bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene Expression Profiling Reveals Unique Pathways Associated with Differential Severity of Lyme Arthritis
Authors: Crandall Hillary , Dunn Diane M. , Ma Ying , Wooten R. Mark , Zachary James F. , Weis John H. , Weiss Robert B. , Weis Janis J.
Published: April 2014

The murine model of Lyme disease provides a unique opportunity to study the localized host response to similar stimulus, Borrelia burgdorferi, in the joints of mice destined to develop severe arthritis (C3H) or mild disease (C57BL/6). Pathways associated with the response to infection and the development of Lyme arthritis were identified by global gene expression patterns using oligonucleotide microarrays. A robust induction of IFN-responsive genes was observed in severely arthritic C3H mice at 1 wk of infection, which was absent from mildly arthritic C57BL/6 mice. In contrast, infected C57BL/6 mice displayed a novel expression profile characterized by genes involved in epidermal differentiation and wound repair, which were decreased in the joints of C3H mice. These expression patterns were associated with disease state rather than inherent differences between C3H and C57BL/6 mice, because C57BL/6-IL-10−/− mice infected with B. burgdorferi develop more severe arthritis than C57BL/6 mice and displayed an early gene expression profile similar to C3H mice. Gene expression profiles at 2 and 4 wk postinfection revealed a common response of all strains that was likely to be important for the host defense to B. burgdorferi and mediated by NF-κB-dependent signaling. The gene expression profiles identified in this study add to the current understanding of the host response to B. burgdorferi and identify two novel pathways that may be involved in regulating the severity of Lyme arthritis.
The IFN-Independent Response to Virus Particle Entry Provides a First Line of Antiviral Defense That Is Independent of TLRs and Retinoic Acid-Inducible Gene I
Authors: Paladino Patrick , Cummings Derek T. , Noyce Ryan S. , Mossman Karen L.
Published: April 2014

The innate immune system responds to pathogen infection by eliciting a nonspecific immune response following the recognition of various pathogen-associated molecular patterns. TLRs and the RNA helicases retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 recognize foreign nucleic acid within endosomal and cytoplasmic compartments, respectively, initiating a signaling cascade that involves the induction of type I IFN through the transcription factors IFN regulatory factor (IRF) 3 and NF-κB. However, a recent paradigm has emerged in which bacterial DNA and double-stranded B-form DNA trigger type I IFN production through an uncharacterized TLR- and RIG-I-independent pathway. We have previously described a response in primary fibroblasts wherein the entry of diverse RNA- and DNA-enveloped virus particles is sufficient to induce a subset of IFN-stimulated genes and a complete antiviral response in an IRF3-dependent, IFN-independent manner. In this study, we show that the innate immune response to virus particle entry is independent of both TLR and RIG-I pathways, confirming the existence of novel innate immune mechanisms that result in the activation of IRF3. Furthermore, we propose a model of innate antiviral immunity in which exposure to increasing numbers of virus particles elevates the complexity of the cellular response from an intracellular, IFN-independent response to one involving secretion of cytokines and activation of infiltrating immune cells.
A New Staphylococcal Anti-Inflammatory Protein That Antagonizes the Formyl Peptide Receptor-Like 1
Authors: Prat Cristina , Bestebroer Jovanka , de Haas Carla J. C. , van Strijp Jos A. G. , van Kessel Kok P. M.
Published: April 2014

Bacteria have developed mechanisms to escape the first line of host defense, which is constituted by the recruitment of phagocytes to the sites of bacterial invasion. We previously described the chemotaxis inhibitory protein of Staphylococcus aureus, a protein that blocks the activation of neutrophils via the formyl peptide receptor (FPR) and C5aR. We now describe a new protein from S. aureus that impaired the neutrophil responses to FPR-like1 (FPRL1) agonists. FPRL1 inhibitory protein (FLIPr) inhibited the calcium mobilization in neutrophils stimulated with MMK-1, WKYMVM, prion-protein fragment PrP106–126, and amyloid β1–42. Stimulation with low concentrations of fMLP was partly inhibited. Directed migration was also completely prevented toward MMK-1 and partly toward fMLP. Fluorescence-labeled FLIPr efficiently bound to neutrophils, monocytes, B cells, and NK cells. HEK293 cells transfected with human C5aR, FPR, FPRL1, and FPRL2 clearly showed that FLIPr directly bound to FPRL1 and, at higher concentrations, also to FPR but not to C5aR and FPRL2. FLIPr can reveal unknown inflammatory ligands crucial during S. aureus infections. As a novel described FPRL1 antagonist, it might lead to the development of therapeutic agents in FPRL1-mediated inflammatory components of diseases such as systemic amyloidosis, Alzheimer’s, and prion disease.
Direct CD28 Costimulation Is Required for CD8+ T Cell-Mediated Resistance to an Acute Viral Disease in a Natural Host
Authors: Fang Min , Sigal Luis J.
Published: April 2014

Previous studies have suggested that, differing from model Ags, viruses that replicate extensively in the host still induce normal CD8+ T cell responses in the absence of CD28 costimulation. Because these studies were performed with viruses that do not normally cause acute disease, an important remaining question is whether CD28 costimulation is required for CD8+ T cell-mediated resistance to widely replicating but pathogenic viruses. To address this question, we studied the role of CD28 costimulation in CD8+ T cell-mediated resistance to mousepox, a disease of the mouse caused by the natural mouse pathogen, the ectromelia virus (ECTV). C57BL/6 (B6) mice are naturally resistant to mousepox, partly due to a fast and strong CD8+ T cell response. We found that B6 mice deficient in CD28 (CD28 knockout (KO)) are highly susceptible to lethal mousepox during the early stages of ECTV infection but can be protected by immunization with the antigenically related vaccinia virus (VACV) or by adoptive transfer of CD28 KO anti-VACV memory CD8+ cells. Of interest, a thorough comparison of the CD8+ T cell responses to ECTV and VACV suggests that the main reason for the susceptibility of CD28 KO mice to mousepox is a reduced response at the early stages of infection. Thus, while in the absence of CD28 costimulation the end point strength of the T cell responses to nonpathogenic viruses may appear normal, CD28 costimulation increases the speed of the T cell response and is essential for resistance to a life-threatening acute viral disease.
Recombinant Soluble Forms of Extracellular TLR4 Domain and MD-2 Inhibit Lipopolysaccharide Binding on Cell Surface and Dampen Lipopolysaccharide-Induced Pulmonary Inflammation in Mice
Authors: Mitsuzawa Hiroaki , Nishitani Chiaki , Hyakushima Naoki , Shimizu Takeyuki , Sano Hitomi , Matsushima Norio , Fukase Koichi , Kuroki Yoshio
Published: April 2014

In this study, we sought the possibility of a new therapeutic strategy for dampening endotoxin-induced inflammation using soluble form of extracellular rTLR4 domain (sTLR4) and soluble form of rMD-2 (sMD-2). Addition of sTLR4 plus sMD-2 was significantly effective in inhibiting LPS-elicited IL-8 release from U937 cells and NF-κB activation in the cells transfected with TLR4 and MD-2 when compared with a single treatment with sTLR4 or sMD-2. Thus, we investigated the role of the extracellular TLR4 domain in interaction of lipid A with MD-2. Biotinylated sTLR4 failed to coprecipitate [3H]lipid A when it was sedimented with streptavidin-agarose, demonstrating that the extracellular TLR4 domain does not directly bind lipid A by itself. The amounts of lipid A coprecipitated with sMD-2 significantly increased when coincubated with sTLR4, and sTLR4 increased the affinity of lipid A for the binding to sMD-2. Soluble CD14 is required for the sTLR4-stimulated increase of lipid A binding to sMD-2. We also found that addition of sTLR4 plus sMD-2 inhibited the binding of Alexa-conjugated LPS to the cells expressing TLR4 and MD-2. Murine lungs that had received sTLR4 plus sMD-2 with LPS did not show any findings indicative of interstitial edema, neutrophil flux, and hemorrhage. Coinstillation of sTLR4 plus sMD-2, but not sTLR4 or sMD-2 alone, significantly decreased neutrophil infiltration and TNF-α levels in bronchoalveolar lavage fluids from LPS-treated mice. This study provides novel usage of sTLR4 and sMD-2 as an antagonist against endotoxin-induced pulmonary inflammation.
Plasminogen Activator Inhibitor Type-1-Deficient Mice Have an Enhanced IFN-γ Response to Lipopolysaccharide and Staphylococcal Enterotoxin B
Authors: Renckens Rosemarijn , Pater Jennie M. , Poll Tom van der
Published: April 2014

Plasminogen activator inhibitor type-1 (PAI-1) is a major inhibitor of fibrinolysis by virtue of its capacity to inhibit urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA). Systemic inflammation is invariably associated with elevated circulating levels of PAI-1, and during human sepsis plasma PAI-1 concentrations predict an unfavorable outcome. Knowledge about the functional role of PAI-1 in a systemic inflammatory response syndrome is highly limited. In this study, we determined the role of endogenous PAI-1 in cytokine release induced by administration of LPS or staphylococcal enterotoxin B (SEB). Both LPS and SEB elicited secretion of PAI-1 into the circulation of normal wild-type (Wt) mice. Relative to Wt mice, PAI-1 gene-deficient (PAI-1−/−) mice demonstrated strongly elevated plasma IFN-γ concentrations after injection of either LPS or SEB. In addition, PAI-1−/− splenocytes released more IFN-γ after incubation with LPS or SEB than Wt splenocytes. Both PAI-1−/− CD4+ and CD8+ T cells produced more IFN-γ upon stimulation with SEB. LPS-induced IFN-γ release in mice deficient for uPA, the uPA receptor, or tPA was not different from IFN-γ release in LPS-treated Wt mice. These results identify a novel function of PAI-1 during systemic inflammation, where endogenous PAI-1 serves to inhibit IFN-γ release by a mechanism that does not depend on its interaction with uPA/uPA receptor or tPA.
IRAK-4 Mutation (Q293X): Rapid Detection and Characterization of Defective Post-Transcriptional TLR/IL-1R Responses in Human Myeloid and Non-Myeloid Cells
Authors: Davidson Donald J. , Currie Andrew J. , Bowdish Dawn M. E. , Brown Kelly L. , Rosenberger Carrie M. , Ma Rebecca C. , Bylund Johan , Campsall Paul A. , Puel Anne , Picard Capucine , Casanova Jean-Laurent , Turvey Stuart E. , Hancock Robert E. W. , Devon Rebecca S. , Speert David P.
Published: April 2014

Innate immunodeficiency has recently been reported as resulting from the Q293X IRAK-4 mutation with consequent defective TLR/IL-1R signaling. In this study we report a method for the rapid allele-specific detection of this mutation and demonstrate both cell type specificity and ligand specificity in defective IL-1R-associated kinase (IRAK)-4-deficient cellular responses, indicating differential roles for this protein in human PBMCs and primary dermal fibroblasts and in LPS, IL-1β, and TNF-α signaling. We demonstrate transcriptional and post-transcriptional defects despite NF-κB signaling and intact MyD88-independent signaling and propose that dysfunctional complex 1 (IRAK1/TRAF6/TAK1) signaling, as a consequence of IRAK-4 deficiency, generates specific defects in MAPK activation that could underpin this patient’s innate immunodeficiency. These studies demonstrate the importance of studying primary human cells bearing a clinically relevant mutation; they underscore the complexity of innate immune signaling and illuminate novel roles for IRAK-4 and the fundamental importance of accessory proinflammatory signaling to normal human innate immune responses and immunodeficiencies.
Spontaneous CD8 T Cell Responses against the Melanocyte Differentiation Antigen RAB38/NY-MEL-1 in Melanoma Patients
Authors: Walton Senta M. , Gerlinger Marco , de la Rosa Olga , Nuber Natko , Knights Ashley , Gati Asma , Laumer Monika , Strauss Laura , Exner Carolin , Schäfer Niklaus , Urosevic Mirjana , Dummer Reinhard , Tiercy Jean-Marie , Mackensen Andreas , Jaeger Elke , Lévy Frédéric , Knuth Alexander , Jäger Dirk , Zippelius Alfred
Published: April 2014

The melanocyte differentiation Ag RAB38/NY-MEL-1 was identified by serological expression cloning (SEREX) and is expressed in the vast majority of melanoma lesions. The immunogenicity of RAB38/NY-MEL-1 has been corroborated previously by the frequent occurrence of specific Ab responses in melanoma patients. To elucidate potential CD8 T cell responses, we applied in vitro sensitization with overlapping peptides spanning the RAB38/NY-MEL-1 protein sequence and the reverse immunology approach. The identified peptide RAB38/NY-MEL-150–58 exhibited a marked response in ELISPOT assays after in vitro sensitization of CD8 T cells from HLA-A∗0201+ melanoma patients. In vitro digestion assays using purified proteasomes provided evidence of natural processing of RAB38/NY-MEL-150–58 peptide. Accordingly, monoclonal RAB38/NY-MEL-150–58-specific T cell populations were capable of specifically recognizing HLA-A2+ melanoma cell lines expressing RAB38/NY-MEL-1. Applying fluorescent HLA-A2/RAB38/NY-MEL-150–58 multimeric constructs, we were able to document a spontaneously developed memory/effector CD8 T cell response against this peptide in a melanoma patient. To elucidate the Ag-processing pathway, we demonstrate that RAB38/NY-MEL-150–58 is produced efficiently by the standard proteasome and the immunoproteasome. In addition to the identification of a RAB38/NY-MEL-1-derived immunogenic CD8 T cell epitope, this study is instrumental for both the onset and monitoring of future RAB38/NY-MEL-1-based vaccination trials.
Cutting Edge: TLR2 Is Required for the Innate Response to Porphyromonas gingivalis: Activation Leads to Bacterial Persistence and TLR2 Deficiency Attenuates Induced Alveolar Bone Resorption
Authors: Burns Elia , Bachrach Gilad , Shapira Lior , Nussbaum Gabriel
Published: April 2014

Periodontitis is a chronic inflammatory disease that leads to destruction of the attachment apparatus of the teeth. The presence of particular oral bacteria and the host inflammatory response contribute to disease progression. Porphyromonas gingivalis is a Gram-negative anaerobe considered to be a major periodontal pathogen. Isolated Ags from P. gingivalis activate innate immune cells through TLR2 or TLR4. We challenged TLR2- and TLR4-deficient mice with live P. gingivalis and studied the inflammatory response and bacterial survival. Wild-type and TLR4-deficient mice produced high levels of cytokines in response to P. gingivalis challenge, whereas cytokine levels were nearly absent or delayed in TLR2-deficient mice. Surprisingly, P. gingivalis was cleared far more rapidly in TLR2-deficient mice. In addition, TLR2-deficient mice resisted bone loss following oral infection with P. gingivalis.
Functional Adaptive CD4 Foxp3 T Cells Develop in MHC Class II-Deficient Mice
Authors: Bochtler Petra , Wahl Christian , Schirmbeck Reinhold , Reimann Jörg
Published: April 2014

CD4 Foxp3 regulatory T (TR) cells are well-defined regulator T cells known to develop in the thymus through positive selection by medium-to-high affinity TCR-MHC interactions. We asked whether Foxp3 TR cells can be generated in the complete absence of MHC class II molecules. CD4 Foxp3 TR cells are found in secondary lymphoid tissues (spleen and lymph nodes) and peripheral tissues (liver) but not the thymus of severely MHC class II-deficient (Aα−/− B6) mice. These TR cells preferentially express CD103 (but not CD25) but up-regulate CD25 surface expression to high levels in response to TCR-mediated activation. MHC class II-independent Foxp3 TR cells down modulate vaccine-induced, specific antiviral CD8 T cell responses of Aα−/− B6 mice in vivo. Furthermore, these TR cells suppress IL-2 release and proliferative responses in vitro of naive CD25− (CD4 or CD8) T cells from normal B6 mice primed by bead-coupled anti-CD3/anti-CD28 Ab as efficiently as CD4CD25high TR cells from congenic, normal B6 mice. MHC class II-independent CD4 Foxp3+ TR cells thus preferentially express the (TGF-β-induced) integrin molecule αE (CD103), are generated mainly in the periphery and efficiently mediate immunosuppressive effects.
γδ T Cells Promote Anterior Chamber-Associated Immune Deviation and Immune Privilege through Their Production of IL-10
Authors: Ashour Hossam M. , Niederkorn Jerry Y.
Published: April 2014

Anterior chamber-associated immune deviation (ACAID) is a form of peripheral tolerance that is induced by introducing Ags into the anterior chamber (AC) of the eye, and is maintained by Ag-specific regulatory T cells (Tregs). ACAID regulates harmful immune responses that can lead to irreparable injury to innocent bystander cells that are incapable of regeneration. This form of immune privilege in the eye is mediated through Tregs and is a product of complex cellular interactions. These involve F4/80+ ocular APCs, B cells, NKT cells, CD4+CD25+ Tregs, and CD8+ Tregs. γδ T cells are crucial for the generation of ACAID and for corneal allograft survival. However, the functions of γδ T cells in ACAID are unknown. Several hypotheses were proposed for determining the functions of γδ T cells in ACAID. The results indicate that γδ T cells do not cause direct suppression of delayed-type hypersensitivity nor do they act as tolerogenic APCs. In contrast, γδ T cells were shown to secrete IL-10 and facilitate the generation of ACAID Tregs. Moreover, the contribution of γδ T cells ACAID generation could be replaced by adding exogenous recombinant mouse IL-10 to ACAID spleen cell cultures lacking γδ T cells.
Rapamycin Promotes Expansion of Functional CD4+CD25+FOXP3+ Regulatory T Cells of Both Healthy Subjects and Type 1 Diabetic Patients
Authors: Battaglia Manuela , Stabilini Angela , Migliavacca Barbara , Horejs-Hoeck Jutta , Kaupper Thomas , Roncarolo Maria-Grazia
Published: April 2014

CD4+CD25+FOXP3+ T regulatory cells (Tregs) are pivotal for the induction and maintenance of peripheral tolerance in both mice and humans. Rapamycin has been shown to promote tolerance in experimental models and to favor CD4+CD25+ Treg-dependent suppression. We recently reported that rapamycin allows in vitro expansion of murine CD4+CD25+FoxP3+ Tregs, which preserve their suppressive function. In the current study, we show that activation of human CD4+ T cells from healthy subjects in the presence of rapamycin leads to growth of CD4+CD25+FOXP3+ Tregs and to selective depletion of CD4+CD25− T effector cells, which are highly sensitive to the antiproliferative effect of the compound. The rapamycin-expanded Tregs suppress proliferation of both syngeneic and allogeneic CD4+ and CD8+ T cells. Interestingly, rapamycin promotes expansion of functional CD4+CD25+FOXP3+ Tregs also in type 1 diabetic patients, in whom a defect in freshly isolated CD4+CD25+ Tregs has been reported. The capacity of rapamycin to allow growth of functional CD4+CD25+FOXP3+ Tregs, but also to deplete T effector cells, can be exploited for the design of novel and safe in vitro protocols for cellular immunotherapy in T cell-mediated diseases.
Dendritic Cell Targeting of Survivin Protein in a Xenogeneic Form Elicits Strong CD4+ T Cell Immunity to Mouse Survivin
Authors: Charalambous Anna , Oks Margarita , Nchinda Godwin , Yamazaki Sayuri , Steinman Ralph M.
Published: April 2014

To determine whether strong CD4+ T cell immunity could be induced to a nonmutated self protein that is important for tumorigenesis, we selectively targeted the xenogeneic form of survivin, a survival protein overexpressed in tumors, to maturing dendritic cells in lymphoid tissues. Dendritic cell targeting via the DEC205 receptor in the presence of anti-CD40 and poly(I:C) as maturation stimuli, induced strong human and mouse survivin-specific CD4+ T cell responses, as determined by IFN-γ, TNF-α, and IL-2 production, as well as the development of lytic MHC class II-restricted T cells and memory. Immunity was enhanced further by depletion of CD25+foxp3+ cells before vaccination. anti-DEC205-human survivin was superior in inducing CD4+ T cell responses relative to other approaches involving survivin plasmid DNA or survivin peptides with adjuvants. However, we were unable to induce CD8+ T cell immunity to survivin by two doses of DEC205-targeted survivin or the other strategies. Therefore, significant CD4+ T cell immunity to a self protein that is overexpressed in most human cancers can be induced by DEC205 targeting of the Ag in its xenogeneic form to maturing DCs.
A Natural Structural Variant of the Mouse TCR β-Chain Displays Intrinsic Receptor Function and Antigen Specificity
Authors: Aublin Anne , Ciofani Maria , Willkomm Nancy , Hamrouni Abdelbasset , Szymczak-Workman Andrea L. , Takahashi Tomio , Sandjeu Yongoua , Guillaume Philippe , Vignali Dario A. A. , Michielin Olivier , Zúñiga-Pflücker Juan Carlos , Maryanski Janet L.
Published: April 2014

The Cβ0 alternate cassette exon is located between the Jβ1 and Cβ1 genes in the mouse TCR β-locus. In T cells with a VDJβ1 rearrangement, the Cβ0 exon may be included in TCRβ transcripts (herein called TCRβ-Cβ0 transcripts), potentially inserting an additional 24 aa between the V and C domains of the TCR β-chain. These TCRβ splice isoforms may be differentially regulated after Ag activation, because we detected TCRβ-Cβ0 transcripts in a high proportion (>60%) of immature and mature T cells having VDJβ1 rearrangements but found a substantially reduced frequency (<35%) of TCRβ-Cβ0 expression among CD8 T cells selected by Ag in vivo. To study the potential activity of the TCRβ-Cβ0 splice variant, we cloned full-length TCR cDNAs by single-cell RT-PCR into retroviral expression vectors. We found that the TCRβ-Cβ0 splice isoform can function during an early stage of T cell development normally dependent on TCR β-chain expression. We also demonstrate that T hybridoma-derived cells expressing a TCRβ-Cβ0 isoform together with the clonally associated TCR α-chain recognize the same cognate peptide-MHC ligand as the corresponding normal αβTCR. This maintenance of receptor function and specificity upon insertion of the Cβ0 peptide cassette signifies a remarkable adaptability for the TCR β-chain, and our findings open the possibility that this splice isoform may function in vivo.
Differential IFN-γ Stimulation of HLA-A Gene Expression through CRM-1-Dependent Nuclear RNA Export
Authors: Browne Sarah K. , Roesser James R. , Zhu Sheng Zu , Ginder Gordon D.
Published: April 2014

IFNs regulate most MHC class I genes by stimulating transcription initiation. As shown previously, IFN-γ controls HLA-A expression primarily at the posttranscriptional level. We have defined two 8-base sequences in a 39-nucleotide region in the 3′-transcribed region of the HLA-A gene that are required for the posttranscriptional response to IFN-γ. Stimulation of HLA-A expression by IFN-γ requires nuclear export of HLA-A mRNA by chromosome maintenance region 1 (CRM-1). Treatment of cells with leptomycin B, a specific inhibitor of CRM-1, completely inhibited IFN-γ induction of HLA-A. Expression of a truncated, dominant-negative form of the nucleoporin NUP214/CAN, ΔCAN, that specifically interacts with CRM-1, also prevented IFN-γ stimulation of HLA-A, providing confirmation of the role of CRM-1. Increased expression of HLA-A induced by IFN-γ also requires protein methylation, as shown by the fact that treatment of SK-N-MC cells or HeLa cells with the PRMT1 inhibitor 5′-methyl-5′-thioadenosine abolished the cellular response to IFN-γ. In contrast with HLA-A, IFN-γ-induced expression of the HLA class Ib gene, HLA-E, was not affected by either 5′-methyl-5′-thioadenosine or leptomycin B. These results provide proof of principle that it is possible to differentially modulate the IFN-γ-induced expression of the HLA-E and HLA-A genes, whose products often mediate opposing effects on cellular immunity to tumor cells, pathogens, and autoantigens.
Vav Proteins Regulate the Plasma Cell Program and Secretory Ig Production
Authors: Stephenson Linda M. , Miletic Ana V. , Kloeppel Tracie , Kusin Shana , Swat Wojciech
Published: April 2014

Plasma cell (PC) development is initiated following B cell activation and controlled by a B lymphocyte-induced maturation protein (Blimp)-1-dependent program involving the concerted action of several proplasma transcriptional regulators. However, the factors that control Blimp-1 expression remain largely unknown. In this context, mice deficient for all three of the Vav family of proteins (Vavnull) develop substantial B cell populations, including marginal zone B cells, yet have a virtual absence of serum Igs, indicating that Vav may be specifically required in PC development and Ig production. We show in this study that mature marginal zone B cells from Vavnull mice proliferate following stimulation with TLR ligands but exhibit severe defects in PC differentiation and Ig secretion. Under conditions inducing PC differentiation, Vavnull B cells fail to efficiently induce Blimp-1, X box-binding protein-1, J chain, or secretory Ig μ transcripts but express IFN-regulatory factor-4 at levels similar to wild-type cells. These data indicate a previously unknown role for Vav as an upstream regulator of Blimp-1.
Pseudomonas Lipopolysaccharide Accelerates Wound Repair via Activation of a Novel Epithelial Cell Signaling Cascade
Authors: Koff Jonathan L. , Shao Matt X. G. , Kim Suil , Ueki Iris F. , Nadel Jay A.
Published: April 2014

The surface of the airway epithelium represents a battleground in which the host intercepts signals from pathogens and activates epithelial defenses to combat infection. Wound repair is an essential function of the airway epithelium in response to injury in chronic airway diseases, and inhaled pathogens such as Pseudomonas bacteria are implicated in the pathobiology of several of these diseases. Because epidermal growth factor receptor (EGFR) activation stimulates wound repair and because LPS activates EGFR, we hypothesized that LPS accelerates wound repair via a surface signaling cascade that causes EGFR phosphorylation. In scrape wounds of NCI-H292 human airway epithelial cells, high concentrations of LPS were toxic and decreased wound repair. However, lower concentrations of LPS accelerated wound repair. This effect was inhibited by treatment with a selective inhibitor of EGFR phosphorylation (AG 1478) and by an EGFR neutralizing Ab. Metalloprotease inhibitors and TNF-α-converting enzyme (TACE) small interfering RNA inhibited wound repair, implicating TACE. Additional studies implicated TGF-α as the active EGFR ligand cleaved by TACE during wound repair. Reactive oxygen species scavengers, NADPH oxidase inhibitors, and importantly small interfering RNA of dual oxidase 1 inhibited LPS-induced wound repair. Inhibitors of protein kinase C isoforms αβ and a TLR-4 neutralizing Ab also inhibited LPS-induced wound repair. Normal human bronchial epithelial cells responded similarly. Thus, LPS accelerates wound repair in airway epithelial cells via a novel TLR-4→protein kinase C αβ→dual oxidase 1→reactive oxygen species→TACE→TGF-α→EGFR phosphorylation pathway.
Inhibition of Macrophage Migration Inhibitory Factor or Its Receptor (CD74) Attenuates Growth and Invasion of DU-145 Prostate Cancer Cells
Authors: Meyer-Siegler Katherine L. , Iczkowski Kenneth A. , Leng Lin , Bucala Richard , Vera Pedro L.
Published: April 2014

Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, is overexpressed in prostate cancer, but the mechanism by which MIF exerts effects on tumor cells remains undetermined. MIF interacts with its identified membrane receptor, CD74, in association with CD44, resulting in ERK 1/2 activation. Therefore, we hypothesized that increased expression or surface localization of CD74 and MIF overexpression by prostate cancer cells regulated tumor cell viability. Prostate cancer cell lines (LNCaP and DU-145) had increased MIF gene expression and protein levels compared with normal human prostate or benign prostate epithelial cells (p < 0.01). Although MIF, CD74, and CD44 variant 9 expression were increased in both androgen-dependent (LNCaP) and androgen-independent (DU-145) prostate cancer cells, cell surface of CD74 was only detected in androgen-independent (DU-145) prostate cancer cells. Therefore, treatments aimed at blocking CD74 and/or MIF (e.g., inhibition of MIF or CD74 expression by RNA interference or treatment with anti-MIF- or anti-CD74- neutralizing Abs or MIF-specific inhibitor, ISO-1) were only effective in androgen-independent prostate cancer cells (DU-145), resulting in decreased cell proliferation, MIF protein secretion, and invasion. In DU-145 xenografts, ISO-1 significantly decreased tumor volume and tumor angiogenesis. Our results showed greater cell surface CD74 in DU-145 prostate cancer cells that bind to MIF and, thus, mediate MIF-activated signal transduction. DU-145 prostate cancer cell growth and invasion required MIF activated signal transduction pathways that were not necessary for growth or viability of androgen-dependent prostate cells. Thus, blocking MIF either at the ligand (MIF) or receptor (CD74) may provide new, targeted specific therapies for androgen-independent prostate cancer.
The Expression and Possible Roles of Chemokine CXCL11 and Its Receptor CXCR3 in the Human Endometrium
Authors: Hirota Yasushi , Osuga Yutaka , Koga Kaori , Yoshino Osamu , Hirata Tetsuya , Morimoto Chieko , Harada Miyuki , Takemura Yuri , Nose Emi , Yano Tetsu , Tsutsumi Osamu , Taketani Yuji
Published: April 2014

IFN-γ secreted by a human embryo and trophoblast cells during implantation is suggested to play an important role in implantation and pregnancy. In the present study, we explored expression and possible functions of CXCL11, a CXC chemokine strongly induced by IFN-γ, and its receptor CXCR3 in the human endometrium. Secreted CXCL11 protein was not detected in cultured endometrial stromal cells (ESC) but was detected in cultured endometrial epithelial cells (EEC). IFN-γ stimulated the protein levels of CXCL11 in a dose-dependent manner in EEC and ESC. CXCL11 secreted from EEC with 100 ng/ml IFN-γ was 220-fold of the control, and 100-fold as compared with that secreted from ESC with the same dose of IFN-γ. CXCR3 was expressed in EEC, ESC, and trophoblast cells. Addition of IFN-γ to EEC increased the chemotactic activity of its culture medium to trophoblast cells and T cells, and the effect was suppressed by immunoneutralization with Abs of three CXCR3 ligands, including anti-CXCL11 Ab. CXCL11 significantly increased BrdU incorporation of ESC, which was inhibited by a p42/44 MAPK pathway inhibitor PD98059. In contrast, CXCL11 significantly decreased BrdU incorporation and increased the release of lactate dehydrogenase and the positive staining of annexin V in EEC. These findings suggest that IFN-γ promotes implantation by stimulating EEC to produce CXCL11, which induces migration of trophoblast cells and T cells, proliferation of ESC, and apoptosis of EEC.
Characterization of the B Cell Epitopes Associated with a Truncated Form of Pseudomonas Exotoxin (PE38) Used to Make Immunotoxins for the Treatment of Cancer Patients
Authors: Onda Masanori , Nagata Satoshi , FitzGerald David J. , Beers Richard , Fisher Robert J. , Vincent James J. , Lee Byungkook , Nakamura Michihiro , Hwang Jaulang , Kreitman Robert J. , Hassan Raffit , Pastan Ira
Published: April 2014

Recombinant immunotoxins composed of an Ab Fv fragment joined to a truncated portion of Pseudomonas exotoxin A (termed PE38) have been evaluated in clinical trials for the treatment of various human cancers. Immunotoxin therapy is very effective in hairy cell leukemia and also has activity in other hemological malignancies; however, a neutralizing Ab response to PE38 in patients with solid tumors prevents repeated treatments to maximize the benefit. In this study, we analyze the murine Ab response as a model to study the B cell epitopes associated with PE38. Sixty distinct mAbs to PE38 were characterized. Mutual competitive binding of the mAbs indicated the presence of 7 major epitope groups and 13 subgroups. The competition pattern indicated that the epitopes are discrete and could not be reproduced using a computer simulation program that created epitopes out of random surface residues on PE38. Using sera from immunotoxin-treated patients, the formation of human Abs to each of the topographical epitopes was demonstrated. One epitope subgroup, E1a, was identified as the principal neutralizing epitope. The location of each epitope on PE38 was determined by preparing 41 mutants of PE38 in which bulky surface residues were mutated to either alanine or glycine. All 7 major epitope groups and 9 of 13 epitope subgroups were identified by 14 different mutants and these retained high cytotoxic activity. Our results indicate that a relatively small number of discrete immunogenic sites are associated with PE38, most of which can be eliminated by point mutations.
Familial NK Cell Deficiency Associated with Impaired IL-2- and IL-15-Dependent Survival of Lymphocytes
Authors: Eidenschenk Céline , Jouanguy Emmanuelle , Alcaïs Alexandre , Mention Jean-Jacques , Pasquier Benoit , Fleckenstein Ingrid M. , Puel Anne , Gineau Laure , Carel Jean-Claude , Vivier Eric , Le Deist Françoise , Casanova Jean-Laurent
Published: April 2014

We previously reported the clinical phenotype of two siblings with a novel inherited developmental and immunodeficiency syndrome consisting of severe intrauterine growth retardation and the impaired development of specific lymphoid lineages, including transient CD8 αβ T lymphopenia and a persistent lack of blood NK cells. We describe here the elucidation of a plausible underlying pathogenic mechanism, with a cellular phenotype of impaired survival of both fresh and herpesvirus saimiri-transformed T cells, in the surviving child. Clearly, NK cells could not be studied. However, peripheral blood T lymphocytes displayed excessive apoptosis ex vivo. Moreover, the survival rates of CD4 and CD8 αβ T cell blasts generated in vitro, and herpesvirus saimiri-transformed T cells cultured in vitro, were low, but not nil, following treatment with IL-2 and IL-15. In contrast, Fas-mediated activation-induced cell death was not enhanced, indicating a selective excess of cytokine deprivation-mediated apoptosis. In keeping with the known roles of IL-2 and IL-15 in the development of NK and CD8 T cells in the mouse model, these data suggest that an impaired, but not abolished, survival response to IL-2 and IL-15 accounts for the persistent lack of NK cells and the transient CD8 αβ T lymphopenia documented in vivo. Impaired cytokine-mediated lymphocyte survival is likely to be the pathogenic mechanism underlying this novel form of inherited and selective NK deficiency in humans.
Modulation of the Effector Functions of a Human IgG1 through Engineering of Its Hinge Region
Authors: Dall’Acqua William F. , Cook Kimberly E. , Damschroder Melissa M. , Woods Robert M. , Wu Herren
Published: April 2014

We report here the engineering of a humanized anti-human EphA2 mAb (mAb 12G3H11) in an effort to explore the relationship between the hinge of a human IgG1 and its effector functions. mAb 12G3H11, used here as a model, is directed against the human receptor tyrosine kinase EphA2, which is an actively investigated target for cancer therapy due to its up-regulation in many cancer cells. Various rational modifications were introduced into the hinge region of mAb 12G3H11. These mutations were predicted to modulate the hinge’s length, flexibility, and/or biochemical properties. We show that the upper and middle hinge both play important, although functionally distinct roles. In particular, middle hinge modifications predicted to decrease its rigidity or length as well as eliminating either one of its two cysteine residues had a strong negative impact on C1q binding and complement-dependent cytotoxicity. Disruption of covalent bonds between both H chains may account in part for these effects. We also describe middle hinge mutants with a significantly decreased ability to bind FcγRIIIA and trigger Ab-dependent cell-mediated cytotoxicity. Conversely, we also generated upper hinge mutants exhibiting an increase in C1q binding and complement-dependent cytotoxicity activity. Therefore, this approach represents a novel strategy to fine-tune the biological activity of a given human IgG1. We also define, for the first time in such a systematic fashion, the relationship between various characteristics of the middle and upper hinge and the corresponding effector functions.
Roles of the Ig κ Light Chain Intronic and 3′ Enhancers inIgkSomatic Hypermutation
Authors: Inlay Matthew A. , Gao Heather H. , Odegard Valerie H. , Lin Tongxiang , Schatz David G. , Xu Yang
Published: April 2014

Somatic hypermutation (SHM) of the rearranged Ig genes is required for the affinity maturation of Abs. SHM is almost exclusively targeted to the rearranged Ig loci, but the mechanism of this gene-specific targeting remains unclear. The Ig κ L chain locus contains multiple enhancers, including the MAR/intronic (iEκ) and 3′ enhancers (3′Eκ). Previous transgenic studies indicate that both κ enhancers are individually necessary for SHM of Igk. In contrast, later studies of Ag-selected Vκ genes in 3′Eκ−/− mice found no absolute requirement for 3′Eκ in κ SHM. To address the roles of the two κ enhancers in SHM in a physiological context, we analyzed SHM of the endogenous Igk in mice with a targeted deletion of either iEκ or 3′Eκ in Peyer’s patch germinal center B cells. Our findings indicate that, although 3′Eκ is quantitatively important for SHM of Igk, iEκ is not required for κ SHM. In addition, a reduction of κ mRNA levels is also detected in activated 3′Eκ−/− B cells. These findings suggest that iEκ and 3′Eκ play distinct roles in regulating Igk transcription and SHM.
Dynamic and Transient Remodeling of the Macrophage IL-10 Promoter during Transcription
Authors: Zhang Xia , Edwards Justin P. , Mosser David M.
Published: April 2014

To gain insight into the molecular mechanism(s) whereby macrophages produce large amounts of IL-10, we analyzed IL-10 gene expression and temporally correlated it with modifications to chromatin associated with the IL-10 promoter. In resting cells, which make essentially no cytokines, the IL-10 promoter is associated with histones containing little or no detectable modifications. Macrophages stimulated in the presence of immune complexes begin to produce high levels of IL-10 pre-mRNA transcripts within minutes of stimulation. Coincident with this transcription was a rapid and dynamic phosphorylation of histone H3 at specific sites in the IL-10 promoter. Histone phosphorylation was closely followed by the binding of transcription factors to the IL-10 promoter. Blocking the activation of ERK prevented histone phosphorylation and transcription factor binding to the IL-10 promoter. In contrast to histone phosphorylation, the peak of histone acetylation at this promoter did not occur until after transcription had peaked. Inhibition of histone deactylase did not alter IL-10 gene expression, suggesting that phosphorylation but not acetylation was the proximal event responsible for IL-10 transcription. Our findings reveal a rapid and well-orchestrated series of events in which ERK activation causes a rapid and transient phosphorylation of histone H3 at specific regions of the IL-10 promoter, resulting in a transient exposure of the IL-10 promoter to the transcription factors that bind there. This exposure is essential for the efficient induction of IL-10 gene expression in macrophages. To our knowledge, this represents a unique way in which the expression of a cytokine gene is regulated in macrophages.
Interleukin-13 Enhances Cyclooxygenase-2 Expression in Activated Rat Brain Microglia: Implications for Death of Activated Microglia
Authors: Yang Myung-Soon , Ji Kyung-Ae , Jeon Sae-Bom , Jin Byung-Kwan , Kim Seung U. , Jou Ilo , Joe Eunhye
Published: April 2014

Brain inflammation has recently attracted widespread interest because it is a risk factor for the onset and progression of brain diseases. In this study, we report that cyclooxygenase-2 (COX-2) plays a key role in the resolution of brain inflammation by inducing the death of microglia. We previously reported that IL-13, an anti-inflammatory cytokine, induced the death of activated microglia. These results revealed that IL-13 significantly enhanced COX-2 expression and production of PGE2 and 15-deoxy-Δ12,14-PGJ2 (15d-PGJ2) in LPS-treated microglia. Two other anti-inflammatory cytokines, IL-10 and TGF-β, neither induced microglial death nor enhanced COX-2 expression or PGE2 or 15d-PGJ2 production. Therefore, we hypothesized that the effect of IL-13 on COX-2 expression may be linked to death of activated microglia. We found that COX-2 inhibitors (celecoxib and NS398) suppressed the death of microglia induced by a combination of LPS and IL-13 and that exogenous addition of PGE2 and 15d-PGJ2 induced microglial death. Agonists of EP2 (butaprost) and peroxisome proliferator-activated receptor γ (ciglitazone) mimicked the effect of PGE2 and 15d-PGJ2, and an EP2 antagonist (AH6809) and a peroxisome proliferator-activated receptor γ antagonist (GW9662) suppressed microglial death induced by LPS in combination with IL-13. In addition, IL-13 potentiated LPS-induced activation of JNK, and the JNK inhibitor SP600125 suppressed the enhancement of COX-2 expression and attenuated microglial death. Taken together, these results suggest that IL-13 enhanced COX-2 expression in LPS-treated microglia through the enhancement of JNK activation. Furthermore, COX-2 products, PGE2 and 15d-PGJ2, caused microglial death, which terminates brain inflammation.
Activation of Ca2+-Dependent Signaling by TLR2
Authors: Chun Jarin , Prince Alice
Published: April 2014

Upon contact with airway epithelial cells, bacterial products activate Ca2+ fluxes that are required for induction of NF-κB-dependent gene expression. TLR2 is apically displayed on airway cells, making it a likely transducer linking bacterial stimuli and kinases that affect Ca2+ release. Using biochemical and genetic approaches, we demonstrate that TLR2 ligands stimulate release of Ca2+ from intracellular stores by activating TLR2 phosphorylation by c-Src, and recruiting PI3K and phospholipase Cγ to affect Ca2+ release through inositol (1,4,5) trisphosphate receptors. In the absence of TLR2, murine macrophages as well as airway cells do not generate Ca2+ fluxes or induce proinflammatory signaling. Thus, Ca2+ participates as a second messenger in TLR2-dependent signaling and provides another target to modulate proinflammatory responses to bacterial infection.
Clustering of Pre-B Cell Integrins Induces Galectin-1-Dependent Pre-B Cell Receptor Relocalization and Activation
Authors: Rossi Benjamin , Espeli Marion , Schiff Claudine , Gauthier Laurent
Published: April 2014

Interactions between B cell progenitors and bone marrow stromal cells are essential for normal B cell differentiation. We have previously shown that an immune developmental synapse is formed between human pre-B and stromal cells in vitro, leading to the initiation of signal transduction from the pre-BCR. This process relies on the direct interaction between the pre-BCR and the stromal cell-derived galectin-1 (GAL1) and is dependent on GAL1 anchoring to cell surface glycosylated counterreceptors, present on stromal and pre-B cells. In this study, we identify α4β1 (VLA-4), α5β1 (VLA-5), and α4β7 integrins as major GAL1-glycosylated counterreceptors involved in synapse formation. Pre-B cell integrins and their stromal cell ligands (ADAM15/fibronectin), together with the pre-BCR and GAL1, form a homogeneous lattice at the contact area between pre-B and stromal cells. Moreover, integrin and pre-BCR relocalizations into the synapse are synchronized and require actin polymerization. Finally, cross-linking of pre-B cell integrins in the presence of GAL1 is sufficient for driving pre-BCR recruitment into the synapse, leading to the initiation of pre-BCR signaling. These results suggest that during pre-B/stromal cell synapse formation, relocalization of pre-B cell integrins mediated by their stromal cell ligands drives pre-BCR clustering and activation, in a GAL1-dependent manner.
Electron Transport Complex I Is Required for CD8+ T Cell Function
Authors: Yi John S. , Holbrook Beth C. , Michalek Ryan D. , Laniewski Nathan G. , Grayson Jason M.
Published: April 2014

After Ag encounter, CD8+ T cells become activated and begin to proliferate. Early during infection, when Ag-specific effector CD8+ T cells are proliferating, producing cytokines, and lysing infected cells in vivo, their mitochondrial potential is increased. The purpose of the experiments presented here was to determine whether mitochondrial function was required for CD8+ T cell function. To block mitochondrial function, transgenic CD8+ T cells were incubated with increasing doses of rotenone, an inhibitor of electron transport complex I. Within minutes of T cell activation, rotenone incubation decreased the production of H2O2, calcium flux, and ERK1/2 phosphorylation. Failure to undergo signal transduction resulted in a decrease in T cell division initiated by peptide-coated cells, CD3/CD28 Abs, and PMA/ionomycin stimulation. Decreased function following rotenone incubation was not restricted to naive cells, as effector and memory CD8+ T cells isolated directly ex vivo from lymphocytic choriomeningitis virus-infected mice displayed decreased production of IFN-γ and TNF-α production after peptide stimulation. Furthermore, incubation with rotenone decreased degranulation of effector and memory cells, a critical step in the cytolysis of infected cells. These data suggest that electron transport complex I is required for CD8+ T cell signal transduction, proliferation, cytokine production, and degranulation.
Divergent Generation of Heterogeneous Memory CD4 T Cells
Authors: Moulton Vaishali R. , Bushar Nicholas D. , Leeser David B. , Patke Deepa S. , Farber Donna L.
Published: April 2014

Mechanisms for the generation of memory CD4 T cells and their delineation into diverse subsets remain largely unknown. In this study, we demonstrate in two Ag systems, divergent generation of heterogeneous memory CD4 T cells from activated precursors in distinct differentiation stages. Specifically, we show that influenza hemagglutinin- and OVA-specific CD4 T cells activated for 1, 2, and 3 days, respectively, exhibit gradations of differentiation by cell surface phenotype, IFN-γ production, and proliferation, yet all serve as direct precursors for functional memory CD4 T cells when transferred in vivo into Ag-free mouse hosts. Using a conversion assay to track the immediate fate of activated precursors in vivo, we show that day 1- to 3-activated cells all rapidly convert from an activated phenotype (CD25highIL-7RlowCD44high) to a resting memory phenotype (IL-7RhighCD25lowCD44high) 1 day after antigenic withdrawal. Paradoxically, stable memory subset delineation from undifferentiated (day 1- to 2-activated) precursors was predominantly an effector memory (CD62Llow) profile, with an increased proportion of central memory (CD62Lhigh) T cells arising from more differentiated (day 3-activated) precursors. Our findings support a divergent model for generation of memory CD4 T cells directly from activated precursors in multiple differentiation states, with subset heterogeneity maximized by increased activation and differentiation during priming.