bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of Vesicle-Associated Membrane Protein-2, Through Q-SolubleN-Ethylmaleimide-Sensitive Factor Attachment Protein Receptor/R-SolubleN-Ethylmaleimide-Sensitive Factor Attachment Protein Receptor Interaction, in the Exocytosis of Specific and Tertiary Granules of Human Neutrophils
Authors: Mollinedo Faustino , Martín-Martín Belén , Calafat Jero , Nabokina Svetlana M. , Lazo Pedro A. 
Published: April 2014

AbstractWe have examined the role of the R-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) synaptobrevin-2/vesicle-associated membrane protein (VAMP)-2 in neutrophil exocytosis. VAMP-2, localized in the membranes of specific and gelatinase-containing tertiary granules in resting human neutrophils, resulted translocated to the cell surface following neutrophil activation under experimental conditions that induced exocytosis of specific and tertiary granules. VAMP-2 was also found on the external membrane region of granules docking to the plasma membrane in activated neutrophils. Specific Abs against VAMP-2 inhibited Ca2+ and GTP-γ-S-induced exocytosis of CD66b-enriched specific and tertiary granules, but did not affect exocytosis of CD63-enriched azurophilic granules, in electropermeabilized neutrophils. Tetanus toxin disrupted VAMP-2 and inhibited exocytosis of tertiary and specific granules. Activation of neutrophils led to the interaction of VAMP-2 with the plasma membrane Q-SNARE syntaxin 4, and anti-syntaxin 4 Abs inhibited exocytosis of specific and tertiary granules in electropermeabilized neutrophils. Immunoelectron microscopy showed syntaxin 4 on the plasma membrane contacting with docked granules in activated neutrophils. These data indicate that VAMP-2 mediates exocytosis of specific and tertiary granules, and that Q-SNARE/R-SNARE complexes containing VAMP-2 and syntaxin 4 are involved in neutrophil exocytosis.
CpG DNA Induces Self and Cross-Hyporesponsiveness of RAW264.7 Cells in Response to CpG DNA and Lipopolysaccharide: Alterations in IL-1 Receptor-Associated Kinase Expression
Authors: Yeo Seon-Ju , Yoon Jae-Geun , Hong Soon-Cheol , Yi Ae-Kyung 
Published: April 2014

AbstractExposure of macrophages to LPS induces a state of hyporesponsiveness to subsequent challenge with LPS. It has not been known whether previous exposure to CpG DNA induces a similar suppressive response to subsequent stimulation with CpG DNA. In the present study, we demonstrate that pretreatment with CpG DNA induces suppression of cytokine release in a murine macrophage-like cell RAW264.7 in response to subsequent challenge by CpG DNA. Additionally, CpG DNA-mediated activation of mitogen-activated protein kinases, including c-Jun NH2-terminal kinase, extracellular signal-regulated kinase, and p38, and activation of transcription factors AP-1, CREB, NF-κB, and STAT1 are greatly suppressed in the cells pre-exposed to CpG DNA. Pretreatment with CpG DNA also partially inhibited LPS-mediated production of cytokines and activation of mitogen-activated protein kinases and transcription factors. Neither LPS nor CpG DNA treatment inhibited Toll-like receptor 4, MD2, Toll-like receptor 9, myeloid differentiation factor 88, Toll/IL-1R domain-containing adaptor protein, Tollip, and TNF-α receptor-associated factor 6 expression. Interestingly, CpG DNA or LPS stimulation led to the inhibition of IL-1R-associated kinase expression. These results indicate that CpG DNA-induced refractory of RAW264.7 cells may be, at least in part, due to suppressed IL-1R-associated kinase expression.
Regulation of Cyclooxygenase-2 Expression by Macrophages in Response to Double-Stranded RNA and Viral Infection
Authors: Steer Sarah A. , Moran Jason M. , Maggi Leonard B. , Buller R. Mark L. , Perlman Harris , Corbett John A. 
Published: April 2014

AbstractIn this study the regulation of macrophage expression of cyclooxygenase-2 (COX-2) in response to dsRNA and virus infection was examined. Treatment of RAW 264.7 macrophages with dsRNA results in COX-2 mRNA accumulation and protein expression and the production of PGE2. Similar to dsRNA, encephalomyocarditis virus (EMCV) infection of RAW 264.7 cells stimulates COX-2 expression and PGE2 accumulation. The dsRNA-dependent protein kinase (PKR), which has been shown to participate in the regulation of gene expression in response to dsRNA and virus infection, does not appear to participate in the regulation of COX-2 expression by macrophages. Expression of dominant negative mutants of PKR in RAW 264.7 cells fails to attenuate dsRNA- and EMCV-induced COX-2 expression or PGE2 production. Furthermore, dsRNA and EMCV stimulate COX-2 expression and PGE2 accumulation to similar levels in macrophages isolated from wild-type and PKR-deficient mice. Recently, a novel PKR-independent role for the calcium-independent phospholipase A2 (iPLA2) in the regulation of inducible NO synthase expression by macrophages in response to virus infection has been identified. The selective iPLA2 suicide substrate inhibitor bromoenol lactone prevents dsRNA- and EMCV-stimulated inducible NO synthase expression; however, bromoenol lactone does not attenuate dsRNA- or EMCV-induced COX-2 expression by macrophages. In contrast, inhibition of NF-κB activation prevents dsRNA-stimulated COX-2 expression and PGE2 accumulation by macrophages. These findings indicate that virus infection and treatment with dsRNA stimulate COX-2 expression by a mechanism that requires the activation of NF-κB and that is independent of PKR or iPLA2 activation.
Selective IκB Kinase Expression in Airway Epithelium Generates Neutrophilic Lung Inflammation
Authors: Sadikot Ruxana T. , Han Wei , Everhart M. Brett , Zoia Ornella , Peebles R. Stokes , Jansen E. Duco , Yull Fiona E. , Christman John W. , Blackwell Timothy S. 
Published: April 2014

AbstractTo determine whether NF-κB activation is sufficient to generate lung inflammation in vivo, we selectively expressed a constitutively active form of IκB kinase 1 (cIKK1) or IκB kinase 2 (cIKK2) in airway epithelium. After intratracheal administration of adenoviral vectors expressing cIKK1 or cIKK2 to transgenic reporter mice that express Photinus luciferase under the control of an NF-κB-dependent promoter, we detected significantly increased luciferase activity over time (up to 96 h). Compared with control mice treated with adenoviral vectors expressing β-galactosidase, lung bioluminescence and tissue luciferase activity were increased in NF-κB reporter mice treated with adenovirus (Ad)-cIKK1 or Ad-cIKK2. NF-κB activation in lungs of Ad-cIKK1- and Ad-cIKK2-treated mice was confirmed by immunoblots for RelA and EMSA from lung nuclear protein extracts. Mice treated with Ad-cIKK1 or Ad-cIKK2 showed induction of mRNA expression of several chemokines and cytokines in lung tissue. In lung lavage fluid, mice treated with Ad-cIKK1 or Ad-cIKK2 showed elevated concentrations of NF-κB-dependent chemokines macrophage-inflammatory protein 2 and KC and increased numbers of neutrophils. Coadministration of adenoviral vectors expressing a transdominant inhibitor of NF-κB with Ad-cIKK1 or Ad-cIKK2 resulted in abrogated NF-κB activation and other parameters of lung inflammation, demonstrating that the observed inflammatory effects of Ad-cIKK1 and Ad-cIKK2 were dependent on NF-κB activation by these kinases. These data show that selective expression of IκB kinases in airway epithelium results in NF-κB activation, inflammatory mediator production, and neutrophilic lung inflammation. Therapies targeted to NF-κB in lung epithelium may be beneficial in treating inflammatory lung diseases.
CD8αβ T Cells Are Not Essential to the Pathogenesis of Arthritis or Colitis in HLA-B27 Transgenic Rats
Authors: May Ekkehard , Dorris Martha L. , Satumtira Nimman , Iqbal Imran , Rehman Muhammad I. , Lightfoot Ellis , Taurog Joel D. 
Published: April 2014

AbstractThe class I MHC allele HLA-B27 is highly associated with the human spondyloarthropathies, but the basis for this association remains poorly understood. Transgenic rats with high expression of HLA-B27 develop a multisystem inflammatory disease that includes arthritis and colitis. To investigate whether CD8αβ T cells are needed in this disease, we depleted these cells in B27 transgenic rats before the onset of disease by adult thymectomy plus short-term anti-CD8α mAb treatment. This treatment induced profound, sustained depletion of CD8αβ T cells, but failed to suppress either colitis or arthritis. To address the role of CD8α+β− cells, we studied four additional groups of B27 transgenic rats treated with: 1) continuous anti-CD8α mAb, 2) continuous isotype-matched control mAb, 3) the thymectomy/pulse anti-CD8α regimen, or 4) no treatment. Arthritis occurred in ∼40% of each group, but was most significantly reduced in severity in the anti-CD8α-treated group. In addition to CD8αβ T cells, two sizeable CD8α+β− non-T cell populations were also reduced by the anti-CD8α treatment: 1) NK cells, and 2) a CD4+CD8+CD11b/c+CD161a+CD172a+ monocyte population that became expanded in diseased B27 transgenic rats. These data indicate that HLA-B27-retricted CD8+ T cells are unlikely to serve as effector cells in the transgenic rat model of HLA-B27-associated disease, in opposition to a commonly invoked hypothesis concerning the role of B27 in the spondyloarthropathies. The data also suggest that one or more populations of CD8α+β− non-T cells may play a role in the arthritis that occurs in these rats.
Cutting Edge: Homeostatic Proliferation of Peripheral T Lymphocytes Is Regulated by Clonal Competition
Authors: Troy Amy E. , Shen Hao 
Published: April 2014

AbstractHomeostatic proliferation functions to maintain peripheral T cell numbers and is regulated by cytokines. In this study, we provide evidence that T cell homeostasis is also regulated by clonal competition. Naive polyclonal T cells divided when transferred to TCR transgenic hosts, as did monoclonal T cells when transferred to TCR transgenic hosts of differing clonotype. However, T cells did not divide in hosts of identical clono-type. Transgenic T cell proliferation was inhibited in irradiated hosts of the same clonotype, while cotransferred nontransgenic T cells proliferated extensively. These results show that clonal competition is a component of homeostasis that may contribute to selection of the peripheral T cell repertoire.
Hypoxia Regulates Expression and Activity of Kv1.3 Channels in T Lymphocytes: A Possible Role in T Cell Proliferation
Authors: Conforti Laura , Petrovic Milan , Mohammad Dina , Lee Susan , Ma Qing , Barone Sharon , Filipovich Alexandra H. 
Published: April 2014

AbstractT lymphocytes are exposed to hypoxia during their development and also when they migrate to hypoxic pathological sites such as tumors and wounds. Although hypoxia can affect T cell development and function, the mechanisms by which immune cells sense and respond to changes in O2-availability are poorly understood. K+ channels encoded by the Kv1.3 subtype of the voltage-dependent Kv1 gene family are highly expressed in lymphocytes and are involved in the control of membrane potential and cell function. In this study, we investigate the sensitivity of Kv1.3 channels to hypoxia in freshly isolated human T lymphocytes and leukemic Jurkat T cells. Acute exposure to hypoxia (20 mmHg, 2 min) inhibits Kv1.3 currents in both cell types by 20%. Prolonged exposure to hypoxia (1% O2 for 24 h) selectively decreases Kv1.3 protein levels in Jurkat T cells by 47%, but not Kvβ2 and SK2 Ca-activated K+ channel subunit levels. The decrease in Kv1.3 protein levels occurs with no change in Kv1.3 mRNA expression and is associated with a significant decrease in K+ current density. A decrease in Kv1.3 polypeptide levels similar to that obtained during hypoxia is produced by Kv1.3 channel blockage. Our results indicate that hypoxia produces acute and long-term inhibition of Kv1.3 channels in T lymphocytes. This effect could account for the inhibition of lymphocyte proliferation during hypoxia. Indeed, we herein present evidence showing that hypoxia selectively inhibits TCR-mediated proliferation and that this inhibition is associated with a decrease in Kv1.3 proteins.
Program Death-1 Engagement Upon TCR Activation Has Distinct Effects on Costimulation and Cytokine-Driven Proliferation: Attenuation of ICOS, IL-4, and IL-21, But Not CD28, IL-7, and IL-15 Responses
Authors: Bennett Frann , Luxenberg Deborah , Ling Vincent , Wang I-Ming , Marquette Kim , Lowe David , Khan Nighat , Veldman Geertruida , Jacobs Kenneth A. , Valge-Archer Viia E. , Collins Mary , Carreno Beatriz M. 
Published: April 2014

AbstractThe program death 1 (PD-1) receptor and its ligands, PD-1 ligand (PD-L)1 and PD-L2, define a novel regulatory pathway with potential inhibitory effects on T, B, and monocyte responses. In the present study, we show that human CD4+ T cells express PD-1, PD-L1, and PD-L2 upon activation, and Abs to the receptor can be agonists or antagonists of the pathway. Under optimal conditions of stimulation, ICOS but not CD28 costimulation can be prevented by PD-1 engagement. IL-2 levels induced by costimulation are critical in determining the outcome of the PD-1 engagement. Thus, low to marginal IL-2 levels produced upon ICOS costimulation account for the greater sensitivity of this pathway to PD-1-mediated inhibition. Interestingly, exogenous IL-2, IL-7, and IL-15 but not IL-4 and IL-21 can rescue PD-1 inhibition, suggesting that among these cytokines only those that activate STAT5 can rescue PD-1 inhibition. As STAT5 has been implicated in the maintenance of IL-2Rα expression, these results suggest that IL-7 and IL-15 restore proliferation under conditions of PD-1 engagement by enhancing high-affinity IL-2R expression and hence, IL-2 responsiveness.
Either IL-2 or IL-12 Is Sufficient to Direct Th1 Differentiation by Nonobese Diabetic T Cells
Authors: Zhou Weisong , Zhang Feng , Aune Thomas M. 
Published: April 2014

AbstractTh cell differentiation from naive precursors is a tightly controlled process; the most critical differentiation factor is the action of the driving cytokine: IL-12 for Th1 development, IL-4 for Th2 development. We found that CD4+ T cells from nonobese diabetic mice spontaneously differentiate into IFN-γ-producing Th1 cells in response to polyclonal TCR stimulation in the absence of IL-12 and IFN-γ. Instead, IL-2 was necessary and sufficient to direct T cell differentiation to the Th1 lineage by nonobese diabetic CD4+ T cells. Its ability to direct Th1 differentiation of both naive and memory CD4+ T cells was clearly uncoupled from its ability to stimulate cell division. Autocrine IL-2-driven Th1 differentiation of nonobese diabetic T cells may represent a genetic liability that favors development of IFN-γ-producing autoreactive T cells.
Down-Modulation of Responses to Type I IFN Upon T Cell Activation
Authors: Dondi Elisabetta , Rogge Lars , Lutfalla Georges , Uzé Gilles , Pellegrini Sandra 
Published: April 2014

Abstract
The immunomodulatory role of type I IFNs (IFN-α/β) in shaping T cell responses has been demonstrated, but the direct effects of IFN on T cells are still poorly characterized. Particularly, because IFN exert an antiproliferative activity, it remains elusive how the clonal expansion of effector T cells can paradoxically occur in the event of an infection when large amounts of IFN are produced. To address this issue, we have studied the effects of type I IFN in an in vitro differentiation model of human primary CD4+ T cells. We found that IFN-α treatment of resting naive T cells delayed their entry into the cell cycle after TCR triggering. Conversely, the ongoing expansion of effector T cells was not inhibited by the presence of IFN. Moreover, activated T cells showed a significantly reduced induction of IFN-sensitive genes, as compared with naive precursors, and this decline occurred independently of subset-specific polarization. The residual type I IFN response measured in activated T cells was found sufficient to inhibit replication of the vesicular stomatitis virus. Our data suggest that the activation of T lymphocytes includes regulatory processes that restrain the transcriptional response to IFN and allow the proliferation of effector cells in the presence of this cytokine.
Protection Against Experimental Autoimmune Encephalomyelitis Generated by a Recombinant Adenovirus Vector Expressing the Vβ8.2 TCR Is Disrupted by Coadministration with Vectors Expressing Either IL-4 or -10
Authors: Braciak Todd A. , Pedersen Brian , Chin Judy , Hsiao Clay , Ward E. Sally , Maricic Igor , Jahng Alex , Graham Frank L. , Gauldie Jack , Sercarz Eli E. , Kumar Vipin 
Published: April 2014

AbstractAdenovirus vectors are increasingly being used for genetic vaccination and may prove highly suitable for intervention in different pathological conditions due to their capacity to generate high level, transient gene expression. In this study, we report the use of a recombinant adenovirus vector to induce regulatory responses for the prevention of autoimmune diseases through transient expression of a TCR β-chain. Immunization of B10.PL mice with a recombinant adenovirus expressing the TCR Vβ8.2 chain (Ad5E1 mVβ8.2), resulted in induction of regulatory type 1 CD4 T cells, directed against the framework region 3 determinant within the B5 peptide (aa 76–101) of the Vβ8.2 chain. This determinant is readily processed and displayed in an I-Au context, on ambient APC. Transient genetic delivery of the TCR Vβ8.2 chain protected mice from Ag-induced experimental autoimmune encephalomyelitis. However, when the Ad5E1 mVβ8.2 vector was coadministered with either an IL-4- or IL-10-expressing vector, regulation was disrupted and disease was exacerbated. These results highlight the importance of the Th1-like cytokine requirement necessary for the generation and activity of effective regulatory T cells in this model of experimental autoimmune encephalomyelitis.
Long Term Maintenance of IgE-Mediated Memory in Mast Cells in the Absence of Detectable Serum IgE
Authors: Kubo Shuichi , Nakayama Toshinori , Matsuoka Kunie , Yonekawa Hiromichi , Karasuyama Hajime 
Published: April 2014

AbstractMast cells and basophils involved in allergic responses do not have clonotypic Ag receptors. However, they can acquire Ag specificity through binding of Ag-specific IgE to FcεRI expressed on their surface. Previous studies demonstrated that IgE binding induced the stabilization and accumulation of FcεRI on the cell surface and resulted in up-regulation of FcεRI. In this study we have further analyzed the maintenance of IgE-mediated memory in mast cells and basophils in vivo by comparing kinetics of serum IgE levels, FcεRI expression, and ability to induce systemic anaphylaxis. A single i.v. injection of trinitrophenyl-specific IgE induced 8-fold up-regulation of FcεRI expression on peritoneal mast cells in B cell-deficient (μm−/−) mice. Serum IgE levels became undetectable by day 6, but the treatment of mice with anti-IgE mAb induced a significant drop in body temperature on days 14, 28, and 42. The administration of trinitrophenyl -BSA, but not BSA, in place of anti-IgE mAb gave similar results, indicating the Ag specificity of the allergic response. This long term maintenance of Ag-specific reactivity in the allergic response was also observed in normal mice passively sensitized with IgE even though the duration was shorter than that in B cell-deficient mice. The appearance of IgE with a different specificity did not interfere with the maintenance of IgE-mediated memory of mast cells and basophils. These results suggest that IgE-mediated stabilization and up-regulation of FcεRI enables mast cells and basophils not only to acquire Ag specificity, but also to maintain memory in vivo for lengthy periods of time.
Differential Requirements for Expression of CD80/86 and CD40 on B Cells for T-Dependent Antibody Responses In Vivo
Authors: Lumsden Joanne M. , Williams Joy A. , Hodes Richard J. 
Published: April 2014

AbstractThe CD80/86-CD28 and CD40-CD40 ligand costimulatory pathways are essential for Th cell-dependent B cell responses that generate high-affinity, class-switched Ab in vivo. Disruption of either costimulatory pathway results in defective in vivo humoral immune responses, but it remains unclear to what extent this is due to deficient activation of Th cells and/or of B cells. To address this issue, we generated mixed chimeras in which CD80/86- or CD40-deficient bone marrow-derived cells coexist with wild-type (WT) cells, thereby providing the functional T cell help and accessory cell functions required for fully competent B cell responses. We were then able to assess the requirement for CD80/86 or CD40 expression on B cells producing class-switched Ig in response to a T-dependent Ag. In CD80/86 WT plus CD80/86 double-knockout mixed chimeras, both WT- and CD80/86-deficient B cells produced IgG1 and IgE responses, indicating that direct signaling by CD80/86 is not essential for efficient B cell activation. In marked contrast, only WT IgG1 and IgE responses were detected in the chimeras containing CD40-deficient cells, demonstrating that CD40 expression on B cells is essential for class switching by those B cells. Thus, while disrupting either the CD80/86-CD28 or the CD40-CD40 ligand costimulatory pathway abrogates T-dependent B cell immune responses, the two pathways are nonredundant and mediated by distinct mechanisms.
Complement Component 3 Is Required for Optimal Expansion of CD8 T Cells During a Systemic Viral Infection
Authors: Suresh M. , Molina Hector , Salvato Maria S. , Mastellos Dimitrios , Lambris John D. , Sandor Matyas 
Published: April 2014

AbstractIn addition to its established role in innate immune mechanisms, complement component C3 is also of critical importance in B cell activation and T cell-dependent Ab responses. In this study, we have examined the requirement for C3 in the generation of primary CD8 T cell responses to an acute systemic viral infection. We compared Ag-specific CD8 T cell responses to lymphocytic choriomeningitis virus (LCMV) between wild-type (+/+) and C3-deficient (C3−/−) mice on both 129/B6 and B6 backgrounds. These studies revealed that C3 activity is required for optimal expansion of LCMV-specific effector CD8 T cells in an epitope-dependent fashion, which is influenced by the genetic background of the mice. Studies in complement receptor 1/2 (CR1/CR2)-deficient mice showed that regulation of LCMV-specific CD8 T cell responses by C3 is not dependent upon CR1/CR2. These findings may have implications in vaccine development, therapy of autoimmune diseases, and prevention of graft rejection.