bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adenovirus-Specific CD4+ T Cell Clones Recognizing Endogenous Antigen Inhibit Viral Replication In Vitro through Cognate Interaction
Authors: Heemskerk Bianca , van Vreeswijk Tamara , Veltrop-Duits Louise A. , Sombroek Claudia C. , Franken Kees , Verhoosel Renate M. , Hiemstra Pieter S. , van Leeuwen Daphne , Ressing Maaike E. , Toes René E. M. , van Tol Maarten J. D. , Schilham Marco W. 
Published: April 2014

Abstract
Human adenovirus (HAdV) infection is a frequent and potentially severe complication following allogeneic stem cell transplantation in children. Because treatment with antiviral drugs is often ineffective, adoptive transfer of donor-derived HAdV-specific T cells able to control viral replication of HAdV of multiple serotypes may be an option for therapy. In healthy donors, predominantly HAdV-specific T cells expressing CD4 are detected. In this study, a preclinical in vitro model was used to measure the antiviral effect of HAdV-specific CD4+ T cells. CD4+ HAdV-specific T cell clones restricted by HLA class II molecules were generated and most of these clones recognized conserved peptides derived from the hexon protein. These cross-reactive T cell clones were able to control viral replication of multiple serotypes of HAdV in EBV-transformed B cells (B-LCL), melanoma cells (MJS) and primary bronchial epithelial cells through cognate interaction. The HAdV-specific CD4+ T cell clones were able to specifically lyse infected target cells using a perforin-dependent mechanism. Antigenic peptides were also presented to the CD4+ T cell clones when derived from endogenously produced hexon protein. Together, these results show that cross-reactive HAdV-specific CD4+ T cells can control replication of HAdV in vitro and provide a rationale for the use of HAdV-specific T cells in adoptive immunotherapy protocols for control of life-threatening HAdV-infections in immunocompromised patients.
Synergism between CpG-Containing Oligodeoxynucleotides and IL-2 Causes Dramatic Enhancement of Vaccine-Elicited CD8+ T Cell Responses
Authors: Kochenderfer James N. , Chien Christopher D. , Simpson Jessica L. , Gress Ronald E. 
Published: April 2014

Abstract
Novel anticancer vaccination regimens that can elicit large numbers of Ag-specific T cells are needed. When we administered therapeutic vaccines containing the MHC class I-presented self-peptide tyrosinase-related protein (TRP)-2180–188 and CpG-containing oligodeoxynucleotides (CpG ODN) to mice, growth of the TRP-2-expressing B16F1 melanoma was not inhibited compared with growth in mice that received control vaccinations. When we added systemic IL-2 to the TRP-2180–188 plus CpG ODN vaccines, growth of B16F1 was inhibited in a CD8-dependent, epitope-specific manner. Vaccines containing TRP-2180–188 without CpG ODN did not cause epitope-specific tumor growth inhibition when administered with IL-2. The antitumor efficacy of the different regimens correlated with their ability to elicit TRP-2180–188-specific CD8+ T cell responses. When we administered TRP-2180–188 plus CpG ODN-containing vaccines with systemic IL-2, 18.2% of CD8+ T cells were specific for TRP-2180–188. Identical TRP-2180–188 plus CpG ODN vaccines given without IL-2 elicited a TRP-2180–188-specific CD8+ T cell response of only 1.1% of CD8+ T cells. Vaccines containing TRP-2180–188 without CpG ODN elicited TRP-2180–188-specific responses of 2.8% of CD8+ T cells when administered with IL-2. There was up to a 221-fold increase in the absolute number of TRP-2180–188-specific CD8+ T cells when IL-2 was added to TRP-2180–188 plus CpG ODN-containing vaccines. Peptide plus CpG ODN vaccines administered with IL-2 generated epitope-specific CD8+ T cells by a mechanism that depended on endogenous IL-6. This is the first report of synergism between CpG ODN and IL-2. This synergism caused a striking increase in vaccine-elicited CD8+ T cells and led to epitope-specific antitumor immunity.
Differential Pattern Recognition Receptor Expression but Stereotyped Responsiveness in Rat Spleen Dendritic Cell Subsets
Authors: Hubert François-Xavier , Voisine Cécile , Louvet Cédric , Heslan Jean-Marie , Ouabed Asmahan , Heslan Michèle , Josien Régis 
Published: April 2014

Abstract
Dendritic cells (DC) are a heterogeneous population of APC endowed with specific functions. The nature of the DC subset involved in the course of an immune response to a specific pathogen might be important for inducing the appropriate effectors. In addition, each DC subset might also exhibit intrinsic functional plasticity. In the rat, spleen DC can be separated into three morphological and phenotypical distinct subsets, namely CD4+, CD4−, and plasmacytoid DC (pDC), whose frequencies are strain dependent. We correlated the expression of TLR and nucleotide-binding oligomerization domain 2 (NOD2) in these DC subsets to their in vitro responsiveness to specific ligands. CD4− DC expressed high levels of TLR1, 2, 3, and 10 mRNA, low TLR4, 5, 6, 7, and 9, and very low, if any, TLR8. pDC had a restricted repertoire characterized by high TLR7 and 9. CD4+ DC expressed all TLR and 10-fold higher levels of NOD2 mRNA than CD4− and pDC. Upon stimulation by TLR and NOD2 ligands, each DC subset responded in quite a stereotyped fashion. TLR2/6, 3, 4, 5, 9, and NOD2 triggering induced CD4− DC to mature and produce high IL-12p40, low IL-10, and TNF-α. TLR7/8 and 9 triggering induced pDC to mature and produce copious amounts of IL-6, IL-12p40, and TNF-α and low IFN-α. CD4+ DC were very poor producers of inflammatory cytokines. This study suggests that the nature of spleen DC responses to pathogens is dependent on subset specific-stimulation rather than intrinsic plasticity.
Activation of Plasmacytoid Dendritic Cells with TLR9 Agonists Initiates Invariant NKT Cell-Mediated Cross-Talk with Myeloid Dendritic Cells
Authors: Montoya Carlos J. , Jie Hyun-Bae , Al-Harthi Lena , Mulder Candice , Patiño Pablo J. , Rugeles María T. , Krieg Arthur M. , Landay Alan L. , Wilson S. Brian 
Published: April 2014

AbstractCD1d-restricted invariant NK T (iNKT) cells and dendritic cells (DCs) have been shown to play crucial roles in various types of immune responses, including TLR9-dependent antiviral responses initiated by plasmacytoid DCs (pDCs). However, the mechanism by which this occurs is enigmatic because TLRs are absent in iNKT cells and human pDCs do not express CD1d. To explore this process, pDCs were activated with CpG oligodeoxyribonucleotides, which stimulated the secretion of several cytokines such as type I and TNF-α. These cytokines and other soluble factors potently induced the expression of activation markers on iNKT cells, selectively enhanced double-negative iNKT cell survival, but did not induce their expansion or production of cytokines. Notably, pDC-derived factors licensed iNKT cells to respond to myeloid DCs: an important downstream cellular target of iNKT cell effector function and a critical contributor to the initiation of adaptive immune responses. This interaction supports the notion that iNKT cells can mediate cross-talk between DC subsets known to express mutually exclusive TLR and cytokine profiles.
Nonspecific Desensitization, Functional Memory, and the Characteristics of SHIP Phosphorylation following IgE-Mediated Stimulation of Human Basophils
Authors: MacGlashan Donald , Vilariño Natalia 
Published: April 2014

AbstractPrevious studies of secretion from basophils have demonstrated the phenomenon called nonspecific desensitization, the ability of one IgE-mediated stimulus to alter the cell’s response to other non-cross-reacting IgE-mediated stimuli, and a process that would modify phosphatidylinositol 3,4,5-phosphate levels was speculated to be responsible for nonspecific desensitization. The current studies examined the changes and characteristics of SHIP1 phosphorylation as a measure of SHIP1 participation in the reaction. Based on the earlier studies, two predictions were made that were not observed. First, the kinetics of SHIP1 phosphorylation were similar to reaction kinetics of other early signals and returned to resting levels while nonspecific desensitization remained. Second, in contrast to an expected exaggerated SHIP phosphorylation, cells in a state of nonspecific desensitization showed reduced SHIP phosphorylation (compared with cells not previously exposed to a non-cross-reacting Ag). Discordant with expectations concerning partial recovery from nonspecific desensitization, treatment of cells with DNP-lysine to dissociate bound DNP-HSA, either enhanced or had no effect on SHIP phosphorylation following a second Ag. These experiments also showed a form of desensitization that persisted despite dissociation of the desensitizing Ag. Recent studies and the results of these studies suggest that loss of early signaling components like syk kinase may account for some of the effects of nonspecific desensitization and result in a form of immunological memory of prior stimulation. Taken together, the various characteristics of SHIP phosphorylation were not consistent with expectations for a signaling element involved in nonspecific desensitization, but instead one which itself undergoes nonspecific desensitization.
CTLA-4 Overexpression Inhibits T Cell Responses through a CD28-B7-Dependent Mechanism
Authors: Engelhardt John J. , Sullivan Timothy J. , Allison James P. 
Published: April 2014

AbstractCTLA-4 has been shown to be an important negative regulator of T cell activation. To better understand its inhibitory action, we constructed CTLA-4 transgenic mice that display constitutive cell surface expression of CTLA-4 on CD4 and CD8 T cells. In both in vivo and in vitro T cell responses, CTLA-4 overexpression inhibits T cell activation. This inhibition is dependent on B7 and CD28, suggesting that overexpressed CTLA-4 inhibits responses by competing with CD28 for B7 binding or by interfering with CD28 signaling. In addition, expression of the transgene decreases the number of CD25+Foxp3+ T cells in these mice, but does not affect their suppressive ability. Our data confirm the activity of CTLA-4 as a negative regulator of T cell activation and that its action may be by multiple mechanisms.
Epigenetic Remodeling of theIL-2andIFN-γ Loci in Memory CD8 T Cells Is Influenced by CD4 T Cells
Authors: Northrop John K. , Thomas Rajan M. , Wells Andrew D. , Shen Hao 
Published: April 2014

AbstractMemory T cells (TM) are able to rapidly exert effector functions, including immediate effector cytokine production upon re-encounter with Ag, which is critical for protective immunity. Furthermore, this poised state is maintained as TM undergo homeostatic proliferation over time. We examined the molecular basis underlying this enhanced functional capacity in CD8 TM by comparing them to defective CD8 TM generated in the absence of CD4 T cells. Unhelped CD8 TM are defective in many functions, including the immediate expression of cytokines, such as IL-2 and IFN-γ. Our data show that this defect in IL-2 and IFN-γ production is independent of clonal selection, functional avidity maturation, and the integrity of proximal TCR signaling, but rather involves epigenetic modification of these cytokine genes. Activated Ag-specific CD8 T cells exhibit rapid DNA demethylation at the IL-2 and IFN-γ loci and substantial histone acetylation at the IFN-γ promoter and enhancer regions. These epigenetic modifications occur early after infection at the effector stage and are maintained through memory development. However, activated unhelped CD8 T cells, which fail to develop into functional memory and are incapable of rapid cytokine production, exhibit increased DNA methylation at the IL-2 promoter and fail to acetylate histones at the IFN-γ locus. Thus, CD4 T cell help influences epigenetic modification during CD8 TM differentiation and these epigenetic changes provide a molecular basis for the enhanced responsiveness and the maintenance of a “ready-to-respond” state in CD8 TM.
Grb2 and Gads Exhibit Different Interactions with CD28 and Play Distinct Roles in CD28-Mediated Costimulation
Authors: Watanabe Ryosuke , Harada Yohsuke , Takeda Kei , Takahashi Jun , Ohnuki Kazunobu , Ogawa Shuhei , Ohgai Daisuke , Kaibara Nanako , Koiwai Osamu , Tanabe Kazunari , Toma Hiroshi , Sugamura Kazuo , Abe Ryo 
Published: April 2014

Abstract
Although both CD28 and ICOS bind PI3K and provide stimulatory signal for T cell activation, unlike CD28, ICOS does not costimulate IL-2 secretion. CD28 binds both PI3K and Grb2, whereas ICOS binds only PI3K. We have generated an ICOS mutant, which can bind Grb2 by replacement of its PI3K binding motif YMFM with the CD28 YMNM motif, and shown that it induces significant activation of the IL-2 promoter. However, this mutant ICOS was insufficient to activate the NF-κB pathway. In this study, we show that Gads, but not Grb2, is essential for CD28-mediated NF-κB activation, and its binding to CD28 requires the whole CD28 cytoplasmic domain in addition to the YMNM motif. Mutagenesis experiments have indicated that mutations in the N-terminal and/or C-terminal PXXP motif(s) of CD28 significantly reduce their association with Gads, whereas their associations with Grb2 are maintained. They induced strong activity of the NFAT/AP-1 reporter comparable with the CD28 wild type, but weak activity of the NF-κB reporter. Grb2- and Gads-dominant-negative mutants had a strong effect on NFAT/AP-1 reporter, but only Gads-dominant-negative significantly inhibited NF-κB reporter. Our data suggest that, in addition to the PI3K binding motif, the PXXP motif in the CD28 cytoplasmic domain may also define a functional difference between the CD28- and ICOS-mediated costimulatory signals by binding to Gads.
Prostaglandin E2 Augments IL-10 Signaling and Function
Authors: Cheon HyeonJoo , Rho Young Hee , Choi Seong Jae , Lee Young Ho , Song Gwan Gyu , Sohn Jeongwon , Won Nam Hee , Ji Jong Dae 
Published: April 2014

Abstract
In inflamed joints of rheumatoid arthritis, PGE2 is highly expressed, and IL-10 and IL-6 are also abundant. PGE2 is a well-known activator of the cAMP signaling pathway, and there is functional cross-talk between cAMP signaling and the Jak-STAT signaling pathway. In this study, we evaluated the modulating effect of PGE2 on STAT signaling and its biological function induced by IL-10 and IL-6, and elucidated its mechanism in THP-1 cells. STAT phosphorylation was determined by Western blot, and gene expression was analyzed using real-time PCR. Pretreatment with PGE2 significantly augmented IL-10-induced STAT3 and STAT1 phosphorylation, as well as suppressors of cytokine signaling 3 (SOCS3) and IL-1R antagonist gene expression. In contrast, PGE2 suppressed IL-6-induced phosphorylation of STAT3 and STAT1. These PGE2-induced modulating effects were largely reversed by actinomycin D. Pretreatment with dibutyryl cAMP augmented IL-10-induced, but did not change IL-6-induced STAT3 phosphorylation. Misoprostol, an EP2/3/4 agonist, and butaprost, an EP2 agonist, augmented IL-10-induced STAT3 phosphorylation and SOCS3 gene expression, but sulprostone, an EP1/3 agonist, had no effect. H89, a protein kinase A inhibitor, and LY294002, a PI3K inhibitor, diminished PGE2-mediated augmentation of IL-10-induced STAT3 phosphorylation. In this study, we found that PGE2 selectively regulates cytokine signaling via increased intracellular cAMP levels and de novo gene expression, and these modulating effects may be mediated through EP2 or EP4 receptors. PGE2 may modulate immune responses by alteration of cytokine signaling in THP-1 cells.
Germinal Center Function in the Spleen during Simian HIV Infection in Rhesus Monkeys
Authors: Margolin David H. , Saunders Erika H. , Bronfin Benjamin , de Rosa Nicole , Axthelm Michael K. , Goloubeva Olga G. , Eapen Sara , Gelman Rebecca S. , Letvin Norman L. 
Published: April 2014

AbstractInfection with HIV-1, SIV, or simian HIV is associated with abnormalities in the number, size, and structure of germinal centers (GCs). To determine whether these histopathologic abnormalities are associated with abnormalities in Ab development, we analyzed nucleotide sequences of Igs from splenic GCs of simian HIV-infected macaques. Virus-specific GCs were identified in frozen splenic tissue sections by inverse immunohistochemistry using rHIV-1 gp120 as a probe. B cells from envelope-specific GCs were isolated from these sections using laser capture microdissection. Their Igs were amplified from cDNA using nested PCR, then cloned and sequenced. Nucleotide sequences were recovered from nine multimember clonal lineages. Within each lineage, sequences had similar V-D-J or V-J junctions but differed by somatic mutations distributed throughout the variable domain. The clones were highly mutated, similar to that previously reported for HIV-1-specific human IgG Abs. The average clone had 37 mutations in the V region, for a frequency of 0.11 mutations/base. The mutational pattern was strikingly nonrandom, with somatic mutations occurring preferentially at RGYW/WRCY hotspots. Transition mutations were favored over transversions, with C→T and G→A replacements together accounting for almost one-third of all mutations. Analysis of replacement and silent mutations in the framework and CDRs suggests that the Igs were subjected to affinity selection. These data demonstrate that the process of Ab maturation is not seriously disrupted in GCs during the early stages of immunodeficiency virus infection, and that Env-specific Igs developing in GCs are subject to extensive somatic mutation and profound selection pressures.
Sumoylation of Daxx Regulates IFN-Induced Growth Suppression of B Lymphocytes and the Hormone Receptor-Mediated Transactivation
Authors: Muromoto Ryuta , Ishida Masato , Sugiyama Kenji , Sekine Yuichi , Oritani Kenji , Shimoda Kazuya , Matsuda Tadashi 
Published: April 2014

Abstract
Daxx has been shown to play an essential role in type I IFN-mediated suppression of B cell development and apoptosis. Recently, we demonstrated that Tyk2 is directly involved in IFN signaling for the induction and translocation of Daxx, which may result in growth arrest and/or apoptosis of B lymphocyte progenitors. To clarify the molecular mechanisms of how Daxx acts on growth suppression of B lymphocytes, we examined functions of a sumoylation-defective Daxx KA mutant (Daxx K630/631A), which substituted Lys 630 and Lys 631 to Ala. Importantly, Daxx KA localized in the cytoplasm, whereas wild-type Daxx localized in the nucleus. Murine pro-B cell line Ba/F3 expressing Daxx KA revealed a resistance to the IFN-induced growth suppression. It is noteworthy that treatment with an exportin inhibitor, leptomycin B, resulted in nuclear localization of Daxx KA and recovery of the IFN-induced growth suppression in Ba/F3 cells. Moreover, Daxx KA decreased the binding potential to promyelocytic leukemia protein (PML), and overexpression of PML recruited Daxx KA into PML oncogenic domains. Notably, a Daxx-small ubiquitin-related modifier fusion protein exhibited increased nuclear localization and ability to suppress cell growth in Ba/F3 cells. These results demonstrate that the IFN-induced growth suppression of B lymphocytes requires nuclear localization of Daxx through its sumoylation and proper interactions with PML.
Granzyme M Directly Cleaves Inhibitor of Caspase-Activated DNase (CAD) to Unleash CAD Leading to DNA Fragmentation
Authors: Lu Hongxia , Hou Qiang , Zhao Tongbiao , Zhang Honglian , Zhang Qixiang , Wu Lianfeng , Fan Zusen 
Published: April 2014

Abstract
Granzyme (Gzm)M is constitutively highly expressed in NK cells that may play a critical role in NK cell-mediated cytolysis. However, the function of GzmM has been less defined. Just one report showed GzmM induces a caspase-independent death pathway. In this study, we demonstrate a protein transfection reagent Pro-Ject can efficiently transport GzmM into target cells. GzmM initiates caspase-dependent apoptosis with typical apoptotic nuclear morphology. GzmM induces DNA fragmentation, not DNA nicking. GzmM can directly degrade inhibitor of caspase-activated DNase to release the nuclease activity of caspase-activated DNase for damaging DNA. Furthermore, GzmM cleaves the DNA damage sensor enzyme poly(ADP-ribose) polymerase to prevent cellular DNA repair and force apoptosis.
GM1 Binding-Deficient Exotoxin Is a Potent Noninflammatory Broad Spectrum Intradermal Immunoadjuvant
Authors: Zoeteweij J. Paul , Epperson Diane E. , Porter Jackie D. , Zhang Chen X. , Frolova Olga Y. , Constantinides Anita P. , Fuhrmann Steven R. , El-Amine Moustapha , Tian Jing-Hui , Ellingsworth Larry R. , Glenn Gregory M. 
Published: April 2014

AbstractIntradermal (i.d.) immunization is a promising route of vaccine administration. Suitable i.d. adjuvants are important to increase vaccine efficacy in poorly responding populations such as the elderly or for dose-sparing strategies in the face of vaccine shortages. Bacterial exotoxins, such as Escherichia coli heat-labile enterotoxin (LT), exert strong immunostimulatory effects through binding to monosialoganglioside (GM1) cell surface receptors; however, injection is hampered by local inflammation. We demonstrate that the injection of LT formulations deficient in GM1 binding by mutation (LT(G33D)) or in vitro ligand coupling does not cause localized edema and inflammation in mice, yet these formulations retain potent adjuvant activity by enhancing functional Ab and cellular immune responses to coadministered Ags. Complete protection against in vivo lethal tetanus toxin challenge and the induction of Ag-specific CTL responses capable of killing target cells in vivo indicated in vivo efficacy of the induced immune responses. LT(G33D) proved superior to standard alum adjuvant regarding the magnitude and breadth of the induced immune responses. Immunizations in complex ganglioside knockout mice revealed a GM1-independent pathway of LT adjuvanticity. Immunostimulation by i.d. LT(G33D) is explained by its ability to induce migration of activated APCs to the proximal draining lymph nodes. LT(G33D) is a promising candidate adjuvant for human trials of parenteral vaccines in general and for current i.d. vaccine development in particular.
Epithelial Cell IκB-Kinase β Has an Important Protective Role inClostridium difficileToxin A-Induced Mucosal Injury
Authors: Chae Sungwon , Eckmann Lars , Miyamoto Yukiko , Pothoulakis Charalabos , Karin Michael , Kagnoff Martin F. 
Published: April 2014

AbstractToxin A released by Clostridium difficile interacts with the single layer of intestinal epithelial cells that lines the host’s intestinal tract and leads to mucosal damage and inflammation that manifests clinically as antibiotic-associated diarrhea and pseudomembranous colitis. Activation of the transcription factor NF-κB in intestinal epithelial cells is important for regulating the expression of epithelial cell proinflammatory genes and cell survival. However, the role of NF-κB activation in the pathogenesis of C. difficile toxin A-induced colitis is unknown. To determine the functional importance in vivo of NF-κB activation in intestinal epithelium in the pathogenesis of C. difficile-induced colitis, we used mutant mice that do not activate the classical NF-κB signaling pathway in intestinal epithelial cells due to a conditional deficiency in those cells of the IκB-kinase β (IKKβ) subunit of IKK. C. difficile toxin A challenge of intestinal loops in intestinal epithelial cell IKKβ-deficient mice induced a rapid and significant increase in intestinal epithelial apoptosis compared with littermate controls. This was accompanied by a significant increase in acute mucosal inflammation, mucosal injury, luminal fluid secretion, and bacterial translocation. We conclude that activation of intestinal epithelial cell NF-κB by toxin A plays an important host mucosal protective role after C. difficile toxin A exposure that is mediated, at least in part, through promoting epithelial cell survival by abrogating epithelial cell apoptosis.