bluuebunny/crossref_metadata_2025_split huggingface dataset:
NF-κB-Inducing Kinase Is Dispensable for Activation of NF-κB in Inflammatory Settings but Essential for Lymphotoxin β Receptor Activation of NF-κB in Primary Human Fibroblasts
Authors: Smith Clive , Andreakos Evangelos , Crawley James B. , Brennan Fionula M. , Feldmann Marc , Foxwell Brian M. J. 
Published: April 2014

AbstractThe transcription factor NF-κB is of major importance in the biology of pro-inflammatory cytokines, such as TNF-α and IL-1α, and thereby is intimately involved in the process of inflammation. Understanding the mechanisms by which NF-κB is activated in response to inflammatory stimuli has become a major goal of inflammation research. The discovery of NF-κB-inducing kinase (NIK) as a TNFR-associated factor-interacting enzyme and a potential activator of the IκBα-kinase complex appeared to have identified an important element of the NF-κB activition pathway, a view that was supported by several subsequent studies. However, recent experiments in the alymphoplasia (aly/aly) mouse, which has missense point mutation (G885R) in NIK, has challenged that view. The reasons for the discrepancy between the different studies is unclear and could be due to multiple factors, such as cell type, species of cell, or primary vs transformed cell lines. One system that has not been investigated is primary human cells. Using an adenoviral vector encoding kinase-deficient NIK, we have investigated the role of NIK in LPS, IL-1, TNF-α, and lymphotoxin (LT) βR signaling in primary human cells and TNF-α expression from rheumatoid tissue. These data show that, in the primary systems tested, NIK has a restricted role in LTβR signaling and is not required by the other stimuli tested. Also, there is no apparent role for NIK in the process of TNF-α production in human rheumatoid arthritis. These data also highlight the potential problems in extrapolating the function of signaling pathways between primary and transfected cell lines.
IL-18-Binding Protein Protects Against Lipopolysaccharide- Induced Lethality and Prevents the Development of Fas/Fas Ligand-Mediated Models of Liver Disease in Mice
Authors: Faggioni Raffaella , Cattley Russell C. , Guo Jane , Flores Silvia , Brown Heather , Qi Meiying , Yin Songmei , Hill David , Scully Sheila , Chen Ching , Brankow David , Lewis Jeffrey , Baikalov Claudia , Yamane Harvey , Meng Tina , Martin Frank , Hu Sylvia , Boone Tom , Senaldi Giorgio 
Published: April 2014

AbstractIL-18-binding protein (IL-18BP) is a natural IL-18 inhibitor. Human IL-18BP isoform a was produced as fusion construct with human IgG1 Fc and assessed for binding and neutralizing IL-18. IL-18BP-Fc binds human, mouse, and rat IL-18 with high affinity (KD 0.3–5 nM) in a BIAcore-based assay. In vitro, IL-18BP-Fc blocks IL-18 (100 ng/ml)-induced IFN-γ production by KG1 cells (EC50 = 0.3 μg/ml). In mice challenged with an LD90 of LPS (15 mg/kg), IL-18BP-Fc (5 mg/kg) administered 10 min before LPS blocks IFN-γ production and protects against lethality. IL-18BP-Fc administered 10 min before LPS blocks IFN-γ production induced by LPS (5 mg/kg) with ED50 of 0.005 mg/kg. Furthermore, IL-18BP-Fc (5 mg/kg) abrogates LPS (5 mg/kg)-induced IFN-γ production even when administered 6 days before LPS but shows no effect when administered 9 or 12 days before LPS. Given 10 min before LPS challenge to mice primed 12 days in advance with heat-killed Propionibacterium acnes, IL-18BP-Fc prevents LPS-induced liver damage and IFN-γ and Fas ligand expression. Given at the moment of priming with P. acnes, IL-18BP-Fc decreases P. acnes-induced granuloma formation, macrophage-inflammatory protein-1α and macrophage-inflammatory protein-2 production and prevents sensitization to LPS. IL-18BP-Fc also prevents Con A-induced liver damage and IFN-γ and Fas ligand expression as well as liver damage induced by Pseudomonas aeruginosa exotoxin A or by anti-Fas agonistic Ab. In conclusion, IL-18BP can be engineered and produced in recombinant form to generate an IL-18 inhibitor, IL-18BP-Fc, endowed with remarkable in vitro and in vivo properties of binding and neutralizing IL-18.
Regulation of CD8 Expression in Mast Cells by Exogenous or Endogenous Nitric Oxide
Authors: Nohara Osamu , Kulka Marianna , Déry René E. , Wills Fiona L. , Hirji Nadir S. , Gilchrist Mark , Befus A. Dean 
Published: April 2014

AbstractWe recently reported a novel CD8 molecule on rat alveolar macrophages and peritoneal mast cells (PMC). However, little is known about the regulation of CD8 expression and function on these cells. We investigated the regulation of CD8 expression on PMC by NO, because NO can regulate inflammatory responses and also because anti-CD8 Ab stimulates inducible NO synthase and NO production by PMC and alveolar macrophages. Ligation of CD8α on PMC with Ab (OX8) induced CD8α mRNA expression after 3–6 h, and flow cytometry demonstrated that OX8 treatment increased CD8α protein expression compared with PMC treated with isotype control IgG1. To test whether NO mediates the up-regulation of CD8α, we used the NO donor S-nitrosoglutathione (500 μM) and NO synthase inhibitors (NG-monomethyl-l-arginine and NG-nitro-l-arginine methyl ester; 100 μM). S-nitrosoglutathione up-regulated both mRNA and protein expression of CD8α in PMC compared with that in sham-treated cells, while NO synthase inhibitors down-regulated OX8 Ab-induced CD8α expression. To investigate how NO regulates CD8 expression on PMC, we examined the cGMP-dependent pathway using 8-bromo-cGMP (2 mM) and the guanylate cyclase inhibitor, 1H-oxadiazoloquinoxalin-1-one (20 μM). 8-Bromo-cGMP up-regulated CD8 expression, whereas 1H-oxadiazoloquinoxalin-1-one down-regulated its expression. Thus, ligation of CD8 up-regulates CD8 expression on PMC, a response mediated at least in part by NO through a cGMP-dependent pathway. The significance of this up-regulation of CD8α on mast cells (MC) is unclear, but since ligation of CD8 on MC with OX8 Ab can alter gene expression and mediator secretion, up-regulation of CD8 may enhance the MC response to natural ligation of this novel form of CD8.
Hydrodynamic Shear Regulates the Kinetics and Receptor Specificity of Polymorphonuclear Leukocyte-Colon Carcinoma Cell Adhesive Interactions
Authors: Jadhav Sameer , Bochner Bruce S. , Konstantopoulos Konstantinos 
Published: April 2014

AbstractThe ability of tumor cells to metastasize hematogenously is regulated by their interactions with polymorphonuclear leukocytes (PMNs). However, the mechanisms mediating PMN binding to tumor cells under physiological shear forces remain largely unknown. This study was designed to characterize the molecular interactions between PMNs and tumor cells as a function of the dynamic shear environment, using two human colon adenocarcinoma cell lines (LS174T and HCT-8) as models. PMN and colon carcinoma cell suspensions, labeled with distinct fluorophores, were sheared in a cone-and-plate rheometer in the presence of the PMN activator fMLP. The size distribution and cellular composition of formed aggregates were determined by flow cytometry. PMN binding to LS174T cells was maximal at 100 s−1 and decreased with increasing shear. At low shear (100 s−1) PMN CD11b alone mediates PMN-LS174T heteroaggregation. However, L-selectin, CD11a, and CD11b are all required for PMN binding to sialyl Lewisx-bearing LS174T cells at high shear (800 s−1). In contrast, sialyl Lewisx-low HCT-8 cells fail to aggregate with PMNs at high shear conditions, despite extensive adhesive interactions at low shear. Taken together, our data suggest that PMN L-selectin initiates LS174T cell tethering at high shear by binding to sialylated moieties on the carcinoma cell surface, whereas the subsequent involvement of CD11a and CD11b converts these transient tethers into stable adhesion. This study demonstrates that the shear environment of the vasculature modulates the dynamics and molecular constituents mediating PMN-tumor cell adhesion.
Antigen Discovery in Chronic Human Inflammatory Central Nervous System Disease: Panning Phage-Displayed Antigen Libraries Identifies the Targets of Central Nervous System-Derived IgG in Subacute Sclerosing Panencephalitis
Authors: Burgoon Mark P. , Owens Gregory P. , Carlson Sharon , Maybach Amy L. , Gilden Donald H. 
Published: April 2014

AbstractThe presence of increased IgG in the brains of humans with infectious and inflammatory CNS diseases of unknown etiology such as multiple sclerosis may be a clue to the cause of disease. For example, the intrathecally synthesized oligoclonal bands in diseases such as subacute sclerosing panencephalitis (SSPE) or cryptococcal meningitis have been shown to represent Ab directed against the causative agents, measles virus (MV), or Cryptococcus neoformans, respectively. Using SSPE as a model system, we developed a strategy to identify the antigenic targets of the intrathecal disease-relevant IgG in chronic human inflammatory and demyelinating diseases of the CNS. Libraries of cDNA Ags were displayed on the surface of T7Select bacteriophage and biopanned on IgG extracted from the brain of an SSPE patient, or on a monospecific recombinant Fab identified from SSPE brain. After three or six rounds of biopanning on either Ab, positive phage-displayed Ags reacting with IgG were enriched to 35–77% of all panned clones. Sequence analysis of the positive clones identified fragments of the nucleocapsid protein of MV, the cause of SSPE. The sensitivity of the system was determined by diluting the positive clones from this SSPE phage-displayed library at a ratio of 10−6 into another phage-displayed library that did not contain any detectable MV Ags; after six rounds of panning, the positive clones comprised 34% of all phage and were also shown to be MV nucleocapsid specific. This strategy will be useful to identify potentially rare Ags in diseases of unknown cause.
Enhancing Effect of IL-1, IL-17, and TNF-α on Macrophage Inflammatory Protein-3α Production in Rheumatoid Arthritis: Regulation by Soluble Receptors and Th2 Cytokines
Authors: Chabaud Martine , Page Guillaume , Miossec Pierre 
Published: April 2014

AbstractMacrophage inflammatory protein (MIP)-3α is a chemokine involved in the migration of T cells and immature dendritic cells. To study the contribution of proinflammatory cytokines and chemokines to the recruitment of these cells in rheumatoid arthritis (RA) synovium, we looked at the effects of the monocyte-derived cytokines ΙL-1β and TNF-α and the T cell-derived cytokine IL-17 on MIP-3α production by RA synoviocytes. Addition of ΙL-1β, IL-17, and TNF-α induced MIP-3α production in a dose-dependent manner. At optimal concentrations, ΙL-1β (100 pg/ml) was much more potent than IL-17 (100 ng/ml) and TNF-α (100 ng/ml). When combined at lower concentrations, a synergistic effect was observed. Conversely, the anti-inflammatory cytokines IL-4 and IL-13 inhibited MIP-3α production by activated synoviocytes, but IL-10 had no effect. Synovium explants produced higher levels of MIP-3α in RA than osteoarthritis synovium. MIP-3α-producing cells were located in the lining layer and perivascular infiltrates in close association with CD1a immature dendritic cells. Addition of exogenous IL-17 or ΙL-1β to synovium explants increased MIP-3α production. Conversely, specific soluble receptors for ΙL-1β, IL-17, and TNF-α inhibited MIP-3α production to various degrees, but 95% inhibition was obtained only when the three receptors were combined. Similar optimal inhibition was also obtained with IL-4, but IL-13 and IL-10 were less active. These findings indicate that interactions between monocyte and Th1 cell-derived cytokines contribute to the recruitment of T cells and dendritic cells by enhancing the production of MIP-3α by synoviocytes. The inhibitory effect observed with cytokine-specific inhibitors and Th2 cytokines may have therapeutic applications.
Possible Role of Organ-Specific Autoantigen for Fas Ligand-Mediated Activation-Induced Cell Death in Murine Sjögren’s Syndrome
Authors: Ishimaru Naozumi , Yanagi Kumiko , Ogawa Kouichi , Suda Takashi , Saito Ichiro , Hayashi Yoshio 
Published: April 2014

AbstractActivation-induced cell death (AICD) is a well-known mechanism of peripheral T cell tolerance that depends upon an interaction between Fas and Fas ligand (FasL). In this study, we demonstrate that the administration of a soluble form of anti-FasL Ab, FLIM58, results in severe destructive autoimmune exocrinopathy in the murine model of human Sjögren’s syndrome (SS), and we found that an organ-specific autoantigen may play an important role on down-modulation of AICD. A high titer of serum autoantibodies against 120-kDa α-fodrin autoantigen was detected in the FLIM58-treated mice, and splenic T cell culture supernatants contained high levels of IFN-γ. In vitro T cell apoptosis assay indicated that FasL-mediated AICD is down-regulated by autoantigen stimulation in spleen cells from the murine SS model, but not from Fas-deficient MRL/lpr mice and FasL-deficient MRL/gld mice. FasL undergo metalloproteinase-mediated proteolytic processing in their extracellular domains, resulting in the release of soluble trimeric ligands (soluble FasL). We showed that the processing of soluble FasL occurs in autoantigen-specific CD4+ T cells, and that a significant increase in expressions of metalloproteinase-9 mRNA was observed in spleen cells from SS model mice. These findings indicate that the increased generation of soluble FasL inhibits the normal AICD process, leading to the proliferation of effector CD4+ T cells in the murine SS model.
CD18 Activation Epitopes Induced by Leukocyte Activation
Authors: Beals Chan R. , Edwards Ana C. , Gottschalk Rebecca J. , Kuijpers Taco W. , Staunton Donald E. 
Published: April 2014

Abstract
The cell surface adhesion molecule LFA-1 coordinates leukocyte trafficking and is a costimulatory molecule for T cell activation. We developed a panel of mAbs that recognize activation epitopes on the CD18 subunit, and show that stimulation of T lymphocytes appears to be accompanied by a conformational change in a subpopulation of LFA-1 that does not require ligand binding. Activation epitope up-regulation requires divalent cations, is sensitive to cellular signal transduction events, and correlates with cell adhesion. In addition, the stimulated appearance of these activation epitopes is absent in cell lines from patients with leukocyte adhesion deficiency-1/variant that has previously been shown to be defective in LFA-1 activation. Thus, these activation epitope Abs can be used to dissect signal transmission to CD18. Evidence suggests that these CD18 activation epitopes are induced early in cellular activation and are independent of actin rearrangement necessary for avid adhesion. We have also determined that function-blocking CD18 Abs inhibit the induction of activation epitopes. One activation epitope Ab binds to a site on CD18 distinct from that of the blocking Abs, indicating that the blocking Abs suppress a conformational change in LFA-1. We also find that these neoepitopes are present on rLFA-1 with high affinity for ICAM-1 and their binding is modulated in parallel with the affinity of LFA-1 for ICAM-1. Collectively, these neoepitope Abs identify a subpopulation of LFA-1 most likely with high affinity for ICAM-1 and necessary for LFA-1 function.
Human B Cell Activation by Autologous NK Cells Is Regulated by CD40-CD40 Ligand Interaction: Role of Memory B Cells and CD5+ B Cells
Authors: Blanca Isaac R. , Bere Earl W. , Young Howard A. , Ortaldo John R. 
Published: April 2014

Abstract
NK cells are a subpopulation of lymphocytes characterized primarily by their cytolytic activity. They are recognized as an important component of the immune response against virus infection and tumors. In addition to their cytolytic activity, NK cells also participate either directly or indirectly in the regulation of the ongoing Ab response. More recently, it has been suggested that NK cells have an important role in the outcome of autoimmune diseases. Here, we demonstrate that human NK cells can induce autologous resting B cells to synthesize Ig, including switching to IgG and IgA, reminiscent of a secondary Ab response. B cell activation by the NK cell is contact-dependent and rapid, suggesting an autocrine B cell-regulated process. This NK cell function is T cell-independent, requires an active cytoplasmic membrane, and is blocked by anti-CD40 ligand (anti-CD154) or CD40-mIg fusion protein, indicating a critical role for CD40-CD40 ligand interaction. Depletion studies also demonstrate that CD5+ B cells (autoreactive B-1 cells) and a heterogeneous population of CD27+ memory B cells play a critical role in the Ig response induced by NK cells. The existence of this novel mechanism of B cell activation has important implications in innate immunity, B cell-mediated autoimmunity, and B cell neoplasia.
A Dominant Jurkat T Cell Mutation That Inhibits LFA-1-Mediated Cell Adhesion Is Associated with Increased Cell Growth
Authors: Cherry Lisa K. , Weber Kim S. C. , Klickstein Lloyd B. 
Published: April 2014

Abstract
LFA-1 exists in a low avidity state on resting leukocytes and is believed to adopt a high avidity state when the cells are exposed to a stimulus. Current evidence supports both aggregation of LFA-1 on the cell surface and conformational changes in the reversible acquisition of a high avidity state. We studied this regulation by selecting a Jurkat T cell clone, J-lo1.3, that expresses LFA-1 yet fails to bind to purified ICAM-1 despite treatment of the cells with PMA or Mn2+. Several lines of evidence demonstrated the absence of any changes within LFA-1 itself. LFA-1 protein purified from the J-lo1.3 clone and the wild-type Jurkat clone, Jn.9, were found to be functionally equivalent. The cDNA sequences encoding the LFA-1 α- and β-chains from J-lo1.3 were identical with the published sequences except for nine base pairs. However, these differences were also found in a Jurkat mutant with a constitutively avid phenotype, J+hi1.19 or the wild-type Jn.9 genomic or cDNA. Fusion of J-lo1.3 with Jn.9 yielded hybrids that exhibited the J-lo1.3 adhesion phenotype, which indicated a dominant mutation in J-lo1.3. This phenotype was relatively specific for LFA-1 among all integrins expressed by Jurkat. Interestingly, the J-lo1.3 cells had a 1.2-fold faster doubling time than did the Jn.9 cells. Reversion of J-lo1.3 to the wild-type adhesion phenotype by mutagenesis and selection also decreased the growth rate. These data support a connection between cellular growth and cellular adhesion in lymphocytes.
Tolerance or Immunity to a Tumor Antigen Expressed in Somatic Cells Can Be Determined by Systemic Proinflammatory Signals at the Time of First Antigen Exposure
Authors: Frazer Ian H. , Kluyver Rachel De , Leggatt Graham R. , Yang Guo Hua , Dunn Linda , White Olivia , Harris Craig , Liem Amy , Lambert Paul 
Published: April 2014

Abstract
Mice transgenic for the E7 tumor Ag of human papillomavirus type 16, driven from a keratin 14 promoter, express E7 in keratinocytes but not dendritic cells. Grafted E7-transgenic skin is not rejected by E7-immunized mice that reject E7-transduced transplantable tumors. Rejection of recently transplanted E7-transgenic skin grafts, but not of control nontransgenic grafts or of established E7-transgenic grafts, is induced by systemic administration of live or killed Listeria monocytogenes or of endotoxin. Graft recipients that reject an E7 graft reject a subsequent E7 graft more rapidly and without further L. monocytogenes exposure, whereas recipients of an E7 graft given without L. monocytogenes do not reject a second graft, even if given with L. monocytogenes. Thus, cross-presentation of E7 from keratinocytes to the adaptive immune system occurs with or without a proinflammatory stimulus, but proinflammatory stimuli at the time of first cross-presentation of Ag can determine the nature of the immune response to the Ag. Furthermore, immune effector mechanisms responsible for rejection of epithelium expressing a tumor Ag in keratinocytes are different from those that reject an E7-expressing transplantable tumor. These observations have implications for immunotherapy for epithelial cancers.
2B4 (CD244)-Mediated Activation of Cytotoxicity and IFN-γ Release in Human NK Cells Involves Distinct Pathways
Authors: Chuang Samuel S. , Kumaresan Pappanaicken R. , Mathew Porunelloor A. 
Published: April 2014

Abstract
2B4 (CD244), a member of the CD2 subset of the Ig superfamily receptors, is expressed on all human NK cells, a subpopulation of T cells, basophils and monocytes. 2B4 activates NK cell mediated cytotoxicity, induces secretion of IFN-γ and matrix metalloproteinases, and NK cell invasiveness. Although there has been several molecules shown to interact with 2B4, the signaling mechanism of 2B4-mediated activation of NK cells is still unknown. In this study, we found cross-linking of 2B4 on YT cells, a human NK cell line, results in the increased DNA binding activity of activator protein-1 (AP-1), an important regulator of nuclear gene expression in leukocytes. We investigated the possible role of various signaling molecules that may be involved in the activation of lytic function of YT cells via 2B4. Treatment of YT cells with various specific inhibitors indicate that 2B4-stimulation of YT cells in spontaneous and Ab-dependent cytotoxicity is Ras/Raf dependent and involves multiple MAPK signaling pathways (ERK1/2 and p38). However, only inhibitors of transcription and p38 inhibited 2B4-mediated IFN-γ release indicating distinct pathways are involved in cytotoxicity and cytokine release. In this study we also show that 2B4 constitutively associates with the linker for activation of T cells (LAT) and that 2B4 may mediate NK cell activation via a LAT-dependent signaling pathway. These results indicate that 2B4-mediated activation of NK cells involves complex interactions involving LAT, Ras, Raf, ERK and p38 and that cytolytic function and cytokine production may be regulated by distinct pathways.
Fas Ligand Engagement of Resident Peritoneal Macrophages In Vivo Induces Apoptosis and the Production of Neutrophil Chemotactic Factors
Authors: Hohlbaum Andreas M. , Gregory Meredith S. , Ju Shyr-Te , Marshak-Rothstein Ann 
Published: April 2014

Abstract
Fas ligand (FasL) is a potent proapoptotic type-II transmembrane protein that can cause cell death in Fas+ target populations. Despite the presumed “silent” nature of apoptotic cell death, forced expression of FasL can induce a dramatic inflammatory response. To elucidate the in vivo mechanism(s) linking FasL and inflammation, we used a membrane-bound cell-free form of FasL (mFasL-vesicle preparation (VP)). We found that i.p. injection of FasL-microvesicles led to the rapid activation and subsequent demise of Mac1high resident peritoneal macrophages. Apoptosis of Mac1high peritoneal macrophages was observed within 0.5 h of mFasL-VP injection and correlated with the detection of increased macrophage inflammatory protein (MIP)-2 levels in peritoneal lavage fluid as well as induced RNA expression of IL-1β, MIP-2, MIP-1α, and MIP-1β. In vitro culture of purified peritoneal populations identified Mac1high cells as the major cytokine/chemokine producers in response to mFasL-VP. Purified Mac1high cells exposed to FasL could restore the ability of Fas-deficient mice to mount an inflammatory response. Our data demonstrate that the FasL-mediated inflammatory response starts with the production of proinflammatory mediators by preapoptotic resident tissue macrophages and suggest a general mechanism responsible for neutrophil inflammation seen in cases of FasL-expressing allografts.