bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat Shock Protein 70 Is a Potential Virulence Factor in MurineToxoplasmaInfection Via Immunomodulation of Host NF-κB and Nitric Oxide
Authors: Dobbin Caroline A. , Smith Nicholas C. , Johnson Alan M. 
Published: April 2014

AbstractWe propose that the 70-kDa heat shock protein (HSP70) protects virulent Toxoplasma gondii from the effects of the host by immunomodulation. This hypothesis was tested using quercetin and antisense oligonucleotides targeting the start codon of the virulent T. gondii HSP70 gene. Oligonucleotides were transiently transfected into two virulent (RH, ENT) and two avirulent (ME49, C) strains of T. gondii, significantly reducing HSP70 expression in treated parasites. Virulent parasites with reduced HSP70 expression displayed reduced proliferation in vivo, as measured by the number of tachyzoites present in spleens of infected mice. They also exhibited an enhanced rate of conversion from tachyzoites to bradyzoites in vitro. Our results implicate HSP70 as a means by which virulent strains of T. gondii evade host proinflammatory responses: when RAW 264.7 cells were exposed to parasites with reduced HSP70 expression, differential expression of inducible NO synthase (iNOS) and cell NO production were observed between infections with normal and HSP70-deficient T. gondii. iNOS message levels were significantly increased when host cells were infected with HSP70 reduced virulent tachyzoites and HSP70-related inhibition of iNOS transcription resulted in altered host NO production by virulent T. gondii infection. Virulent parasites expressing reduced levels of HSP70 initiated significantly more NF-κB activation in host splenocytes than infections with untreated parasites. Neither proliferative ability nor conversion from tachyzoites to bradyzoites was affected by lack of HSP70 in avirulent strains of T. gondii. Furthermore, avirulent T. gondii strains induced high levels of host iNOS expression and NO production, regardless of HSP70 expression in these parasites, and inhibition of HSP70 had no significant effects on translocation of NF-κB to the nucleus. Therefore, the 70-kDa parasite stress protein may be part of an important survival strategy by which virulent strains down-regulate host parasiticidal mechanisms.
Differential Effects of Ebselen on Neutrophil Recruitment, Chemokine, and Inflammatory Mediator Expression in a Rat Model of Lipopolysaccharide-Induced Pulmonary Inflammation
Authors: Haddad El-Bdaoui , McCluskie Kerryn , Birrell Mark A. , Dabrowski Dominika , Pecoraro Michela , Underwood Steve , Chen Bei , De Sanctis George T. , Webber Steve E. , Foster Martyn L. , Belvisi Maria G. 
Published: April 2014

Abstract
We postulated that the seleno-organic compound ebselen would attenuate neutrophil recruitment and activation after aerosolized challenge with endotoxin (LPS) through its effect as an antioxidant and inhibitor of gene activation. Rats were given ebselen (1–100 mg/kg i.p.) followed by aerosolized LPS exposure (0.3 mg/ml for 30 min). Airway inflammatory indices were measured 4 h postchallenge. Bronchoalveolar lavage (BAL) fluid cellularity and myeloperoxidase activity were used as a measure of neutrophil recruitment and activation. RT-PCR analysis was performed in lung tissue to assess gene expression of TNF-α, cytokine-induced neutrophil chemoattractant-1 (CINC-1), macrophage-inflammatory protein-2 (MIP-2), ICAM-1, IL-10, and inducible NO synthase. Protein levels in lung and BAL were also determined by ELISA. Ebselen pretreatment inhibited neutrophil influx and activation as assessed by BAL fluid cellularity and myeloperoxidase activity in cell-free BAL and BAL cell homogenates. This protective effect was accompanied by a significant reduction in lung and BAL fluid TNF-α and IL-1β protein and/or mRNA levels. Ebselen pretreatment also prevented lung ICAM-1 mRNA up-regulation in response to airway challenge with LPS. This was not a global effect of ebselen on LPS-induced gene expression, because the rise in lung and BAL CINC-1 and MIP-2 protein levels were unaffected as were lung mRNA expressions for CINC-1, MIP-2, IL-10, and inducible NO synthase. These data suggest that the anti-inflammatory properties of ebselen are achieved through an inhibition of lung ICAM-1 expression possibly through an inhibition of TNF-α and IL-1β, which are potent neutrophil recruiting mediators and effective inducers of ICAM-1 expression.
Cutting Edge: Thymocyte-Independent and Thymocyte-Dependent Phases of Epithelial Patterning in the Fetal Thymus
Authors: Klug David B. , Carter Carla , Gimenez-Conti Irma B. , Richie Ellen R. 
Published: April 2014

AbstractThymic epithelial cells (TECs) in adult mice have been classified into distinct subsets based on keratin expression profiles. To explore the emergence of TEC subsets during ontogeny, we analyzed keratin 8 and keratin 5 expression at several stages of fetal development in normal C57BL/6J mice. In addition, thymic epithelial development and compartmentalization were explored in recombination-activating gene 2/common cytokine receptor γ-chain-deficient and Ikaros-null mice that sustain early and profound blocks in thymocyte differentiation. The results demonstrate that initial patterning of the thymic epithelial compartment as defined by differential keratin expression does not depend on inductive signals from hematopoietic cells. However, thymocyte-derived signals are required during late fetal stages for continued development and maintenance of TEC subsets in the neonate and adult.
Severe Immunodeficiency Has Opposite Effects on Neuronal Survival in Glutamate-Susceptible and -Resistant Mice: Adverse Effect of B Cells
Authors: Schori Hadas , Lantner Frida , Shachar Idit , Schwartz Michal 
Published: April 2014

Abstract
The resistance of rats or mice to glutamate-induced toxicity depends on their ability to spontaneously manifest a T cell-dependent response to the insult. Survival of retinal ganglion cells (RGCs) exposed to glutamate in BALB/c SCID mice (a strain relatively resistant to glutamate toxicity) was significantly worse than in the wild type. In the susceptible C57BL/6J mouse strain, however, significantly more RGCs survived among SCID mutants than in the matched wild type. RGC survival in the SCID mutants of the two strains was similar. These results suggest 1) that immunodeficiency might be an advantage in strains incapable of spontaneously manifesting protective T cell-dependent immunity and 2) that B cells might be destructive in such cases. After exposure of RGCs to toxic glutamate concentrations in three variants of B cell-deficient C57BL/6J mice, namely muMT−/− (B cell knockout mice) and Ii−/− mice reconstituted with transgenically expressed low levels of Ii p31 isoforms (p31 mice) or Ii p41 isoforms (p41 mice), significantly more RGCs survived in these mice than in the wild type. The improved survival was diminished by replenishment of the B cell-deficient mice with B cells derived from the wild type. It thus seems that B cells have an adverse effect on neuronal recovery after injury, at least in a strain that is unable to spontaneously manifest a T cell-dependent protective mechanism. These findings have clear implications for the design of immune-based therapies for CNS injury.
Enforced Expression ofRunx2Perturbs T Cell Development at a Stage Coincident with β-Selection
Authors: Vaillant François , Blyth Karen , Andrew Linda , Neil James C. , Cameron Ewan R. 
Published: April 2014

AbstractThe development of T cells in the thymus is regulated by a series of stage-specific transcription factors. Deregulated expression of these factors can lead to alterations in thymocyte development with the production of aberrant cell subsets and predispose to tumor formation. The three genes of the Runx family are multilineage regulators of differentiation that have been reported to be expressed in the T cell lineage. However, their roles in thymocyte development and T cell function are largely unknown. While the Runx2/Cbfa1/AML3/Pebp2αa gene plays a primary role in osteogenesis and regulates a number of key bone regulatory genes, we show here that Runx2 is also expressed during the earliest phase of thymic development, in the double-negative subset. Furthermore, enforced expression of Runx2 in transgenic mice under the CD2 promoter was found to affect T cell development at a stage coincident with β-selection, resulting in an expansion of double-negative CD4 and CD8 immature single-positive cells. Unlike wild-type controls this preselection population (CD4−CD8+heat-stable Ag+TCR−) is in a nonproliferative state, but appears to be primed for further transformation events. Overall the data suggest that Runx2 accelerates development to the CD8 immature single-positive stage, but retards subsequent differentiation to the double-positive stage. Thus, Runx2 joins a small group of transcription factors that can interfere with early T cell development, cause an expansion of a specific subset, and predispose to lymphoma.
Surfactant Protein D Reduces Alveolar Macrophage Apoptosis In Vivo
Authors: Clark Howard , Palaniyar Nades , Strong Peter , Edmondson Jess , Hawgood Samuel , Reid Kenneth B. M. 
Published: April 2014

Abstract
Surfactant protein D (SP-D) is a molecule of the innate immune system that recognizes the patterns of surface carbohydrate on pathogens and targets them for phagocytosis and killing. SP-D-deficient mice show an increased number of macrophages in the alveolar space, excess surfactant phospholipid, overproduction of reactive oxygen species, and the development of emphysema. We report here that SP-D-deficient mice have a 5- to 10-fold increase in the number of apoptotic and necrotic alveolar macrophages, as defined by annexin V and propidium iodine staining, respectively. Intrapulmonary administration of a truncated 60-kDa fragment of human recombinant SP-D reduces the number of apoptotic and necrotic alveolar macrophages and partially corrects the lipid accumulation in SP-D-deficient mice. The same SP-D fragment binds preferentially to apoptotic and necrotic alveolar macrophages in vitro, suggesting that SP-D contributes to immune homeostasis in the lung by recognizing and promoting removal of necrotic and apoptotic cells.
A Role for the α-Chain Connecting Peptide Motif in Mediating TCR-CD8 Cooperation
Authors: Naeher Dieter , Luescher Immanuel F. , Palmer Ed 
Published: April 2014

Abstract
To generate peripheral T cells that are both self-MHC restricted and self-MHC tolerant, thymocytes are subjected to positive and negative selection. How the TCR discriminates between positive and negative selection ligands is not well understood, although there is substantial evidence that the CD4 and CD8 coreceptors play an important role in this cell fate decision. We have previously identified an evolutionarily conserved motif in the TCR, the α-chain connecting peptide motif (α-CPM), which allows the TCR to deliver positive selection signals. Thymocytes expressing α-CPM-deficient receptors do not undergo positive selection, whereas their negative selection is not impaired. In this work we studied the ligand binding and receptor function of α-CPM-deficient TCRs by generating T cell hybridomas expressing wild-type or α-CPM-deficient forms of the T1 TCR. This Kd-restricted TCR is specific for a photoreactive derivative of the Plasmodium berghei circumsporozoite peptide252–260 IASA-YIPSAEK(ABA)I and is therefore amenable to TCR photoaffinity labeling. The experiments presented in this work show that α-CPM-deficient TCRs fail to cooperate with CD8 to enhance ligand binding and functional responses.
Preventing NK Cell Activation by Donor Dendritic Cells Enhances Allospecific CD4 T Cell Priming and Promotes Th Type 2 Responses to Transplantation Antigens
Authors: Coudert Jérôme D. , Coureau Christiane , Guéry Jean-Charles 
Published: April 2014

AbstractAlthough much progress has been made in understanding the role of NK cells in bone marrow transplantation, little is known about their function in CD4 T cell-mediated allograft rejection. We have previously shown that in the absence of CD8 T lymphocyte priming, the in vivo default development pathway of alloreactive CD4 T cells was strongly biased toward Th2 phenotype acquisition. In this study, we investigate the impact of NK cells on the activation and differentiation of alloreactive CD4 T cells in various donor/recipient combinations. Our data demonstrate that defective inhibition of host NK cells by donor APCs including dendritic cells (DCs) results in diminished allospecific Th cell responses associated with the development of effector Th cells producing IFN-γ rather than type 2 cytokines. Turning host NK cells off was sufficient to restore strong alloreactive CD4 T cell priming and Th2 cell development. Similar results were obtained by analyzing the effect of NK cell activation on CD4 T cell responses to skin allografts. However, despite the dramatic effect of NK cells on alloreactive Th1/Th2 cell development, the kinetics of skin graft rejection were not affected. Thus, Th2 differentiation is a major pathway of alloreactive CD4 T cell development during solid organ transplant rejection, as long as host NK and CD8 T cells are not activated. We propose the hypothesis that MHC class I-driven interactions between donor DCs and host NK cells or CD8 T cells might result in DC-carried signals controlling the dynamics of alloreactive CD4 T cell priming and polarization.
Regulation and Specificity ofMHC2TAPromoter Usage in Human Primary T Lymphocytes and Cell Line
Authors: Wong Athena W. , Ghosh Nilanjan , McKinnon Karen P. , Reed William , Piskurich Janet F. , Wright Kenneth L. , Ting Jenny P.-Y. 
Published: April 2014

AbstractAlthough activated human T cells express MHC class II antigens, the regulation of these antigens in T cells is poorly understood. This study focuses on the control of the MHC2TA gene in these cells. MHC2TA encodes the transcriptional master regulator of MHC class II, the class II trans-activator (CIITA). It has at least three distinct promoters (PI, PIII, and PIV), each active in an overlapping subset of cell types and directing a slightly different product. This report used highly purified blood T cells prepared by negative immunoselection to analyze CIITA. Real-time PCR analysis indicates that resting T cells do not express detectable CIITA transcript, while activated T cells express the PIII CIITA form. Transient transfection of activated blood T cells using wild-type and mutant PIII promoter-reporter constructs shows that two promoter elements, activation response element-1 (ARE-1) and ARE-2, are important for PIII function. cAMP response element binding protein, a known activator of gene expression in activated T cells, activates PIII in primary T cells. However, an intact ARE-2 site is not required for this activation, indicating that cAMP response element binding protein does not activate via this site. EMSAs indicate that an activating transcription factor/cAMP response element binding protein/cAMP response element modulator family member, but not phosphorylated cAMP response element binding protein-1, binds to ARE-2. ARE-2 also forms a complex with an unidentified protein. The ARE-2 binding protein is constitutively expressed in a DR+ T cell line, reflecting differences between the DR+ cell line and primary blood lymphocytes. These results show that MHC2TA PIII is induced in activated T lymphocytes, and that the induced binding of ARE-2 is a crucial step in this process.
Differential Kinetics of Antigen-Specific CD4+ and CD8+ T Cell Responses in the Regression of Retrovirus-Induced Sarcomas
Authors: Schepers Koen , Toebes Mireille , Sotthewes Gitte , Vyth-Dreese Florry A. , Dellemijn Trees A. M. , Melief Cornelis J. M. , Ossendorp Ferry , Schumacher Ton N. M. 
Published: April 2014

AbstractDespite the accepted role for CD4+ T cells in immune control, little is known about the development of Ag-specific CD4+ T cell immunity upon primary infection. Here we use MHC class II tetramer technology to directly visualize the Ag-specific CD4+ T cell response upon infection of mice with Moloney murine sarcoma and leukemia virus complex (MoMSV). Significant numbers of Ag-specific CD4+ T cells are detected both in lymphoid organs and in retrovirus-induced lesions early during infection, and they express the 1B11-reactive activation-induced isoform of CD43 that was recently shown to define effector CD8+ T cell populations. Comparison of the kinetics of the MoMSV-specific CD4+ and CD8+ T cell responses reveals a pronounced shift toward CD8+ T cell immunity at the site of MoMSV infection during progression of the immune response. Consistent with an important early role of Ag-specific CD4+ T cell immunity during MoMSV infection, CD4+ T cells contribute to the generation of virus-specific CD8+ T cell immunity within the lymphoid organs and are required to promote an inflammatory environment within the virus-infected tissue.
Vaccination with Recombinant Alphavirus or Immune-Stimulating Complex Antigen Against Respiratory Syncytial Virus
Authors: Chen Margaret , Hu Ke-Fei , Rozell Björn , Örvell Claes , Morein Bror , Liljeström Peter 
Published: April 2014

AbstractRespiratory syncytial virus (RSV) causes severe respiratory diseases in infants and young children. Inappropriate immunity to the virus can lead to disease enhancement upon subsequent infection. In this study, we have characterized the antiviral immunity elicited by the recombinant Semliki Forest virus (SFV) encoding the RSV fusion (F) and attachment (G) protein, and compared with that induced by the immune-stimulating complex (ISCOM)-incorporated FG proteins. Antiviral immunity against RSV elicited nasally or parentally by either of the immunogen having divergent profiles could reduce lung RSV titers upon challenge. However, resistance to RSV without disease enhancement was only observed in those vaccinated with SFV recombinants via nasal route. Presence of postvaccination pulmonary IFN-γ response to the H-2Kd-restricted T cell epitope (F85–93; KYKNAVTEL) was found to be associated with absence of enhanced pulmonary disease and goblet cell hyperplasia as well as reduced Th2-cytokine expression. This result demonstrates that the SFV recombinants can result in enhanced clearance of RSV without enhancing the RSV-associated disease, and underlines the importance in priming pulmonary MHC class I-restricted T cells when RSV FG-based vaccines are used.
Complement-Induced Impairment of Innate Immunity During Sepsis
Authors: Huber-Lang Markus S. , Younkin Ellen M. , Sarma J. Vidya , McGuire Stephanie R. , Lu Kristina T. , Guo Ren Feng , Padgaonkar Vaishalee A. , Curnutte John T. , Erickson Richard , Ward Peter A. 
Published: April 2014

AbstractThis study defines the molecular basis for defects in innate immunity involving neutrophils during cecal ligation/puncture (CLP)-induced sepsis in rats. Blood neutrophils from CLP rats demonstrated defective phagocytosis and defective assembly of NADPH oxidase, the latter being due to the inability of p47phox to translocate from the cytosol to the cell membrane of neutrophils after cell stimulation by phorbol ester (PMA). The appearance of these defects was prevented by in vivo blockade of C5a in CLP rats. In vitro exposure of neutrophils to C5a led to reduced surface expression of C5aR and defective assembly of NADPH oxidase, as defined by failure in phosphorylation of p47phox and its translocation to the cell membrane, together with failure in phosphorylation of p42/p44 mitogen-activated protein kinases. These data identify a molecular basis for defective innate immunity involving neutrophils during sepsis.
The Early IL-4 Response toLeishmania majorand the Resulting Th2 Cell Maturation Steering Progressive Disease in BALB/c Mice Are Subject to the Control of Regulatory CD4+CD25+ T Cells
Authors: Aseffa Abraham , Gumy Alain , Launois Pascal , MacDonald H. Robson , Louis Jacques A. , Tacchini-Cottier Fabienne 
Published: April 2014

AbstractSusceptibility and development of Th2 cells in BALB/c mice infected with Leishmania major result from early IL-4 production by Vβ4Vα8 CD4+ T cells in response to the Leishmania homolog of mammalian RACK1 Ag. A role for CD4+CD25+ regulatory T cells in the control of this early IL-4 production was investigated by depleting in vivo this regulatory T cell population. Depletion induced an increase in the early burst of IL-4 mRNA in the draining lymph nodes of BALB/c mice, and exacerbated the course of disease with higher levels of IL-4 mRNA and protein in their lymph nodes. We further showed that transfer of 107 BALB/c spleen cells that were depleted of CD4+CD25+ regulatory T cells rendered SCID mice susceptible to infection and allowed Th2 differentiation while SCID mice reconstituted with 107 control BALB/c spleen cells were resistant to infection with L. major and developed a Th1 response. Treatment with a mAb against IL-4 upon infection with L. major in SCID mice reconstituted with CD25-depleted spleen cells prevented the development of Th2 polarization and rendered them resistant to infection. These results demonstrate that CD4+CD25+ regulatory T cells play a role in regulating the early IL-4 mRNA and the subsequent development of a Th2 response in this model of infection.
Induction of CD8+ T Lymphocytes by Salmonella typhimurium Is Independent of Salmonella Pathogenicity Island 1-Mediated Host Cell Death
Authors: Wijburg Odilia L. C. , van Rooijen Nico , Strugnell Richard A. 
Published: April 2014

Abstract
Salmonella are intracellular bacterial pathogens that reside and replicate inside macrophages, and attenuated strains of Salmonella typhimurium can be used to deliver heterologous Ags for MHC class I and/or MHC class II-restricted presentation. Recently, it was shown that invasion of macrophages by S. typhimurium may result in the death of host macrophages via a mechanism harboring features of apoptotic and necrotic cell death. However, it is unknown whether this bacterial-induced host cell death affects immunity. In addition, it has been hypothesized that macrophage death following infection with S. typhimurium and subsequent uptake of apoptotic cells by APC are fundamental to the induction of CTL responses. In this study we investigated the in vivo induction of Ag-specific CD8+ T lymphocyte responses and compared CD8+ T lymphocyte responses elicited with S. typhimurium strains carrying a mutation in their invA gene, and therefore an inability to induce Salmonella pathogenicity island 1 (SPI-1)-mediated macrophage death, with responses elicited by an attenuated ΔaroAD strain. Ag-specific CD8+ T lymphocyte responses were analyzed using IFN-γ ELISPOT, tetramer binding, and in vivo and in vitro CTL assays. Our results showed that ΔaroAD and ΔaroADΔinvA induced comparable levels of Ag-specific CD8+ T lymphocyte responses as well as protective, Ag-specific B and CD4+ T lymphocyte immunity. Furthermore, experiments in macrophage-depleted mice showed that CD8+ T lymphocyte responses were effectively induced in the absence of macrophages. Together, our results imply that in this infection model, SPI-1-mediated cell death does not affect the immunological defense response and is not important for the induction of CD8+ T lymphocyte responses.