bluuebunny/crossref_metadata_2025_split huggingface dataset:
Replication-Dependent Potent IFN-α Induction in Human Plasmacytoid Dendritic Cells by a Single-Stranded RNA Virus
Authors: Hornung Veit , Schlender Jörg , Guenthner-Biller Margit , Rothenfusser Simon , Endres Stefan , Conzelmann Karl-Klaus , Hartmann Gunther 
Published: April 2014

Abstract
Plasmacytoid dendritic cells sense viral ssRNA or its degradation products via TLR7/8 and CpG motifs within viral DNA via TLR9. Although these two endosomal pathways operate independently of viral replication, little is known about the detection of actively replicating viruses in plasmacytoid dendritic cell (PDC). Replication and transcription of the viral genome of ssRNA viruses as well as many DNA viruses lead to the formation of cytosolic dsRNA absent in noninfected cells. In this study, we used human respiratory syncytial virus (HRSV) encoding a fusion (F) protein for direct cytosolic entry. Both HRSV infection and cytosolic delivery of a 65-nt dsRNA led to potent IFN-α induction in PDC, but not in myeloid dendritic cells. Inactivation of HRSV by UV irradiation abrogated IFN-α induction in PDC. The comparison of two respiratory syncytial virus (RSV) constructs carrying either the HRSV or the bovine RSV F protein revealed that F-mediated cytosolic entry of RSV was absolutely required for IFN-α induction in PDC. HRSV-induced IFN-α production was independent of endosomal acidification and of protein kinase R (PKR) kinase activity, as demonstrated with chloroquine and the PKR inhibitor 2-aminopurine, respectively. In contrast, the induction of IFN-α by the TLR7/8 ligand R848, by the TLR9 ligand CpG-A ODN 2216, and by inactivated influenza virus (TLR7/8 dependent) was completely blocked by 2-aminopurine. IFN-α induction by mouse pathogenic Sendai virus was not affected in PKR- and MyD88-deficient mice, confirming that a ssRNA virus, which is able to directly enter host cells via fusion at the plasma membrane, can be detected by PDC independently of PKR, TLR7/8, and TLR9.
4-1BB and OX40 Act Independently to Facilitate Robust CD8 and CD4 Recall Responses
Authors: Dawicki Wojciech , Bertram Edward M. , Sharpe Arlene H. , Watts Tania H. 
Published: April 2014

Abstract
Mice deficient in OX40 or 4-1BB costimulatory pathways show defects in T cell recall responses, with predominant effects on CD4 vs CD8 T cells, respectively. However, OX40L can also stimulate CD8 T cells and 4-1BBL can influence CD4 T cells, raising the possibility of redundancy between the two TNFR family costimulators. To test this possibility, we generated mice deficient in both 4-1BBL and OX40L. In an adoptive transfer model, CD4 T cells expressed 4-1BB and OX40 sequentially in response to immunization, with little or no overlap in the timing of their expression. Under the same conditions, CD8 T cells expressed 4-1BB, but no detectable OX40. Thus, in vivo expression of 4-1BB and OX40 can be temporally and spatially segregated. In the absence of OX40L, there were decreased CD4 T cells late in the primary response and no detectable secondary expansion of adoptively transferred CD4 T cells under conditions in which primary expansion was unaffected. The 4-1BBL had a minor effect on the primary response of CD4 T cells in this model, but showed larger effects on the secondary response, although 4-1BBL−/− mice show less impairment in CD4 secondary responses than OX40L−/− mice. The 4-1BBL−/− and double knockout mice were similarly impaired in the CD8 T cell response, whereas OX40L−/− and double knockout mice were similarly impaired in the CD4 T cell response to both protein Ag and influenza virus. Thus, 4-1BB and OX40 act independently and nonredundantly to facilitate robust CD4 and CD8 recall responses.
Mechanism of Prostaglandin (PG)E2-Induced Prolactin Expression in Human T Cells: Cooperation of Two PGE2 Receptor Subtypes, E-Prostanoid (EP) 3 and EP4, Via Calcium- and Cyclic Adenosine 5′-Monophosphate-Mediated Signaling Pathways
Authors: Gerlo Sarah , Verdood Peggy , Gellersen Birgit , Hooghe-Peters Elisabeth L. , Kooijman Ron 
Published: April 2014

Abstract
We previously reported that prolactin gene expression in the T-leukemic cell line Jurkat is stimulated by PGE2 and that cAMP acts synergistically with Ca2+ or protein kinase C on the activation of the upstream prolactin promoter. Using the transcription inhibitor actinomycin D, we now show that PGE2-induced prolactin expression requires de novo prolactin mRNA synthesis and that PGE2 does not influence prolactin mRNA stability. Furthermore, PGE2-induced prolactin expression was inhibited by protein kinase inhibitor fragment 14–22 and BAPTA-AM, which respectively, inhibit protein kinase A- and Ca2+-mediated signaling cascades. Using specific PGE2 receptor agonists and antagonists, we show that PGE2 induces prolactin expression through engagement of E-prostanoid (EP) 3 and EP4 receptors. We also found that PGE2 induces an increase in intracellular cAMP concentration as well as intracellular calcium concentration via EP4 and EP3 receptors, respectively. In transient transfections, 3000 bp flanking the leukocyte prolactin promoter conferred a weak induction of the luciferase reporter gene by PGE2 and cAMP, whereas cAMP in synergy with ionomycin strongly activated the promoter. Mutation of a C/EBP responsive element at −214 partially abolished the response of the leukocyte prolactin promoter to PGE2, cAMP, and ionomycin plus cAMP.
Extract of Reishi Polysaccharides Induces Cytokine Expression via TLR4-Modulated Protein Kinase Signaling Pathways
Authors: Hsu Hsien-Yeh , Hua Kuo-Feng , Lin Chun-Cheng , Lin Chun-Hung , Hsu Jason , Wong Chi-Huey 
Published: April 2014

Abstract
We have demonstrated that an extract of Ganoderma lucidum (Reishi or Ling-Zhi) polysaccharides (EORP) exerts immunomodulating activities by stimulating the expression of inflammatory cytokines from mouse spleen cells. Interestingly, via responding to LPS in genetic variation of murine macrophage HeNC2 and GG2EE cell lines, and using TLR4 Ab blockage in human blood-derived monocytic macrophages, we have found that the TLR4, but not complement receptor type 3, is a putative receptor of EORP, mediating the consequent immunomodulating events associated with IL-1 gene expression. Based on our studies of reactive oxygen species production, polymyxin B inhibition, and protein tyrosine kinase (PTK) activity, we ruled out the possibility of LPS contamination in EORP. We have found that EORP differentially modulates the protein kinase (PK)-mediated signal transduction pathways associated with inflammatory cytokine IL-1. In human macrophages and murine macrophage J774A.1 cells, EORP was found to up-regulate IL-1 secretion and pro-IL-1 (precursor of IL-1) as well as IL-1-converting enzyme expression. Specifically, EORP rapidly stimulates PTK-mediated phosphorylation, followed by induction of PKs and activation of MAPKs: ERK, JNK, and p38. Using PK inhibitors in the kinase activity assays, Western blot analyses and IL-1 ELISA, we have extensively examined and dissected the role of individual PK in the regulation of pro-IL-1/IL-1. Our findings establish that EORP-mediated signaling pathways are involved in the pro-IL-1/IL-1 regulation: PTK/protein kinase C/MEK1/ERK and PTK/Rac1/p21-activated kinase/p38.
Evidence of a Novel IL-2/15Rβ-Targeted Cytokine Involved in Homeostatic Proliferation of Memory CD8+ T Cells
Authors: Kamimura Daisuke , Ueda Naoko , Sawa Yukihisa , Hachida Shinji , Atsumi Toru , Nakagawa Takayuki , Sawa Shin-ichiro , Jin Gui-Hua , Suzuki Haruhiko , Ishihara Katsuhiko , Murakami Masaaki , Hirano Toshio 
Published: April 2014

Abstract
The homeostasis of memory CD8+ T cells is regulated by cytokines. IL-15 is shown to promote the proliferation of memory CD8+ T cells, while IL-2 suppresses their division in vivo. This inhibitory effect of IL-2 appears to occur indirectly, through other cell populations including CD25+CD4+ T cells; however, the details of this mechanism remain unclear. In this study, we show that 1) both Ag-experienced and memory phenotype CD8+ T cells divided after the depletion of IL-2 in vivo; 2) this division occurred normally and CD44highIL-2/15Rβhigh CD8+ T cells generated after IL-2 depletion in IL-15 knockout (KO) and in IL-7-depleted IL-15 KO mice; 3) surprisingly, the blockade of IL-2/15Rβ signaling in IL-2-depleted IL-15 KO mice completely abolished the division of memory CD8+ T cells, although the only cytokines known to act through IL-2/15Rβ are IL-2 and IL-15; and 4) the expression of IL-2/15Rβ molecules on memory CD8+ T cells was required for their division induced by IL-2 depletion. These results demonstrate that the depletion of IL-2 in vivo induced memory CD8+ T cell division by an IL-15-independent but by an IL-2/15Rβ-dependent mechanism, suggesting the existence of a novel IL-2/15Rβ-utilizing cytokine that acts directly on memory CD8+ T cells to promote cell division.
Induction of Bystander Suppression by Feeding Antigen Occurs despite Normal Clonal Expansion of the Bystander T Cell Population
Authors: Millington Owain R. , Mowat Allan McI. , Garside Paul 
Published: April 2014

Abstract
The induction of bystander suppression, whereby the response against one Ag is suppressed when it is presented in the context of an Ag to which tolerance is already established, would be an important property of oral tolerance, because it would allow treatment of autoimmune and hypersensitivity responses where the initiating Ag is not known. Although bystander suppression has been described in oral tolerance, it is not known how its effects are mediated at the level of the bystander T cells. In addition, previous studies have not compared regimes in which Ag is fed in a tolerogenic or immunogenic manner, meaning that the possible effects of Ag competition have not been excluded. In this study we have used two populations of Ag-specific TCR transgenic CD4+ T cells to examine the cellular basis of bystander suppression associated with oral tolerance in mice in vitro and in vivo. Our results show that bystander responses can be inhibited by feeding Ag and that these effects are more pronounced in mice fed protein in tolerogenic form than after feeding Ag with mucosal adjuvant. However, the expansion of the bystander-specific CD4+ T cells is not influenced by the presence of oral tolerance. Thus, bystander suppression does not reflect clonal deletion or reduced clonal expansion of the bystander T cells, but may act by altering the functional differentiation of bystander T cells.
Vasoactive Intestinal Peptide Modulates Langerhans Cell Immune Function
Authors: Kodali Sreedevi , Ding Wanhong , Huang Jing , Seiffert Kristina , Wagner John A. , Granstein Richard D. 
Published: April 2014

AbstractEpidermal nerves lie in close proximity to Langerhans cells (LC) and are capable of releasing peptides that modulate LC function, including calcitonin gene-related peptide and pituitary adenylate cyclase-activating polypeptide. The neuropeptide vasoactive intestinal peptide (VIP) has also been found in cutaneous nerves and mRNA, for the VIP receptor vasoactive intestinal peptide receptor type 1, and vasoactive intestinal peptide receptor type 2 have been found in murine LC and the LC-like cell line XS106. We examined the effects of VIP on LC function and cutaneous immunity. VIP inhibited elicitation of a delayed-type hypersensitivity response in previously immunized mice by epidermal cells enriched for LC content pulsed with Ag in vitro. VIP also inhibited the ability of unseparated epidermal cells to present Ag to a T cell clone and hybridoma and the ability of highly enriched LCs to present to the T cell clone. Inhibition of presentation to the hybridoma was observed with an antigenic peptide that does not require processing, suggesting that VIP is active at a step independent of Ag processing. To elucidate the mechanism(s) by which VIP may mediate these effects, we determined the effects of VIP on LC cytokine production using the XS106 cell line as a surrogate for LC. VIP augmented the production of the IL-10 in LPS-stimulated XS106 cells while down-regulating IL-12 and IL-1β production. Thus, VIP, like pituitary adenylate cyclase-activating polypeptide and calcitonin gene-related peptide, down-regulates LC function and the associated immune response.
Dietary Docosahexaenoic Acid Suppresses T Cell Protein Kinase Cθ Lipid Raft Recruitment and IL-2 Production
Authors: Fan Yang-Yi , Ly Lan H. , Barhoumi Rola , McMurray David N. , Chapkin Robert S. 
Published: April 2014

Abstract
To date, the proximal molecular targets through which dietary n-3 polyunsaturated fatty acids (PUFA) suppress the inflammatory process have not been elucidated. Because cholesterol and sphingolipid-enriched rafts have been proposed as platforms for compartmentalizing dynamically regulated signaling assemblies at the plasma membrane, we determined the in vivo effects of fish oil and highly purified docosahexaenoic acid (DHA; 22:6n-3) on T cell microdomain lipid composition and the membrane subdomain distribution of signal-transducing molecules (protein kinase C (PKC)θ, linker for activation of T cells, and Fas/CD95), before and after stimulation. Mice were fed diets containing 5 g/100 g corn oil (control), 4 g/100 g fish oil (contains a mixture of n-3 PUFA) plus 1 g/100 g corn oil, or 4 g/100 g corn oil plus 1 g/100 g DHA ethyl ester for 14 days. Dietary n-3 PUFA were incorporated into splenic T cell lipid raft and soluble membrane phospholipids, resulting in a 30% reduction in raft sphingomyelin content. In addition, polyclonal activation-induced colocalization of PKCθ with lipid rafts was reduced by n-3 PUFA feeding. With respect to PKCθ effector pathway signaling, both AP-1 and NF-κB activation, IL-2 secretion, and lymphoproliferation were inhibited by fish oil feeding. Similar results were obtained when purified DHA was fed. These data demonstrate for the first time that dietary DHA alters T cell membrane microdomain composition and suppresses the PKCθ signaling axis.
Follicular Dendritic Cell Regulation of CXCR4-Mediated Germinal Center CD4 T Cell Migration
Authors: Estes Jacob D. , Thacker Tyler C. , Hampton Denise L. , Kell Sariah A. , Keele Brandon F. , Palenske Emily A. , Druey Kirk M. , Burton Gregory F. 
Published: April 2014

Abstract
Follicular dendritic cells (FDCs) up-regulate the chemokine receptor CXCR4 on CD4 T cells, and a major subpopulation of germinal center (GC) T cells (CD4+CD57+), which are adjacent to FDCs in vivo, expresses high levels of CXCR4. We therefore reasoned that GC T cells would actively migrate to stromal cell-derived factor-1 (CXCL12), the CXCR4 ligand, and tested this using Transwell migration assays with GC T cells and other CD4 T cells (CD57−) that expressed much lower levels of CXCR4. Unexpectedly, GC T cells were virtually nonresponsive to CXCL12, whereas CD57−CD4 T cells migrated efficiently despite reduced CXCR4 expression. In contrast, GC T cells efficiently migrated to B cell chemoattractant-1/CXCL13 and FDC supernatant, which contained CXCL13 produced by FDCs. Importantly, GC T cell nonresponsiveness to CXCL12 correlated with high ex vivo expression of regulator of G protein signaling (RGS), RGS13 and RGS16, mRNA and expression of protein in vivo. Furthermore, FDCs up-regulated both RGS13 and RGS16 mRNA expression in non-GC T cells, resulting in their impaired migration to CXCL12. Finally, GC T cells down-regulated RGS13 and RGS16 expression in the absence of FDCs and regained migratory competence to CXCL12. Although GC T cells express high levels of CXCR4, signaling through this receptor appears to be specifically inhibited by FDC-mediated expression of RGS13 and RGS16. Thus, FDCs appear to directly affect GC T cell migration within lymphoid follicles.
Differential Gene Expression Modulated by the Cytoplasmic Domain of FcγRIa (CD64) α-Chain
Authors: Qin Hongwei , Edberg Jeffrey C. , Gibson Andrew W. , Page Grier P. , Teng Lihong , Kimberly Robert P. 
Published: April 2014

Abstract
The cytoplasmic domain (CY) of the ligand-binding α-chain of the γ-chain-associated FcRs can modulate receptor function such as phagocytosis, endocytosis, and intracellular trafficking of receptor-Ag complexes. To assess the potential role of the CY domain of human FcγRIa (CD64) α-chain in the transcriptional regulation of receptor-induced gene expression, we developed stably transfected murine macrophage cell lines expressing a full-length or a CY deletion mutant (tail-less) of human FcγRIa to analyze gene expression in response to receptor-specific cross-linking. Using the Affymetrix murine genome U74Av2 GeneChip array, we observed &gt;100 candidate genes having ≥2-fold difference expression at 1.5 and 3 h after stimulation. Focusing on several immunologically related genes, we confirmed differential expression of M-CSF, macrophage inhibitory cytokine-1, leukocyte-specific protein 1, MIP-2, and IL-1R antagonist by RT-PCR and RNase protection assays. Analysis of mRNA stability indicated that the differential regulation of gene expression by the CY of the CD64 α-chain is at the level of gene transcription. Our results indicate that the CY of the CD64 α-chain modulates transcriptional activity induced by receptor-specific engagement in macrophages and provides a framework for understanding distinct expression profiles elicited by different Fc γ-chain-associated receptors.
The 3′ Untranslated Region of the Membrane-Bound IL-1R Accessory Protein mRNA Confers Tissue-Specific Destabilization
Authors: Jensen Liselotte E. , Whitehead Alexander S. 
Published: April 2014

Abstract
IL-1α and IL-1β are proinflammatory cytokines that promote activation of intracellular signaling cascades, leading to stabilization of certain mRNAs and activation of transcription factors. IL-1R type I (IL-1RI) binds IL-1α and IL-1β, and subsequent recruitment of the membrane-bound IL-1R accessory protein (mIL-1RAcP) facilitates signal transduction. Two alternatively spliced isoforms, soluble IL-1RAcP (sIL-1RAcP) and sIL-1RAcP-β, which lack transmembrane and intracellular domains, have been described. The sIL-1RAcP and possibly sIL-1RAcP-β can inhibit IL-1 signaling. Proportional expression of the different IL-1RAcP splice variants may be an important determinant of responsiveness to IL-1. We show that although both mIL-1RAcP and sIL-1RAcP mRNAs are widely expressed in human tissue, their relative proportions differ significantly in a tissue-specific manner. Turnover studies revealed that the sIL-1RAcP mRNA has a half-life of ∼48 h in both the kidney cell line 293 and the hepatoma cell line HepG2. The mIL-1RAcP mRNA has a similar half-life in 293 cells, but a considerably shorter half-life of ∼5 h in HepG2 cells. Using luciferase reporter constructs, we demonstrated that this specific destabilization of the mIL-1RAcP mRNA in the latter cell type is mediated by its 2.8-kb 3′-untranslated region. Deletion analysis further established that the cell line-specific instability does not involve AU-rich elements, but is mediated by several novel elements that appear to act independently; such elements may be recognized by proteins expressed specifically in some, but not all, tissues. These data demonstrate that the cellular capacity to respond to IL-1 is tightly regulated in a tissue-specific manner.
Genetic Manipulation of Telomerase in HIV-Specific CD8+ T Cells: Enhanced Antiviral Functions Accompany the Increased Proliferative Potential and Telomere Length Stabilization
Authors: Dagarag Mirabelle , Evazyan Tandik , Rao Nagesh , Effros Rita B. 
Published: April 2014

Abstract
A large proportion of the CD8+ T cell pool in persons chronically infected with HIV consists of cells that show features of replicative senescence, an end stage characterized by irreversible cell cycle arrest, multiple genetic and functional changes, and shortened telomeres. The objective of our research was to determine whether constitutive expression of the gene for the human telomerase (hTERT) can prevent senescence-induced impairments in human virus-specific CD8+ T cells, particularly in the context of HIV-1 disease. Our results indicate that hTERT-expressing HIV-specific CD8+ lymphocytes show both an enhanced and sustained capacity to inhibit HIV-1 replication in in vitro coculture experiments, as well as prolonged ability to produce IFN-γ and TNF-α in response to stimulation with HIV-1-derived peptides, as compared with vector-transduced controls. Loss of CD28 expression, the signature change of replicative senescence in cell culture, was retarded in those CD8+ T cell cultures that had high levels of CD28 at the time of hTERT transduction. These findings suggest that telomere shortening may be the primary driving force behind several aspects of CD8+ T cell dysfunction associated with replicative senescence. We also demonstrate reduced accumulation of the p16INK4a and p21WAF1 cell cycle inhibitors in hTERT-transduced lymphocytes, providing a possible mechanism by which stable hTERT expression is able to circumvent the senescence barrier in CD8+ T cells. Given the key role of CD8+ T cell function in controlling a variety of acute and latent viral infections, approaches to retard the functional decrements associated with replicative senescence may lead to novel types of immunotherapy.
Helminth Infection Protects Mice from Anaphylaxis via IL-10-Producing B Cells
Authors: Mangan Niamh E. , Fallon Rosemary E. , Smith Philip , van Rooijen Nico , McKenzie Andrew N. , Fallon Padraic G. 
Published: April 2014

Abstract
Modulation of the immune system by infection with helminth parasites, including schistosomes, is proposed to reduce the levels of allergic responses in infected individuals. In this study we investigated whether experimental infection with Schistosoma mansoni could alter the susceptibility of mice to an extreme allergic response, anaphylaxis. We formally demonstrate that S. mansoni infection protects mice from an experimental model of systemic fatal anaphylaxis. The worm stage of infection is shown to mediate this protective effect. In vivo depletion studies demonstrated an imperative role for B cells and IL-10 in worm-mediated protection. Furthermore, worm infection of mice increases the frequency of IL-10-producing B cells compared with that in uninfected mice. However, transfer of B cells from worm-infected mice or in vitro worm-modulated B cells to sensitized recipients exacerbated anaphylaxis, which was attributed to the presence of elevated levels of IL-4-producing B cells. Worm-modulated, IL-10-producing B cells from IL-4-deficient, but not IL-5-, IL-9- or IL-13-deficient, mice conferred complete resistance to anaphylaxis when transferred to naive mice. Therefore, we have dissected a novel immunomodulatory mechanism induced by S. mansoni worms that is dependent on an IL-10-producing B cell population that can protect against allergic hypersensitivity. These data support a role for helminth immune modulation in the hygiene hypothesis and further illustrate the delicate balance between parasite induction of protective regulatory (IL-10) responses and detrimental (IL-4) allergic responses.