigated whether and where CD4+CD25+ Treg contribute to the development of chronic hepatitis B (CHB). One hundred twenty-one patients were enrolled, including 16 patients with acute hepatitis B, 76 with CHB, and 29 with chronic severe hepatitis B. We demonstrated that in chronic severe hepatitis B patients, the frequencies of CD4+CD25+ Treg in both PBMC and liver-infiltrating lymphocytes were significantly increased and there was a dramatic increase of FoxP3+-cell and inflammatory cell infiltration in the liver compared with healthy controls. In CHB patients, circulating CD4+CD25+ Treg frequency significantly correlates with serum viral load. In acute hepatitis B patients, circulating CD4+CD25+ Treg frequency was initially low and with time, the profile reversed to exhibit an increased number of circulating Treg in the convalescent phase and restored to normal levels upon resolution. In PBMC taken from infected patients, depletion of CD4+CD25+ Treg led to an increase of IFN-γ production by HBV-Ag-stimulated PBMC. In addition, CD4+CD25+ Treg were capable of suppressing proliferation of autologous PBMC mediated by HBV Ags, which probably reflects the generation of HBV-Ag-specific Treg in circulation and in the liver of HBV-infected patients. Together, our findings suggest that CD4+CD25+ Treg play an active role not only in modulating effectors of immune response to HBV infection, but also in influencing the disease prognosis in patients with hepatitis B.
IL-2 Immunotoxin Therapy Modulates Tumor-Associated Regulatory T Cells and Leads to Lasting Immune-Mediated Rejection of Breast Cancers in neu-Transgenic Mice
Authors: Knutson Keith L. , Dang Yushe , Lu Hailing , Lukas Jason , Almand Bond , Gad Ekram , Azeke Ehizoje , Disis Mary L. 
Published: April 2014

Abstract
Studies in cancer patients have suggested that breast tumors recruit regulatory T cells (Tregs) into the tumor microenvironment. The extent to which local Tregs suppress antitumor immunity in breast cancer is unknown. We questioned whether inhibiting systemic Tregs with an IL-2 immunotoxin in a model of neu-mediated breast cancer, the neu-transgenic mouse, could impact disease progression and survival. As in human breast cancer, cancers that develop in these mice attract Tregs into the tumor microenvironment to levels of ∼10–25% of the total CD4+ T cells. To examine the role of Tregs in blocking immune-mediated rejection of tumor, we depleted CD4+CD25+ T cells with an IL-2 immunotoxin. The treatment depleted Tregs without concomitant lymphopenia and markedly inhibited tumor growth. Depletion of Tregs resulted in a persistent antitumor response that was maintained over a month after the last treatment. The clinical response was immune-mediated because adoptive transfer of Tregs led to a complete abrogation of the therapeutic effects of immunotoxin treatment. Further, Treg down-modulation was accompanied by increased Ag-specific immunity against the neu protein, a self Ag. These results suggest that Tregs play a major role in preventing an effective endogenous immune response against breast cancer and that depletion of Tregs, without any additional immunotherapy, may mediate a significant antitumor response.
Injury-Induced Suppression of Effector T Cell Immunity Requires CD1d-Positive APCs and CD1d-Restricted NKT Cells
Authors: Palmer Jessica L. , Tulley Julia M. , Kovacs Elizabeth J. , Gamelli Richard L. , Taniguchi Masaru , Faunce Douglas E. 
Published: April 2014

Abstract
Overwhelming infection remains the leading cause of death from serious burn injury despite recent advances in the care of burn patients and a better understanding of immune and inflammatory consequences of injury. In this study, we report a critical requirement for CD1d-restricted NKT cells and CD1d expression by APCs in the immune dysfunction that occurs early after burn injury. Using a well-established murine scald injury model with BALB/c and BALB/c CD1d knockout mice, we investigated whether peripheral T cell immunity was affected by the presence or absence of CD1d-restricted NKT cells in the early stages after injury. Using Ag-specific delayed-type hypersensitivity, T cell proliferation, and cytokine production as indices of immune responsiveness, we observed that both CD1d expression by APCs and CD1d-restricted NKT cells are required for immune suppression after injury. Via adoptive transfer of splenocytes from injured mice to uninjured recipients, we found injury-induced suppression of immunity to be Ag specific, long lasting, and critically dependent on cell surface expression of CD1d by APCs. Together, our results suggest that the defects in T cell responsiveness that occur subsequent to severe burn injury are not merely the result of global or passive suppression, but instead represent an active form of CD1d/NKT cell-dependent immunologic tolerance.
Cutting Edge: Activation of Murine TLR8 by a Combination of Imidazoquinoline Immune Response Modifiers and PolyT Oligodeoxynucleotides
Authors: Gorden Keith K. B. , Qiu Xiaohong X. , Binsfeld Christine C. A. , Vasilakos John P. , Alkan Sefik S. 
Published: April 2014

Abstract
Synthetic immune response modifiers (IRM) such as imidazoquinolines can selectively activate human TLR7 or TLR8. Although these endosomal TLRs are close relatives, TLR7-deficient mice are unresponsive to TLR8 agonist IRMs. Similarly, natural ssRNA cannot activate murine TLR8, leading to the belief that murine TLR8 is nonfunctional. In this study, we transfected HEK293 cells with murine TLR8 and NF-κB reporter constructs and stimulated them with combinations of IRM and oligodeoxynucleotides (ODNs). When stimulated with TLR7 or TLR8 agonists alone, no NF-κB response was observed. However, a combination of polyT ODN plus the TLR8 agonist activated NF-κB, whereas polyT ODN plus the TLR7 agonist did not activate. Primary mouse cells responded to the IRM/polyT ODN by secreting TNF. Cells from TLR7−/− and TLR9−/− mice responded to the IRM/polyT ODN combination, whereas MyD88−/− cells did not respond. In conclusion, this study demonstrates for the first time that mouse TLR8 is functional.
Cutting Edge: Resistance to HIV-1 Infection among African Female Sex Workers Is Associated with Inhibitory KIR in the Absence of Their HLA Ligands
Authors: Jennes Wim , Verheyden Sonja , Demanet Christian , Adjé-Touré Christiane A. , Vuylsteke Bea , Nkengasong John N. , Kestens Luc 
Published: April 2014

Abstract
NK cells are regulated in part by killer Ig-like receptors (KIR) that interact with HLA molecules on potential target cells. KIR and HLA loci are highly polymorphic and certain KIR/HLA combinations were found to protect against HIV disease progression. We show in this study that KIR/HLA interactions also influence resistance to HIV transmission. HIV-exposed but seronegative female sex workers in Abidjan, Côte d’Ivoire, frequently possessed inhibitory KIR genes in the absence of their cognate HLA genes: KIR2DL2/KIR2DL3 heterozygosity in the absence of HLA-C1 and KIR3DL1 homozygosity in the absence of HLA-Bw4. HIV-seropositive female sex workers were characterized by corresponding inhibitory KIR/HLA pairings: KIR2DL3 homozygosity together with HLA-C1 and a trend toward KIR3DL1/HLA-Bw4 homozygosity. Absence of ligands for inhibitory KIR could lower the threshold for NK cell activation. In addition, exposed seronegatives more frequently possessed AB KIR genotypes, which contain more activating KIR. The data support an important role for NK cells and KIR/HLA interactions in antiviral immunity.
Cutting Edge: Inherent and Acquired Resistance to Radiation-Induced Apoptosis in B Cells: A Pivotal Role for STAT3
Authors: Otero Dennis C. , Poli Valeria , David Michael , Rickert Robert C. 
Published: April 2014

Abstract
Radiation-induced apoptosis (RiA) is used therapeutically for tumor cell ablation as well as a tool to characterize hemopoietic cell lineages. We report that the peritoneal B-1 B cell subset is selectively resistant to RiA. Inherent radioresistance is not shared by splenic B-2 or B-1 cells. However, it is conferred upon B-2 cells by BCR crosslinking in the presence of IL-6 or IL-10. In vivo experiments with gene-targeted mice confirm that IL-6 and, to a lesser extent, IL-10 are the relevant stimuli that combine with BCR ligands to promote B-1 cell radioresistance. STAT3 promotes cell survival in response to selected growth factors, and is activated by combined BCR crosslinking and IL-6 (IL-10). Importantly, STAT3−/− B-1 cells become susceptible to irradiation, indicating that STAT3 activation by the BCR in the presence of IL costimuli account for the inherent radioresistance of peritoneal B-1 B cells.
Cutting Edge: The Phosphoinositide 3-Kinase p110δ Is Critical for the Function of CD4+CD25+Foxp3+ Regulatory T Cells
Authors: Patton Daniel T. , Garden Oliver A. , Pearce Wayne P. , Clough Louise E. , Monk Clare R. , Leung Eva , Rowan Wendy C. , Sancho Sara , Walker Lucy S. K. , Vanhaesebroeck Bart , Okkenhaug Klaus 
Published: April 2014

Abstract
CD4+CD25+Foxp3+ regulatory T cells (Tregs) contribute to the maintenance of peripheral tolerance by inhibiting the expansion and function of conventional T cells. Treg development and homeostasis are regulated by the Ag receptor, costimulatory receptors such as CD28 and CTLA-4, and cytokines such as IL-2, IL-10, and TGF-β. Here we show that the proportions of Tregs in the spleen and lymph nodes of mice with inactive p110δ PI3K (p110δD910A/D910A) are reduced despite enhanced Treg selection in the thymus. p110δD910A/D910A CD4+CD25+Foxp3+ Tregs showed attenuated suppressor function in vitro and failed to secrete IL-10. In adoptive transfer experiments, p110δD910A/D910A T cells failed to protect against experimental colitis. The identification of p110δ as an intracellular signaling protein that regulates the activity of CD4+CD25+Foxp3+ Tregs may facilitate the further elucidation of the molecular mechanisms responsible for Treg-mediated suppression.
Cyclophosphamide-Induced Type-1 Diabetes in the NOD Mouse Is Associated with a Reduction of CD4+CD25+Foxp3+ Regulatory T Cells
Authors: Brode Sven , Raine Tim , Zaccone Paola , Cooke Anne 
Published: April 2014

Abstract
Regulatory T cells (Tregs) have been implicated as key players in immune tolerance as well as suppression of antitumor responses. The chemotherapeutic alkylating agent cyclophosphamide (CY) is widely used in the treatment of tumors and some autoimmune conditions. Although previous data has demonstrated that Tregs may be preferentially affected by CY, its relevance in promoting autoimmune conditions has not been addressed. The nonobese diabetic mouse spontaneously develops type-1 diabetes (T1D). We demonstrate in this study that CY targets CD4+CD25+Foxp3+ Tregs in vivo. CD4+CD25+ T cells isolated from CY-treated mice display reduced suppressive activity in vitro and increased expression of apoptotic markers. Although Treg numbers rapidly recovered to pretreatment levels in the peripheral lymphoid tissues, Tregs failed to recover proportionally within pancreatic infiltrates. T1D progression was effectively prevented by adoptive transfer of a small number of islet Ag-specific CD4+CD25+ Tregs to CY-treated recipients. Prevention of T1D was associated with reduced T cell activation and higher Treg proportions in the pancreas. We conclude that acceleration of T1D by CY is associated with a reduction in CD4+CD25+Foxp3+ Tregs and can be prevented by transfer of CD4+CD25+ Tregs.
Prime-Boost with Alternating DNA Vaccines Designed to Engage Different Antigen Presentation Pathways Generates High Frequencies of Peptide-Specific CD8+ T Cells
Authors: Radcliffe Joanna N. , Roddick Joanne S. , Friedmann Peter S. , Stevenson Freda K. , Thirdborough Stephen M. 
Published: April 2014

AbstractThe route for presentation of Ag to CD8+ or CD4+ T cells following DNA vaccination is critical for determining outcome, but the pathways involved are unclear. In this study, we compare two different DNA vaccine designs aimed to elicit CD8+ T cell responses against a specific peptide-epitope either by direct- or cross-presentation. Each carries sequences from tetanus toxin (TT) to provide essential CD4+ T cell help. In the first already proven design, the peptide-epitope is fused to the N-terminal domain of fragment C from TT. This appears to act mainly by cross-presentation. In the second design, the peptide-epitope is encoded by a minigene, with induction of Th responses mediated by coexpression of a hybrid invariant chain molecule, incorporating a single determinant from TT (p30) in exchange for class II-associated invariant chain peptide. This design appears to act mainly via direct presentation from transfected APCs. Both vaccines mediated Th-dependent priming of CD8+ T cells in mice, but the kinetics and level of the responses differed markedly, consistent with engagement of distinct pathways of Ag presentation. Importantly, the vaccines could be combined in an alternating prime-boost regime, in either order, generating substantially expanded memory CD8+ T cells, with potent effector function. Taken together, these results demonstrate that vaccination protocols involving different modes of Ag presentation at prime and boost can significantly improve the effectiveness of immunization.
Antibody Responses to Mycobacterial and Self Heat Shock Protein 65 in Autoimmune Arthritis: Epitope Specificity and Implication in Pathogenesis
Authors: Kim Hong Ro , Kim Eugene Y. , Cerny Jan , Moudgil Kamal D. 
Published: April 2014

Abstract
Many autoimmune diseases are believed to involve primarily T cell-mediated effector mechanisms. There is increasing realization, however, that Abs may also play a vital role in the propagation of T cell-driven disorders. In this study, on the rat adjuvant-induced arthritis (AA) model of human rheumatoid arthritis, we examined the characteristics of serum Ab response to mycobacterial heat shock protein (hsp) 65 (Bhsp65), self (rat) hsp65 (Rhsp65), and linear peptides spanning these two molecules. The AA-resistant WKY (RT.1l) rat responded to the heat-killed Mycobacterium tuberculosis immunization with a rapid burst of Abs to both Bhsp65 and Rhsp65. These Abs reacted with numerous peptide epitopes; however, this response was reduced to a few epitopes with time. On the contrary, the susceptible Lewis (RT.1l) rat developed a relatively lower Ab response to Bhsp65, and Abs to Rhsp65 did not appear until the recovery from the disease. The Ab response in Lewis rats diversified with progression of AA, and there was an intriguing overlap between the repertoire of Bhsp65-reactive B and T cells during the recovery phase of AA. Nonetheless, subsets of the repertoire of the late Abs in both rat strains became focused on the same epitope regions of Bhsp65 and Rhsp65. The functional relevance of these Abs was evident from the results showing that sera from recovery phase Lewis or WKY rats, but not that of naive rats, afforded protection against subsequent AA. These results are of significance in further understanding of the role of humoral immunity in the pathogenesis of autoimmune arthritis.