bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of NKT Cell Differentiation by Tissue-Specific Microenvironments
Authors: Yang Yang , Ueno Aito , Bao Min , Wang Zhongying , Im Jin Seon , Porcelli Steven , Yoon Ji-Won 
Published: April 2014

AbstractCD1d-restricted Vα14 NKT cells play an important role in both Th1- and Th2-type immune responses. To determine whether NKT cells develop two functionally distinct subsets that provoke different types of responses, we examined the phenotypes and cellular functions of NK1.1+ and DX5+ T cells. We found that both NK1.1+ and DX5+ T cells are CD1d-restricted Vα14 T cells with identical Ag specificities, phenotypes, tissue locations, and functions. Similar to the NK1.1 marker, the DX5 marker (CD49b) is expressed on mature NKT cells in both NK1.1 allele-positive and allele-negative strains. However, when NK1.1+ and DX5+ NKT cells isolated from different tissues were compared, we found that thymic and splenic NKT cells differed not only in their cytokine profiles, but also in their phenotype and requirements for costimulatory signals. Thymic NKT cells displayed the phenotype of activated T cells and could be fully activated by TCR ligation. In contrast, splenic NKT cells displayed the phenotype of memory T cells and required a costimulatory signal for activation. Furthermore, the function and phenotype of thymic and splenic NKT cells were modulated by APCs from various tissues that expressed different levels of costimulatory molecules. Modulation of NKT cell function and differentiation may be mediated by synergic effects of costimulatory molecules on the surface of APCs. The results of the present study suggest that the costimulatory signals of tissue-specific APCs are key factors for NKT cell differentiation, and these signals cannot be replaced by anti-CD28 or anti-CD40 ligand Abs.
Function of Bruton’s Tyrosine Kinase during B Cell Development Is Partially Independent of Its Catalytic Activity
Authors: Middendorp Sabine , Dingjan Gemma M. , Maas Alex , Dahlenborg Katarina , Hendriks Rudolf W. 
Published: April 2014

AbstractThe Tec family member Bruton’s tyrosine kinase (Btk) is a cytoplasmic protein tyrosine kinase that transduces signals from the pre-B and B cell receptor (BCR). Btk is involved in pre-B cell maturation by regulating IL-7 responsiveness, cell surface phenotype changes, and the activation of λ L chain gene rearrangements. In mature B cells, Btk is essential for BCR-mediated proliferation and survival. Upon BCR stimulation, Btk is transphosphorylated at position Y551, which promotes its catalytic activity and subsequently results in autophosphorylation at position Y223 in the Src homology 3 domain. To address the significance of Y223 autophosphorylation and the requirement of enzymatic activity for Btk function in vivo, we generated transgenic mice that express the autophosphorylation site mutant Y223F and the kinase-inactive mutant K430R, respectively. We found that Y223 autophosphorylation was not required for the regulation of IL-7 responsiveness and cell surface phenotype changes in differentiating pre-B cells, or for peripheral B cell differentiation. However, expression of the Y223F-Btk transgene could not fully rescue the reduction of λ L chain usage in Btk-deficient mice. In contrast, transgenic expression of kinase-inactive K430R-Btk completely reconstituted λ usage in Btk-deficient mice, but the defective modulation of pre-B cell surface markers, peripheral B cell survival, and BCR-mediated NF-κB induction were partially corrected. From these findings, we conclude that: 1) autophosphorylation at position Y223 is not essential for Btk function in vivo, except for regulation of λ L chain usage, and 2) during B cell development, Btk partially acts as an adapter molecule, independent of its catalytic activity.
OX40-Mediated Memory T Cell Generation Is TNF Receptor-Associated Factor 2 Dependent
Authors: Prell Rodney A. , Evans Dean E. , Thalhofer Colin , Shi Tom , Funatake Castle , Weinberg Andrew D. 
Published: April 2014

AbstractTumor necrosis factor receptor-associated factor 2 (TRAF2), an adapter protein that associates with the cytoplasmic tail of OX40, may play a critical role in OX40-mediated signal transduction. To investigate the in vivo role of TRAF2 in OX40-mediated generation of Ag-specific memory T cells, we bred OVA-specific TCR transgenic mice to TRAF2 dominant-negative (TRAF2 DN) mice. Following Ag stimulation and OX40 engagement of TRAF2 DN T cells in vivo, the number of long-lived OVA-specific T cells and effector T cell function was dramatically reduced when compared with wild-type T cells. We also demonstrate that CTLA-4 is down-regulated following OX40 engagement in vivo and the OX40-specific TRAF2 DN defect was partially overcome by CTLA-4 blockade in vivo. The data provide evidence that TRAF2 is linked to OX40-mediated memory T cell expansion and survival, and point to the down-regulation of CTLA-4 as a possible control element to enhance early T cell expansion through OX40 signaling.
Inhibition of NF-κB Activation and Its Target Genes by Heparin-Binding Epidermal Growth Factor-Like Growth Factor
Authors: Mehta Veela B. , Besner Gail E. 
Published: April 2014

AbstractMany cells upon injury mount extensive, compensatory responses that increase cell survival; however, the intracellular signals that regulate these responses are not completely understood. Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has been implicated as a cytoprotective agent. We have previously demonstrated that pretreatment of human intestinal epithelial cells with HB-EGF significantly decreased cytokine-induced activation of inducible NO synthase mRNA expression and NO production and protected the cells from apoptosis and necrosis. However, the mechanisms by which HB-EGF exerts these effects are not known. Here we show that cytokine exposure (IL-1β and IFN-γ) induced NF-κB activation and IL-8 and NO production in DLD-1 cells. Transient expression of a dominant negative form of IκBα decreased NO production, suggesting that the cytokines stimulated NO production in part through activation of NF-κB. HB-EGF dramatically suppressed NF-κB activity and IL-8 release and decreased NO production in cells pretreated with HB-EGF. HB-EGF blocked NF-κB activation by inhibiting IκB kinase activation and IκB phosphorylation and degradation, thus interfering with NF-κB nuclear translocation, DNA-binding activity, and NF-κB-dependent transcriptional activity. The data demonstrate that HB-EGF decreases inflammatory cytokine and NO production by interfering with the NF-κB signaling pathway. Inhibition of NF-κB may represent one of the mechanisms by which HB-EGF exerts its potent anti-inflammatory and cytoprotective effects.
Activation of Antigen-Specific CD8 T Cells Results in Minimal Killing of Bystander Bacteria
Authors: Jiang Jiu , Zenewicz Lauren A. , San Mateo Lani R. , Lau Lisa L. , Shen Hao 
Published: April 2014

AbstractMemory CD8 T cells play a critical role in protective immunity against intracellular pathogens. In addition to their ability to specifically recognize and lyse infected targets, activated CD8 T cells secrete cytokines that induce phagocytic cells to engulf and kill bacterial pathogens. In this study, we asked whether activation of Ag-specific CD8 T cells results in nonspecific killing of bystander bacteria during a mixed infection. Mice with epitope-specific memory CD8 T cells were coinfected with two isogenic strains of recombinant Listeria monocytogenes that differ in the cognate epitope. Recall responses by epitope-specific CD8 T cells rapidly inhibited the growth of epitope-bearing bacteria, impeding the course of infection within 6 h after challenge. This rapid inhibition was highly specific and did not affect the growth of coinfecting bacteria without the epitope. CTL recall did not enhance activation of innate immune cells, as evidenced by the absence of inducible NO synthase production in infectious foci. Our observations demonstrate the remarkable specificity of the bactericidal mechanisms of CTL and reveal the possibility for escape mutants to prevail in the hostile environment of a specific immune response. This implication has a bearing on subunit vaccine design strategies and understanding failure of immunization against bacterial infection.
Inhibition of Th1- and Th2-Mediated Airway Inflammation by the Sphingosine 1-Phosphate Receptor Agonist FTY720
Authors: Sawicka Elzbieta , Zuany-Amorim Claudia , Manlius Corinne , Trifilieff Alexandre , Brinkmann Volker , Kemeny David M. , Walker Christoph 
Published: April 2014

Abstract
The sphingosine 1-phosphate receptor agonist FTY720 is a novel immunomodulator that sequesters lymphocytes in secondary lymphoid organs and thereby prevents their migration to sites of inflammation. However, there is currently no information available on whether this drug affects Th1 or Th2 cell-mediated lung-inflammatory responses. The effect of FTY720 was therefore investigated in a murine airway inflammation model using OVA-specific, in vitro differentiated, and adoptively transferred Th1 and Th2 cells. Both Th1 and Th2 cells express a similar pattern of FTY720-targeted sphingosine 1-phosphate receptors. The OVA-induced Th1-mediated airway inflammation characterized by increased numbers of lymphocytes and neutrophils in bronchoalveolar lavage fluid was significantly inhibited by oral FTY720 treatment. Similarly, FTY720 suppressed the Th2 cell-induced bronchoalveolar lavage fluid eosinophilia and the infiltration of T lymphocytes and eosinophils into the bronchial tissue. Moreover, the Ag-induced bronchial hyperresponsiveness to inhaled metacholine was almost completely blocked. The inhibitory effect of FTY720 on airway inflammation, induction of bronchial hyperresponsiveness, and goblet cell hyperplasia could be confirmed in an actively Ag-sensitized murine asthma model, clearly indicating that Th2 cell-driven allergic diseases such as asthma could benefit from such treatment.
Immune Modulation in Multiple Sclerosis Patients Treated with the Pregnancy Hormone Estriol
Authors: Soldan Samantha S. , Retuerto Ana Isabel Alvarez , Sicotte Nancy L. , Voskuhl Rhonda R. 
Published: April 2014

AbstractThe protective effect of pregnancy on putative Th1-mediated autoimmune diseases, such as multiple sclerosis and rheumatoid arthritis, is associated with a Th1 to Th2 immune shift during pregnancy. The hormone estriol increases during pregnancy and has been shown to ameliorate experimental autoimmune encephalomyelitis and collagen-induced arthritis. In addition, estrogens induce cytokine changes consistent with a Th1 to Th2 shift when administered in vitro to human immune cells and in vivo to mice. In a pilot trial, oral estriol treatment of relapsing remitting multiple sclerosis patients caused significant decreases in enhancing lesions on brain magnetic resonance imaging. Here, the immunomodulatory effects of oral estriol therapy were assessed. PBMCs collected longitudinally during the trial were stimulated with mitogens, recall Ags, and glatiramer acetate. Cytokine profiles of stimulated PBMCs were determined by intracellular cytokine staining (IL-5, IL-10, IL-12 p40, TNF-α, and IFN-γ) and cytometric bead array (IL-2, IL-4, IL-5, IL-10, TNF-α, and IFN-γ). Significantly increased levels of IL-5 and IL-10 and decreased TNF-α were observed in stimulated PBMC isolated during estriol treatment. These changes in cytokines correlated with reductions of enhancing lesions on magnetic resonance imaging in relapsing remitting multiple sclerosis. The increase in IL-5 was primarily due to an increase in CD4+ and CD8+ T cells, the increase in IL-10 was primarily due to an increase in CD64+ monocytes/macrophages with some effect in T cells, while the decrease in TNF-α was primarily due to a decrease in CD8+ T cells. Further study of oral estriol therapy is warranted in Th1-mediated autoimmune diseases with known improvement during pregnancy.
Cutting Edge: Stimulation with the Cognate Self-Antigen Induces Expression of the Ly49A Receptor on Self-Reactive T Cells Which Modulates Their Responsiveness
Authors: Saurer Leslie , Seibold Inge , Vallan Claudio , Held Werner , Mueller Christoph 
Published: April 2014

Abstract
NK cell self-tolerance is maintained by inhibitory receptors specific for MHC class I molecules. Inhibitory NK receptors are also expressed on memory CD8 T cells but their biological relevance on T cells is unclear. In this study, we describe the expression of the Ly49A receptor on a subset of autoreactive T cells which persist in mice double-transgenic for the lymphocytic choriomeningitis virus-derived peptide gp33 and a TCRαβ specific for the gp33. No Ly49A-expressing cells are found in TCRαβ single-transgenic mice, indicating that the presence of the autoantigen is required for Ly49A induction. Direct evidence for an Ag-specific initiation of Ly49A expression has been obtained in vitro after stimulation of autoreactive TCRαβ T cells with the cognate self-Ag. This expression of Ly49A substantially reduces Ag-specific activation of autoreactive T cells. These findings thus suggest that autoantigen-specific induction of inhibitory NK cell receptors on T cells may contribute to peripheral self-tolerance.
Cutting Edge: A Potent Adjuvant Effect of Ligand to Receptor Activator of NF-κB Gene for Inducing Antigen-Specific CD8+ T Cell Response by DNA and Viral Vector Vaccination
Authors: Miyahira Yasushi , Akiba Hisaya , Katae Masaharu , Kubota Kaori , Kobayashi Seiki , Takeuchi Tsutomu , García-Sastre Adolfo , Fukuchi Yoshinosuke , Okumura Ko , Yagita Hideo , Aoki Takashi 
Published: April 2014

Abstract
The ligand to receptor activator of NF-κB (RANK-L)/RANK interaction has been implicated in CD40 ligand/CD40-independent T cell priming by dendritic cells. In this report, we show that the coadministration of the RANK-L gene with a Trypanosoma cruzi gene markedly enhances the induction of Trypanosoma Ag-specific CD8+ T cells and improves the DNA vaccine efficacy. A similarly potent adjuvant effect of the RANK-L gene on the induction of Ag-specific CD8+ T cells was also observed when recombinant influenza virus expressing murine malaria Ag was used as an immunogen. In contrast, the coadministration of the CD40L gene was not effective in these systems. Our results demonstrated, for the first time, the potent immunostimulatory effect of the RANK-L gene to improve the CD8+ T cell-mediated immunity against infectious agents.
B Lymphocyte Development in Rabbit: Progenitor B Cells and Waning of B Lymphopoiesis
Authors: Jasper Paul J. , Zhai Shi-Kang , Kalis Susan L. , Kingzette Mae , Knight Katherine L. 
Published: April 2014

AbstractIn mammals that use gut-associated lymphoid tissues for expansion and somatic diversification of the B cell repertoire, B lymphopoiesis occurs early in ontogeny and does not appear to continue throughout life. In these species, including sheep, rabbit, and cattle, little is known about the pathway of B cell development and the time at which B lymphopoiesis wanes. We examined rabbit bone marrow by immunofluorescence with anti-CD79a and anti-μ and identified both proB and preB cells. The proB cells represent the vast majority of B-lineage cells in the bone marrow at birth and by incorporation of 5-bromo-2′-deoxyuridine, they appear to be a dynamic population. PreB cells reach maximum levels in the bone marrow at 3 wk of age, and B cells begin to accumulate at 7 wk of age. We cloned two VpreB and one λ5 gene and demonstrated that they are expressed within B-lineage cells in bone marrow. VpreB and λ5 coimmunoprecipitated with the μ-chain in lysates of 293T cells transfected with VpreB, λ5, and μ, indicating that VpreB, λ5, and μ-chains associate in a preB cell receptor-like complex. By 16 wk of age, essentially no proB or preB cells are found in bone marrow and by PCR amplification, B cell recombination excision circles were reduced 200-fold. By 18 mo of age, B cell recombination excision circles were reduced 500- to 1000-fold. We suggest that B cell development in the rabbit occurs primarily through the classical, or ordered, pathway and show that B lymphopoiesis is reduced over 99% by 16 wk of age.
Neuronal Repellent Slit2 Inhibits Dendritic Cell Migration and the Development of Immune Responses
Authors: Guan Hongbing , Zu Guorui , Xie Yi , Tang Hao , Johnson Martin , Xu Xiaochun , Kevil Christophe , Xiong Wen-Cheng , Elmets Craig , Rao Yi , Wu Jane Y. , Xu Hui 
Published: April 2014

Abstract
One of the essential functions of dendritic cells is to take up Ags in peripheral tissues and migrate into secondary lymphoid organs to present Ags to lymphocytes for the induction of immune responses. Although many studies have demonstrated that the migration of dendritic cells is closely associated with the development of immune responses, little is known about factors that inhibit dendritic cell migration and control the extent of immune responses to Ag stimulation. We show that Slit2, a neuronal repellent factor, is up-regulated in the skin by allergen sensitization and down-regulates the migration of Langerhans cells. The effect is mediated by direct interaction of Slit2 with cells that express a Slit-specific receptor, Robo1. Slit2-mediated inhibition of Langerhans cell migration results in suppression of contact hypersensitivity responses. These findings provide insights into a novel mechanism by which Slit2 functions as an anti-inflammatory factor for the initiation of immune responses.
CD43 Modulates Severity and Onset of Experimental Autoimmune Encephalomyelitis
Authors: Ford Mandy L. , Onami Thandi M. , Sperling Anne I. , Ahmed Rafi , Evavold Brian D. 
Published: April 2014

Abstract
Experimental autoimmune encephalomyelitis (EAE) is a mouse model of multiple sclerosis characterized by infiltration of activated CD4+ T lymphocytes into tissues of the CNS. This study investigated the role of CD43 in the induction and progression of EAE. Results demonstrate that CD43-deficient mice have reduced and delayed clinical and histological disease severity relative to CD43+/+ mice. This reduction was characterized by decreased CD4+ T cell infiltration of the CNS of CD43−/− mice but similar numbers of Ag-specific T cells in the periphery, suggesting a defect in T cell trafficking to the CNS. The absence of CD43 also affected cytokine production, as myelin oligodendrocyte glycoprotein (MOG) 35–55-specific CD43−/− CD4+ T cells exhibited reduced IFN-γ and increased IL-4 production. CD43−/− CD4+ MOG-primed T cells exhibited reduced encephalitogenicity relative to CD43+/+ cells upon adoptive transfer into naive recipients. These results suggest a role for CD43 in the differentiation and migration of MOG35–55-specific T cells in EAE, and identify it as a potential target for therapeutic intervention.
Proinflammatory Cytokines Dominate the Early Immune Response to Filarial Parasites
Authors: Babu Subash , Nutman Thomas B. 
Published: April 2014

Abstract
Although the early human immune response to the infective-stage larvae (L3) of Brugia malayi has not been well-characterized in vivo (because of the inability to determine the precise time of infection), the consensus has been that it must involve a predominant Th2 environment. We have set up an in vitro system to study this early immune response by culturing PBMC from unexposed individuals with live L3 of B. malayi. After 24 h of culture, T cell responses were examined by flow cytometry and by quantitative real-time RT-PCR for multiple cytokines. T cells were activated early following exposure to L3 as indicated by up-regulation of surface markers CD69 and CD71. The frequency of T cells expressing proinflammatory Th1 cytokines (IFN-γ, TNF-α, GM-CSF, IL-1α, and IL-8) but not Th2 cytokines (IL-4, IL-5, IL-6, IL-10, and IL-13) was significantly increased in response to L3. This T cell response occurred in both the CD4 and CD8 T cell compartment and was restricted to the effector/memory pool (CD45RO+). This T cell response was not due to LPS activity from the parasite or from its endosymbiont, Wolbachia; moreover, it required the presence of APC as well as direct contact with live L3. Real-time RT-PCR analysis of multiple cytokines in the T cells confirmed the increased expression of proinflammatory Th1 cytokines. Up-regulation of these cytokines suggests that the primary immune response to the live infective stage of the parasite is not predominantly Th2 in nature but rather dominated by a proinflammatory response.
Mycobacterium aviumInhibition of IFN-γ Signaling in Mouse Macrophages: Toll-Like Receptor 2 Stimulation Increases Expression of Dominant-Negative STAT1β by mRNA Stabilization
Authors: Alvarez Gail R. , Zwilling Bruce S. , Lafuse William P. 
Published: April 2014

AbstractMycobacterial infections of macrophages have been shown to inhibit the ability of the macrophage to respond to IFN-γ. We previously reported that Mycobacterium avium infection of mouse macrophages decreases IFN-γ-induced STAT1 tyrosine phosphorylation and STAT1 DNA binding. Because macrophages respond to M. avium through Toll-like receptor 2 (TLR2), we determined whether TLR2 stimulation inhibits the response to IFN-γ. Treatment of mouse RAW264.7 macrophages with TLR2 agonists inhibited the induction of IFN-γ-inducible genes by IFN-γ. In contrast to M. avium infection, TLR2 agonists did not inhibit the IFN-γ induction of DNA-binding activity of STAT1 and the tyrosine phosphorylation of STAT1α. Instead, IFN-γ induction of RAW264.7 cells treated with TLR2 agonists resulted in an increase in the tyrosine phosphorylation of the dominant-negative STAT1β. TLR2 stimulation of RAW264.7 cells increased both STAT1β protein and mRNA expression, suggesting that the increased STAT1β phosphorylation results from increased STAT1β expression. Because STAT1α and STAT1β mRNA have different 3′ untranslated regions, and 3′ untranslated regions can regulate mRNA stability, we examined the effects of TLR2 stimulation on mRNA stability. TLR2 stimulation of RAW264.7 cells increased the stability of STAT1β mRNA, while not affecting the stability of STAT1α mRNA. The ability of STAT1β to function as a dominant negative was confirmed by overexpression of STAT1β in RAW264.7 macrophages by transient transfection, which inhibited IFN-γ-induced gene expression. These findings suggest that M. avium infection of mouse macrophages inhibits IFN-γ signaling through a TLR2-dependent increase in STAT1β expression by mRNA stablization and a TLR2-independent inhibition of STAT1 tyrosine phosphorylation.
Surface Translocation of Pactolus Is Induced by Cell Activation and Death, but Is Not Required for Neutrophil Migration and Function
Authors: Garrison Sean , Hojgaard Andrias , Margraf Rebecca , Weis Janis J. , Weis John H. 
Published: April 2014

Abstract
Pactolus is a cell surface protein expressed by murine neutrophils. Pactolus is similar to the β integrins, except it lacks a functional metal ion-dependent adhesion site domain and is expressed without an α-chain partner. The majority of the Pactolus protein is held within the cell in dense granules in a highly glycosylated form. This intracellular form of Pactolus can be released to the cell surface following inflammatory activation or ligation of Pactolus on the cell surface. In addition, intracellular Pactolus translocates to the neutrophil surface following induction of apoptosis. Neutrophil activation studies suggest that Pactolus does not serve as an activating or phagocytic receptor for the neutrophil. To further define the function of Pactolus, a Pactolus-null mouse was generated. Pactolus-deficient animals mature appropriately and possess normal numbers of neutrophils, display appropriate migration into sites of inflammation, and combat introduced infections efficiently. These data suggest that Pactolus does not function as a neutrophil phagocytic or adhesion receptor, but may instead serve as a sugar-bearing ligand for lectin recognition by other cells.