bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Comparison of Constrained MPC With PID Controller for Heave Disturbance Attenuation in Offshore Managed Pressure Drilling Systems
Authors: Nikoofard Amirhossein , Johansen Tor Arne , Mahdianfar Hessam , Pavlov Alexey
Published: April 2014

AbstractThis paper presents a constrained finite horizon model predictive control (MPC) scheme for regulation of the annular pressure in a well during managed pressure drilling from a floating vessel subject to heave motion. In addition to the robustness of a controller,
how to deal with heave disturbances despite uncertainties in the friction factor and bulk modulus is investigated. The stochastic model describing sea waves in the North Sea is used to simulate the heave disturbances. The results show that the closed-loop simulation without disturbance has
a fast regulation response, without any overshoot, and is better than a proportional-integral-derivative controller. The constrained MPC for managed pressure drilling shows further improved disturbance rejection capabilities with measured or predicted heave disturbance. Monte Carlo simulations
show that the constrained MPC has a good performance to regulate set point and attenuate the effect of heave disturbance in case of significant uncertainties in the well parameter values.
Using Terrain Navigation to Improve Marine Vessel Navigation Systems
Authors: Hagen Ove Kent , Ånonsen Kjetil Bergh
Published: April 2014

AbstractTerrain navigation has been used extensively by underwater vehicles in the last decade. By comparing bathymetric measurements with a digital terrain model (DTM), one can estimate a global position of a vehicle underwater, where GPS signals are unavailable. With the
increasing threat of GPS signal jammers and spoofers to marine vessels, GPS-independent techniques are becoming more interesting for surface vessels as well. This paper explores the idea and challenges of using terrain navigation to detect GPS spoofing and as a substitute position source during
GPS jamming. A robust navigation system is suggested based on a GPS-aided INS augmented by terrain navigation. The INS and terrain navigation system of the HUGIN AUV was adapted to a surface vessel and tested in two experiments on the coast of Norway in scenarios simulating GPS jamming. The
results from the experiments clearly indicate the feasibility of such a system, if a DTM of the area is available and the terrain is well suited for terrain navigation.
Arctic Communication Challenges
Authors: Bekkadal Fritz
Published: April 2014

AbstractThe vast geographic distances and the economic importance of activities in remote areas like the Arctic demand new innovative radio-based solutions. There are numerous unsolved research challenges pertaining to (broadband) radio communication coverage and satellite
navigation reliability throughout the large region composed of the Norwegian Exclusive Economic Zone and the Arctic waters.This paper outlines these challenges and the current situation, in addition to identifying future systems capable of mitigating the crucial lack of adequate electronic
communications infrastructure in the High North.
Seed damage and sources of yield loss by Sitodiplosis mosellana (Diptera: Cecidomyiidae) in resistant wheat varietal blends relative to susceptible wheat cultivars in western Canada
Authors: Smith M.A.H. , Wise I.L. , Fox S.L. , Vera C.L. , DePauw R.M. , Lukow O.M.
Published: April 2014

Spring wheat varieties with the Sm1 gene for resistance to wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), were compared with susceptible wheat (Triticum Linnaeus; Poaceae) with respect to sources of yield loss and reduction in market value from wheat midge feeding damage. Four resistant varietal blends (90% Sm1 wheat plus 10% susceptible refuge) and four susceptible cultivars were grown in replicated experiments at eight locations in western Canada. Frequencies and 1000-kernel weights of undamaged and midge-damaged seeds were assessed before harvest by dissecting samples of ripe spikes, and after harvest in samples of cleaned grain. Spike data were used to estimate yield losses from reduced weight of damaged seeds and loss of severely damaged seeds (⩽8 mg) at harvest. Among midge-damaged seeds in spikes, few were severely damaged in resistant varietal blends, whereas most were severely damaged in susceptible cultivars. Cleaned, harvested grain of resistant varietal blends and susceptible cultivars had similar frequencies of midge damage and were assessed similar market grades. The primary benefit of midge-resistant wheat was reduced yield loss due to seed damage by wheat midge larvae. Resistant wheat did not protect against loss of market grade, but market value could increase due to larger yields.
Consumption of flea beetles (Phyllotreta, Coleoptera: Chrysomelidae) by spiders in field habitats detected by molecular analysis
Authors: Ekbom Barbara , Kuusk Anna-Karin , Malsher Gerard , Åström Sandra , Cassel-Lundhagen Anna
Published: April 2014

Flea beetles, Phyllotreta Chevrolat (Coleoptera: Chrysomelidae) species, are often found in oilseed rape (OSR), Brassica napus Linnaeus (Brassicaceae). Among predators in the generalist predator complex present in agricultural fields, wolf spiders (Araneae: Lycosidae) are found on the ground and cobweb spiders (Araneae: Theridiidae) build webs in the foliage. We present group-specific primers developed for five flea beetle species within the genus Phyllotreta and study the incidence of predation of flea beetles by these spider groups using DNA-based gut-content analysis. Wolf spiders of the genus Pardosa Koch and the cobweb spider, Phylloneta impressa (Koch), were collected in three winter OSR fields. Flea beetle densities as well as the occurrence of predators and alternative prey were monitored. In total 19.4% of the collected Pardosa tested positive for flea beetle DNA in the polymerase chain reaction analyses, whereas 10% P. impressa were positive. Pardosa were more likely to be positive for flea beetle DNA when Pardosa activity density was low. Phylloneta impressa were more likely to be positive for flea beetle DNA if they were positive for pollen beetle DNA. Implications of these results for conservation biological control and future studies of food webs in OSR are discussed.
Validation of a methodology for rearingSpalangia cameroni(Hymenoptera: Pteromalidae) onCeratitis capitata(Diptera: Tephritidae)
Authors: Tormos J. , Sabater-Muñoz B. , Asís J.D. , Beitia F.
Published: April 2014

Spalangia cameroniPerkins (Hymenoptera: Pteromalidae) is a pupal parasitoid of the Medfly,Ceratitis capitata(Wiedmann) (Diptera: Tephritidae), one of the principal pests of Spanish agriculture.Spalangia cameroniis a potential biocontrol agent for this pest if methods can be developed to mass-rear it effectively onC. capitata. Here, we report on the use of freeze-killed pupae ofC. capitatato maintain a laboratory colony ofS. cameroni, with a view to setting up a mass-rearing protocol. Realised fecundity, adult progeny, sex ratio, and superparasitism level were the principal parameters analysed. No significant differences were found in respect of these parameters between living or freeze-killed Medfly pupae used as hosts, although sex ratios showed a bias towards females in the case of freeze-killed pupae. Freeze-killed pupae were concluded to present the best option for the laboratory-rearing ofS. cameroni, on account of ease of rearing, and avoidance of the emergence of Medfly adults.
First Nearctic record ofDiolcogaster claritibia(Hymenoptera: Braconidae: Microgastrinae), with notes on taxonomic status and natural history
Authors: Fernandez-Triana Jose , Shaw Mark R. , Cardinal Sophie , Dosdall Lloyd , Mason Peter
Published: April 2014

The Microgastrinae waspDiolcogaster claritibia(Papp, 1959) (Hymenoptera: Braconidae), a parasitoid of the diamondback moth,Plutella xylostella(Linnaeus, 1758) (Lepidoptera: Plutellidae), is recorded from the Nearctic region (Alberta, Manitoba, and Ontario, Canada) for the first time. In spite of some minor morphological and molecular (DNA barcoding) differences, the available data indicate that the European and New World specimens should be considered one species, but more specimens and loci need to be sampled to conclusively determine the phylogeographic history of the species.Diolcogaster claritibiaseems to be widely distributed within the Holarctic, and the molecular data suggest that it was recently introduced to North America from Europe.
Therapeutic Effect of IVIG on Inflammatory Arthritis in Mice Is Dependent on the Fc Portion and Independent of Sialylation or Basophils
Authors: Campbell Ian K. , Miescher Sylvia , Branch Donald R. , Mott Patrick J. , Lazarus Alan H. , Han Dongji , Maraskovsky Eugene , Zuercher Adrian W. , Neschadim Anton , Leontyev Danila , McKenzie Brent S. , Käsermann Fabian
Published: April 2014

High-dose i.v. Ig (IVIG) is used to treat various autoimmune and inflammatory diseases; however, the mechanism of action remains unclear. Based on the K/BxN serum transfer arthritis model in mice, IVIG suppression of inflammation has been attributed to a mechanism involving basophils and the binding of highly sialylated IgG Fc to DC-SIGN–expressing myeloid cells. The requirement for sialylation was examined in the collagen Ab-induced arthritis (CAbIA) and K/BxN serum transfer arthritis models in mice. High-dose IVIG (1–2 g/kg body weight) suppressed inflammatory arthritis when given prophylactically. The same doses were also effective in the CAbIA model when given subsequent to disease induction. In this therapeutic CAbIA model, the anti-inflammatory effect of IVIG was dependent on IgG Fc but not F(ab′)2 fragments. Removal of sialic acid residues by neuraminidase had no impact on the anti-inflammatory activity of IVIG or Fc fragments. Treatment of mice with basophil-depleting mAbs did not abrogate the suppression of either CAbIA or K/BxN arthritis by IVIG. Our data confirm the therapeutic benefit of IVIG and IgG Fc in Ab-induced arthritis but fail to support the significance of sialylation and basophil involvement in the mechanism of action of IVIG therapy.
Kinetics of B Cell Responses to Plasmodium falciparum Erythrocyte Membrane Protein 1 in Ghanaian Women Naturally Exposed to Malaria Parasites
Authors: Ampomah Paulina , Stevenson Liz , Ofori Michael F. , Barfod Lea , Hviid Lars
Published: April 2014

Naturally acquired protective immunity to Plasmodium falciparum malaria takes years to develop. It relies mainly on Abs, particularly IgG specific for Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) proteins on the infected erythrocyte surface. It is only partially understood why acquisition of clinical protection takes years to develop, but it probably involves a range of immune-evasive parasite features, not least of which are PfEMP1 polymorphism and clonal variation. Parasite-induced subversion of immunological memory and expansion of “atypical” memory B cells may also contribute. In this first, to our knowledge, longitudinal study of its kind, we measured B cell subset composition, as well as PfEMP1-specific Ab levels and memory B cell frequencies, in Ghanaian women followed from early pregnancy up to 1 y after delivery. Cell phenotypes and Ag-specific B cell function were assessed three times during and after pregnancy. Levels of IgG specific for pregnancy-restricted, VAR2CSA-type PfEMP1 increased markedly during pregnancy and declined after delivery, whereas IgG levels specific for two PfEMP1 proteins not restricted to pregnancy did not. Changes in VAR2CSA-specific memory B cell frequencies showed typical primary memory induction among primigravidae and recall expansion among multigravidae, followed by contraction postpartum in all. No systematic changes in the frequencies of memory B cells specific for the two other PfEMP1 proteins were identified. The B cell subset analysis confirmed earlier reports of high atypical memory B cell frequencies among residents of P. falciparum–endemic areas, and indicated an additional effect of pregnancy. Our study provides new knowledge regarding immunity to P. falciparum malaria and underpins efforts to develop PfEMP1-based vaccines against this disease.
Heat Shock Proteins as Endogenous Adjuvants in Sterile and Septic Inflammation
Authors: Quintana Francisco J. , Cohen Irun R.
Published: April 2014

Heat shock proteins (HSPs) have been reported to stimulate the immune system via innate receptors. However, the role of HSPs as endogenous adjuvants has been challenged by reports claiming that pure HSPs are not innate ligands; it is only the bacterial molecules trapped by the HSPs that can signal the innate immune system. In this review, we discuss data suggesting that both views, in essence, are correct; pure HSPs are indeed innate immunostimulators, but HSPs can also function as transducers of pathogen signals. In other words, HSPs perform diverse functions in two alternative modes of inflammation: sterile inflammation, which results from endogenous stimuli and is necessary for body maintenance, and septic inflammation, which protects us from environmental pathogens. Endogenous HSPs are key players in the modulation of these two modes of inflammation, and as such, they are potential targets for new and more efficient therapies for cancer, infections, and autoimmunity.
Follicular Dendritic Cells Catalyze Hepatocyte Growth Factor (HGF) Activation in the Germinal Center Microenvironment by Secreting the Serine Protease HGF Activator
Authors: Tjin Esther P. M. , Bende Richard J. , Derksen Patrick W. B. , van Huijstee Anne-Pauline , Kataoka Hiroaki , Spaargaren Marcel , Pals Steven T.
Published: April 2014

Ag-specific B cell differentiation, the process that gives rise to plasma cells and memory B cells, involves the formation of germinal centers (GC). Within the GC microenvironment, multiple steps of B cell proliferation, selection, and maturation take place, which are controlled by the BCR in concert with cytokines and contact-dependent signals from follicular dendritic cells (FDCs) and T cells. Signaling by the multifunctional cytokine hepatocyte growth factor (HGF) and its receptor MET has been shown to induce integrin-mediated adhesion of B cells to VCAM-1, which is expressed by FDCs. In the present study we have examined the expression of regulatory components of the HGF/MET pathway, including HGF activator (HGFA), within the secondary lymphoid organ microenvironment. We show that MET is expressed by both centroblasts and plasma cells, and that HGFA is expressed by plasma cells. Because we have shown that HGF is a potent growth and survival factor for malignant plasma cells, HGF may also serve as a survival factor for normal plasma cells. Furthermore, we demonstrate that FDCs are the major source for HGF and its activator within the GC microenvironment. Both HGF and HGFA are expressed by FDCs in the GC dark zone (CD21high/CD23low), but not in the light zone (CD21high/CD23high). These findings suggest that HGF and HGFA provided by dark zone FDCs help to regulate the proliferation, survival, and/or adhesion of MET-positive centroblasts.
Gi-Protein-Dependent Inhibition of IL-12 Production Is Mediated by Activation of the Phosphatidylinositol 3-Kinase-Protein 3 Kinase B/Akt Pathway and JNK
Authors: la Sala Andrea , Gadina Massimo , Kelsall Brian L.
Published: April 2014

Ligands for certain Gi-protein-coupled receptors (GiPCRs) potently inhibit the production of IL-12 by human monocytes. We addressed the intracellular signaling mechanisms by which this occurs using primary human cells. Stimulation with the GiPCR ligands C5a and 1-deoxy-1-[6-[(3-iodophenyl)methyl]amino]-9H-purine-9-y1]-N-methyl-β-d-ribofuranuronamide (IB-MECA) blocked the production of IL-12 p70 by human monocytes stimulated with LPS and IFN-γ. In addition, C5a reduced the expression of mRNA for IL-12 p35, p40, IL-23 p19, and IL-27 p28. This effect was due neither to a down-regulation of TLR4 or IFN-γ receptor on the cell surface nor to interference with IFN-γ signaling, because IFN-γ-induced up-regulation of HLA-DR and CD40 were unaffected. C5a or IB-MECA activated the PI3K/Akt signaling pathway and induced the phosphorylation of the MAPK p38, ERK, and JNK. Inhibition of the PI3K/Akt signaling pathway with wortmannin or an inhibitor of Akt activity, and inhibition of JNK but not ERK prevented IL-12 and IL-23 suppression by C5a. These data extend observations on IL-12 suppression by C5a to IL-23 and IL-27, and are the first to demonstrate the intracellular signaling events leading to IL-12 and IL-23 inhibition after GiPCR activation.
In Vivo Generation of Pathogen-Specific Th1 Cells in the Absence of the IFN-γ Receptor
Authors: Haring Jodie S. , Badovinac Vladimir P. , Olson Matthew R. , Varga Steven M. , Harty John T.
Published: April 2014

The precise mechanisms that govern the commitment of CD4 T cells to become Th1 or Th2 cells in vivo are incompletely understood. Recent experiments demonstrate colocalization of the IFN-γR chains with the TCR during activation of naive CD4 T cells, suggesting that association of these molecules may be involved in determining lineage commitment. To test the role of IFN-γ and its receptor in the generation of Th1 Ag-specific CD4 T cells, we analyzed mice after infection with Listeria monocytogenes or lymphocytic choriomeningitis virus. In the absence of IFN-γ, Ag-specific CD4 T cells were generated in response to both these infections. In addition, IFN-γ-producing (Th1) Ag-specific CD4 T cells were generated in mice lacking the ligand-binding chain of the IFN-γR (IFN-γR1−/−) or the signaling chain (IFN-γR2−/−). There was no increase in the number of IL-4-producing Ag-specific CD4 T cells, nor was there a decrease in the expression of T-bet in the absence of functional IFN-γ signaling, indicating that the cells were committed Th1 cells. Thus, both chains of the IFN-γR are dispensable for the generation of Th1 Ag-specific CD4 T cells after infection in vivo.
Intraepithelial NK Cell-Derived IL-13 Induces Intestinal Pathology Associated with Nematode Infection
Authors: McDermott Jacqueline R. , Humphreys Neil E. , Forman Simon P. , Donaldson Debra D. , Grencis Richard K.
Published: April 2014

IL-13 is a Th2-derived cytokine associated with pathological changes in asthma and ulcerative colitis. Moreover, it plays a major role in the control of gut nematode infection and associated immunopathology. The current paradigm is that these effects are due to T cell-derived IL-13. We show in this study that an innate source of IL-13, the intraepithelial NK cell, is responsible for the disruption of intestinal tissue architecture and induction of goblet cell hyperplasia that characterizes infection with the intestinal helminth Trichinella spiralis. IL-13 or IL-4Rα (but not IL-4) null mice failed to induce intestinal pathology. Unexpectedly, SCID and athymic mice developed the same pathology found in immunocompetent mice following infection. Moreover, immunodeficient mice expressed IL-13 in the intestine, and abnormal mucosal pathology was reduced by in vivo administration of a soluble IL-13 antagonist. IL-13 expression was induced in non-T intraepithelial CD3− NK cells. Epithelial cells expressed the IL-13 signaling receptor, IL-13Rα1, and after infection, IL-4Rα. Furthermore, the soluble IL-13 decoy receptor IL-13Rα2, which regulates IL-13 responses, was also induced upon infection. These data provide the first evidence that intestinal tissue restructuring during helminth infection is an innate event dependent on IL-13 production by NK cells resident in the epithelium of the intestine.
Functional Analysis of Granzyme M and Its Role in Immunity to Infection
Authors: Pao Lily I. , Sumaria Nital , Kelly Janice M. , Dommelen Serani van , Cretney Erika , Wallace Morgan E. , Anthony Desiree A. , Uldrich Adam P. , Godfrey Dale I. , Papadimitriou John M. , Mullbacher Arno , Degli-Esposti Mariapia A. , Smyth Mark J.
Published: April 2014

Cytotoxic lymphocytes express a large family of granule serine proteases, including one member, granzyme (Grz)M, with a unique protease activity, restricted expression, and distinct gene locus. Although a number of Grzs, including GrzM, have been shown to mediate target cell apoptosis in the presence of perforin, the biological activity of Grz has been restricted to control of a number of viral pathogens, including two natural mouse pathogens, ectromelia, and murine CMV (MCMV). In this article, we describe the first reported gene targeting of GrzM in mice. GrzM-deficient mice display normal NK cell/T cell development and homeostasis and intact NK cell-mediated cytotoxicity of tumor targets as measured by membrane damage and DNA fragmentation. GrzM-deficient mice demonstrated increased susceptibility to MCMV infection typified by the presence of more viral inclusions and transiently higher viral burden in the visceral organs of GrzM-deficient mice compared with wild-type (WT) mice. The cytotoxicity of NK cells from MCMV-infected GrzM-deficient mice remained unchanged and, like WT control mice, GrzM-deficient mice eventually effectively cleared MCMV infection from the visceral organs. In contrast, GrzM-deficient mice were as resistant as WT control mice to mouse pox ectromelia infection, as well as challenge with a number of NK cell-sensitive tumors. These data confirm a role for GrzM in the host response to MCMV infection, but suggest that GrzM is not critical for NK cell-mediated cytotoxicity.
An Innate Immune System Cell Is a Major Determinant of Species-Related Susceptibility Differences to Fungal Pneumonia
Authors: Shao Xiuping , Mednick Aron , Alvarez Mauricio , van Rooijen Nico , Casadevall Arturo , Goldman David L.
Published: April 2014

Rats and mice are considered resistant and susceptible hosts, respectively, for experimental cryptococcosis. For both species, alveolar macrophages (AM) are central components of the host response to pulmonary Cryptococcus neoformans infection. We explored the role of AM in three strains of mice and three strains of rats during cryptococcal infection by comparing the outcome of infection after macrophage depletion using liposomal clodronate. AM depletion was associated with enhancement and amelioration of disease in rats and mice, respectively, as measured by lung fungal burden. The apparent protective role for AM in rats correlated with enhanced anticryptococcal activity as measured by phagocytic activity, oxidative burst, lysozyme secretion, and ability to limit intracellular growth of C. neoformans. Furthermore, rat AM were more resistant to lysis in association with intracellular infection. In summary, differences in AM function in rats and mice suggest an explanation for the species differences in susceptibility to C. neoformans based on the inherent efficacy of a central effector cell of the innate immune system.
Complement Regulator-Acquiring Surface Protein 1 Imparts Resistance to Human Serum in Borrelia burgdorferi
Authors: Brooks Chad S. , Vuppala Santosh R. , Jett Amy M. , Alitalo Antti , Meri Seppo , Akins Darrin R.
Published: April 2014

Factor H and factor H-like protein 1 (FH/FHL-1) are soluble serum proteins that negatively regulate the alternative pathway of complement. It is now well recognized that many pathogenic bacteria, including Borrelia burgdorferi, bind FH/FHL-1 on their cell surface to evade complement-mediated destruction during infection. Recently, it was suggested that B. burgdorferi open reading frame bbA68, known as complement regulator-acquiring surface protein 1 (CRASP-1), encodes the major FH/FHL-1-binding protein of B. burgdorferi. However, because several other proteins have been identified on the surface of B. burgdorferi that also can bind FH/FHL-1, it is presently unclear what role CRASP-1 plays in serum resistance. To examine the contribution of CRASP-1 in serum resistance, we generated a B. burgdorferi mutant that does not express CRASP-1. The B. burgdorferi CRASP-1 mutant, designated B31cF-CRASP-1, was found to be as susceptible to human serum as a wild-type strain of Borrelia garinii 50 known to be sensitive to human serum. To further examine the role of CRASP-1 in serum resistance, we also created a shuttle vector that expresses CRASP-1 from the native B. burgdorferi gene, which was designated pKFSS-1::CRASP-1. When the pKFSS-1::CRASP-1 construct was transformed into the B. burgdorferi B31cF-CRASP-1 mutant, wild-type levels of serum resistance were restored. Additionally, when pKFSS-1::CRASP-1 was transformed into the serum-sensitive B. garinii 50 isolate, human serum resistance was imparted on this strain to a level indistinguishable from wild-type B. burgdorferi. The combined data led us to conclude that CRASP-1 expression is necessary for B. burgdorferi to resist killing by human serum.
A Novel Viral System for Generating Antigen-Specific T Cells
Authors: Moran Timothy P. , Collier Martha , McKinnon Karen P. , Davis Nancy L. , Johnston Robert E. , Serody Jonathan S.
Published: April 2014

Dendritic cell (DC)-based vaccines are increasingly used for the treatment of patients with malignancies. Although these vaccines are typically safe, consistent and lasting generation of tumor-specific immunity has been rarely demonstrated. Improved methods for delivering tumor Ags to DCs and approaches for overcoming tolerance or immune suppression to self-Ags are critical for improving immunotherapy. Viral vectors may address both of these issues, as they can be used to deliver intact tumor Ags to DCs, and have been shown to inhibit the suppression mediated by CD4+CD25+ regulatory T cells. We have evaluated the potential use of Venezuelan equine encephalitis virus replicon particles (VRPs) for in vitro Ag delivery to human monocyte-derived DCs. VRPs efficiently transduced immature human DCs in vitro, with ∼50% of immature DCs expressing a vector-driven Ag at 12 h postinfection. VRP infection of immature DCs was superior to TNF-α treatment at inducing phenotypic maturation of DCs, and was comparable to LPS stimulation. Additionally, VRP-infected DC cultures secreted substantial amounts of the proinflammatory cytokines IL-6, TNF-α, and IFN-α. Finally, DCs transduced with a VRP encoding the influenza matrix protein (FMP) stimulated 50% greater expansion of FMP-specific CD8+ CTL when compared with TNF-α-matured DCs pulsed with an HLA-A*0201-restricted FMP peptide. Thus, VRPs can be used to deliver Ags to DCs resulting in potent stimulation of Ag-specific CTL. These findings provide the rationale for future studies evaluating the efficacy of VRP-transduced DCs for tumor immunotherapy.
Cutting Edge: Roles of Caspase-8 and Caspase-10 in Innate Immune Responses to Double-Stranded RNA
Authors: Takahashi Ken , Kawai Taro , Kumar Himanshu , Sato Shintaro , Yonehara Shin , Akira Shizuo
Published: April 2014

Upon viral infection, host cells trigger antiviral immune responses by inducing type I IFN and inflammatory cytokines. dsRNA generated during viral replication is recognized by the cytoplasmic RNA helicases retinoic acid-inducible gene I and melanoma differentiation-associated gene 5, which interact with an adaptor, IFN-β promoter stimulator-1, to activate the transcription factors NF-κB and IFN regulatory factor 3. In this article we demonstrate that caspase-8 and caspase-10 are involved in these pathways. Both caspases were cleaved during dsRNA stimulation, and overexpression of a cleaved form of these caspases activated NF-κB. Knockdown of caspase-10 or caspase-8 in a human cell line resulted in the reduction of inflammatory cytokine production. Cells derived from caspase-8-deficient mice also showed reduced expression of inflammatory cytokines as well as NF-κB activation. Furthermore, the Fas-associated death domain protein interacted with these two caspases and IFN-β promoter stimulator 1. These results indicate that caspase-8 and caspase-10 are essential components that mediate NF-κB-dependent inflammatory responses in antiviral signaling.
Immune Complex-Loaded Dendritic Cells Are Superior to Soluble Immune Complexes as Antitumor Vaccine
Authors: Schuurhuis Danita H. , van Montfoort Nadine , Ioan-Facsinay Andreea , Jiawan Reshma , Camps Marcel , Nouta Jan , Melief Cornelis J. M. , Verbeek J. Sjef , Ossendorp Ferry
Published: April 2014

Dendritic cells (DCs) play an important role in the induction of T cell responses. FcγRs, expressed on DCs, facilitate the uptake of complexed Ag, resulting in efficient MHC class I and MHC class II Ag presentation and DC maturation. In the present study, we show that prophylactic immunization with DCs loaded with Ag-IgG immune complexes (ICs) leads to efficient induction of tumor protection in mice. Therapeutic vaccinations strongly delay tumor growth or even prevent tumors from growing out. By depleting CD4+ and CD8+ cell populations before tumor challenge, we identify CD8+ cells as the main effector cells involved in tumor eradication. Importantly, we show that DCs that are preloaded in vitro with ICs are at least 1000-fold more potent than ICs injected directly into mice or DCs loaded with the same amount of noncomplexed protein. The contribution of individual FcγRs to Ag presentation, T cell response induction, and induction of tumor protection was assessed. We show that FcγRI and FcγRIII are capable of enhancing MHC class I-restricted Ag presentation to CD8+ T cells in vitro and that these activating FcγRs on DCs are required for efficient priming of Ag-specific CD8+ cells in vivo and induction of tumor protection. These findings show that targeting ICs via the activating FcγRs to DCs in vitro is superior to direct IC vaccination to induce protective tumor immunity in vivo.
Oral Nickel Tolerance: Fas Ligand-Expressing Invariant NK T Cells Promote Tolerance Induction by Eliciting Apoptotic Death of Antigen-Carrying, Effete B Cells
Authors: Nowak Michael , Kopp Frank , Roelofs-Haarhuis Karin , Wu Xianzhu , Gleichmann Ernst
Published: April 2014

Whereas oral nickel administration to C57BL/6 mice (Nihigh mice) renders the animals tolerant to immunization with NiCl2 combined with H2O2 as adjuvant, as determined by ear-swelling assay, it fails to tolerize Jα18−/− mice, which lack invariant NKT (iNKT) cells. Our previous work also showed that Nihigh splenic B cells can adoptively transfer the nickel tolerance to untreated (Nilow) recipients, but not to Jα18−/− recipients. In this study, we report that oral nickel administration increased the nickel content of splenic Nihigh B cells and up-regulated their Fas expression while down-regulating expression of bcl-2 and Bcl-xL, thus giving rise to an Ag-carrying, apoptosis-prone B cell phenotype. Although oral nickel up-regulated Fas expression on B cells of both wild-type Nihigh and Jα18−/− Nihigh mice, only the former showed a reduced number of total B cells in spleen when compared with untreated, syngeneic mice, indicating that iNKT cells are involved in B cell homeostasis by eliciting apoptosis of effete B cells. Upon transfer of Nihigh B cells, an infectious spread of nickel tolerance ensues, provided the recipients are immunized with NiCl2/H2O2. As a consequence of immunization, Fas ligand-positive (FasL+) iNKT cells appeared in the spleen and apparently elicited apoptosis of Nihigh B cells. The apoptotic Nihigh B cells were taken up by splenic dendritic cells, which thereby became tolerogenic for nickel-reactive Nilow T cells. In conclusion, FasL+ iNKT cells may act as ready-to-kill sentinels of innate immunity, but at the same time assist in tolerance induction by eliciting Fas/FasL-mediated apoptosis of effete, Ag-containing B cells.
Targeted Disruption of CD38 Accelerates Autoimmune Diabetes in NOD/Lt Mice by Enhancing Autoimmunity in an ADP-Ribosyltransferase 2-Dependent Fashion
Authors: Chen Jing , Chen Yi-Guang , Reifsnyder Peter C. , Schott William H. , Lee Chul-Ho , Osborne Melissa , Scheuplein Felix , Haag Friedrich , Koch-Nolte Friedrich , Serreze David V. , Leiter Edward H.
Published: April 2014

Ubiquitously expressed CD38 and T cell-expressed ADP-ribosyltransferase 2 (ART2) are ectoenzymes competing for NAD substrate. CD38 exerts pleiotropic actions in hemopoietic and nonhemopoietic compartments via effects on calcium mobilization. ART2 is an ADP-ribosyltransferase on naive CD4+ and CD8+ T cells. ART2-catalyzed ADP-ribosylation of the P2X7 purinoreceptor elicits apoptosis. Transfer of a genetically disrupted CD38 allele into the autoimmune diabetes-prone NOD/Lt background accelerated diabetes onset in both sexes, whereas transfer of a disrupted ART2 complex had no effect. However, the fact that the accelerated pathogenesis mediated by CD38 deficiency required ART2 activity was demonstrated by combining both ART2 and CD38 deficiencies. Reciprocal bone marrow reconstitution studies demonstrated accelerated diabetes only when CD38-deficient bone marrow was transferred into CD38-deficient recipients. Neither decreases in β cell function nor viability were indicated. Rather, the balance between T-effectors and T-regulatory cells was disturbed in CD38-deficient but ART2-intact NOD mice. In these mice, significant reductions in total viable CD8+ T cells were observed. This was accompanied by an age-dependent increase in a diabetogenic CD8 clonotype. This in turn correlated with impaired T-regulatory development (10-fold reduction in Foxp3 mRNA expression). These changes were corrected when CD38 deficiency was combined with ART2 deficiency. Both ART2-deficient and CD38/ART2 combined deficient T cells were resistant to NAD-induced killing in vitro, whereas CD38-deficient but ART2-intact T cells showed increased sensitivity, particularly the CD4+CD25+ subset. Unexpectedly, diabetes development in the combined CD38/ART2 stock was strongly suppressed, possibly through epistatic interactions between genes linked to the targeted CD38 on Chromosome 5 and the ART2 complex on Chromosome 7.
Phospholipase Cγ2 Dosage Is Critical for B Cell Development in the Absence of Adaptor Protein BLNK
Authors: Xu Shengli , Huo Jianxin , Chew Weng-Keong , Hikida Masaki , Kurosaki Tomohiro , Lam Kong-Peng
Published: April 2014

B cell linker (BLNK) protein and phospholipase Cγ2 (PLCγ2) are components of the BCR signalosome that activate calcium signaling in B cells. Mice lacking either molecule have a severe but incomplete block in B lymphopoiesis. In this study, we generated BLNK−/−PLCγ2−/− mice to examine the effect of simultaneous disruption of both molecules on B cell development. We showed that BLNK−/−PLCγ2−/− mice had compounded defects in B cell maturation compared with either single mutant, suggesting that these two molecules cooperatively or synergistically signaled B lymphopoiesis. However, Ig H chain allelic exclusion was maintained in single and double mutants, indicating that signals propagated by BLNK and PLCγ2 were not involved in this process. Interestingly, in the absence of BLNK, B cell development was dependent on plcγ2 gene dosage. This was evidenced by the proportionate decrease in splenic B cell population and increase in bone marrow surface pre-BCR+ cells in PLCγ2-diploid, -haploid, and -null animals. Intracellular calcium signaling and ERK activation in response to BCR engagement were also proportionately decreased and delayed, respectively, with stepwise reduction of plcγ2 dosage in a BLNKnull background. Thus, these data indicate the importance of BLNK not only as a conduit to specifically channel BCR-signaling pathways and as a scaffold for the assembling of macromolecular complex, but also as an efficient aggregator or concentrator of PLCγ2 molecules to effect optimal signaling for B cell generation and activation.
Adaptive Islet-Specific Regulatory CD4 T Cells Control Autoimmune Diabetes and Mediate the Disappearance of Pathogenic Th1 Cells In Vivo
Authors: Weber Sarah E. , Harbertson Judith , Godebu Elana , Mros Guthrie A. , Padrick Ryan C. , Carson Bryan D. , Ziegler Steven F. , Bradley Linda M.
Published: April 2014

Adaptive regulatory T cells that develop from naive CD4 cells in response to exposure to Ag can act as immunotherapeutic agents to control immune responses. We show that effectors generated from murine islet-specific CD4 cells by TCR stimulation with IL-2 and TGF-β1 have potent suppressive activity. They prevent spontaneous development of type 1 diabetes in NOD mice and inhibit development of pancreatic infiltrates and disease onset orchestrated by Th1 effectors. These regulatory T cells do not require innate CD25+ regulatory cells for generation or function, nor do they share some characteristics typically associated with them, including expression of CD25. However, the adaptive population does acquire the X-linked forkhead/winged helix transcription factor, FoxP3, which is associated with regulatory T cell function and maintains expression in vivo. One mechanism by which they may inhibit Th1 cells is via FasL-dependent cytotoxicity, which occurs in vitro. In vivo, they eliminate Th1 cells in lymphoid tissues, where Fas/FasL interactions potentially play a role because Th1 cells persist when this pathway is blocked. The results suggest that adaptive regulatory CD4 cells may control diabetes in part by impairing the survival of islet-specific Th1 cells, and thereby inhibiting the localization and response of autoaggressive T cells in the pancreatic islets.
Early Growth Response Gene 1 Provides Negative Feedback to Inhibit Entry of Progenitor Cells into the Thymus
Authors: Schnell Frederick J. , Zoller Allison L. , Patel Seema R. , Williams Ifor R. , Kersh Gilbert J.
Published: April 2014

The size of the thymus can be greatly influenced by changes in the small number of early progenitors in the thymus. However, it is not known whether thymic cellularity feeds back to regulate the recruitment, survival, and expansion of progenitors. The transcription factor early growth response gene 1 (Egr1) has been implicated in controlling proliferation and survival in many cell types. We have previously shown that mice deficient in Egr1 have increased thymic cellularity. We now show that Egr1 regulates a negative feedback signal that controls the entry of cells into the thymus. Egr1-deficient mice have higher percentages of early T lineage progenitors in the thymus, yet Egr1-deficient mice have normal numbers of myelolymphoid progenitors in the bone marrow, and Egr1-deficient thymocytes show normal rates of apoptosis and proliferation at all stages of development. Evidence from mixed bone marrow chimeras shows that the ability of Egr1 to control progenitor recruitment is mediated by bone marrow-derived cells, but is not cell autonomous. Furthermore, Egr1-deficient thymuses have increased P-selectin expression. The data suggest that Egr1 mediates a feedback mechanism whereby the number of resident double negative thymocytes controls the entry of new progenitors into the thymus by regulating P-selectin expression on thymic endothelial cells.
Control of Autoimmune Myocarditis and Multiorgan Inflammation by Glucocorticoid-Induced TNF Receptor Family-Related Proteinhigh, Foxp3-Expressing CD25+ and CD25− Regulatory T Cells
Authors: Ono Masahiro , Shimizu Jun , Miyachi Yoshiki , Sakaguchi Shimon
Published: April 2014

Anomalies of naturally occurring CD4+ regulatory T cells (Treg) cause severe autoimmune/inflammatory diseases in humans and rodents. The transcription factor Foxp3 is currently the most specific marker for natural CD4+ Treg, but it would be useful if other Treg markers, particularly cell surface molecules, could be elucidated. We demonstrate in this study that the vast majority of Foxp3-expressing CD4+ T cells (whether CD25+ or CD25−) show constitutive high-level expression of glucocorticoid-induced TNFR family-related gene/protein (GITR). Transfer of T cell or thymocyte suspensions depleted of GITRhigh cells produces in BALB/c nude mice a wider spectrum and more severe forms of autoimmune diseases than does transfer of similar cell suspensions depleted of CD25+CD4+ T cells only. Notably, mice that receive cells depleted of GITRhigh populations develop severe multiorgan inflammation that includes fatal autoimmune myocarditis resembling giant cell myocarditis in humans, accompanying high-titer anti-myosin autoantibodies. Similar transfer of GITRhigh-depleted cells from prediabetic NOD mice to NOD-SCID mice accelerates the development of diabetes and induces skeletal muscle myositis and other autoimmune/inflammatory diseases. We conclude that GITRhigh, Foxp3-expressing natural Treg, containing both CD25+ and CD25− cell populations, contribute to preventing a variety of autoimmune/inflammatory diseases, and depletion of these cells allows the activation of even weak or rare autoreactive T cells yielding widespread severe autoimmune disease. Diseases induced in this way include many which have been suspected of an autoimmune etiology in humans without much evidence. GITRhigh, Foxp3-expressing natural Treg represent a potential target for the treatment and prevention of these diseases.
STAT5-Mediated Signals Sustain a TCR-Initiated Gene Expression Program toward Differentiation of CD8 T Cell Effectors
Authors: Verdeil Grégory , Puthier Denis , Nguyen Catherine , Schmitt-Verhulst Anne-Marie , Auphan-Anezin Nathalie
Published: April 2014

Poorly functional effector CD8 T cells are generated in some pathological situations, including responses to weakly antigenic tumors. To identify the molecular bases for such defective differentiation, we monitored gene expression in naive monoclonal CD8 T cells during responses to TCR ligands of different affinity. We further evaluated whether responses to weak Ags may be improved by addition of cytokines. Transient gene expression was observed for a cluster of genes in response to the weak TCR agonist. Strikingly, gene expression was stabilized by low dose IL-2. This IL-2-sustained gene cluster encoded notably transcripts for CD25, cytolytic effector molecules (granzyme B) and TNF-R family costimulatory molecules (glucocorticoid-induced TNF-R (GITR), OX40, and 4-1BB). IL-2-enhanced surface expression or function was also demonstrated in vivo for these genes. A constitutive active form of STAT5 mimicked the IL-2 effect by sustaining transcripts for the same gene cluster. Consistent with this, under conditions of low avidity TCR engagement and IL-2 treatment, endogenous STAT5 binding to 4-1BB and granzyme B promoters was demonstrated by chromatin immunoprecipitation. This study highlights those genes for which IL-2, via STAT5 activation, acts as a stabilizer of gene regulation initiated by TCR signals, contributing to the development of a complete CD8 T cell effector program.
Cloning and Characterization of Mannose-Binding Lectin from Lamprey (Agnathans)
Authors: Takahashi Momoe , Iwaki Daisuke , Matsushita Akiko , Nakata Munehiro , Matsushita Misao , Endo Yuichi , Fujita Teizo
Published: April 2014

The recognition of pathogens is mediated by a set of pattern recognition molecules that recognize conserved pathogen-associated molecular patterns shared by broad classes of microorganisms. Mannose-binding lectin (MBL) is one of the pattern recognition molecules and activates complement in association with MBL-associated serine protease (MASP) via the lectin pathway. Recently, an MBL-like lectin was isolated from the plasma of a urochordate, the solitary ascidian. This ascidian lectin has a carbohydrate recognition domain, but the collagen-like domain was replaced by another sequence. To elucidate the origin of MBLs, the aim of this study is to determine the structure and function of the MBL homolog in lamprey, the most primitive vertebrate. Using an N-acetylglucosamine (GlcNAc)-agarose column, MBL-like lectin (p25) was isolated from lamprey serum and cDNA cloning was conducted. From the deduced amino acid sequence this lectin has a collagenous region and a typical carbohydrate recognition domain. This lectin also binds mannose, glucose, and GlcNAc, but not galactose, indicating that it is structurally and functionally similar to the mammalian MBLs. Furthermore, it associated with lamprey MASPs, and the MBL-MASP activated lamprey C3 in fluid-phase and on the surface of pathogens. In conjunction with the phylogenetic analysis, it seems likely that the lamprey MBL is an ortholog of the mammalian MBL. Because acquired immunity seems to have been established only from jawed vertebrates onward, the lectin complement pathway in lamprey, as one of the major contributors to innate immunity, plays a pivotal role in defending the body against microorganisms.
Effect of d-Alanylation of (Lipo)Teichoic Acids of Staphylococcus aureus on Host Secretory Phospholipase A2 Action before and after Phagocytosis by Human Neutrophils
Authors: Hunt Catherine L. , Nauseef William M. , Weiss Jerrold P.
Published: April 2014

Invading bacteria such as Staphylococcus aureus induce mobilization of professional phagocytes (e.g., neutrophils) and extracellular antibacterial proteins (e.g., group IIA phospholipase A2 (gIIA PLA2)). Accumulation of gIIA PLA2 in inflammatory fluids confers potent extracellular antistaphylococcal activity and at lower concentrations promotes bacterial phospholipid degradation during phagocytosis of S. aureus by human neutrophils. d-alanylation of (lipo) teichoic acids of S. aureus increases bacterial resistance to gIIA PLA2 ∼100-fold, raising the possibility that the resistance of ingested S. aureus to related gV and gX secretory PLA2 present in human neutrophil granules depends on d-alanylation mediated by the dlt operon. However, we show that isogenic wild-type and dltA S. aureus are equally resistant to gV/X PLA2 during phagocytosis and when exposed to the purified enzymes. The fates of wild-type and dltA S. aureus exposed to serum and human neutrophils differed significantly only when extracellular gIIA PLA2 was also present before phagocytosis. The extreme potency of the gIIA PLA2 toward dltA S. aureus suggests that even small amounts of this extracellular enzyme mobilized early in inflammation could contribute substantially to the overall cytotoxicity of acute inflammatory exudates toward S. aureus when d-alanylation of (lipo)teichoic acids is limiting.
Contrasting Roles for Domain 4 of VCAM-1 in the Regulation of Cell Adhesion and Soluble VCAM-1 Binding to Integrin α4β1
Authors: Woodside Darren G. , Kram Ronda M. , Mitchell Jason S. , Belsom Tracie , Billard Matthew J. , McIntyre Bradley W. , Vanderslice Peter
Published: April 2014

Cell adhesion mediated by the interaction between integrin α4β1 and VCAM-1 is important in normal physiologic processes and in inflammatory and autoimmune disease. Numerous studies have mapped the α4β1 binding sites in VCAM-1 that mediate cell adhesion; however, little is known about the regions in VCAM-1 important for regulating soluble binding. In the present study, we demonstrate that 6D VCAM-1 (an alternatively spliced isoform of VCAM-1 lacking Ig-like domain 4) binds α4β1 with a higher relative affinity than does the full-length form of VCAM-1 containing 7 Ig-like extracellular domains (7D VCAM-1). In indirect binding assays, the EC50 of soluble 6D VCAM-1 binding to α4β1 on Jurkat cells (in 1 mM MnCl2) was 2 × 10−9 M, compared with 7D VCAM-1 at 11 × 10−9 M. When used in solution to inhibit α4β1 mediated cell adhesion, the IC50 of 6D VCAM-1 was 13 × 10−9 M, compared with 7D VCAM-1 measured at 150 × 10−9 M. Removal of Ig-like domains 4, 5, or 6, or simply substituting Asp328 in domain 4 of 7D VCAM-1 with alanine, caused increased binding of soluble 7D VCAM-1 to α4β1. In contrast, cells adhered more avidly to 7D VCAM-1 under shear force, as it induced cell spreading at lower concentrations than did 6D VCAM-1. Finally, soluble 6D VCAM-1 acts as an agonist through α4β1 by augmenting cell migration and inducing cell aggregation. These results indicate that the domain 4 of VCAM-1 plays a contrasting role when VCAM-1 is presented in solution or as a cell surface-expressed adhesive substrate.