bluuebunny/crossref_metadata_2025_split huggingface dataset:
Positive and Negative Transcriptional States of a Variegating Immunoglobulin Heavy Chain (IgH) Locus Are Maintained by a cis-Acting Epigenetic Mechanism
Authors: Ronai Diana , Berru Maribel , Shulman Marc J. 
Published: April 2014

Abstract
Analyses of transgene expression have defined essential components of a locus control region (LCR) in the JH-Cμ intron of the IgH locus. Targeted deletion of this LCR from the endogenous IgH locus of hybridoma cells results in variegated expression, i.e., cells can exist in two epigenetically inherited states in which the Igμ H chain gene is either active or silent; the active or silent state is typically transmitted to progeny cells through many cell divisions. In principle, cells in the two states might differ either in their content of specific transcription factors or in a cis-acting feature of the IgH locus. To distinguish between these mechanisms, we generated LCR-deficient, recombinant cell lines in which the Igμ H chain genes were distinguished by a silent mutation and fused cells in which the μ gene was active with cells in which μ was silent. Our analysis showed that both parental active and silent transcriptional states were preserved in the hybrid cell, i.e., that two alleles of the same gene in the same nucleus can exist in two different states of expression through many cell divisions. These results indicate that the expression of the LCR-deficient IgH locus is not fully determined by the cellular complement of transcription factors, but is also subject to a cis-acting, self-propagating, epigenetic mark. The methylation inhibitor, 5-azacytidine, reactivated IgH in cells in which this gene was silent, suggesting that methylation is part of the epigenetic mark that distinguishes silent from active transcriptional states.
Complement C3b/C3d and Cell Surface Polyanions Are Recognized by Overlapping Binding Sites on the Most Carboxyl-Terminal Domain of Complement Factor H
Authors: Hellwage Jens , Jokiranta T. Sakari , Friese Manuel A. , Wolk Tobias U. , Kampen Eva , Zipfel Peter F. , Meri Seppo 
Published: April 2014

AbstractFactor H (FH) is a potent suppressor of the alternative pathway of C in plasma and when bound to sialic acid- or glycosaminoglycan-rich surfaces. Of the three interaction sites on FH for C3b, one interacts with the C3d part of C3b. In this study, we generated recombinant constructs of FH and FH-related proteins (FHR) to define the sites required for binding to C3d. In FH, the C3d-binding site was localized by surface plasmon resonance analysis to the most C-terminal short consensus repeat domain (SCR) 20. To identify amino acids of FH involved in binding to C3d and heparin, we compared the sequences of FH and FHRs and constructed a homology-based molecular model of SCR19–20 of FH. Subsequently, we created an SCR15–20 mutant with substitutions in five amino acids that were predicted to be involved in the binding interactions. These mutations reduced binding of the SCR15–20 construct to both C3b/C3d and heparin. Binding of the wild-type SCR15–20, but not the residual binding of the mutated SCR15–20, to C3d was inhibited by heparin. This indicates that the heparin- and C3d-binding sites are overlapping. Our results suggest that a region in the most C-terminal domain of FH is involved in target recognition by binding to C3b and surface polyanions. Mutations in this region, as recently reported in patients with familial hemolytic uremic syndrome, may lead to indiscriminatory C attack against self cells.
Nippostrongylus brasiliensisCan Induce B7-Independent Antigen-Specific Development of IL-4-Producing T Cells from Naive CD4 T Cells In Vivo
Authors: Liu Zhugong , Liu Qian , Pesce John , Whitmire Jeannette , Ekkens Melinda J. , Foster Anthony , VanNoy Jansie , Sharpe Arlene H. , Urban Joseph F. , Gause William C. 
Published: April 2014

AbstractTh2 immune responses to a number of infectious pathogens are dependent on B7-1/B7-2 costimulatory molecule interactions. We have now examined the Th2 immune response to Nippostrongylus brasiliensis (Nb) in B7-1/B7-2−/− mice and show that Th2 effector cells develop that can mediate worm expulsion and produce substantial Th2 cytokines comparable with wild-type infected mice; however, in marked contrast, B cell Ag-specific Ab production is abrogated after B7 blockade. To examine the mechanism of T cell activation, OVA-specific DO11.10 T cells were transferred to recipient mice, which were then immunized with a combination of Nb plus OVA or either alone. Only the combination of Nb plus OVA triggered T cell differentiation to OVA-specific Th2 cells, suggesting that Nb acts as an adjuvant to stimulate Ag-specific naive T cells to differentiate to effector Th2 cells. Furthermore, using the DO11.10 TCR-transgenic T cell adoptive transfer model, we show that blocking B7-1/B7-2 interactions does not impair nonparasite Ag-specific DO11.10 Th2 cell differentiation; however, DO11.10 T cell cycle progression and migration to the B cell zone are inhibited.
Requisite Elements in Vaccine Immunity to Blastomyces dermatitidis: Plasticity Uncovers Vaccine Potential in Immune-Deficient Hosts
Authors: Wüthrich Marcel , Filutowicz Hanna I. , Warner Tom , Klein Bruce S. 
Published: April 2014

Abstract
Understanding fundamental mechanisms of vaccine immunity will allow proper use and optimization of vaccines. Vaccination with a genetically engineered, live, attenuated strain of Blastomyces dermatitidis carrying a targeted deletion at the BAD1 locus confers sterilizing immunity against experimental lethal pulmonary infection. We found in this study that αβ T cells are requisite for durable vaccine immunity, whereas other T and B cells are dispensable. In immune-competent animals, CD4+ T-cell derived cytokines TNF-α and IFN-γ mediate vaccine immunity. Surprisingly, these factors are dispensable in immune-deficient animals, which rely on alternate mechanisms for robust vaccine immunity, yet still require O2− production rather than generation of NO. Our results clarify the cellular and molecular bases behind the first genetically engineered fungal vaccine. They also illustrate a sharp difference in vaccine mechanisms between immune-competent and immune-deficient hosts, which underscores the plasticity of residual immune elements in compromised hosts, and points to the feasibility of developing vaccines against invasive fungal infection in this fast growing patient population.
C-Reactive Protein Mediates Protection from Lipopolysaccharide Through Interactions With FcγR
Authors: Mold Carolyn , Rodriguez Wilfredo , Rodic-Polic Bojana , Du Clos Terry W. 
Published: April 2014

AbstractC-reactive protein (CRP) is a component of the acute phase response to infection, inflammation, and trauma. A major activity of acute phase proteins is to limit the inflammatory response. It has been demonstrated that CRP protects mice from lethal doses of LPS. In the mouse, CRP binds to the regulatory receptor, FcγRIIb, and to the γ-chain-associated receptor, FcγRI. The goal ofthis study was to determine whether FcγRs are necessary for the protective effect of CRP. The ability of CRP to protect mice from a lethal dose of LPS was confirmed using injections of 500 and 250 μg of CRP at 0 and 12 h. CRP treatment of FcγRIIb-deficient mice increased mortality after LPS challenge and increased serum levels of TNF and IL-12 in response to LPS. CRP did not protect FcR γ-chain-deficient mice from LPS-induced mortality. Treatment of normal mice, but not γ-chain-deficient mice, with CRP increased IL-10 levels following LPS injection. In vitro, in the presence of LPS, CRP enhanced IL-10 synthesis and inhibited IL-12 synthesis by bone marrow macrophages from normal, but not γ-chain-deficient mice. The protective effect of CRP appears to be mediated by binding to FcγRI and FcγRII resulting in enhanced secretion of the anti-inflammatory cytokine IL-10 and the down-regulation of IL-12. These results suggest that CRP can alter the cytokine profile of mouse macrophages by acting through FcγR leading to a down-regulation of the inflammatory response.
Hydrogen Peroxide Induces Murine Macrophage Chemokine Gene Transcription Via Extracellular Signal-Regulated Kinase- and Cyclic Adenosine 5′-Monophosphate (cAMP)-Dependent Pathways: Involvement of NF-κB, Activator Protein 1, and cAMP Response Element Binding Protein
Authors: Jaramillo Maritza , Olivier Martin 
Published: April 2014

Abstract
Hydrogen peroxide (H2O2) has been shown to act as a second messenger that activates chemokine expression. In the present study, we investigated the mechanisms underlying this cellular regulation in the murine macrophage cell line B10R. We report that H2O2 increases mRNA expression of various chemokines, macrophage-inflammatory protein (MIP)-1α/CC chemokine ligand (CCL)3, MIP-1β/CCL4, MIP-2/CXC chemokine ligand 2, and monocyte chemoattractant protein-1/CCL2, by activating the extracellular signal-regulated kinase (ERK) pathway and the nuclear translocation of the transcription factors NF-κB, AP-1, and CREB. Blockage of the ERK pathway with specific inhibitors against mitogen-activated protein kinase kinase 1/2 and ERK1/ERK2 completely abolished both the H2O2-mediated chemokine up-regulation and the activation of all NF studied. Similarly, selective inhibition of cAMP and NF-κB strongly down-regulated the induction of all chemokine transcripts as well as CREB and NF-κB activation, respectively. Of interest, we detected a significant decrease of NF-κB, AP-1, and CREB DNA binding activities by reciprocal competition for these binding sites when either specific cold oligonucleotides (NF-κB, AP-1, and CREB) or Abs against various transcription factor subunits (p50, p65, c-Fos, Jun B, c-Jun, and CREB-1) were added. These findings indicate that cooperation between ERK- and cAMP-dependent pathways seems to be required to achieve the formation of an essential transcriptional factor complex for maximal H2O2-dependent chemokine modulation. Finally, experiments performed with actinomycin D suggest that H2O2-mediated MIP-1β mRNA up-regulation results from transcriptional control, whereas that of MIP-1α, MIP-2, and monocyte chemoattractant protein-1 is due to both gene transcription activation and mRNA posttranscriptional stabilization.
Differential Role of IFN-γ-Inducible Protein 10 kDa in a Cockroach Antigen-Induced Model of Allergic Airway Hyperreactivity: Systemic Versus Local Effects
Authors: Thomas Molly S. , Kunkel Steven L. , Lukacs Nicholas W. 
Published: April 2014

AbstractThe ability of IFN-γ to antagonize established Th2 type allergic responses is well documented. To investigate the role of IFN-γ-inducible protein 10 kDa (IP10) in the allergic response, we chose to investigate the effect of IP10 neutralization on an established Th2 response. Systemic neutralization of IP10 at the time of allergen challenge increased airway hyperreactivity as well as airway eosinophil accumulation. Interestingly, IFN-γ levels were markedly reduced in both the lung and peripheral lymph node following IP10 neutralization. Furthermore, the number of CXCR3+CD4+ T cells was decreased in the peripheral lymph node following neutralization of IP10. Introduction of exogenous IP10 into the airway at the time of allergen challenge also dramatically increased eosinophil accumulation in the airway. Protein levels of IL-4, IL-5, and IL-13 were significantly increased in the lung following exogenous airway administration of IP10 with allergen. Interestingly, airway hyperreactivity was significantly decreased at early time points following concurrent IP10 and allergen challenge but rebounded at 24 and 48 h post allergen challenge. Although IP10 may initially be acting locally to dampen the allergic response, its ability to recruit eosinophils may ultimately supersede any immunomodulatory effect it may have in an established allergic response. These results suggest that while systemic levels of IP10 are beneficial in controlling the allergic response, possibly by regulating cellular trafficking in the lymph node, local administration of exogenous IP10 into an established allergic response may be detrimental.
Interactions Between Hemopoietically Derived TNF and Central Nervous System-Resident Glial Chemokines Underlie Initiation of Autoimmune Inflammation in the Brain
Authors: Murphy Craig A. , Hoek Robert M. , Wiekowski Maria T. , Lira Sergio A. , Sedgwick Jonathon D. 
Published: April 2014

AbstractTumor necrosis factor is a proinflammatory cytokine that induces directly many of the components required for inflammation to proceed rapidly. We show in this study that the interplay between TNF and chemokines, now recognized to be essential for normal secondary lymphoid tissue development, is also a feature of CNS inflammation, and that the two apparently dissimilar biological processes share many properties. Thus, induction of seven chemokines, including T cell activation gene 3 (TCA3), monocyte chemoattractant protein-1, and IFN-γ-inducible protein-10 within the CNS during experimental autoimmune encephalomyelitis fails to occur early in the inflammatory process in TNF-deficient mice, despite local expression of monokines and IFN-γ. The critical source of TNF in CNS inflammation is the infiltrating hemopoietic cell, and, in its absence, chemokine expression by irradiation-resistant CNS-resident cells fails. The CCR8 ligand, TCA3, is shown to be produced predominantly by resident microglia of the CNS in response to TNF. Using CCR8−/− mice, evidence is provided that TCA3-CCR8 interactions contribute to rapid-onset CNS inflammation. Thus, through TNF production, the hemopoietic compartment initiates the signals for its own movement into tissues, although the tissue ultimately defines the nature of that movement. Chemokines are a major, although not exclusive, mechanism by which tissues regulate leukocyte movement in response to TNF.
An Aspirin-Triggered Lipoxin A4 Stable Analog Displays a Unique Topical Anti-Inflammatory Profile
Authors: Schottelius Arndt J. , Giesen Claudia , Asadullah Khusru , Fierro Iolanda M. , Colgan Sean P. , Bauman John , Guilford William , Perez Hector D. , Parkinson John F. 
Published: April 2014

Abstract
Lipoxins and 15-epi-lipoxins are counter-regulatory lipid mediators that modulate leukocyte trafficking and promote the resolution of inflammation. To assess the potential of lipoxins as novel anti-inflammatory agents, a stable 15-epi-lipoxin A4 analog, 15-epi-16-p-fluorophenoxy-lipoxin A4 methyl ester (ATLa), was synthesized by total organic synthesis and examined for efficacy relative to a potent leukotriene B4 (LTB4) receptor antagonist (LTB4R-Ant) and the clinically used topical glucocorticoid methylprednisolone aceponate. In vitro, ATLa was 100-fold more potent than LTB4R-Ant for inhibiting neutrophil chemotaxis and trans-epithelial cell migration induced by fMLP, but was ∼10-fold less potent than the LTB4R-Ant in blocking responses to LTB4. A broad panel of cutaneous inflammation models that display pathological aspects of psoriasis, atopic dermatitis, and allergic contact dermatitis was used to directly compare the topical efficacy of ATLa with that of LTB4R-Ant and methylprednisolone aceponate. ATLa was efficacious in all models tested: LTB4/Iloprost-, calcium ionophore-, croton oil-, and mezerein-induced inflammation and trimellitic anhydride-induced allergic delayed-type hypersensitivity. ATLa was efficacious in mouse and guinea pig skin inflammation models, exhibiting dose-dependent effects on edema, neutrophil or eosinophil infiltration, and epidermal hyperproliferation. We conclude that the LXA4 and aspirin-triggered LXA4 pathways play key anti-inflammatory roles in vivo. Moreover, these results suggest that ATLa and related LXA4 analogs may have broad therapeutic potential in inflammatory disorders and could provide an alternative to corticosteroids in certain clinical settings.
Mitochondrial Reactive Oxygen Species Regulate Spatial Profile of Proinflammatory Responses in Lung Venular Capillaries
Authors: Parthasarathi Kaushik , Ichimura Hideo , Quadri Sadiqa , Issekutz Andrew , Bhattacharya Jahar 
Published: April 2014

Abstract
Cytokine-induced lung expression of the endothelial cell (EC) leukocyte receptor P-selectin initiates leukocyte rolling. To understand the early EC signaling that induces the expression, we conducted real-time digital imaging studies in lung venular capillaries. To compare receptor- vs nonreceptor-mediated effects, we infused capillaries with respectively, TNF-α and arachidonate. At concentrations adjusted to give equipotent increases in the cytosolic Ca2+, both agents increased reactive oxygen species (ROS) production and EC P-selectin expression. Blocking the cytosolic Ca2+ increases abolished ROS production; blocking ROS production abrogated P-selectin expression. TNF-α, but not arachidonate, released Ca2+ from endoplasmic stores and increased mitochondrial Ca2+. Furthermore, Ca2+ depletion abrogated TNF-α responses partially, but arachidonate responses completely. These differences in Ca2+ mobilization by TNF-α and arachidonate were reflected in spatial patterning in the capillary in that the TNF-α effects were localized at branch points, while the arachidonate effects were nonlocalized and extensive. Furthermore, mitochondrial blockers inhibited the TNF-α- but not the arachidonate-induced responses. These findings indicate that the different modes of Ca2+ mobilization determined the spatial patterning of the proinflammatory response in lung capillaries. Responses to TNF-α revealed that EC mitochondria regulate the proinflammatory process by generating ROS that activate P-selectin expression.
Essential Role of the Adhesion Receptor LFA-1 for T Cell-Dependent Fulminant Hepatitis
Authors: Matsumoto Goichi , Tsunematsu Satoshi , Tsukinoki Kei-ichi , Ohmi Yasushi , Iwamiya Mariko , Oliveira-dos-Santos Antonio , Tone Daisuke , Shindo Junichi , Penninger Josef M. 
Published: April 2014

AbstractViral hepatitis affects more than 2 billion people worldwide. In particular, no effective treatment exists to abrogate death and liver damage in fulminant hepatitis. Activation of T cells is an initial and critical event in the pathogenesis of liver damage in autoimmune and viral hepatitis. The precise molecular mechanisms that induce T cell-mediated hepatocyte injury remain largely unclear. In mice, T cell-dependent hepatitis and acute liver damage can be modeled using ConA. In this study, we examined the role of the adhesion receptor LFA-1 in ConA-induced acute hepatic damage using LFA-1−/− (CD11a) mice. Massive liver cell apoptosis and metabolic liver damage were observed in LFA-1+/+ mice following ConA injection. By contrast, LFA-1−/− mice were completely resistant to ConA-induced hepatitis and none of the LFA-1−/− mice showed any hepatic damage. Whereas activated hepatic T cells remained in the liver in LFA-1+/+ mice, activated T cells were rapidly cleared from the livers of LFA-1−/− mice. Mechanistically, T cells from LFA-1−/− mice showed markedly reduced cytotoxicity toward liver cells as a result of impaired, activation-dependent adhesion. Importantly, adoptive transfer of hepatic T cells from LFA-1+/+ mice, but not from LFA-1−/− mice, sensitized LFA-1−/− mice to ConA-induced hepatitis. Thus, LFA-1 expression on T cells is necessary and sufficient for T cell-mediated liver damage in vivo. These results provide the first genetic evidence on an adhesion receptor, LFA-1, that has a crucial role in fulminant hepatitis. These genetic data identify LFA-1 as a potential key target for the treatment of T cell-mediated hepatitis and the prevention of liver damage.
IL-13 Receptor-Targeted Cytotoxin Cancer Therapy Leads to Complete Eradication of Tumors with the Aid of Phagocytic Cells in Nude Mice Model of Human Cancer
Authors: Kawakami Koji , Kawakami Mariko , Puri Raj K. 
Published: April 2014

Abstract
Tumor-directed therapeutic approaches require unique or overexpressed specific Ag or receptor as a target to achieve selective tumor killing. However, heterogeneous expression of these targets on tumor cells limits the efficacy of this form of therapy. In this study, we forced abundant expression of IL-13Rα2 chain by plasmid-mediated gene transfer in head and neck, as well as prostate tumors to provide a potential target. This was followed by successfully treating xenograft tumor-bearing nude mice with IL-13R-directed cytotoxin (IL13-PE38QQR). Although we did not observe an indirect cytotoxic bystander effect conveyed to nontransduced tumor cells in vitro, our approach in vivo led to a complete regression of established tumors transfected with IL-13Rα2 chain in most animals. We found that the tumor eradication was achieved in part by infiltration of macrophages and NK cells, assessed by immunohistochemistry. Moreover, head and neck tumors xenografted in macrophage-depleted nude mice were less sensitive to the antitumor effect of IL-13 cytotoxin. Because we did not observe vector-related toxicity in any vital organs, our novel combination strategy of gene transfer of IL-13Rα2 chain and receptor-directed cytotoxin therapy may be a useful approach for the treatment of localized cancer.
TCR-Like Human Antibodies Expressed on Human CTLs Mediate Antibody Affinity-Dependent Cytolytic Activity
Authors: Chames Patrick , Willemsen Ralph A. , Rojas Gertrudis , Dieckmann Detlef , Rem Louise , Schuler Gerold , Bolhuis Reinder L. , Hoogenboom Hennie R. 
Published: April 2014

Abstract
The permanent genetic programming via gene transfer of autologous T cells with cell surface receptors directed toward tumor-related Ags holds great promise for the development of more-specific tumor therapies. In this study we have explored the use of Abs directed to MHC-peptide complexes (or TCR-like Abs) to engraft CTLs with exquisite specificity for cancer cells. First, we affinity matured in vitro a previously selected TCR-like Ab, Fab-G8, which is highly specific for the peptide melanoma-associated Ag-A1 presented by the HLA-A1 molecule. A combination of L chain shuffling, H chain-targeted mutagenesis, and in vitro selection of phage display libraries yielded a Fab-G8 Ab derivative, Fab-Hyb3, with an 18-fold improved affinity yet identical peptide fine specificity. Fab-G8 and Fab-Hyb3 were expressed on primary human T lymphocytes as cell surface-anchored Fab, demonstrating that T cells expressing the high-affinity Fab-Hyb3 molecule eradicate tumor cells much more effectively. Furthermore, the gain in ligand-binding affinity resulted in a 2-log improvement in the detection of peptide/MHC complexes on melanoma-associated Ag-A1 peptide-loaded cells. In summary, an affinity-matured Ab specifically recognizing a cancer-related peptide/MHC complex was generated and used to improve the tumor cell killing capacity of human T cells. This strategy, based on engraftment of T cells with in vitro engineered Abs, is an attractive alternative to the laborious, and in many cases unsuccessful, generation of highly potent tumor-specific T lymphocytes.