bluuebunny/crossref_metadata_2025 huggingface dataset:
T Cell Costimulus-Independent and Very Efficacious Inhibition of Tumor Growth in Mice Bearing Subcutaneous or Leukemic Human B Cell Lymphoma Xenografts by a CD19-/CD3- Bispecific Single-Chain Antibody Construct
Authors: Dreier Torsten , Baeuerle Patrick A. , Fichtner Iduna , Grün Michael , Schlereth Bernd , Lorenczewski Grit , Kufer Peter , Lutterbüse Ralf , Riethmüller Gert , Gjorstrup Per , Bargou Ralf C.
Published: April 2014

We have recently demonstrated that a recombinant single-chain bispecific Ab construct, bscCD19xCD3, in vitro induces rapid B lymphoma-directed cytotoxicity at picomolar concentrations with unstimulated peripheral T cells. In this study, we show that treatment of nonobese diabetic SCID mice with submicrogram doses of bscCD19xCD3 could prevent growth of s.c. human B lymphoma xenografts and essentially cured animals when given at an early tumor stage. The effect was dose dependent, dependent on E:T ratio and the time between tumor inoculation and administration of bscCD19xCD3. No therapeutic effect was seen in the presence of human lymphocytes alone, a vehicle control, or with a bispecific single-chain construct of identical T cell-binding activity but different target specificity. In a leukemic nonobese diabetic SCID mouse model, treatment with bscCD19xCD3 prolonged survival of mice in a dose-dependent fashion. The human lymphocytes used as effector cells in both animal models did not express detectable T cell activation markers at the time of coinoculation with tumor cells. The bispecific Ab therefore showed an in vivo activity comparable to that observed in cell culture with respect to high potency and T cell costimulus independence. These properties make bscCD19xCD3 superior to previously investigated CD19 bispecific Ab-based therapies.
HIV-Specific CD8+ T Cell Function in Children with Vertically Acquired HIV-1 Infection Is Critically Influenced by Age and the State of the CD4+ T Cell Compartment
Authors: Sandberg Johan K. , Fast Noam M. , Jordan Kimberly A. , Furlan Scott N. , Barbour Jason D. , Fennelly Glenn , Dobroszycki Joanna , Spiegel Hans M. L. , Wiznia Andrew , Rosenberg Michael G. , Nixon Douglas F.
Published: April 2014

The immunology of vertical HIV transmission differs from that of adult infection in that the immune system of the infant is not fully matured, and the factors that influence the functionality of CD8+ T cell responses against HIV in children remain largely undefined. We have investigated CD8+ T cell responses in 65 pediatric subjects with vertically acquired HIV-1 infection. Vigorous, broad, and Ag dose-driven CD8+ T cell responses against HIV Ags were frequently observed in children who were older than 3 years of age and maintained CD4+ T cell counts >400 cells/μl. In contrast, younger age or a CD4+ T cell count <400 cells/μl was associated with poor CD8+ T cell responses and high HIV loads. Furthermore, subjects with a severely depleted and phenotypically altered CD4+ T cell compartment had circulating Gag-specific CD8+ T cells with impaired IFN-γ production. When viral load was not suppressed by antiviral treatment, subjects that fell below the putative age and CD4+ T cell count thresholds had significantly reduced CD8+ T cell responses and significantly higher viral loads. Thus, the data suggest that fully effective HIV-specific CD8+ T cell responses take years to develop despite an abundance of Ag in early life, and responses are further severely impaired, independent of age, in children who have a depleted or skewed CD4+ T cell compartment. The results are discussed in relation to differences between the neonatal and adult immune systems in the ability to respond to HIV infection.
Cutting Edge: SDS-Stable Fas Microaggregates: An Early Event of Fas Activation Occurring with Agonistic Anti-Fas Antibody but Not with Fas Ligand
Authors: Legembre Patrick , Beneteau Marie , Daburon Sophie , Moreau Jean-François , Taupin Jean-Luc
Published: April 2014

The 45 kDa Fas or CD95 receptor triggers apoptosis via the caspase cascade when stimulated by its ligand FasL or by agonistic Abs. Activated Fas receptors seem to oligomerize very early into SDS-stable and reducing agent-resistant microaggregates of 200–250 kDa on SDS-PAGE. However, these microaggregates have so far only been reported using agonistic anti-Fas Abs, and no results have been reported using FasL. Here, we demonstrate that the microaggregates do not form in response to FasL, while they always appear in response to the agonistic Ab, in four different cell lines and in normal lymphocytes from human blood. Therefore, the Fas microaggregates are not required for the induction of apoptosis via FasL. These results also suggest that subtle differences exist in the apoptotic pathways triggered by anti-Fas agonistic Abs and by FasL.
Cutting Edge: Efficient MHC Class I Cross-Presentation during Early Vaccinia Infection Requires the Transfer of Proteasomal Intermediates between Antigen Donor and Presenting Cells
Authors: Serna Amparo , Ramirez Maria C. , Soukhanova Anna , Sigal Luis J.
Published: April 2014

Priming of CD8+ T cells requires presentation of short peptides bound to MHC class I molecules of professional APCs. Cross-presentation is a mechanism whereby professional APC present on their own MHC class I molecules peptides derived from degradation of Ags synthesized by other Ag “donor cells.” The mechanism of cross-presentation is poorly understood, and the nature of the transferred Ag is unknown. In this report, we demonstrate that the bulk of a cross-presented Ag transferred from donor cells recently infected with vaccinia virus are proteasomal products that are susceptible to peptidases within the donor cell cytosol and not full-length proteins or mature epitopes either free or bound to chaperones.
Cutting Edge: Self-Peptides Drive the Peripheral Expansion of CD4+CD25+ Regulatory T Cells
Authors: Cozzo Cristina , Larkin Joseph , Caton Andrew J.
Published: April 2014

CD4+CD25+ regulatory T cell selection is initiated by high-specificity interactions with self-peptides in the thymus, although how these cells respond to cytokine-derived signals and to re-exposure to self-peptide:MHC complexes in the periphery is not well understood. We have used a transgenic mouse system, in which the peptide that induces thymic selection of a clonal population of CD4+CD25+ regulatory T cells is known, to show that CD4+CD25+ T cells proliferate in response to their selecting self-peptide in vivo. Moreover, they do not proliferate in response to lymphopenia in the absence of the selecting self-peptide, reflecting a low level of expression of the high affinity receptor for IL-7 (CD127) relative to conventional CD4+ T cells. That their selecting self-peptide is both required for and promotes the peripheral expansion of CD4+CD25+ regulatory T cells may direct their accumulation in sites where the self-peptide is expressed.
CD4+ T Cell-Associated Pathophysiology Critically Depends on CD18 Gene Dose Effects in a Murine Model of Psoriasis
Authors: Kess Daniel , Peters Thorsten , Zamek Jan , Wickenhauser Claudia , Tawadros Samir , Loser Karin , Varga Georg , Grabbe Stephan , Nischt Roswitha , Sunderkötter Cord , Müller Werner , Krieg Thomas , Scharffetter-Kochanek Karin
Published: April 2014

In a CD18 hypomorphic polygenic PL/J mouse model, the severe reduction of CD18 (β2 integrin) to 2–16% of wild-type levels leads to the development of a psoriasiform skin disease. In this study, we analyzed the influence of reduced CD18 gene expression on T cell function, and its contribution to the pathogenesis of this disease. Both CD4+ and CD8+ T cells were significantly increased in the skin of affected CD18 hypomorphic mice. But only depletion of CD4+ T cells, and not the removal of CD8+ T cells, resulted in a complete clearance of the psoriasiform dermatitis. This indicates a central role of CD4+ T cells in the pathogenesis of this disorder, further supported by the detection of several Th1-like cytokines released predominantly by CD4+ T cells. In contrast to the CD18 hypomorphic mice, CD18 null mutants of the same strain did not develop the psoriasiform dermatitis. This is in part due to a lack of T cell emigration from dermal blood vessels, as experimental allergic contact dermatitis could be induced in CD18 hypomorphic and wild-type mice, but not in CD18 null mutants. Hence, 2–16% of CD18 gene expression is obviously sufficient for T cell emigration driving the inflammatory phenotype in CD18 hypomorphic mice. Our data suggest that the pathogenic involvement of CD4+ T cells depends on a gene dose effect with a reduced expression of the CD18 protein in PL/J mice. This murine inflammatory skin model may also have relevance for human polygenic inflammatory diseases.
Tethering of Apoptotic Cells to Phagocytes through Binding of CD47 to Src Homology 2 Domain-Bearing Protein Tyrosine Phosphatase Substrate-1
Authors: Tada Kazutoshi , Tanaka Masato , Hanayama Rikinari , Miwa Keiko , Shinohara Azusa , Iwamatsu Akihiro , Nagata Shigekazu
Published: April 2014

Apoptotic cells are swiftly phagocytosed by macrophages and immature dendritic cells. In this study, we found that one mouse macrophage cell line (BAM3) engulfed apoptotic thymocytes, but not a lymphoma cell line (WR19L). mAbs that inhibited the phagocytosis of apoptotic thymocytes by BAM3 were identified. Purification of the Ag revealed that it was Src homology 2 domain-bearing protein tyrosine phosphatase substrate-1 (SHPS-1). CD47, the ligand for SHPS-1, was expressed in mouse thymocytes, but not in WR19L. When WR19L was transformed with CD47, the transformants, after induction of apoptosis, could be phagocytosed by BAM3. The WR19L transformants expressing CD47 were more efficiently engulfed in vivo by splenic dendritic cells than the parental WR19L. Masking of the phosphatidylserine exposed on apoptotic thymocytes inhibited the engulfment, whereas the anti-SHPS-1 mAb inhibited not only the engulfment, but also the binding of apoptotic cells to phagocytes. These results indicate that macrophages require CD47 and phosphatidylserine on apoptotic cells for engulfment, and suggest that the interaction between CD47 and SHPS-1 works as a tethering step in the phagocytosis.
Aberrant Extracellular and Dendritic Cell (DC) Surface Expression of Heat Shock Protein (hsp)70 in the Rheumatoid Joint: Possible Mechanisms of hsp/DC-Mediated Cross-Priming
Authors: Martin Carla A. , Carsons Steven E. , Kowalewski Robert , Bernstein David , Valentino Michael , Santiago-Schwarz Frances
Published: April 2014

We describe, in rheumatoid arthritis (RA), abnormalities in the expression and distribution of heat shock protein (hsp) and dendritic cells (DCs) that are conducive to cross-priming and DC cross-talk. As detected by ELISA, inducible (i)hsp70 was dramatically increased in RA synovial fluid (RASF) vs normal human and RA sera and osteoarthritis and gout synovial fluid. Immunoblot analysis of fresh RASF cells revealed marked increases in ihsp70 and activation of its transcription factor heat shock factor-1, compared with fresh normal peripheral blood cells. Flow cytometry and microscopy demonstrated high levels of ihsp70 on the surface of RASF myeloid DCs (but not normal myeloid DCs) that occurred concurrently with hspRs (CD91/CD14). ihsp70 present in RASF exhibited chaperoning potential, as indicated by the capture of ihsp70 present in RASF on the surface of normal DCs. Binding was partially competitively inhibited by excess α2-macroglobulin, indicating that hspRs in addition to CD91 participate in the capture process. These data indicate that ihsp70 may chaperone autologous Ags into immature RASF DCs via hspRs, and that cross-talk between DCs coexpressing hsp/hspRs reflects a disease process in RA. The induction of surface ihsp70 on normal cells after sublethal heat stress and the release of ihsp70 from normal DCs after inflammatory stress also suggest that the pattern of ihsp70 expression in RASF occurs in response to sustained stress.
In Vitro Differentiation from Naive to Mature E-Selectin Binding CD4 T Cells: Acquisition of Skin-Homing Properties Occurs Independently of Cutaneous Lymphocyte Antigen Expression
Authors: Takahashi Ryo , Mizukawa Yoshiko , Yamazaki Yoshimi , Hayakawa Kazuhito , Hayakawa Jun , Kudo Akihiko , Shiohara Tetsuo
Published: April 2014

We previously showed that skin-homing CD4 T cells in peripheral blood can be subdivided into three populations on the basis of the expression pattern of the cutaneous lymphocyte Ag (CLA) and fucosyltransferase VII (FucT-VII): FucT-VII+CLA−, FucT-VII+CLA+, and FucT-VII−CLA+. In view of the known late appearance of CLA during T cell differentiation, T cells programmed to attain skin-homing properties may start to generate E-selectin-binding epitopes at early stages of differentiation before induction of CLA expression. To this end, the in vitro differentiation from naive to CLA+ memory T cells was followed after activation with anti-CD3 mAb. Here we demonstrate that naive skin-homing CD4 T cell precursors undergo a linear differentiation process from the FucT-VII+CLA− phenotype to the FucT-VII+CLA+ phenotype and eventually to the FucT-VII−CLA+ phenotype. The appearance of the FucT-VII+CLA− subset coincided with or could be immediately followed by the generation of E-selectin binding epitopes, and even after E-selectin-binding epitopes were no longer detectable, CLA remained expressed for prolonged periods of time, suggesting that induction of functional E-selectin ligands depends primarily on the expression of FucT-VII, but not CLA. Immunofluorescence and confocal microscopy studies of these T cells confirm that most E-selectin ligands were found independently of CLA expression.
Human ErbB-2 (Her-2) Transgenic Mice: A Model System for Testing Her-2 Based Vaccines
Authors: Piechocki Marie P. , Ho Ye-Shih , Pilon Shari , Wei Wei-Zen
Published: April 2014

Her-2 transgenic (Tg) mice were generated with wild-type human c-ErbB-2 (Her-2) under the whey acidic protein promoter. They are tolerant to Her-2 and appropriate for testing Her-2 vaccines. The expression of transmembrane ErbB-2 from the whey acidic protein-Her-2 cassette and its up-regulation by insulin and hydrocortisone was verified by in vitro transfection. The transgene cassette was microinjected into fertilized eggs from B6C3 (C3H × C57BL/6) females mated with B6C3 males. Transgene-positive mice were backcrossed onto C57BL/6 mice. Human ErbB-2 was expressed in the secretory mammary epithelia during pregnancy and lactation and expressed constitutively in the Bergman glia cells within the molecular layer of the cerebellum. Overt, neoplastic transformation was not detected in any tissue examined. Tolerance to Her-2 was demonstrated by inoculating mice with a syngenic tumor expressing high levels of human ErbB-2. Tumors grew exclusively in Her-2 Tg mice without inducing an Ab response, while the nontransgenic littermates remained tumor free for 10 mo and mounted a robust anti-ErbB-2 Ab response. When immunized five times with plasmid DNA encoding secErbB-2 and GM-CSF, respectively, ∼33% of the Her-2 Tg mice rejected a lethal challenge of EL-4/E2 tumor cells, whereas all immunized littermates rejected the tumor. Therefore, Her-2 Tg mice express human ErbB-2 in the brain and mammary gland and demonstrated tolerance to ErbB-2 which was partially overcome by DNA vaccination. The breakable tolerance of Her-2 Tg mice resembles that in human and these mice are particularly suited for testing human ErbB-2 based vaccines.
Role of Antiproliferative B Cell Translocation Gene-1 as an Apoptotic Sensitizer in Activation-Induced Cell Death of Brain Microglia
Authors: Lee Heasuk , Cha Sanghoon , Lee Myung-Shik , Cho Gyeong Jae , Choi Wan Sung , Suk Kyoungho
Published: April 2014

Mouse brain microglial cells undergo apoptosis on exposure to inflammatory stimuli, which is considered as an autoregulatory mechanism to control their own activation. Here, we present evidence that an antiproliferative B cell translocation gene 1 (BTG1) constitutes a novel apoptotic pathway of LPS/IFN-γ-activated microglia. The expression of BTG1 was synergistically enhanced by LPS and IFN-γ in BV-2 mouse microglial cells as well as in primary microglia cultures. Levels of BTG1 expression inversely correlated with a proliferative capacity of the microglial cells. Tetracycline-based conditional expression of BTG1 not only suppressed microglial proliferation but also increased the sensitivity of microglial cells to NO-induced apoptosis, suggesting a novel mechanism of cooperation between LPS and IFN-γ in the induction of microglial apoptosis. An increase in BTG1 expression, however, did not affect microglial production of NO, TNF-α, or IL-1β, indicating that the antiproliferative BTG1 is important in the activation-induced apoptosis of microglia, but not in the activation itself. The synergistic action of LPS and IFN-γ in the microglial BTG1 induction and apoptosis was dependent on the Janus kinase/STAT1 pathway, but not IFN-regulatory factor-1, as demonstrated by a pharmacological inhibitor of Janus kinase (AG490), STAT1 dominant negative mutant, and IFN-regulatory factor-1-deficient mice. Taken together, antiproliferative BTG1 may participate in the activation-induced cell death of microglia by lowering the threshold for apoptosis; BTG1 increases the sensitivity of microglia to apoptogenic action of autocrine cytotoxic mediator, NO. Our results point out an important link between the proliferative state of microglia and their sensitivity to apoptogenic agents.
Estradiol Treatment Redirects the Isotype of the Autoantibody Response and Prevents the Development of Autoimmune Arthritis
Authors: Latham Kary A. , Zamora Alex , Drought Heather , Subramanian Sandhya , Matejuk Agata , Offner Halina , Rosloniec Edward F.
Published: April 2014

A number of clinical and experimental observations have been made relating elevated estrogen levels with the amelioration of autoimmune diseases, yet questions remain about the levels required for efficacy as well as the mechanism of disease inhibition. Using the collagen-induced arthritis (CIA) model, we have studied the effects of physiological, sustained levels of 17β-estradiol in preventing the development of autoimmune arthritis and analyzed the changes in the autoimmune response. Using time-release pellets of 17β-estradiol, arthritis development was significantly inhibited in three different strains of CIA-susceptible mice compared with the effect of placebo treatment, and serum estradiol levels similar to those of mice in estrus were found to be equally effective as higher estradiol concentrations. Analysis of the autoimmune response in the estradiol-treated mice indicated that T cell production of IFN-γ was markedly decreased, and significant decreases were also observed in levels of IL-10 and GM-CSF produced by lymph nodes cells from estradiol-treated mice. Although the total IgG anti-CII response was only minimally affected by estrogen treatment, a significant reduction in the levels of IgG2a anti-CII Abs and an increase in the levels of IgG1 anti-CII Abs were observed in estradiol-treated mice. These data indicate that estradiol treatment altered the Th profile of the autoimmune T cell response, which, in turn, altered the production of IgG Abs to an isotype that is poor at fixing complement, an important component in the immunopathogenesis of CIA.
Distinct Effects of STAT5 Activation on CD4+ and CD8+ T Cell Homeostasis: Development of CD4+CD25+ Regulatory T Cells versus CD8+ Memory T Cells
Authors: Burchill Matthew A. , Goetz Christine A. , Prlic Martin , O’Neil Jennifer J. , Harmon Ian R. , Bensinger Steven J. , Turka Laurence A. , Brennan Paul , Jameson Stephen C. , Farrar Michael A.
Published: April 2014

Using transgenic mice that express a constitutively active version of STAT5b, we demonstrate that STAT5 plays a key role in governing B cell development and T cell homeostasis. STAT5 activation leads to a 10-fold increase in pro-B, but not pro-T, cells. Conversely, STAT5 signaling promotes the expansion of mature αβ T cells (6-fold increase) and γδ and NK T cells (3- to 4-fold increase), but not of mature B cells. In addition, STAT5 activation has dramatically divergent effects on CD8+ vs CD4+ T cells, leading to the selective expansion of CD8+ memory-like T cells and CD4+CD25+ regulatory T cells. These results establish that activation of STAT5 is the primary mechanism underlying both IL-7/IL-15-dependent homeostatic proliferation of naive and memory CD8+ T cells and IL-2-dependent development of CD4+CD25+ regulatory T cells.
IL-4 and IL-13 InduceSOCS-1Gene Expression in A549 Cells by Three Functional STAT6-Binding Motifs Located Upstream of the Transcription Initiation Site
Authors: Hebenstreit Daniel , Luft Petra , Schmiedlechner Angela , Regl Gerhard , Frischauf Anna-Maria , Aberger Fritz , Duschl Albert , Horejs-Hoeck Jutta
Published: April 2014

Proteins of the suppressors of cytokine signaling (SOCS) family have important functions as negative regulators of cytokine signaling. We show here that SOCS-1 expression can be induced in the human epithelial lung cell line A549 by IL-4 and IL-13. Analysis of reporter gene constructs under control of the SOCS-1 promoter provides evidence that IL-4- and IL-13-induced up-regulation is dependent on three IFN-γ-activated sequence motifs of the sequence TTC(N)4GAA, which is known for binding STAT6. The three motifs are situated close to each other ∼600 bp upstream of the transcriptional initiation site. When mutations were inserted into all three IFN-γ-activated sequence motifs at the same time, IL-4-IL-13-induced luciferase activity was abrogated. With single and double mutants, promoter activity was diminished in comparison with the wild-type promoter. STAT6 is therefore required for IL-4-IL-13-dependent SOCS-1 expression in A549 cells, and the three identified binding motifs cooperate to induce maximal transcription. EMSAs conducted with nuclear extracts of IL-4- and IL-13-stimulated A549 cells showed that STAT6 was able to bind to each of the three binding motifs. Finally, cotransfection of a SOCS-1 expression vector inhibited activation of SOCS-1 promoter luciferase constructs. Thus, SOCS-1 is able to autoregulate its expression via a negative feedback loop.
CD4+/CD25+ Regulatory Cells Inhibit Activation of Tumor-Primed CD4+ T Cells with IFN-γ-Dependent Antiangiogenic Activity, as well as Long-Lasting Tumor Immunity Elicited by Peptide Vaccination
Authors: Casares Noelia , Arribillaga Laura , Sarobe Pablo , Dotor Javier , Lopez-Diaz de Cerio Ascensión , Melero Ignacio , Prieto Jesús , Borrás-Cuesta Francisco , Lasarte Juan J.
Published: April 2014

CD25+ regulatory T (T reg) cells suppress the activation/proliferation of other CD4+ or CD8+ T cells in vitro. Also, down-regulation of CD25+ T reg cells enhance antitumor immune responses. In this study, we show that depletion of CD25+ T reg cells allows the host to induce both CD4+ and CD8+ antitumoral responses following tumor challenge. Simultaneous depletion of CD25+ and CD8+ cells, as well as adoptive transfer experiments, revealed that tumor-specific CD4+ T cells, which emerged in the absence of CD25+ T reg cells, were able to reject CT26 colon cancer cells, a MHC class II-negative tumor. The antitumoral effect mediated by CD4+ T cells was dependent on IFN-γ production, which exerted a potent antiangiogenic activity. The capacity of the host to mount this antitumor response is lost once the number of CD25+ T reg cells is restored over time. However, CD25+ T reg cell depletion before immunization with AH1 (a cytotoxic T cell determinant from CT26 tumor cells) permits the induction of a long-lasting antitumoral immune response, not observed if immunization is conducted in the presence of regulatory cells. A study of the effect of different levels of depletion of CD25+ T reg cells before immunization with the peptide AH1 alone, or in combination with a Th determinant, unraveled that Th cells play an important role in overcoming the suppressive effect of CD25+ T reg on the induction of long-lasting cellular immune responses.
Promiscuity of MHC Class Ib-Restricted T Cell Responses
Authors: Ploss Alexander , Lauvau Gregoire , Contos Brian , Kerksiek Kristen M. , Guirnalda Patrick D. , Leiner Ingrid , Lenz Laurel L. , Bevan Michael J. , Pamer Eric G.
Published: April 2014

Murine infection with the Gram-positive intracellular bacterium Listeria monocytogenes activates CD8+ T cells that recognize bacterially derived N-formyl methionine peptides in the context of H2-M3 MHC class Ib molecules. Three peptides, fMIGWII, fMIVIL, and fMIVTLF, are targets of L. monocytogenes-specific CD8+ T cells. To investigate epitope cross-recognition by H2-M3-restricted CD8+ T cells, we deleted the sequence encoding fMIGWII from a virulent strain of L. monocytogenes. Infection with fMIGWII-deficient L. monocytogenes unexpectedly primed CD8+ T cells that stain with fMIGWII/H2-M3 tetramers and lyse fMIGWII-coated target cells in vivo. Because the fMIGWII sequence is nonredundant, we speculated that other bacterially derived Ags are priming these responses. HPLC peptide fractionation of bacterial culture supernatants revealed several distinct L. monocytogenes-derived peptides that are recognized by fMIGWII-specific T cells. Our results demonstrate that the dominant H2-M3-restricted CD8+ T cell population, although reactive with fMIGWII, is primed by other, non-fMIGWII peptides derived from L. monocytogenes. Although this degree of Ag receptor promiscuity is unusual for the adaptive immune system, it may be a more common feature of T cell responses restricted by nonpolymorphic MHC class Ib molecules.
Allogeneic T Cells Treated with Amotosalen Prevent Lethal Cytomegalovirus Disease without Producing Graft-versus-Host Disease Following Bone Marrow Transplantation
Authors: Roback John D. , Hossain Mohammad S. , Lezhava Levan , Gorechlad John W. , Alexander Sabina A. , Jaye David L. , Mittelstaedt Stephen , Talib Sohel , Hearst John E. , Hillyer Christopher D. , Waller Edmund K.
Published: April 2014

Infusion of donor antiviral T cells can provide protective immunity for recipients of hemopoietic progenitor cell transplants, but may cause graft-vs-host disease (GVHD). Current methods of separating antiviral T cells from the alloreactive T cells that produce GVHD are neither routine nor rapid. In a model of lethal murine CMV (MCMV) infection following MHC-mismatched bone marrow transplantation, infusion of MCMV-immune donor lymphocytes pretreated with the DNA cross-linking compound amotosalen prevented MCMV lethality without producing GVHD. Although 95% of mice receiving 30 × 106 pretreated donor lymphocytes survived beyond day +100 without MCMV disease or GVHD, all mice receiving equivalent numbers of untreated lymphocytes rapidly died of GVHD. In vitro, amotosalen blocked T cell proliferation without suppressing MCMV peptide-induced IFN-γ production by MCMV-primed CD8+ T cells. In vivo, pretreated lymphocytes reduced hepatic MCMV load by 4-log10 and promoted full hemopoietic chimerism. Amotosalen-treated, MCMV tetramer-positive memory (CD44high) CD8+ T cells persisted to day +100 following infusion, and expressed IFN-γ when presented with viral peptide. Pretreated T cells were effective at preventing MCMV lethality over a wide range of concentrations. Thus, amotosalen treatment rapidly eliminates the GVHD activity of polyclonal T cells, while preserving long-term antiviral and graft facilitation effects, and may be clinically useful for routine adoptive immunotherapy.
Cross-Talk in the Innate Immune System: Neutrophils Instruct Recruitment and Activation of Dendritic Cells during Microbial Infection
Authors: Bennouna Soumaya , Bliss Susan K. , Curiel Tyler J. , Denkers Eric Y.
Published: April 2014

Type I inflammatory cytokines are essential for immunity to many microbial pathogens, including Toxoplasma gondii. Dendritic cells (DC) are key to initiating type 1 immunity, but neutrophils are also a source of chemokines and cytokines involved in Th1 response ignition. We found that T. gondii triggered neutrophil synthesis of CC chemokine ligand (CCL)3, CCL4, CCL5, and CCL20, chemokines that were strongly chemotactic for immature DC. Moreover, supernatants obtained from parasite-stimulated polymorphonuclear leukocytes induced DC IL-12(p40) and TNF-α production. Parasite-triggered neutrophils also released factors that induced DC CD40 and CD86 up-regulation, and this response was dependent upon parasite-triggered neutrophil TNF-α production. In vivo evidence that polymorphonuclear leukocytes exert an important influence on DC activation was obtained by examining splenic DC cytokine production following infection of neutrophil-depleted mice. These animals displayed severely curtailed splenic DC IL-12 and TNF-α production, as revealed by ex vivo flow cytometric analysis and in vitro culture assay. Our results reveal a previously unrecognized regulatory role for neutrophils in DC function during microbial infection, and suggest that cross-talk between these cell populations is an important component of the innate immune response to infection.
Sustained Nitric Oxide Delivery Delays Nitric Oxide-Dependent Apoptosis in Macrophages: Contribution to the Physiological Function of Activated Macrophages
Authors: Hortelano Sonsoles , Través Paqui G. , Zeini Miriam , Alvarez Alberto M. , Boscá Lisardo
Published: April 2014

Treatment of the macrophage cell line RAW 264.7 with the short-lived NO donor S-nitrosoglutathione triggers apoptosis through the release of mitochondrial mediators. However, continuous supply of NO by long-lived NO donors protected cells from apoptosis through mechanisms that involved the maintenance or an increase in the levels of the inhibitor of apoptosis proteins (IAPs) cIAP-1, cIAP-2, and xIAP and decreases in the accumulation of p53 and in the levels and targeting of Bax to the mitochondria. As a result of these changes, the activation of caspases 9 and 3 was notably delayed, expanding the time of viability of the macrophages. Moreover, inhibition of NO synthase 2 activity after 8 h of stimulation of RAW 264.7 cells with LPS and IFN-γ accelerated apoptosis via an increase in the processing and activation of caspases. These data suggest that NO exerts an important role in the autoregulation of apoptosis in macrophages.
Curcumin Suppresses Janus Kinase-STAT Inflammatory Signaling through Activation of Src Homology 2 Domain-Containing Tyrosine Phosphatase 2 in Brain Microglia
Authors: Kim Hee Young , Park Eun Jung , Joe Eun-hye , Jou Ilo
Published: April 2014

Curcumin has been strongly implicated as an anti-inflammatory agent, but the precise mechanisms of its action are largely unknown. In this study, we show that the inhibitory action of curcumin on Janus kinase (JAK)-STAT signaling can contribute to its anti-inflammatory activity in the brain. In both rat primary microglia and murine BV2 microglial cells, curcumin effectively suppressed the ganglioside-, LPS-, or IFN-γ-stimulated induction of cyclooxygenase-2 and inducible NO synthase, important enzymes that mediate inflammatory processes. These anti-inflammatory effects appear to be due, at least in part, to the suppression of the JAK-STAT inflammatory signaling cascade. Curcumin markedly inhibited the phosphorylation of STAT1 and 3 as well as JAK1 and 2 in microglia activated with gangliosides, LPS, or IFN-γ. Curcumin consistently suppressed not only NF binding to IFN-γ-activated sequence/IFN-stimulated regulatory element, but also the expression of inflammation-associated genes, including ICAM-1 and monocyte chemoattractant protein 1, whose promoters contain STAT-binding elements. We further show that activation of Src homology 2 domain-containing protein tyrosine phosphatases (SHP)-2, a negative regulator of JAK activity, is likely to be one of the mechanisms underlying the curcumin-mediated inhibition of JAK-STAT signaling. Treatment of microglial cells with curcumin led to an increase in phosphorylation and association with JAK1/2 of SHP-2, which inhibit the initiation of JAK-STAT inflammatory signaling in activated microglia. Taken together, these data suggest curcumin suppresses JAK-STAT signaling via activation of SHP-2, thus attenuating inflammatory response of brain microglial cells.
Cyclooxygenase-2-Derived E Prostaglandins Down-Regulate Matrix Metalloproteinase-1 Expression in Fibroblast-Like Synoviocytes via Inhibition of Extracellular Signal-Regulated Kinase Activation
Authors: Pillinger Michael H. , Rosenthal Pamela B. , Tolani Sonia N. , Apsel Beth , Dinsell Victoria , Greenberg Jeffrey , Chan Edwin S. L. , Gomez Paul F. , Abramson Steven B.
Published: April 2014

We examined the regulation of matrix metalloproteinase (MMP) production by mitogen-activated protein kinases and cyclooxygenases (COXs) in fibroblast-like synoviocytes (FLSCs). IL-1β and TNF-α stimulated FLSC extracellular signal-regulated kinase (ERK) activation as well as MMP-1 and -13 release. Pharmacologic inhibitors of ERK inhibited MMP-1, but not MMP-13 expression. Whereas millimolar salicylates inhibited both ERK and MMP-1, nonsalicylate COX and selective COX-2 inhibitors enhanced stimulated MMP-1 release. Addition of exogenous PGE1 or PGE2 inhibited MMP-1, reversed the effects of COX inhibitors, and inhibited ERK activation, suggesting that COX-2 activity tonically inhibits MMP-1 production via ERK inhibition by E PGs. Exposure of FLSCs to nonselective COX and selective COX-2 inhibitors in the absence of stimulation resulted in up-regulation of MMP-1 expression in an ERK-dependent manner. Moreover, COX inhibition sufficient to reduce PGE levels increased ERK activity. Our data indicate that: 1) ERK activation mediates MMP-1 but not MMP-13 release from FLSCs, 2) COX-2-derived E PGs inhibit MMP-1 release from FLSCs via inhibition of ERK, and 3) COX inhibitors, by attenuating PGE inhibition of ERK, enhance the release of MMP-1 by FLSC.
Mac-1, but Not LFA-1, Uses Intercellular Adhesion Molecule-1 to Mediate Slow Leukocyte Rolling in TNF-α-Induced Inflammation
Authors: Dunne Jessica L. , Collins Robert G. , Beaudet Arthur L. , Ballantyne Christie M. , Ley Klaus
Published: April 2014

We have previously shown that Mac-1 and LFA-1 play a cooperative role in slow leukocyte rolling in inflamed vessels, and that, although both have a role in leukocyte adhesion, the contribution from LFA-1 exceeds that of Mac-1. In this study, we used mice deficient in ICAM-1 (ICAM-1null) to study the function of ICAM-1 as an endothelial ligand for Mac-1 and LFA-1. The cremaster muscles of these mice were treated with TNF-α and prepared for intravital microscopy. We found that the average rolling velocity in venules was not different in ICAM-1null mice (4.7 μm/s) compared with wild-type mice (5.1 μm/s). Similarly, leukocyte adhesion efficiency in ICAM-1null mice (0.11 ± 0.01 mm) was similar to that in Mac-1−/− (0.12 ± 0.03 mm) mice but significantly increased compared with that in LFA-1−/− (0.08 ± 0.01 mm) mice and significantly reduced from that in wild type (0.26 ± 0.04 mm). When both LFA-1 and ICAM-1 were blocked, rolling velocity increased, and adhesion efficiency and arrest decreased. However, blocking both Mac-1 and ICAM-1 had no greater effect than either blockade alone. We conclude that endothelial ICAM-1 is the main ligand responsible for slow leukocyte rolling mediated by Mac-1, but not LFA-1.
Regulation and Phenotype of an Innate Th1 Cell: Role of Cytokines and the p38 Kinase Pathway
Authors: Yu Jeffrey J. , Tripp Catherine S. , Russell John H.
Published: April 2014

We have explored the phenotype and regulation of Th1 cell activation by the cytokines IL-12 and IL-18. We demonstrate that these two cytokines selectively induce IFN-γ in a differentiated Th1 cell population through the previously described p38 mitogen-activated protein (MAP) kinase pathway. Using a highly selective p38 MAP kinase inhibitor, we demonstrate that it is possible to block IFN-γ induction from activated, differentiated Th1 cells via p38 MAP kinase without disrupting the activation and differentiation of naive T cells or the proliferation of naive or differentiated T cells. In addition, IL-12 and IL-18 provide an Ag and IL-2-independent survival signal to this uniquely differentiated Th1 cell population. We hypothesize that this Ag-independent survival of Th1 cells may participate in an innate inflammatory loop with monocytes at the sites of chronic inflammation. In addition, p38 MAP kinase inhibition of this cytokine-regulated pathway may be a unique mechanism to inhibit chronic inflammation without disruption of Ag-driven activation and function of naive T cells.
FcεRI Signaling of Mast Cells Activates Intracellular Production of Hydrogen Peroxide: Role in the Regulation of Calcium Signals
Authors: Suzuki Yoshihiro , Yoshimaru Tetsuro , Matsui Takashi , Inoue Toshio , Niide Osamu , Nunomura Satoshi , Ra Chisei
Published: April 2014

Earlier studies, including our own, revealed that activation of mast cells is accompanied by production of reactive oxygen species (ROS) that help to mediate the release of the inflammatory mediators, including histamine and eicosanoids. However, little is known about the mechanisms of ROS production, including the species of oxidants produced. In this study we show that in both the RBL-2H3 mast cell line and bone marrow-derived mast cells, FcεRI cross-linking stimulates intracellular oxidative burst, including hydrogen peroxide (H2O2) production, as defined with the oxidant-sensitive dyes dichlorofluorescein and scopoletin and the selective scavenger ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one). The oxidative burst was observed immediately after stimulation and was most likely due to an NAD(P)H oxidase. Experiments using selective pharmacological inhibitors demonstrated that activation of tyrosine kinases and phosphatidylinositol-3-kinase is required for induction of the oxidative burst. Blockade of the oxidative burst by diphenyleneiodonium impaired the release of preformed granular mediators, such as histamine and β-hexosaminidase, and the secretion of newly synthesized leukotriene C4, whereas selective scavenging H2O2 by ebselen impaired leukotriene C4 secretion, but not degranulation. Sustained elevation of cytosolic calcium through store-operated calcium entry was totally abolished when ROS production was blocked. In contrast, selective depletion of H2O2 caused a considerable decrease and delay of the calcium response. Finally, tyrosine phosphorylation of phospholipase Cγ and the linker for activation of T cells, an event required for calcium influx, was suppressed by diphenyleneiodonium and ebselen. These studies demonstrate that activation of the intracellular oxidative burst is an important regulatory mechanism of mast cell responses.
Proinflammatory Cytokines Disrupt Epithelial Barrier Function by Apoptosis-Independent Mechanisms
Authors: Bruewer Matthias , Luegering Andreas , Kucharzik Torsten , Parkos Charles A. , Madara James L. , Hopkins Ann M. , Nusrat Asma
Published: April 2014

It is well known that inflammatory conditions of the intestinal mucosa result in compromised barrier function. Inflammation is characterized by an influx into the mucosa of immune cells that influence epithelial function by releasing proinflammatory cytokines such as IFN-γ and TNF-α. Mucosal barrier function is regulated by the epithelial apical junctional complex (AJC) consisting of the tight junction and the adherens junction. Since the AJC regulates barrier function, we analyzed the influence of IFN-γ and TNF-α on its structure/function and determined the contribution of apoptosis to this process using a model intestinal epithelial cell line, T84, and IFN-γ and TNF-α. AJC structure/function was analyzed by confocal microscopy, biochemical analysis, and physiologic measurement of epithelial gate/fence function. Apoptosis was monitored by determining cytokeratin 18 cleavage and caspase-3 activation. IFN-γ induced time-dependent disruptions in epithelial gate function that were potentiated by coincubation with TNF-α. Tight junction fence function was somewhat disrupted. Cytokine treatment was associated with internalization of AJC transmembrane proteins, junction adhesion molecule 1, occludin, and claudin-1/4 with minimal effects on the cytoplasmic plaque protein zonula occludens 1. Detergent solubility profiles of junction adhesion molecule 1 and E-cadherin and their affiliation with “raft-like” membrane microdomains were modified by these cytokines. Inhibition of cytokine-induced apoptosis did not block induced permeability defects; further emphasizing their primary influence on the epithelial AJC structure and barrier function. Our findings for the first time clearly separate the proapoptotic effects of IFN-γ and TNF-α from their abilities to disrupt barrier function.
Suppression of Immune Induction of Collagen-Induced Arthritis in IL-17-Deficient Mice
Authors: Nakae Susumu , Nambu Aya , Sudo Katsuko , Iwakura Yoichiro
Published: April 2014

Interleukin-17 is a T cell-derived proinflammatory cytokine. This cytokine is suspected to be involved in the development of rheumatoid arthritis (RA) because this cytokine expression is augmented in synovial tissues of RA patients. The pathogenic roles of IL-17 in the development of RA, however, still remain to be elucidated. In this study, effects of IL-17 deficiency on collagen-induced arthritis (CIA) model were examined using IL-17-deficient mice (IL-17−/− mice). We found that CIA was markedly suppressed in IL-17−/− mice. IL-17 was responsible for the priming of collagen-specific T cells and collagen-specific IgG2a production. Thus, these observations suggest that IL-17 plays a crucial role in the development of CIA by activating autoantigen-specific cellular and humoral immune responses.
Toll-Like Receptor-2, but Not Toll-Like Receptor-4, Is Essential for Development of Oviduct Pathology in Chlamydial Genital Tract Infection
Authors: Darville Toni , O’Neill Joshua M. , Andrews Charles W. , Nagarajan Uma M. , Stahl Lynn , Ojcius David M.
Published: April 2014

The roles of Toll-like receptor (TLR) 2 and TLR4 in the host inflammatory response to infection caused by Chlamydia trachomatis have not been elucidated. We examined production of TNF-α and IL-6 in wild-type TLR2 knockout (KO), and TLR4 KO murine peritoneal macrophages infected with the mouse pneumonitis strain of C. trachomatis. Furthermore, we compared the outcomes of genital tract infection in control, TLR2 KO, and TLR4 KO mice. Macrophages lacking TLR2 produced significantly less TNF-α and IL6 in response to active infection. In contrast, macrophages from TLR4 KO mice consistently produced higher TNF-α and IL-6 responses than those from normal mice on in vitro infection. Infected TLR2-deficient fibroblasts had less mRNA for IL-1, IL-6, and macrophage-inflammatory protein-2, but TLR4-deficient cells had increased mRNA levels for these cytokines compared with controls, suggesting that ligation of TLR4 by whole chlamydiae may down-modulate signaling by other TLRs. In TLR2 KO mice, although the course of genital tract infection was not different from that of controls, significantly lower levels of TNF-α and macrophage-inflammatory protein-2 were detected in genital tract secretions during the first week of infection, and there was a significant reduction in oviduct and mesosalpinx pathology at late time points. TLR4 KO mice responded to in vivo infection similarly to wild-type controls and developed similar pathology. TLR2 is an important mediator in the innate immune response to C. trachomatis infection and appears to play a role in both early production of inflammatory mediators and development of chronic inflammatory pathology.
Aberrant Inflammation and Lethality to Septic Peritonitis in Mice Lacking STAT3 in Macrophages and Neutrophils
Authors: Matsukawa Akihiro , Takeda Kiyoshi , Kudo Shinji , Maeda Takako , Kagayama Motoko , Akira Shizuo
Published: April 2014

Stat3 is a transcription factor mediating anti-inflammatory properties of IL-10. In the present study, we demonstrate a pivotal role of Stat3 expressed in innate immune cells during septic peritonitis induced by cecal ligation and puncture (CLP). Mice with targeted disruption of Stat3 in macrophages and neutrophils were succumbed to septic peritonitis induced by CLP. The mice displayed an excessive local and systemic inflammation relative to the control mice, an event that was accompanied by substantial increases in the level of multiple cytokines. Hepatic and renal injury was significantly exacerbated in mice with Stat3 deficiency. Despite enhanced inflammatory responses, the mice failed to facilitate bacterial clearance as compared with the control mice. In addition, the mice exhibited an increased lethality after i.p. inoculation of live bacteria recovered from CLP-mice. In vitro, resident peritoneal macrophages from mice with Stat3 deficiency impaired bactericidal activity relative to the control whereas productions of inflammatory cytokines were significantly augmented when cells were stimulated with a synthetic lipopeptide, macrophage-activating lipopeptide-2 and LPS. Elicited macrophages and neutrophils with Stat3 deficiency also impaired bactericidal activity as compared with those with Stat3. Lysosomal enzyme release, an effector molecule for bacterial clearance, was significantly decreased in elicited leukocytes with Stat3 deficiency while increasing the production of inflammatory cytokines. Altogether, these results suggest that macrophage/neutrophil-specific STAT3 is crucial in not only modulating multiple organ failure associated with systemic inflammation but also intensifying the bactericidal activity, which highlight the significance of cell-specific Stat3 in the protective immunity during sepsis.
Placental Cell Expression of HLA-G2 Isoforms Is Limited to the Invasive Trophoblast Phenotype
Authors: Morales Pedro J. , Pace Judith L. , Platt Jeralyn Sue , Phillips Teresa A. , Morgan Kim , Fazleabas Asgi T. , Hunt Joan S.
Published: April 2014

The HLA-G message is alternatively spliced into multiple transcripts, two of which encode soluble isoforms. To initiate studies on the specific functions of the soluble isoforms, we produced soluble rHLA-G1 (rsG1) and rsG2 in human embryonic kidney 293 cells and characterized the proteins. Both isoforms were glycosylated and formed disulfide-bonded oligomers. Recombinant sG1 associated with β2-microglobulin, whereas rsG2 did not. Mouse mAb generated to rsG1 (1-2C3), which identified exclusively sG1, and mAb generated to rsG2 (26-2H11), which identified both soluble and membrane G2 (m/sG2), were used for immunohistochemical isoform mapping studies on placental tissue sections. Soluble G1 protein was abundant in many subpopulations of trophoblast cells, whereas m/sG2 protein was present exclusively in extravillous cytotrophoblast cells. Although both isolated placental villous cytotrophoblast cells and chorion membrane extravillous cytotrophoblast cells contained mRNAs encoding sG1 and sG2, protein expression was as predicted from the immunostains with m/sG2 present only in the invasive trophoblast subpopulation. Analysis of function by Northern and Western blotting demonstrated that both rsG1 and rsG2 inhibit CD8α expression on PBMC without changing CD3δ expression or causing apoptotic cell death. Collectively, the studies indicate that: 1) both sG1 and m/sG2 are produced in placentas; 2) transcription and translation are linked for sG1, but not G2; 3) expression of G2 is exclusively associated with the invasive phenotype; and 4) the two isoforms of sG may promote semiallogeneic pregnancy by reducing expression of CD8, a molecule required for functional activation of CTL.