bluuebunny/crossref_metadata_2025_split huggingface dataset:
STAT4 Is a Critical Mediator of Early Innate Immune Responses against Pulmonary Klebsiella Infection
Authors: Deng Jane C. , Zeng Xianying , Newstead Michael , Moore Thomas A. , Tsai Wan C. , Thannickal Victor J. , Standiford Theodore J. 
Published: April 2014

Abstract
Bacterial pneumonia is a leading cause of morbidity and mortality in the U.S. An effective innate immune response is critical for the clearance of bacteria from the lungs. IL-12, a key T1 cytokine in innate immunity, signals through STAT4. Thus, understanding how STAT4 mediates pulmonary immune responses against bacterial pathogens will have important implications for the development of rational immunotherapy targeted at augmenting innate immunity. We intratracheally administered Klebsiella pneumoniae to wild-type BALB/c and STAT4 knockout (STAT4−/−) mice. Compared with wild-type controls, STAT4−/− mice had decreased survival following intratracheal Klebsiella administration, which was associated with a higher lung and blood bacterial burden. STAT4−/− animals also displayed impaired pulmonary IFN-γ production and decreased levels of proinflammatory cytokines, including the ELR− CXC chemokines IFN-γ-inducible protein-10 and monokine induced by IFN-γ. Although total lung leukocyte populations were similar between STAT4−/− and wild-type animals following infection, alveolar macrophages isolated from infected STAT4−/− mice had decreased production of proinflammatory cytokines, including IFN-γ, compared with infected wild-type mice. The intrapulmonary overexpression of IFN-γ concomitant with the systemic administration of IFN-γ partially reversed the immune deficits observed in STAT4−/− mice, resulting in improved bacterial clearance from the blood. Collectively, these studies demonstrate that STAT4 is required for the generation of an effective innate host defense against bacterial pathogens of the lung.
Low-DoseSalmonellaInfection Evades Activation of Flagellin-Specific CD4 T Cells
Authors: Srinivasan Aparna , Foley Joseph , Ravindran Rajesh , McSorley Stephen J. 
Published: April 2014

AbstractMany pathogens can establish a lethal infection from relatively small inocula, yet the effect of infectious dose upon CD4 T cell activation is not clearly understood. This issue was examined by tracking Salmonella flagellin-specific SM1 T cells in vivo, after i.v. and oral challenge of mice with virulent Salmonella typhimurium. SM1 T cells rapidly expressed activation markers and expanded in response to high-dose infection but remained completely unresponsive in mice challenged with low doses of Salmonella. SM1 T cells, in these mice, remained unresponsive, despite massive bacterial replication in vivo. Naive SM1 T cells in low-dose Salmonella-infected mice were activated rapidly after the injection of flagellin peptide, demonstrating that these T cells were fully capable of responding, ruling out the possibility of a bacterial-induced suppressive environment. The inability of flagellin-specific SM1 T cells to respond to low-dose infection was not due to Ag down-regulation, because flagellin expression was detected using a functional assay. Together, these data suggest that low-dose Salmonella infection can evade flagellin-specific CD4 T cell activation in vivo.
Reduction of Nitric Oxide Synthase 2 Expression by Distamycin A Improves Survival from Endotoxemia
Authors: Baron Rebecca M. , Carvajal Irvith M. , Liu Xiaoli , Okabe Rachel O. , Fredenburgh Laura E. , Macias Alvaro A. , Chen Yen-Hsu , Ejima Kuniaki , Layne Matthew D. , Perrella Mark A. 
Published: April 2014

Abstract
NO synthase 2 (NOS2) plays an important role in endotoxemia through overproduction of NO. Distamycin A (Dist A) belongs to a class of drugs termed minor-groove DNA binders, which can inhibit transcription factor binding to AT-rich regions of DNA. We and others have previously shown that AT-rich regions of DNA surrounding transcription factor binding sites in the NOS2 promoter are critical for NOS2 induction by inflammatory stimuli in vitro. Therefore, we hypothesized that Dist A would attenuate NOS2 up-regulation in vivo during endotoxemia and improve animal survival. C57BL/6 wild-type (WT) mice treated with Dist A and LPS (endotoxin) showed significantly improved survival compared with animals treated with LPS alone. In contrast, LPS-treated C57BL/6 NOS2-deficient (NOS2−/−) mice did not benefit from the protective effect of Dist A on mortality from endotoxemia. Treatment with Dist A resulted in protection from hypotension in LPS-treated WT mice, but not in NOS2−/− mice. Furthermore, LPS-induced NOS2 expression was attenuated in vivo (WT murine tissues) and in vitro (primary peritoneal and RAW 264.7 murine macrophages) with addition of Dist A. Dist A selectively decreased IFN regulatory factor-1 DNA binding in the enhancer region of the NOS2 promoter, and this IFN regulatory factor-1 site is critical for the effect of Dist A in attenuating LPS induction of NOS2. Our data point to a novel approach in modulating NOS2 expression in vivo during endotoxemia and suggest the potential for alternative treatment approaches for critical illness.
Divergent Trophoblast Responses to Bacterial Products Mediated by TLRs
Authors: Abrahams Vikki M. , Bole-Aldo Paulomi , Kim Yeon Mee , Straszewski-Chavez Shawn L. , Chaiworapongsa Tinnakorn , Romero Roberto , Mor Gil 
Published: April 2014

Abstract
Intrauterine infections have been associated with pregnancy complications that are also linked with increased trophoblast apoptosis. TLRs are key components of the innate immune system which recognize conserved sequences on the surface of pathogens and trigger effector cell functions. We hypothesize that intrauterine infections may cause the excessive trophoblast cell apoptosis observed in abnormal pregnancies and that TLR may provide a mechanism of pathogenesis. In this study we describe the expression and function of TLR-2 and TLR-4 in first trimester trophoblast cells. Although ligation of TLR4 induced cytokine production by trophoblast cells, TLR-2 activation induced apoptosis. TLR-2 mediated apoptosis was dependent upon the Fas-associated death domain, the inactivation of the X-linked inhibitor of apoptosis, and the activation of caspases 8, 9, and 3. These results suggest that certain intrauterine infections may directly induce trophoblast cell death through TLR-2. Our findings provide a novel mechanism of pathogenesis for certain pregnancy complications in which there is engagement of the innate immune system.
Human Plasmacytoid Dendritic Cells Activated by CpG Oligodeoxynucleotides Induce the Generation of CD4+CD25+ Regulatory T Cells
Authors: Moseman E. Ashley , Liang Xueqing , Dawson Amanda J. , Panoskaltsis-Mortari Angela , Krieg Arthur M. , Liu Yong-Jun , Blazar Bruce R. , Chen Wei 
Published: April 2014

Abstract
Plasmacytoid dendritic cells (PDCs) are key effectors in host innate immunity and orchestrate adaptive immune responses. CpG oligodeoxynucleotides (ODN) have potent immunostimulatory effects on PDCs through TLR9 recognition and signaling. Little is known about the effects of CpG ODN on human PDC-mediated T cell priming. Here we show that type B CpG ODN effectively promotes PDCs to prime allogeneic naive CD4+CD25− T cells to differentiate into CD4+CD25+ regulatory T (Treg) cells. The CD4+CD25+ T cells induced by CpG ODN-activated PDCs express forkhead transcription factor 3 and produce IL-10, TGF-β, IFN-γ, and IL-6, but low IL-2 and IL-4. These CD4+CD25+ T cells are hyporesponsive to secondary alloantigen stimulation and strongly inhibit proliferation of autologous or allogeneic naive CD4+ T cells in an Ag-nonspecific manner. CpG ODN-activated PDCs require direct contact with T cells to induce CD4+CD25+ Treg cells. Interestingly, IL-10 and TGF-β were undetectable in the supernatants of CpG ODN-stimulated PDC cultures. Both CpG-A and CpG-C ODN-activated PDCs similarly induced the generation of CD4+CD25+ Treg cells with strong immune suppressive function. This study demonstrates that TLR9 stimulation can promote PDC-mediated generation of CD4+CD25+ Treg cells and suggests PDCs may play an important role in the maintenance of immunological tolerance.
CpG DNA Induces IgG Class Switch DNA Recombination by Activating Human B Cells through an Innate Pathway That Requires TLR9 and Cooperates with IL-10
Authors: He Bing , Qiao Xugang , Cerutti Andrea 
Published: April 2014

AbstractTLRs are pattern recognition receptors that initiate innate immune responses. TLR9 detects microbial DNA with hypomethylated CpG motifs and in humans is preferentially expressed by IFN-α-producing plasmacytoid dendritic cells and B cells. In addition to favoring IFN-α release, TLR9 signals B cell activation, proliferation, and IgM production. Recent findings suggest that CpG DNA-TLR9 interaction plays a key role in systemic lupus erythematosus and rheumatoid arthritis, two autoimmune disorders characterized by dysregulated production of DNA-reactive IgG. We show that CpG DNA initiates germline Cγ1, Cγ2, and Cγ3 gene transcription by activating B cells through a TLR9-mediated NF-κB-Rel-dependent innate pathway that cooperates with IL-10 through STAT proteins and IFN-responsive factors. This pathway is inhibited by chloroquine, a drug that attenuates the clinical manifestations of IgG-mediated autoimmune disorders. Germline Cγ gene transcription is associated with up-regulation of activation-induced cytidine deaminase, a key element of the B cell class switch-inducing machinery, and is followed by class switch DNA recombination from Cμ to Cγ1, Cγ2, and Cγ3. Subsequent IgG production requires additional signals from BCR and a B cell-activating factor of the TNF family (BAFF), produced by dendritic cells upon exposure to IFN-α. Our findings suggest that CpG DNA-TLR9 interaction may be important to initiate or amplify early T cell-independent IgG responses against pathogens. This implies that CpG DNA released during infections may exacerbate autoimmunity by stimulating autoreactive B cells to switch from an IgM to a more pathogenic IgG isotype.
Critical Role of TNF Receptor Type-2 (p75) as a Costimulator for IL-2 Induction and T Cell Survival: A Functional Link to CD28
Authors: Kim Edward Y. , Teh Hung-Sia 
Published: April 2014

Abstract
CD28 provides important signals that lower the threshold of T cell activation, augment the production of IL-2, and promote T cell survival. The recent identification of a second family of costimulatory molecules within the TNFR family has reshaped the “two-signal” model of T cell activation. In this study the role of p75 as a T cell costimulatory molecule in controlling cell fate during TCR/CD28-mediated stimulation was examined. We found that p75-deficient T cells possess a profound defect in IL-2 production in response to TCR/CD28-mediated stimulation. Examination of key signaling intermediates revealed that TCR proximal events such as global tyrosine phosphorylation and ZAP70 phosphorylation, as well as downstream MAPK cascades are unperturbed in p75-deficient T cells. In contrast, p75 is nonredundantly coupled to sustained AKT activity and NF-κB activation in response to TCR/CD28-mediated stimulation. Moreover, p75-deficient T cells possess a defect in survival during the early phase of T cell activation that is correlated with a striking defect in Bcl-xL expression. These data indicate discrete effects of p75 on the intracellular signaling milieu during T cell activation, and reveal the synergistic requirement of TCR, CD28, and p75 toward optimal IL-2 induction and T cell survival. We propose that p75 acts as one of the earliest of the identified costimulatory members of the TNFR family, and is functionally linked to CD28 for initiating and determining T cell fate during activation.
An Important Role for Polymeric Ig Receptor-Mediated Transport of IgA in Protection against Streptococcus pneumoniae Nasopharyngeal Carriage
Authors: Sun Keer , Johansen Finn-Eirik , Eckmann Lars , Metzger Dennis W. 
Published: April 2014

Abstract
The importance of IgA for protection at mucosal surfaces remains unclear, and in fact, it has been reported that IgA-deficient mice have fully functional vaccine-induced immunity against several bacterial and viral pathogens. The role of respiratory Ab in preventing colonization by Streptococcus pneumoniae has now been examined using polymeric IgR knockout (pIgR−/−) mice, which lack the ability to actively secrete IgA into the mucosal lumen. Intranasal vaccination with a protein conjugate vaccine elicited serotype-specific anti-capsular polysaccharide Ab locally and systemically, and pIgR−/− mice produced levels of total serum Ab after vaccination that were similar to wild-type mice. However, pIgR−/− mice had ∼5-fold more systemic IgA and 6-fold less nasal IgA Ab than wild-type mice due to defective transport into mucosal tissues. Wild-type, but not pIgR−/− mice were protected against infection with serotype 14 S. pneumoniae, which causes mucosal colonization but does not induce systemic inflammatory responses in mice. The relative importance of secretory IgA in host defense was further shown by the finding that intranasally vaccinated IgA gene-deficient mice were not protected from colonization. Although secretory IgA was found to be important for protection against nasal carriage, it does not appear to have a crucial role in immunity to systemic pneumococcus infection, because both vaccinated wild-type and pIgR−/− mice were fully protected from lethal systemic infection by serotype 3 pneumococci. The results demonstrate the critical role of secretory IgA in protection against pneumococcal nasal colonization and suggest that directed targeting to mucosal tissues will be needed for effective vaccination in humans.
The Antibiotic Polymyxin B Modulates P2X7 Receptor Function
Authors: Ferrari Davide , Pizzirani Cinzia , Adinolfi Elena , Forchap Sylvia , Sitta Barbara , Turchet Laura , Falzoni Simonetta , Minelli Mattia , Baricordi Roberto , Di Virgilio Francesco 
Published: April 2014

Abstract
The natural peptide polymyxin B (PMB) is a well-known and potent antibiotic that binds and neutralizes bacterial endotoxin (LPS), thus preventing its noxious effects among LPS-mediated endotoxin shock in animal models. We have investigated the effect of PMB on responses mediated by the P2X7R in HEK293 and K562 cells transfected with P2X7 cDNA and in mouse and human macrophages. In addition, in view of the potential exploitation of P2X7-directed agonists in antitumor therapy, we also investigated the effect of PMB in B lymphocytes from patients affected by chronic lymphocytic leukemia. PMB, at an optimal concentration dependent on the given cell type, greatly potentiated the effect of nucleotide-mediated P2X7 stimulation. In particular, ATP-mediated Ca2+ influx, plasma membrane permeabilization, and cytotoxicity were enhanced to an extent that, in the presence of PMB, cells were killed by otherwise ineffective nucleotide concentrations. The synergistic effect due to the combined application of ATP and PMB was prevented by incubation with the irreversible P2X blocker oxidized ATP (oATP), but not with the reversible antagonist 1-(N,O-bis(1,5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl)-4-phenilpiperazine (KN-62). Cells lacking P2X7 were fully insensitive to the combined stimulation with PMB and ATP. Furthermore, PMB at the concentrations used had no untoward effects on cell viability. These results point to PMB as a useful tool for the modulation of P2X7R function and suggest that care should be used in the evaluation of ATP-stimulated immune cell responses in the presence of PMB as they may not solely be affected by removal of contaminating LPS.
Human Parvovirus B19 Transgenic Mice Become Susceptible to Polyarthritis
Authors: Takasawa Naruhiko , Munakata Yasuhiko , Ishii Keiko Kumura , Takahashi Yuichi , Takahashi Minako , Fu Yi , Ishii Tomonori , Fujii Hiroshi , Saito Takako , Takano Hiroshi , Noda Tetsuo , Suzuki Misao , Nose Masato , Zolla-Patzner Suzan , Sasaki Takeshi 
Published: April 2014

Abstract
Human parvovirus B19 (B19) often causes acute polyarthritis in adults. In this paper, we analyzed nucleotide sequences of the B19 genome of patients with rheumatoid arthritis (RA), and then introduced the nonstructual protein 1 (NS1) gene of B19 into C57BL/6 mice that had a genetic origin not susceptible to arthritis. The transgenic mice developed no lesions spontaneously, but were susceptible to type II collagen (CII)-induced arthritis. B19 NS1 was expressed in synovial cells on the articular lesions that were histologically characteristic of granulomatous synovitis and pannus formation in cartilage and bone. Serum levels of anti-CII Abs and TNF-α increased in NS1 transgenic mice to the same levels as those of DBA/1 mice, which were susceptible to polyarthritis. Stimulation with CII increased secretion of Th1-type- and Th2-type cytokines in NS1 transgenic mice, indicating that a nonpermissive H-2b haplotype in the wild type of C57BL/6 mice can be made susceptible to polyarthritis through the expression of NS1. This study is the first to show that a viral agent from the joints in humans can cause CII-induced arthritis resembling RA.
A Transient Post-Translationally Modified Form of Cartilage Type II Collagen Is Ignored by Self-Reactive T Cells
Authors: Yamada Hisakata , Dzhambazov Balik , Bockermann Robert , Blom Thomas , Holmdahl Rikard 
Published: April 2014

Abstract
Lysine residues in type II collagen (CII) are normally hydroxylated and subsequently glycosylated in the chondrocyte. The immunodominant T cell epitope of CII involves such post-translationally modified lysine at position 264 that has been shown to be critical in the pathogenesis of murine collagen-induced arthritis and also in human rheumatoid arthritis. In this study we identified a line of transgenic mice expressing a TCR specific for hydroxylated rat CII epitope. They were crossed with transgenic mice expressing the rat CII epitope, either specifically in cartilage (MMC mice) or systemically (TSC mice), to analyze T cell tolerance to a post-translationally modified form of self-CII. The mechanism of T cell tolerance to the hydroxylated CII epitope in TSC mice was found to involve intrathymic deletion and induction of peripheral tolerance. In contrast, we did not observe T cell tolerance in the MMC mice. Analysis of CII prepared from rat or human joint cartilage revealed that most of the lysine 264 is glycosylated rather than remaining hydroxylated. Therefore, we conclude that the transient post-translationally modified form of cartilage CII does not induce T cell tolerance. This lack of T cell tolerance could increase the risk of developing autoimmune arthritis.
Regression of Established Liver Tumor Induced by Monoepitopic Peptide-Based Immunotherapy
Authors: Belnoue Elodie , Guettier Catherine , Kayibanda Michèle , Le Rond Solène , Crain-Denoyelle Anne-Marie , Marchiol Carmen , Ziol Marianne , Fradelizi Didier , Rénia Laurent , Viguier Mireille 
Published: April 2014

Abstract
Most types of cancer are difficult to eradicate, and some, like hepatocellular carcinoma, are almost always fatal. Among various interventions to improve the survival of patients with cancer, immunotherapy seems to hold some promises. However, it requires relevant animal models for preclinical development. In this study we report a new and relevant experimental model where liver tumors grow inside a nontumoral parenchyma of adult mice. This model is based on the intrasplenic injection in syngeneic recipient mice of hepatocytes from transgenic mice expressing SV40 large T oncogene specifically in the liver. Using this model where no apparent spontaneous cellular immune response was observed, immunization using a single injection of monoepitopic SV40 T Ag short peptide was sufficient to provoke liver tumor destruction, leading rapidly to complete remission. Tumor regression was associated with the induction of a long-lasting CD8+ T cell response, observed not only in the spleen but also, more importantly, in the tumoral liver. These results show the efficacy of peptide immunotherapy in the treatment of liver cancer.
The Magnitude of Akt/Phosphatidylinositol 3′-Kinase Proliferating Signaling Is Related to CD45 Expression in Human Myeloma Cells
Authors: Descamps Géraldine , Pellat-Deceunynck Catherine , Szpak Yann , Bataille Régis , Robillard Nelly , Amiot Martine 
Published: April 2014

Abstract
In multiple myeloma, the Akt/PI3K pathway is involved in the proliferation of myeloma cells. In the current study, we have investigated the impact of the CD45 phosphatase in the control of Akt/PI3K activation. We show that Akt activation in response to insulin-like growth factor-1 (IGF-1) is highly variable from one human myeloma cell line to another one. Actually, Akt activation is highly related to whether CD45 is expressed or not. Indeed, both the magnitude and the duration of Akt phosphorylation in response to IGF-1 are more important in CD45− than in CD45+ myeloma cell lines. We next demonstrate a physical association between CD45 and IGF-1 receptor (IGF-1R) suggesting that CD45 could be involved in the dephosphorylation of the IGF-1R. Furthermore, the growth of CD45− myeloma cell lines is mainly or even totally controlled by the PI3K pathway whereas that of CD45+ myeloma cell lines is modestly controlled by it. Indeed, wortmannin, a specific PI3K inhibitor, induced a dramatic growth inhibition in the CD45− myeloma cell lines characterized by a G1 growth arrest, whereas it has almost no effect on CD45+ myeloma cell lines. Altogether, these results suggest that CD45 negatively regulates IGF-1-dependent activation of PI3K. Thus, strategies that block IGF-1R signaling and consequently the Akt/PI3K pathway could be a priority in the treatment of patients with multiple myeloma, especially those lacking CD45 expression that have a very poor clinical outcome.
STAT6-Dependent Differentiation and Production of IL-5 and IL-13 in Murine NK2 Cells
Authors: Katsumoto Takuo , Kimura Motoko , Yamashita Masakatsu , Hosokawa Hiroyuki , Hashimoto Kahoko , Hasegawa Akihiro , Omori Miyuki , Miyamoto Takeshi , Taniguchi Masaru , Nakayama Toshinori 
Published: April 2014

AbstractNK cells differentiate into either NK1 or NK2 cells that produce IFN-γ or IL-5 and IL-13, respectively. Little is known, however, about the molecular mechanisms that control NK1 and NK2 cell differentiation. To address these questions, we established an in vitro mouse NK1/NK2 cell differentiation culture system. For NK1/NK2 cell differentiation, initial stimulation with PMA and ionomycin was required. The in vitro differentiated NK2 cells produced IL-5 and IL-13, but the levels were 20 times lower than those of Th2 or T cytotoxic (Tc)2 cells. No detectable IL-4 was produced. Freshly prepared NK cells express IL-2Rβ, IL-2RγC, and IL-4Rα. After stimulation with PMA and ionomycin, NK cells expressed IL-2Rα. NK1 cells displayed higher cytotoxic activity against Yac-1 target cells. The levels of GATA3 protein in developing NK2 cells were approximately one-sixth of those in Th2 cells. Both NK1 and NK2 cells expressed large amounts of repressor of GATA, the levels of which were equivalent to CD8 Tc1 and Tc2 cells and significantly higher than those in Th2 cells. The levels of histone hyperacetylation of the IL-4 and IL-13 gene loci in NK2 cells were very low and equivalent to those in naive CD4 T cells. The production of IL-5 and IL-13 in NK2 cells was found to be STAT6 dependent. Thus, similar to Th2 cells, NK2 cell development is dependent on STAT6, and the low level expression of GATA3 and the high level expression of repressor of GATA may influence the unique type 2 cytokine production profiles of NK2 cells.