bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human TCR-Binding Affinity is Governed by MHC Class Restriction
Authors: Cole David K. , Pumphrey Nicholas J. , Boulter Jonathan M. , Sami Malkit , Bell John I. , Gostick Emma , Price David A. , Gao George F. , Sewell Andrew K. , Jakobsen Bent K. 
Published: April 2014

Abstract
T cell recognition is initiated by the binding of TCRs to peptide-MHCs (pMHCs), the interaction being characterized by weak affinity and fast kinetics. Previously, only 16 natural TCR/pMHC interactions have been measured by surface plasmon resonance (SPR). Of these, 5 are murine class I, 5 are murine class II, and 6 are human class I-restricted responses. Therefore, a significant gap exists in our understanding of human TCR/pMHC binding due to the limited SPR data currently available for human class I responses and the absence of SPR data for human class II-restricted responses. We have produced a panel of soluble TCR molecules originating from human T cells that respond to naturally occurring disease epitopes and their cognate pMHCs. In this study, we compare the binding affinity and kinetics of eight class-I-specific TCRs (TCR-Is) to pMHC-I with six class-II-specific TCRs (TCR-IIs) to pMHC-II using SPR. Overall, there is a substantial difference in the TCR-binding equilibrium constants for pMHC-I and pMHC-II, which arises from significantly faster on-rates for TCRs binding to pMHC-I. In contrast, the off-rates for all human TCR/pMHC interactions fall within a narrow window regardless of class restriction, thereby providing experimental support for the notion that binding half-life is the principal kinetic feature controlling T cell activation.
Protein Kinase D Interaction with TLR5 Is Required for Inflammatory Signaling in Response to Bacterial Flagellin
Authors: Ivison Sabine M. , Graham Nicholas R. , Bernales Cecily Q. , Kifayet Arnawaz , Ng Natalie , Shobab Leila A. , Steiner Theodore S. 
Published: April 2014

Abstract
Protein kinase D (PKD), also called protein kinase C (PKC)μ, is a serine-threonine kinase that is involved in diverse areas of cellular function such as lymphocyte signaling, oxidative stress, and protein secretion. After identifying a putative PKD phosphorylation site in the Toll/IL-1R domain of TLR5, we explored the role of this kinase in the interaction between human TLR5 and enteroaggregative Escherichia coli flagellin in human epithelial cell lines. We report several lines of evidence that implicate PKD in TLR5 signaling. First, PKD phosphorylated the TLR5-derived target peptide in vitro, and phosphorylation of the putative target serine 805 in HEK 293T cell-derived TLR5 was identified by mass spectrometry. Furthermore, mutation of serine 805 to alanine abrogated responses of transfected HEK 293T cells to flagellin. Second, TLR5 interacted with PKD in coimmunoprecipitation experiments, and this association was rapidly enhanced by flagellin treatment. Third, pharmacologic inhibition of PKC or PKD with Gö6976 resulted in reduced expression and secretion of IL-8 and prevented the flagellin-induced activation of p38 MAPK, but treatment with the PKC inhibitor Gö6983 had no significant effects on these phenotypes. Finally, involvement of PKD in the p38-mediated IL-8 response to flagellin was confirmed by small hairpin RNA-mediated gene silencing. Together, these results suggest that phosphorylation of TLR5 by PKD may be one of the proximal elements in the cellular response to flagellin, and that this event contributes to p38 MAPK activation and production of inflammatory cytokines in epithelial cells.
Protection from Direct Cerebral Cryptococcus Infection by Interferon-γ-Dependent Activation of Microglial Cells
Authors: Zhou Qing , Gault Ruth A. , Kozel Thomas R. , Murphy William J. 
Published: April 2014

Abstract
The brain represents a significant barrier for protective immune responses in both infectious disease and cancer. We have recently demonstrated that immunotherapy with anti-CD40 and IL-2 can protect mice against disseminated Cryptococcus infection. We now applied this immunotherapy using a direct cerebral cryptococcosis model to study direct effects in the brain. Administration of anti-CD40 and IL-2 significantly prolonged the survival time of mice infected intracerebrally with Cryptococcus neoformans. The protection was correlated with activation of microglial cells indicated by the up-regulation of MHC II expression on brain CD45lowCD11b+ cells. CD4+ T cells were not required for either the microglial cell activation or anticryptococcal efficacy induced by this immunotherapy. Experiments with IFN-γ knockout mice and IFN-γR knockout mice demonstrated that IFN-γ was critical for both microglial cell activation and the anticryptococcal efficacy induced by anti-CD40/IL-2. Interestingly, while peripheral IFN-γ production and microglial cell activation were observed early after treatment, negligible IFN-γ was detected locally in the brain. These studies indicate that immunotherapy using anti-CD40 and IL-2 can augment host immunity directly in the brain against C. neoformans infection and that IFN-γ is essential for this effect.
T Cell Activation and Proliferation Characteristic for HIV-Nef Transgenic Mice Is Lymphopenia Induced
Authors: Koenen Paul G. F. , Hofhuis Frans M. , Oosterwegel Mariëtte A. , Tesselaar Kiki 
Published: April 2014

Abstract
The HIV-Nef protein has been implicated in generating high viral loads and T cell activation. Transgenic (tg) mice with constitutive T cell-specific Nef expression show a dramatic reduction in T cell number and highly increased T cell turnover. Previous studies in Nef tg mice attributed this T cell activation to a direct effect of Nef at the cellular level. Given the strongly reduced peripheral T cell numbers, we examined whether this enhanced T cell division might instead be lymphopenia induced. Adoptively transferred naive wild-type T cells into lymphopenic Nef tg mice showed high T cell turnover and obtained the same effector/memory phenotype as the autologous Nef tg T cells, supporting the idea that the microenvironment determines the phenotype of the T cells present. Moreover, in bone marrow chimeras from mixtures of wild-type and Nef tg bone marrow, with a full T cell compartment containing a small proportion of Nef tg T cells, Nef tg T cells kept a naive phenotype. These results demonstrate that T cell activation in the Nef tg mice is lymphopenia induced rather than due to a direct T cell-activating effect of Nef.
NK Cells Stimulate Recruitment of CXCR3+ T Cells to the Brain during Plasmodium berghei-Mediated Cerebral Malaria
Authors: Hansen Diana S. , Bernard Nicholas J. , Nie Catherine Q. , Schofield Louis 
Published: April 2014

Abstract
NK cells are cytotoxic lymphocytes that also secrete regulatory cytokines and can therefore influence adaptive immune responses. NK cell function is largely controlled by genes present in a genomic region named the NK complex. It has been shown that the NK complex is a genetic determinant of murine cerebral malaria pathogenesis mediated by Plasmodium berghei ANKA. In this study, we show that NK cells are required for cerebral malaria disease induction and the control of parasitemia. NK cells were found infiltrating brains of cerebral malaria-affected mice. NK cell depletion resulted in inhibition of T cell recruitment to the brain of P. berghei-infected animals. NK cell-depleted mice displayed down-regulation of CXCR3 expression and a significant reduction of T cells migrating in response to IFN-γ-inducible protein 10, indicating that this chemokine pathway plays an essential role in leukocyte trafficking leading to cerebral disease and fatalities.
Antigen Presentation by Nonhemopoietic Cells Amplifies Clonal Expansion of Effector CD8 T Cells in a Pathogen-Specific Manner
Authors: Thomas Sunil , Kolumam Ganesh A. , Murali-Krishna Kaja 
Published: April 2014

AbstractProfessional APCs of hemopoietic-origin prime pathogen-specific naive CD8 T cells. The primed CD8 T cells can encounter Ag on infected nonhemopoietic cell types. Whether these nonhemopoietic interactions perpetuate effector T cell expansion remains unknown. We addressed this question in vivo, using four viral and bacterial pathogens, by comparing expansion of effector CD8 T cells in bone marrow chimeric mice expressing restricting MHC on all cell types vs mice that specifically lack restricting MHC on nonhemopoietic cell types or radiation-sensitive hemopoietic cell types. Absence of Ag presentation by nonhemopoietic cell types allowed priming of naive CD8 T cells in all four infection models tested, but diminished their sustained expansion by ∼10-fold during lymphocytic choriomeningitis virus and by ≤2-fold during vaccinia virus, vesicular stomatitis virus, or Listeria monocytogenes infections. Absence of Ag presentation by a majority (&gt;99%) of hemopoietic cells surprisingly also allowed initial priming of naive CD8 T cells in all the four infection models, albeit with delayed kinetics, but the sustained expansion of these primed CD8 T cells was markedly evident only during lymphocytic choriomeningitis virus, but not during vaccinia virus, vesicular stomatitis virus, or L. monocytogenes. Thus, infected nonhemopoietic cells can amplify effector CD8 T cell expansion during infection, but the extent to which they can amplify is determined by the pathogen. Further understanding of mechanisms by which pathogens differentially affect the ability of nonhemopoietic cell types to contribute to T cell expansion, how these processes alter during acute vs chronic phase of infections, and how these processes influence the quality and quantity of memory cells will have implications for rational vaccine design.
Enrichment and Persistence of Virus-Specific CTL in the Brain of Simian Immunodeficiency Virus-Infected Monkeys Is Associated with a Unique Cytokine Environment
Authors: Marcondes Maria Cecilia G. , Burdo Tricia H. , Sopper Sieghart , Huitron-Resendiz Salvador , Lanigan Caroline , Watry Debbie , Flynn Claudia , Zandonatti Michelle , Fox Howard S. 
Published: April 2014

AbstractThe host reaction to infection of the brain contributes to a number of CNS pathologies including neuro-AIDS. In this study, we have identified the accumulation of SIV-specific CTL in the brains of SIV-infected animals who have neurophysiological abnormalities but are otherwise asymptomatic. SIV-specific CTL enter the brain early after viral infection and are maintained in the brain even when those reactive with an immunodominant epitope in Tat are lost from the rest of the body. The specialized CNS environment contributes to this unique outcome. Following SIV infection, brain levels of IL-15 were significantly elevated whereas IL-2 was absent, creating an environment that favors CTL persistence. Furthermore, in response to IL-15, brain-derived CD8+ T cells could expand in greater numbers than those from spleen. The accumulation, persistence, and maintenance of CTL in the brain are closely linked to the increased levels of IL-15 in the absence of IL-2 in the CNS following SIV infection.
Vesicular Stomatitis Virus Glycoprotein Displaying Retrovirus-Like Particles Induce a Type I IFN Receptor-Dependent Switch to Neutralizing IgG Antibodies
Authors: Bach Patricia , Kamphuis Elisabeth , Odermatt Bernhard , Sutter Gerd , Buchholz Christian J. , Kalinke Ulrich 
Published: April 2014

Abstract
Vesicular stomatitis virus (VSV) infection rapidly induces IFN-αβ that confers initial survival, whereas long-term protection is mediated by neutralizing IgG responses. Because coadministration of IFN-αβ can enhance Ab responses against soluble Ags, we addressed whether virus-induced IFN-αβ also had an impact on the induction of neutralizing Ab responses. To this end, we generated apathogenic retrovirus-like particles (VLP) displaying the VSV gp (VLP-VSV). Reminiscent of live VSV, VLP-VSV induced VSV-neutralizing IgM responses that switched to IgG in a T help-dependent manner. In type I IFN receptor-deficient (IFNAR−/−) mice, VLP-VSV injection elicited neutralizing IgM, whereas the IgG switch was absent. The lack of subclass switch was associated with a reduced germinal center reaction. Conditional knockout mice with a lymphocyte-specific IFNAR ablation showed normal Ab responses against VLP-VSV, as well as against live VSV. Thus, IFNAR triggering critically promoted the T help-dependent subclass switch of virus-neutralizing Ab responses against VLP-VSV. Interestingly, in the context of VLP-VSV as well as VSV immunization, IFNAR triggering of B lymphocytes did not play a critical role.
Neutrophil Elastase Up-Regulates Cathepsin B and Matrix Metalloprotease-2 Expression
Authors: Geraghty Patrick , Rogan Mark P. , Greene Catherine M. , Boxio Rachel M. M. , Poiriert Tiphaine , O’Mahony Michael , Belaaouaj Abderazzaq , O’Neill Shane J. , Taggart Clifford C. , McElvaney Noel G. 
Published: April 2014

AbstractNeutrophil elastase (NE) activity is increased in many diseases. Other families of proteases, including cathepsins and matrix metalloproteases (MMPs), are also present at elevated levels in similar disease conditions. We postulated that NE could induce expression of cathepsins and MMPs in human macrophages. NE exposure resulted in macrophages, producing significantly greater amounts of cathepsin B and latent and active MMP-2. Cathepsin B and MMP-2 activities were decreased in Pseudomonas-infected NE knockout mice compared with wild-type littermates. We also demonstrate that NE can activate NF-κB in macrophages, and inhibition of NF-κB resulted in a reduction of NE-induced cathepsin B and MMP-2. Also, inhibition of TLR-4 or transfection of macrophages with dominant-negative IL-1R-associated kinase-1 resulted in a reduction of NE-induced cathepsin B and MMP-2. This study describes for the first time a novel hierarchy among proteases whereby a serine protease up-regulates expression of MMPs and cathepsins. This has important implications for therapeutic intervention in protease-mediated diseases.
Neutrophil Transmigration under Shear Flow Conditions In Vitro Is Junctional Adhesion Molecule-C Independent
Authors: Sircar Monica , Bradfield Paul F. , Aurrand-Lions Michel , Fish Richard J. , Alcaide Pilar , Yang Lin , Newton Gail , Lamont Deanna , Sehrawat Seema , Mayadas Tanya , Liang Tony W. , Parkos Charles A. , Imhof Beat A. , Luscinskas Francis W. 
Published: April 2014

Abstract
Endothelial cell junctional adhesion molecule (JAM)-C has been proposed to regulate neutrophil migration. In the current study, we used function-blocking mAbs against human JAM-C to determine its role in human leukocyte adhesion and transendothelial cell migration under flow conditions. JAM-C surface expression in HUVEC was uniformly low, and treatment with inflammatory cytokines TNF-α, IL-1β, or LPS did not increase its surface expression as assessed by FACS analysis. By immunofluorescence microscopy, JAM-C staining showed sparse localization to cell-cell junctions on resting or cytokine-activated HUVEC. Surprisingly, staining of detergent-permeabilized HUVEC revealed a large intracellular pool of JAM-C that showed little colocalization with von Willebrand factor. Adhesion studies in an in vitro flow model showed that functional blocking JAM-C mAb alone had no inhibitory effect on polymorphonuclear leukocyte (PMN) adhesion or transmigration, whereas mAb to ICAM-1 significantly reduced transmigration. Interestingly, JAM-C-blocking mAbs synergized with a combination of PECAM-1, ICAM-1, and CD99-blocking mAbs to inhibit PMN transmigration. Overexpression of JAM-C by infection with a lentivirus JAM-C GFP fusion protein did not increase adhesion or extent of transmigration of PMN or evoke a role for JAM-C in transendothelial migration. These data suggest that JAM-C has a minimal role, if any, in PMN transmigration in this model and that ICAM-1 is the preferred endothelial-expressed ligand for PMN β2 integrins during transendothelial migration.
Dual Effect of AMD3100, a CXCR4 Antagonist, on Bleomycin-Induced Lung Inflammation
Authors: Watanabe Masaki , Matsuyama Wataru , Shirahama Yuko , Mitsuyama Hideo , Oonakahara Ken-ichi , Noma Satoshi , Higashimoto Ikkou , Osame Mitsuhiro , Arimura Kimiyoshi 
Published: April 2014

Abstract
The chemokine receptor CXCR4, which binds the chemokine stromal cell-derived factor 1, has been reported to be involved in the chemotaxis of inflammatory cells. In addition, AMD3100, an antagonist of CXCR4, has been reported to be an attractive drug candidate for therapeutic intervention in several disorders in which CXCR4 is critically involved. However, little is known about the therapeutic value of AMD3100 in the treatment of pulmonary fibrosis. In this study, we examined the effects of AMD3100 on a murine bleomycin-induced pulmonary fibrosis model. Concurrent administration of AMD3100 and bleomycin apparently attenuated bleomycin-induced pulmonary inflammation. In this process, an inhibition of neutrophil recruitment at early stage followed by the decrease of other inflammatory cell recruitment in the lung were observed. In addition, it also inhibited the expression of cytokines, including MCP-1, MIP-2, MIP-1α, and TGF-β. In contrast, when AMD3100 was administered following bleomycin treatment, the bleomycin-induced lung inflammation progressed and resulted in severe pulmonary fibrosis. In this process, an increase of inflammatory cell recruitment, an up-regulation of lung MCP-1 and TGF-β, and a remarkable activation of p44/42 MAPK in neutrophils were observed. U0126, an inhibitor of p44/42 MAPK, significantly abolished these effects. Thus, AMD3100 has dual effect on bleomycin-induced pulmonary fibrosis. Difference of inflammatory cell recruitment and activation might be associated with the dual effect of AMD3100 on bleomycin-induced pulmonary fibrosis.
The Phosphatidylinositol 3-Kinase Signaling Pathway Exerts Protective Effects during Sepsis by Controlling C5a-Mediated Activation of Innate Immune Functions
Authors: Wrann Christiane D. , Tabriz Navid A. , Barkhausen Tanja , Klos Andreas , van Griensven Martijn , Pape Hans C. , Kendoff Daniel O. , Guo Renfeng , Ward Peter A. , Krettek Christian , Riedemann Niels C. 
Published: April 2014

Abstract
The PI3K/Akt signaling pathway has been recently suggested to have controversial functions in models of acute and chronic inflammation. Our group and others have reported previously that the complement split product C5a alters neutrophil innate immunity and cell signaling during the onset of sepsis and is involved in PI3K activation. We report in this study that in vivo inhibition of the PI3K pathway resulted in increased mortality in septic mice accompanied by strongly elevated serum levels of TNF-α, IL-6, MCP-1, and IL-10 during sepsis as well as decreased oxidative burst activity in blood phagocytes. PI3K inhibition in vitro resulted in significant increases in TLR-4-mediated generation of various proinflammatory cytokines in neutrophils, whereas the opposite effect was observed in PBMC. Oxidative burst and phagocytosis activity was significantly attenuated in both neutrophils and monocytes when PI3K activation was blocked. In addition, PI3K inhibition resulted in strongly elevated TLR-4-mediated generation of IL-1β and IL-8 in neutrophils when these cells were costimulated with C5a. C5a-induced priming effects on neutrophil and monocyte oxidative burst activity as well as C5a-induced phagocytosis in neutrophils were strongly reduced when PI3K activation was blocked. Our data suggest that the PI3K/Akt signaling pathway controls various C5a-mediated effects on neutrophil and monocyte innate immunity and exerts an overall protective effect during experimental sepsis.
Systemic Inflammatory Priming in Normal Pregnancy and Preeclampsia: The Role of Circulating Syncytiotrophoblast Microparticles
Authors: Germain Sarah J. , Sacks Gavin P. , Soorana Suren R. , Sargent Ian L. , Redman Christopher W. 
Published: April 2014

Abstract
Systemic inflammatory responsiveness was studied in normal human pregnancy and its specific inflammatory disorder, pre-eclampsia. Compared with nonpregnancy, monocytes were primed to produce more TNF-α throughout normal pregnancy, more IL-12p70 in the first and second trimesters, and more IL-18 in the first trimester only. Intracellular cytokine measurements (TNF-α and IL12p70) showed little change by comparison. IFN-γ production was suppressed in all three trimesters. In pre-eclampsia, IL-18 secretion was increased. Secreted but not intracellular measures of TNF-α and IL-12p70 were also further enhanced compared with normal pregnancy. Inhibition of IFN-γ production was lost and involved both CD56+ NK and CD56− lymphocyte subsets. We determined whether circulating syncytiotrophoblast microparticles (STBM) could contribute to these inflammatory changes. Unbound STBM could be detected in normal pregnancy by the second trimester and increased significantly in the third. They were also bound in vivo to circulating monocytes. Women with pre-eclampsia had significantly more circulating free but not cell-bound STBMs. STBMs prepared by perfusion of normal placental lobules stimulated production of inflammatory cytokines (TNF-α, IL12p70, and IL-18 but not IFN-γ) when cultured with PBMCs from healthy nonpregnant women. Inflammatory priming of PBMCs during pregnancy is confirmed and is established by the first trimester. It is associated with early inhibition of IFN-γ production. The inflammatory response is enhanced in pre-eclampsia with loss of the IFN-γ suppression. Circulating STBMs bind to monocytes and stimulate the production of inflammatory cytokines. It is concluded that they are potential contributors to altered systemic inflammatory responsiveness in pregnancy and pre-eclampsia.
IL-22 Induces Lipopolysaccharide-Binding Protein in Hepatocytes: A Potential Systemic Role of IL-22 in Crohn’s Disease
Authors: Wolk Kerstin , Witte Ellen , Hoffmann Ute , Doecke Wolf-Dietrich , Endesfelder Stefanie , Asadullah Khusru , Sterry Wolfram , Volk Hans-Dieter , Wittig Bianca Maria , Sabat Robert 
Published: April 2014

Abstract
Crohn′s disease (CD) is a common, chronic, inflammatory bowel disease characterized by intestinal infiltration of activated immune cells and distortion of the intestinal architecture. In this study, we demonstrate that IL-22, a cytokine that is mainly produced by activated Th1 and Th17 cells, was present in high quantities in the blood of CD patients in contrast to IFN-γ and IL-17. In a mouse colitis model, IL-22 mRNA expression was elevated predominantly in the inflamed intestine but also in the mesenteric lymph nodes. IL-22BP, the soluble receptor for IL-22, demonstrated an affinity to IL-22 that was at least 4-fold higher than its membrane-bound receptor, and its strong constitutive expression in the intestine and lymph nodes was decreased in the inflamed intestine. To investigate the possible role of systemic IL-22 in CD, we then administered IL-22 to healthy mice and found an up-regulation of LPS-binding protein (LBP) blood levels reaching concentrations known to neutralize LPS. This systemic up-regulation was associated with increased hepatic but not renal or pulmonary LBP mRNA levels. IL-22 also enhanced the secretion of LBP in human primary hepatocytes and HepG2 hepatoma cells in vitro. This increase was mainly transcriptionally regulated and synergistic with that of other LBP inducers. Finally, elevated LBP levels were detected in CD patients and the mouse colitis model. These data suggest that systemic IL-22 may contribute to the prevention of systemic inflammation provoked by LPS present in the blood of CD patients through its induction of hepatic LBP.