bluuebunny/crossref_metadata_2025_split huggingface dataset:
Training the next generation of near‐surface geophysicists: team‐based, student‐led, problem‐solving field exercises, Cumbria, UK
Authors: Pringle J.K. , Cassidy N.J. , Styles P. , Stimpson I.G. , Toon S.M. 
Published: January 2011

ABSTRACTDiscussions with employers of graduate applied geophysicists (reinforced by recent literature) indicate a progressive reduction in the numeracy and literacy of graduating students. In particular, there is a perception that problem‐solving and quantitative analysis skills are not being gained during university studies, which could be partly attributed to an emphasis on classroom lectures and timetable constraints rather than research‐informed and active learning in the field.This paper provides a pedagogic overview of a Masters level, student‐led residential field exercise in the Lake District, Cumbria, UK that has run for eight years. The valley has complex glaciated bedrock buried by recent sediments, which poses a challenge for students to recognize, understand and quantify in three dimensions. Participating student ‘companies’ are set a competitive task to win a contract for a full geophysical valley survey to determine the route of a gas pipeline. Students initially complete a desk study, collating available multi‐disciplinary (geology, remote sensing and geotechnical) data sets. The student‐led field exercise then acts as a geophysical reconnaissance mission, with teams mapping depth to bedrock and estimating extents of any coastal salinity incursions. Full costings are produced to simulate a real work contract and the successful company is awarded the ‘contract’, based on ‘client’ presentations on the final day of the exercise.Comments on the student learning outcomes are provided, including employability skills in team working, problem‐solving, quantitative data analysis, project and budget management and client presentation skills. Recent student evaluations are discussed with very positive comments from graduate geophysicists who have entered related employment emphasizing how the exercise has prepared them for the workplace.
Mucosal Allergic Sensitization to Cockroach Allergens Is Dependent on Proteinase Activity and Proteinase-Activated Receptor-2 Activation
Authors: Arizmendi Narcy G. , Abel Melanie , Mihara Koichiro , Davidson Courtney , Polley Danny , Nadeem Ahmed , El Mays Tamer , Gilmore Brendan F. , Walker Brian , Gordon John R. , Hollenberg Morley D. , Vliagoftis Harissios 
Published: January 2011

AbstractWe have shown that proteinase-activated receptor-2 (PAR2) activation in the airways leads to allergic sensitization to concomitantly inhaled Ags, thus implicating PAR2 in the pathogenesis of asthma. Many aeroallergens with proteinase activity activate PAR2. To study the role of PAR2 in allergic sensitization to aeroallergens, we developed a murine model of mucosal sensitization to cockroach proteins. We hypothesized that PAR2 activation in the airways by natural allergens with serine proteinase activity plays an important role in allergic sensitization. Cockroach extract (CE) was administered to BALB/c mice intranasally on five consecutive days (sensitization phase) and a week later for four more days (challenge phase). Airway hyperresponsiveness (AHR) and allergic airway inflammation were assessed after the last challenge. To study the role of PAR2, mice were exposed intranasally to a receptor-blocking anti-PAR2 Ab before each administration of CE during the sensitization phase. Mucosal exposure to CE induced eosinophilic airway inflammation, AHR, and cockroach-specific IgG1. Heat-inactivated or soybean trypsin inhibitor-treated CE failed to induce these effects, indicating that proteinase activity plays an important role. The use of an anti-PAR2 blocking Ab during the sensitization phase completely inhibited airway inflammation and also decreased AHR and the production of cockroach-specific IgG1. PAR2 activation by CE acts as an adjuvant for allergic sensitization even in the absence of functional TLR4. We conclude that CE induces PAR2-dependent allergic airway sensitization in a mouse model of allergic airway inflammation. PAR2 activation may be a general mechanism used by aeroallergens to induce allergic sensitization.
Ubiquitylation of an Internalized Killer Cell Ig-Like Receptor by Triad3A Disrupts Sustained NF-κB Signaling
Authors: Miah S. M. Shahjahan , Purdy Amanda K. , Rodin Nicholas B. , MacFarlane Alexander W. , Oshinsky Jennifer , Alvarez-Arias Diana A. , Campbell Kerry S. 
Published: January 2011

AbstractKiller cell Ig-like receptor (KIR) with two Ig-like domains and a long cytoplasmic domain 4 (2DL4; CD158d) is a unique KIR expressed on human NK cells, which stimulates cytokine production, but mechanisms regulating its expression and function are poorly understood. By yeast two-hybrid screening, we identified the E3 ubiquitin ligase, Triad3A, as an interaction partner for the 2DL4 cytoplasmic domain. The protein interaction was confirmed in vivo, and Triad3A expression induced polyubiquitylation and degradation of 2DL4. Overexpression of Triad3A selectively abrogated the cytokine-producing function of 2DL4, whereas Triad3A short hairpin RNA reversed ubiquitylation and restored cytokine production. Expression of Triad3A in an NK cell line did not affect receptor surface expression, internalization, or early signaling, but significantly reduced receptor turnover and suppressed sustained NF-κB activation. 2DL4 endocytosis was found to be vital to stimulate cytokine production, and Triad3A expression diminished localization of internalized receptor in early endosomes. Our results reveal a critical role for endocytosed 2DL4 receptor to generate sustained NF-κB signaling and drive cytokine production. We conclude that Triad3A is a key negative regulator of sustained 2DL4-mediated NF-κB signaling from internalized 2DL4, which functions by promoting ubiquitylation and degradation of endocytosed receptor from early endosomes.
TANK-Binding Kinase 1 Attenuates PTAP-Dependent Retroviral Budding through Targeting Endosomal Sorting Complex Required for Transport-I
Authors: Da Qi , Yang Xuanming , Xu Youli , Gao Guangxia , Cheng Genhong , Tang Hong 
Published: January 2011

Abstract
Retroviruses need to bud from producer cells to spread infection. To facilitate its budding, some virus hijacks the multivesicular body (MVB) pathway that is normally used to cargo and degrade ubiquitylated cellular proteins, through interaction between the late domain of Gag polyproteins and the components of MVB machinery. In this study, we demonstrated that TANK-binding kinase 1 (TBK1) directly interacted with VPS37C, a subunit of endosomal sorting complex required for transport-I (ESCRT-I) in the MVB pathway, without affecting the ultrastructure or general function of MVB. Interestingly, overexpression of TBK1 attenuated, whereas short hairpin RNA interference of TBK1 enhanced HIV-1 pseudovirus release from Vero cells in type I IFN (IFN-I)-independent manner. Down-regulation of TBK1 by short hairpin RNA in TZM-bl cells also enhanced live HIV-1 NL4-3 or JR-CSF virus budding without involvement of IFN-I induction. Furthermore, infection of TBK1-deficient mouse embryonic fibroblast cells with a chimeric murine leukemia virus/p6, whose PPPY motif was replaced by PTAP motif of HIV-1, showed that lack of TBK1 significantly enhanced PTAP-dependent, but not PPPY-dependent retrovirus budding. Finally, phosphorylation of VPS37C by TBK1 might regulate the viral budding efficiency, because overexpression of the kinase-inactive mutant of TBK1 (TBK1-K38A) in Vero cells accelerated HIV-1 pseudovirus budding. Therefore, through tethering to VPS37C of the ESCRT-I complex, TBK1 controlled the speed of PTAP-dependent retroviral budding through phosphorylation of VPS37C, which would serve as a novel mechanism of host cell defense independent of IFN-I signaling.
Anaphylaxis and Mortality Induced by Treatment of Mice with Anti–VLA-4 Antibody and Pertussis Toxin
Authors: Ji Niannian , Rao Nagarjun , Guentzel Neal M. , Arulanandam Bernard P. , Forsthuber Thomas G. 
Published: January 2011

AbstractAb-mediated blockade of the adhesion molecule VLA-4 has been shown to ameliorate disease in human multiple sclerosis patients and experimental autoimmune encephalomyelitis (EAE) animal models. We wanted to determine whether anti–VLA-4 Ab treatment affected the function and persistence of autoreactive T cells in mice with EAE. Unexpectedly, we observed a high level of mortality in anti–VLA-4 mAb (PS/2)-treated mice with actively induced EAE despite decreased disease severity. Investigation of the underlying mechanism showed that injection of PS/2 mAb in combination with pertussis toxin resulted in anaphylaxis and mortality. Furthermore, the data showed that CD4+ T cells were required for this effect and suggested a role for IL-1β and TNF-α in the underlying pathology. The results reveal a previously not appreciated deleterious effect of anti–VLA-4 Ab treatment in combination with exposure to pertussis toxin.
Basophils Are the Major Producers of IL-4 during Primary Helminth Infection
Authors: van Panhuys Nicholas , Prout Melanie , Forbes Elizabeth , Min Booki , Paul William E. , Le Gros Graham 
Published: January 2011

AbstractIL-4 production by leukocytes is a key regulatory event that occurs early in the type 2 immune response, which induces allergic reactions and mediates expulsion of parasites. CD4+ T cells and basophils are thought to be the key cell types that produce IL-4 during a type 2 response. In this study, we assessed the relative contribution of both CD4+ T cell- and basophil–IL-4 production during primary and secondary responses to Nippostrongylus brasiliensis using a murine IL-4–enhanced GFP reporter system. During infection, IL-4–producing basophils were detected systemically, and tissue recruitment occurred independent of IL-4/STAT6 signaling. We observed that basophil recruitment to a tissue environment was required for their full activation. Basophil induction in response to secondary infection exhibited accelerated kinetics in comparison with primary infection. However, total basophil numbers were not enhanced, as predicted by previous models of protective immunity. Overall, the induction and migration of IL-4–producing basophils into peripheral tissues was found to be a prominent characteristic of the primary but not memory responses to N. brasiliensis infection, in which CD4+ T cells were identified as the major source of IL-4. Whereas basophils were the major initial producers of IL-4, we determined that normal Th2 differentiation occurs independently of basophils, and depletion of basophils led to an enhancement of inflammatory cell recruitment to the site of infection.
β2 Integrin Induces TCRζ–Syk–Phospholipase C-γ Phosphorylation and Paxillin-Dependent Granule Polarization in Human NK Cells
Authors: March Michael E. , Long Eric O. 
Published: January 2011

AbstractCytotoxic lymphocytes kill target cells through polarized release of the content of lytic granules at the immunological synapse. In human NK cells, signals for granule polarization and for degranulation can be uncoupled: Binding of β2 integrin LFA-1 to ICAM is sufficient to induce polarization but not degranulation, whereas CD16 binding to IgG triggers unpolarized degranulation. In this study, we investigated the basis for this difference. IL-2–expanded human NK cells were stimulated by incubation with plate-bound ligands of LFA-1 (ICAM-1) and CD16 (human IgG). Surprisingly, LFA-1 elicited signals similar to those induced by CD16, including tyrosine phosphorylation of the TCR ζ-chain, tyrosine kinase Syk, and phospholipase C-γ. Whereas CD16 activated Ca2+ mobilization and LAT phosphorylation, LFA-1 did not, but induced strong Pyk2 and paxillin phosphorylation. LFA-1–dependent granule polarization was blocked by inhibition of Syk, phospholipase C-γ, and protein kinase C, as well as by paxillin knockdown. Therefore, common signals triggered by CD16 and LFA-1 bifurcate to provide independent control of Ca2+-dependent degranulation and paxillin-dependent granule polarization.
Deletion of Tristetraprolin Caused Spontaneous Reactive Granulopoiesis by a Non–Cell-Autonomous Mechanism Without Disturbing Long-Term Hematopoietic Stem Cell Quiescence
Authors: Kaplan Ian M. , Morisot Sebastien , Heiser Diane , Cheng Wen-Chih , Kim Min Jung , Civin Curt I. 
Published: January 2011

AbstractTristetraprolin (TTP, Zfp36, Nup475, Tis11) dramatically reduces the stability of target mRNAs by binding to AU-rich elements in their 3′ untranslated regions. Through this mechanism, TTP functions as a rheostatic, temporal regulator of gene expression. TTP knockout (KO) mice exhibit completely penetrant granulocytic hyperplasia. We have shown that the hematopoietic stem-progenitor cell compartment in TTP KO mice is also altered. Although no change was detected in long-term hematopoietic stem cell (HSC) frequency or function, as assayed by immunophenotypic markers or limiting dilution transplants, we observed increases in the frequencies and numbers of short-term HSCs, multipotent progenitors, and granulocyte–monocyte progenitors. This pattern is consistent with “reactive granulopoiesis,” in which committed myeloid progenitors and more primitive progenitors cycle more actively to increase production of mature granulocytes in response to infection or adjuvant. We created reverse chimeras by transplanting wild-type bone marrow into TTP KO mice and found the “reactive granulopoiesis” phenocopied, indicating a non–hematopoietic stem-progenitor cell–autonomous mechanism. Correspondingly, we found elevated levels of the granulopoietic TTP targets IL-1β, TNF-α, and IL-6 in the plasma of TTP KO mice. Consistent with the non–cell-autonomous nature of the phenotype, we found elevated levels of IL-1β, TNF-α, and IL-6 transcripts in the livers of TTP KO mice and no detectable difference in the bone marrows. These findings demonstrate the importance of TTP in inflammatory homeostasis and highlight the ability of the hematopoietic system to respond to stress without significant numbers of quiescent HSCs entering the cell cycle.
Memory CD4 T Cells That Express CXCR5 Provide Accelerated Help to B Cells
Authors: MacLeod Megan K. L. , David Alexandria , McKee Amy S. , Crawford Frances , Kappler John W. , Marrack Philippa 
Published: January 2011

AbstractCD4 T cell help for B cells is critical for effective Ab responses. Although many of the molecules involved in helper functions of naive CD4 T cells have been characterized, much less is known about the helper capabilities of memory CD4 T cells, an important consideration for the design of vaccines that aim to prime protective memory CD4 T cells. In this study, we demonstrate that memory CD4 T cells enable B cells to expand more rapidly and class switch earlier than do primary responding CD4 T cells. This accelerated response does not require large numbers of memory cells, and similar numbers of primary responding cells provide less effective help than do memory cells. However, only memory CD4 T cells that express the B cell follicle homing molecule, CXCR5, are able to accelerate the response, suggesting that the rapidity of the Ab response depends on the ability of CD4 memory T cells to migrate quickly toward B cells.
HLA Class I Allelic Sequence and Conformation Regulate Leukocyte Ig-Like Receptor Binding
Authors: Jones Des C. , Kosmoliaptsis Vasilis , Apps Richard , Lapaque Nicolas , Smith Isobel , Kono Azumi , Chang Chiwen , Boyle Louise H. , Taylor Craig J. , Trowsdale John , Allen Rachel L. 
Published: January 2011

AbstractLeukocyte Ig-like receptors (LILRs) are a family of innate immune receptors predominantly expressed by myeloid cells that can alter the Ag presentation properties of macrophages and dendritic cells. Several LILRs bind HLA class I. Altered LILR recognition due to HLA allelic variation could be a contributing factor in disease. We comprehensively assessed LILR binding to &gt;90 HLA class I alleles. The inhibitory receptors LILRB1 and LILRB2 varied in their level of binding to different HLA alleles, correlating in some cases with specific amino acid motifs. LILRB2 displayed the weakest binding to HLA-B*2705, an allele genetically associated with several autoimmune conditions and delayed progression of HIV infection. We also assessed the effect of HLA class I conformation on LILR binding. LILRB1 exclusively bound folded β2-microglobulin–associated class I, whereas LILRB2 bound both folded and free H chain forms. In contrast, the activating receptor LILRA1 and the soluble LILRA3 protein displayed a preference for binding to HLA-C free H chain. To our knowledge, this is the first study to identify the ligand of LILRA3. These findings support the hypothesis that LILR-mediated detection of unfolded versus folded MHC modulates immune responses during infection or inflammation.
Genetic Labeling Reveals Altered Turnover and Stability of Innate Lymphocytes in Latent Mouse Cytomegalovirus Infection
Authors: Busche Andreas , Schmitz Susanne , Fleige Henrike , Robbins Scott H. , Walzer Thierry , Stewart Charles A. , Förster Reinhold , Messerle Martin , Prinz Immo 
Published: January 2011

AbstractMouse CMV (MCMV) infection rapidly induces the proliferation of NK cells, which correlates with immunological protection. Whether NK cells primed during acute response against MCMV are maintained for the long term is not known. In this study, we used TcrdH2BeGFP mice in which maturing NK cells are genetically labeled with a pulse of very stable histone-2B–eGFP. In this system, we found that the reporter protein was diluted out upon NK cell division during acute MCMV infection. At the same time, mature NK cells in uninfected mice showed only very limited turnover in vivo. Three months after primary infection when MCMV latency was established, the majority of peripheral NK cells still displayed a higher record of proliferation than NK cells in mock-infected controls. This observation included both Ly49H+ and Ly49H– NK cells. Conversely, naive NK cells did not show more proliferation after transfer into latently MCMV-infected mice than that after transfer into mock-infected control mice. This indicated that the observed alterations of the NK cell compartment in MCMV latency were “legacy” (i.e., resulting from prior events during the initial immune response). Together, these results suggest that antiviral immune responses induce sustained alterations of innate lymphocyte populations that extend far beyond the first days of acute infection.
CXCR4 Expression on Activated B Cells Is Downregulated by CD63 and IL-21
Authors: Yoshida Nobuya , Kitayama Daisuke , Arima Masafumi , Sakamoto Akemi , Inamine Ayako , Watanabe-Takano Haruko , Hatano Masahiko , Koike Takao , Tokuhisa Takeshi 
Published: January 2011

AbstractCXCR4 expression is critical for localization of centroblasts in the dark zone of germinal centers (GCs), and centrocytes downregulate CXCR4 and thus leave the dark zone to reside in the light zone. However, mechanisms governing CXCR4 downregulation on centrocytes are not known. In this study, we show that the amount of intracellular CXCR4 in centroblasts was similar to that in centrocytes, suggesting differential control of CXCR4 protein expression in these GC B cells. Restimulation of activated B cells with IL-21, which is a major cytokine produced by T follicular helper cells, accelerated CXCR4 internalization by inducing endocytosis-related GRK6 expression. Although CXCR4 expression was downregulated on GC B cells by IL-21 stimulation, CXCR4low centrocytes developed in the spleens of IL-21R–deficient mice, suggesting other mechanisms for downregulation. The level of CD63 (which recruits CXCR4 to late endosome in CD4 T cells) in centrocytes was more than that in centroblasts and was strikingly elevated in activated Bcl6-deficient B cells. Bcl6, a transcriptional repressor, was detected on the chromatin of the CD63 gene in resting B cells, therefore CD63 is a molecular target of Bcl6. Downregulation of CD63 mRNA in activated Bcl6-deficient B cells by small interfering RNA upregulated CXCR4 expression on the B cells. Furthermore, addition of Bcl6 inhibitor to activated B cell cultures increased CD63 mRNA expression in (and downregulated CXCR4 expression on) those activated B cells. Thus, CXCR4 can be downregulated on activated B cells by IL-21–induced endocytosis and CD63-mediated endosomal recruitment, and these mechanisms may contribute to downregulation of CXCR4 on centrocytes.
Intrinsic Requirement for the Vitamin D Receptor in the Development of CD8αα-Expressing T Cells
Authors: Bruce Danny , Cantorna Margherita T. 
Published: January 2011

AbstractVitamin D and vitamin D receptor (VDR) deficiency results in severe symptoms of experimental inflammatory bowel disease in several different models. The intraepithelial lymphocytes of the small intestine contain large numbers of CD8αα+ T cells that have been shown to suppress the immune response to Ags found there. In this study, we determined the role of the VDR in the development of CD8αα+ T cells. There are fewer total numbers of TCRαβ+ T cells in the gut of VDR knockout (KO) mice, and that reduction was largely in the CD8αα+ TCRαβ+ cells. Conversely TCRγδ+ T cells were normal in the VDR KO mice. The thymic precursors of CD8αα+ TCRαβ+ cells (triple-positive for CD4, CD8αα, and CD8αβ) were reduced and less mature in VDR KO mice. In addition, VDR KO mice had a higher frequency of the CD8αα+ TCRαβ+ precursors (double-negative [DN] TCRαβ+ T cells) in the gut. The proliferation rates of the DN TCRαβ+ gut T cells were less in the VDR KO compared with those in wild type. Low proliferation of DN TCRαβ+ T cells was a result of the very low expression of the IL-15R in this population of cells in the absence of the VDR. Bone marrow transplantation showed that the defect in VDR KO CD8αα+ TCRαβ+ cells was cell intrinsic. Decreased maturation and proliferation of CD8αα+ TCRαβ+ cells in VDR KO mice results in fewer functional CD8αα+ TCRαβ+ T cells, which likely explains the increased inflammation in the gastrointestinal tract of VDR KO and vitamin D-deficient mice.
Nonhematopoietic Cells Are Key Players in Innate Control of Bacterial Airway Infection
Authors: LeibundGut-Landmann Salomé , Weidner Kerstin , Hilbi Hubert , Oxenius Annette 
Published: January 2011

AbstractAirborne pathogens encounter several hurdles during host invasion, including alveolar macrophages (AMs) and airway epithelial cells (AECs) and their products. Although growing evidence indicates pathogen-sensing capacities of epithelial cells, the relative contribution of hematopoietic versus nonhematopoietic cells in the induction of an inflammatory response and their possible interplay is still poorly defined in vivo in the context of infections with pathogenic microorganisms. In this study, we show that nonhematopoietic cells, including AECs, are critical players in the inflammatory process induced upon airway infection with Legionella pneumophila, and that they are essential for control of bacterial infections. Lung parenchymal cells, including AECs, are not infected themselves by L. pneumophila in vivo but rather act as sensors and amplifiers of inflammatory cues delivered by L. pneumophila-infected AM. We identified AM-derived IL-1β as the critical mediator to induce chemokine production in nonhematopoietic cells in the lung, resulting in swift and robust recruitment of infection-controlling neutrophils into the airways. These data add a new level of complexity to the coordination of the innate immune response to L. pneumophila and illustrate how the cross talk between leukocytes and nonhematopoietic cells contributes to efficient host protection.