bluuebunny/crossref_metadata_2025 huggingface dataset:
TLR Signaling Mediated by MyD88 Is Required for a Protective Innate Immune Response by Neutrophils to Citrobacter rodentium
Authors: Lebeis Sarah L. , Bommarius Bettina , Parkos Charles A. , Sherman Melanie A. , Kalman Daniel
Published: April 2014

Enteropathogenic Escherichia coli, enterohemorrhagic E. coli, and Citrobacter rodentium are classified as attaching and effacing pathogens based on their ability to adhere to intestinal epithelium via actin-filled membranous protrusions (pedestals). Infection of mice with C. rodentium causes breach of the colonic epithelial barrier, a vigorous Th1 inflammatory response, and colitis. Ultimately, an adaptive immune response leads to clearance of the bacteria. Whereas much is known about the adaptive response to C. rodentium, the role of the innate immune response remains unclear. In this study, we demonstrate for the first time that the TLR adaptor MyD88 is essential for survival and optimal immunity following infection. MyD88−/− mice suffer from bacteremia, gangrenous mucosal necrosis, severe colitis, and death following infection. Although an adaptive response occurs, MyD88-dependent signaling is necessary for efficient clearance of the pathogen. Based on reciprocal bone marrow transplants in conjunction with assessment of intestinal mucosal pathology, repair, and cytokine production, our findings suggest a model in which TLR signaling in hemopoietic and nonhemopoietic cells mediate three distinct processes: 1) induction of an epithelial repair response that maintains the protective barrier and limits access of bacteria to the lamina propria; 2) production of KC or other chemokines that attract neutrophils and thus facilitate killing of bacteria; and 3) efficient activation of an adaptive response that facilitates Ab-mediated clearance of the infection. Taken together, these experiments provide evidence for a protective role of innate immune signaling in infections caused by attaching and effacing pathogens.
Negative Regulation of TLR Responses by the Neuropeptide CGRP Is Mediated by the Transcriptional Repressor ICER
Authors: Harzenetter Marit D. , Novotny Alexander R. , Gais Petra , Molina Carlos A. , Altmayr Felicitas , Holzmann Bernhard
Published: April 2014

Communication between the nervous and immune systems involves the release of neuropeptides, such as calcitonin gene-related peptide (CGRP), from sensory nerves during inflammation. CGRP may inhibit the activities of both innate and adaptive immune cells, but the molecular pathways underlying this function are largely unknown. In this study, we identify CGRP as a potent inhibitor of TLR-stimulated production of inflammatory mediators, such as TNF-α and CCL4, by murine dendritic cells. Inhibition of TLR responses was independent of IL-10 and did not involve perturbation of canonical TLR signaling, including activation of MAPK and NF-κB. Instead, the inhibitory activity of CGRP was mediated by the cAMP/protein kinase A pathway leading to rapid up-regulation of the transcriptional repressor, inducible cAMP early repressor (ICER). Ectopically expressed ICER directly repressed the LPS-stimulated activity of a synthetic Tnf promoter, as well as TNF-α protein production driven by the endogenous promoter. Inhibition of dendritic cell gene expression by CGRP was associated with the presence of a composite cAMP response element/κB promoter element. In a murine model of endotoxemia, CGRP markedly attenuated serum TNF-α levels, and this effect was associated with the up-regulation of ICER. Together, these results establish a novel pathway for the negative regulation of TLR responses through the nervous system that critically involves induction of the transcriptional repressor ICER by the neuropeptide CGRP.
Aspirin-Triggered Lipoxins Override the Apoptosis-Delaying Action of Serum Amyloid A in Human Neutrophils: A Novel Mechanism for Resolution of Inflammation
Authors: El Kebir Driss , József Levente , Khreiss Tarek , Pan Wanling , Petasis Nicos A. , Serhan Charles N. , Filep János G.
Published: April 2014

Elevated plasma levels of the acute-phase reactant serum amyloid A (SAA) have been used as a marker and predictor of inflammatory diseases. SAA regulates leukocyte activation; however, it is not known whether it also modulates neutrophil apoptosis, which is critical to the optimal expression and resolution of inflammation. Culture of human neutrophils with SAA (0.1–20 μg/ml) markedly prolonged neutrophil longevity by delaying constitutive apoptosis. SAA evoked concurrent activation of the ERK and PI3K/Akt signaling pathways, leading to phosphorylation of BAD at Ser112 and Ser136, respectively, and to prevention of collapse of mitochondrial transmembrane potential, cytochrome c release, and caspase-3 activation. These actions were abrogated by pharmacological inhibition of the formyl peptide receptor, ERK or PI3K. Furthermore, aspirin-triggered 15-epi-lipoxin A4 (15-epi-LXA4) and its stable analog 15-epi-16-p-fluorophenoxy-LXA4, which binds to the same receptor as SAA, effectively overrode the antiapoptosis signal from SAA even when neutrophils were treated with 15-epi-LXA4 at either 1 or 4 h postculture with SAA. 15-Epi-LXA4 itself did not affect neutrophil survival and apoptosis. Our results indicate that SAA at clinically relevant concentrations promotes neutrophil survival by suppressing the apoptotic machinery, an effect that can be opposed by 15-epi-LXA4. The opposing actions of SAA and aspirin-triggered 15-epi-LXA4 may contribute to the local regulation of exacerbation and resolution of inflammation, respectively.
Intercellular Adhesion Molecule-1 Deficiency Attenuates the Development of Skin Fibrosis in Tight-Skin Mice
Authors: Matsushita Yukiyo , Hasegawa Minoru , Matsushita Takashi , Fujimoto Manabu , Horikawa Mayuka , Fujita Tomoyuki , Kawasuji Ayako , Ogawa Fumihide , Steeber Douglas A. , Tedder Thomas F. , Takehara Kazuhiko , Sato Shinichi
Published: April 2014

The tight-skin (TSK/+) mouse, a genetic model for systemic sclerosis, develops cutaneous fibrosis. Although a fibrillin 1 gene mutation and immunological abnormalities have been demonstrated, the roles of adhesion molecules have not been investigated. To directly assess roles of adhesion molecules in skin fibrosis, TSK/+ mice lacking L-selectin and/or ICAM-1 were generated. The deficiency of ICAM-1, but not L-selectin, significantly suppressed (∼48%) the development of skin sclerosis in TSK/+ mice. Similarly, ICAM-1 antisense oligonucleotides inhibited skin fibrosis in TSK/+ mice. Although T cell infiltration was modest into the skin of TSK/+ mice, ICAM-1 deficiency down-regulated this migration, which is consistent with the established roles of endothelial ICAM-1 in leukocyte infiltration. In addition, altered phenotype or function of skin fibroblasts was remarkable and dependent on ICAM-1 expression in TSK/+ mice. ICAM-1 expression was augmented on TSK/+ dermal fibroblasts stimulated with IL-4. Although growth or collagen synthesis of TSK/+ fibroblasts cultured with IL-4 was up-regulated, it was suppressed by the loss or blocking of ICAM-1. Collagen expression was dependent on the strain of fibroblasts, but not on the strain of cocultured T cells. Thus, our findings indicate that ICAM-1 expression contributes to the development of skin fibrosis in TSK/+ mice, especially via ICAM-1 expressed on skin fibroblasts.
Memory CD8+ T Cells Require CD28 Costimulation
Authors: Borowski Annie B. , Boesteanu Alina C. , Mueller Yvonne M. , Carafides Caterina , Topham David J. , Altman John D. , Jennings Stephen R. , Katsikis Peter D.
Published: April 2014

CD8+ T cells are a critical component of the adaptive immune response against infections and tumors. A current paradigm in immunology is that naive CD8+ T cells require CD28 costimulation, whereas memory CD8+ T cells do not. We show here, however, that during viral infections of mice, costimulation is required in vivo for the reactivation of memory CD8+ T cells. In the absence of CD28 costimulation, secondary CD8+ T cell responses are greatly reduced and this impairs viral clearance. The failure of CD8+ T cells to expand in the absence of CD28 costimulation is CD4+ T cell help independent and is accompanied by a failure to down-regulate Bcl-2 and by cell cycle arrest. This requirement for CD28 costimulation was shown in both influenza A and HSV infections. Thus, contrary to current dogma, memory CD8+ T cells require CD28 costimulation to generate maximal secondary responses against pathogens. Importantly, this CD28 requirement was shown in the context of real infections were multiple other cytokines and costimulators may be up-regulated. Our findings have important implications for pathogens, such as HIV and measles virus, and tumors that evade the immune response by failing to provide CD28 costimulation. These findings also raise questions about the efficacy of CD8+ T cell-based vaccines against such pathogens and tumors.
CD4+CD28null T Cells in Autoimmune Disease: Pathogenic Features and Decreased Susceptibility to Immunoregulation
Authors: Thewissen Marielle , Somers Veerle , Hellings Niels , Fraussen Judith , Damoiseaux Jan , Stinissen Piet
Published: April 2014

To determine the role of expanded CD4+CD28null T cells in multiple sclerosis and rheumatoid arthritis pathology, these cells were phenotypically characterized and their Ag reactivity was studied. FACS analysis confirmed that CD4+CD28null T cells are terminally differentiated effector memory cells. In addition, they express phenotypic markers that indicate their capacity to infiltrate into tissues and cause tissue damage. Whereas no reactivity to the candidate autoantigens myelin basic protein and collagen type II was observed within the CD4+CD28null T cell subset, CMV reactivity was prominent in four of four HC, four of four rheumatoid arthritis patients, and three of four multiple sclerosis patients. The level of the CMV-induced proliferative response was found to be related to the clonal diversity of the response. Interestingly, our results illustrate that CD4+CD28null T cells are not susceptible to the suppressive actions of CD4+CD25+ regulatory T cells. In conclusion, this study provides several indications for a role of CD4+CD28null T cells in autoimmune pathology. CD4+CD28null T cells display pathogenic features, fill up immunological space, and are less susceptible to regulatory mechanisms. However, based on their low reactivity to the autoantigens tested in this study, CD4+CD28null T cells most likely do not play a direct autoaggressive role in autoimmune disease.
The Lipopolysaccharide Adjuvant Effect on T Cells Relies on Nonoverlapping Contributions from the MyD88 Pathway and CD11c+ Cells
Authors: McAleer Jeremy P. , Zammit David J. , Lefrançois Leo , Rossi Robert J. , Vella Anthony T.
Published: April 2014

Bacterial LPS is a natural adjuvant that induces profound effects on T cell clonal expansion, effector differentiation, and long-term T cell survival. In this study, we delineate the in vivo mechanism of LPS action by pinpointing a role for MyD88 and CD11c+ cells. LPS induced long-term survival of superantigen-stimulated CD4 and CD8 T cells in a MyD88-dependent manner. By tracing peptide-stimulated CD4 T cells after adoptive transfer, we showed that for LPS to mediate T cell survival, the recipient mice were required to express MyD88. Even when peptide-specific CD4 T cell clonal expansion was dramatically boosted by enforced OX40 costimulation, OX40 only synergized with LPS to induce survival when the recipient mice expressed MyD88. Nevertheless, these activated, but moribund, T cells in the MyD88−/− mice acquired effector properties, such as the ability to synthesize IFN-γ, demonstrating that effector differentiation is not automatically coupled to a survival program. We confirmed this notion in reverse fashion by showing that effector differentiation was not required for the induction of T cell survival. Hence, depletion of CD11c+ cells did not affect LPS-driven specific T cell survival, but CD11c+ cells were paramount for optimal effector T cell differentiation as measured by IFN-γ potential. Thus, LPS adjuvanticity is based on MyD88 promoting T cell survival, while CD11c+ cells support effector T cell differentiation.
The Bw Cells, a Novel B Cell Population Conserved in the Whole Genus Mus
Authors: Thiriot Aude , Drapier Anne-Marie , Vieira Paulo , Fitting Catherine , Cavaillon Jean-Marc , Cazenave Pierre-André , Rueff-Juy Dominique
Published: April 2014

In common laboratory mouse strains, which are derived from the crossing between three subspecies, peritoneal B cells are enriched in B-1a cells characterized by the CD5+Mac-1+B220lowIgMhighIgDlowCD43+CD9+ phenotype. Intriguingly in other vertebrates, CD5+Mac-1+ cells have never been found in a specific anatomic site. To ascertain the peculiarity of the CD5+ peritoneal B cells in laboratory mice, we analyzed the peritoneal B cell subsets in 9 inbred and 39 outbred wild-derived mouse strains belonging to 13 different species/subspecies. We found that most of these strains do not have the CD5+ B-1a cell population. However, all of these strains including classical laboratory mouse strains, have variable proportions of a novel B cell population: Bw, which is characterized by a unique phenotype (CD5−Mac-1+B220highIgMhighIgDhighCD43−CD9−) and is not restricted to the peritoneal cavity. Bw cells are also distinct from both B-1 and B-2 cells from a functional point of view both by proliferative responses, cytokine secretion and Ab synthesis. Moreover, transfer experiments show that bone marrow and fetal liver cells from wild mice can give rise to Bw cells in alymphoid mice. The conservation of this B cell population, but not of the CD5+ B-1a, during evolution of the genus Mus, its readiness to respond to TLR ligands and to produce high concentration of autoantibodies suggest that Bw cells play a key role in innate immunity.
Secretory Leukoprotease Inhibitor in Mucosal Lymph Node Dendritic Cells Regulates the Threshold for Mucosal Tolerance
Authors: Samsom Janneke N. , van der Marel Arnold P. J. , van Berkel Lisette A. , van Helvoort Joop M. L. M. , Simons-Oosterhuis Ytje , Jansen Wendy , Greuter Mascha , Nelissen Rob L. H. , Meeuwisse Cees M. L. , Nieuwenhuis Edward E. S. , Mebius Reina E. , Kraal Georg
Published: April 2014

The notion that the mucosal immune system maintains a tolerogenic response to harmless Ags while continually being challenged with microbial products seems an enigma. The aim of this study was to unravel mechanisms that are involved in regulating the development of tolerance under constant microbial pressure. The tolerogenic response to Ags administered via the nasal mucosa is dependent on the organized lymphoid tissue of the cervical lymph nodes (LN). We show that cervical LN differentially express secretory leukoprotease inhibitor (SLPI) compared with peripheral LN. SLPI was expressed by dendritic cells (DCs) and because SLPI is known to suppress LPS responsiveness, it was hypothesized that its expression in mucosal DCs may be required to regulate cellular activation to microbial products. Indeed, compared with wild-type controls, bone marrow-derived DCs from SLPI−/− mice released more inflammatory cytokines and enhanced T cell proliferation after stimulation with low dose LPS. This increased sensitivity to LPS was accompanied by increased NF-κB p65 activation in SLPI−/− DCs. In vivo, nasal application of OVA with LPS to SLPI−/− mice resulted in enhanced DC activation in the cervical LN reflected by increased costimulatory molecule expression and release of inflammatory cytokines. This led to failure to maintain tolerance to nasal OVA application in the presence of low doses of LPS. We propose that expression of SLPI functions as a rheostat by controlling the level of bacterial stimuli that induce mucosal DC activation. As such, it regulates the quality of the ensuing Ag-specific immune response in the mucosa draining LN.
Type 1 IFN Mediates Cross-Talk between Innate and Adaptive Immunity That Abrogates Transplantation Tolerance
Authors: Thornley Thomas B. , Phillips Nancy E. , Beaudette-Zlatanova Britte C. , Markees Thomas G. , Bahl Kapil , Brehm Michael A. , Shultz Leonard D. , Kurt-Jones Evelyn A. , Mordes John P. , Welsh Raymond M. , Rossini Aldo A. , Greiner Dale L.
Published: April 2014

TLR activation of innate immunity prevents the induction of transplantation tolerance and shortens skin allograft survival in mice treated with costimulation blockade. The mechanism by which TLR signaling mediates this effect has not been clear. We now report that administration of the TLR agonists LPS (TLR4) or polyinosinic:polycytidylic acid (TLR3) to mice treated with costimulation blockade prevents alloreactive CD8+ T cell deletion, primes alloreactive CTLs, and shortens allograft survival. The TLR4- and MyD88-dependent pathways are required for LPS to shorten allograft survival, whereas polyinosinic:polycytidylic acid mediates its effects through a TLR3-independent pathway. These effects are all mediated by signaling through the type 1 IFN (IFN-αβ) receptor. Administration of IFN-β recapitulates the detrimental effects of TLR agonists on transplantation tolerance. We conclude that the type 1 IFN generated as part of an innate immune response to TLR activation can in turn activate adaptive immune responses that abrogate transplantation tolerance. Blocking of type 1 IFN-dependent pathways in patients may improve allograft survival in the presence of exogenous TLR ligands.
Cell Surface Colony-Stimulating Factor 1 Can Be Cleaved by TNF-α Converting Enzyme or Endocytosed in a Clathrin-Dependent Manner
Authors: Horiuchi Keisuke , Miyamoto Takeshi , Takaishi Hironari , Hakozaki Akihiro , Kosaki Naoto , Miyauchi Yoshiteru , Furukawa Mitsuru , Takito Jiro , Kaneko Hironori , Matsuzaki Kenichiro , Morioka Hideo , Blobel Carl P. , Toyama Yoshiaki
Published: April 2014

CSF-1 is a hemopoietic growth factor, which plays an essential role in macrophage and osteoclast development. Alternative splice variants of CSF-1 are synthesized as soluble or membrane-anchored molecules, although membrane CSF-1 (mCSF-1) can be cleaved from the cell membrane to become soluble CSF-1. The activities involved in this proteolytic processing, also referred to as ectodomain shedding, remain poorly characterized. In the present study, we examined the properties of the mCSF-1 sheddase in cell-based assays. Shedding of mCSF-1 was up-regulated by phorbol ester treatment and was inhibited by the metalloprotease inhibitors GM6001 and tissue inhibitor of metalloproteases 3. Moreover, the stimulated shedding of mCSF-1 was abrogated in fibroblasts lacking the TNF-α converting enzyme (TACE, also known as a disintegrin and metalloprotease 17) and was rescued by expression of wild-type TACE in these cells, strongly suggesting that the stimulated shedding is TACE dependent. Additionally, we observed that mCSF-1 is predominantly localized to intracellular membrane compartments and is efficiently internalized in a clathrin-dependent manner. These results indicate that the local availability of mCSF-1 is actively regulated by ectodomain shedding and endocytosis. This mechanism may have important implications for the development and survival of monocyte lineage cells.
Developmental Exposure to Noninherited Maternal Antigens Induces CD4+ T Regulatory Cells: Relevance to Mechanism of Heart Allograft Tolerance
Authors: Molitor-Dart Melanie L. , Andrassy Joachim , Kwun Jean , Kayaoglu H. Ayhan , Roenneburg Drew A. , Haynes Lynn D. , Torrealba Jose R. , Bobadilla Joseph L. , Sollinger Hans W. , Knechtle Stuart J. , Burlingham William J.
Published: April 2014

We hypothesize that developmental exposure to noninherited maternal Ags (NIMA) results in alloantigen-specific natural and adaptive T regulatory (TR) cells. We compared offspring exposed to maternal H-2d (NIMAd) with nonexposed controls. In vitro assays did not reveal any differences in T cell responses pretransplant. Adoptive transfer assays revealed lower lymphoproliferation and greater cell surface TGF-β expression on CD4+ T cells of NIMAd-exposed vs control splenocytes. NIMAd-exposed splenocytes exhibited bystander suppression of tetanus-specific delayed-type hypersensitivity responses, which was reversed with Abs to TGF-β and IL-10. Allospecific T effector cells were induced in all mice upon i.v. challenge with B6D2F1 splenocytes or a DBA/2 heart transplant, but were controlled in NIMAd-exposed mice by TR cells to varying degrees. Some (40%) NIMAd-exposed mice accepted a DBA/2 allograft while others (60%) rejected in delayed fashion. Rejector and acceptor NIMAd-exposed mice had reduced T effector responses and increased Foxp3+ TR cells (CD4+CD25+Foxp3+ TR) in spleen and lymph nodes compared with controls. The key features distinguishing NIMAd-exposed acceptors from all other mice were: 1) higher frequency of IL-10- and TGF-β-producing cells primarily in the CD4+CD25+ T cell subset within lymph nodes and allografts, 2) a suppressed delayed-type hypersensitivity response to B6D2F1 Ags, and 3) allografts enriched in LAP+, Foxp3+, and CD4+ T cells, with few CD8+ T cells. We conclude that the beneficial NIMA effect is due to induction of NIMA-specific TR cells during ontogeny. Their persistence in the adult, and the ability of the host to mobilize them to the graft, may determine whether NIMA-specific tolerance is achieved.
Induction of Robust Diabetes Resistance and Prevention of Recurrent Type 1 Diabetes Following Islet Transplantation by Gene Therapy
Authors: Tian Chaorui , Ansari Mohammed Javeed I. , Paez-Cortez Jesus , Bagley Jessamyn , Godwin Jonathan , Donnarumma Michela , Sayegh Mohamed H. , Iacomini John
Published: April 2014

We have previously shown that the development of type 1 diabetes (T1D) can be prevented in nonobese diabetic (NOD) mice by reconstitution with autologous hemopoietic stem cells retrovirally transduced with viruses encoding MHC class II I-A β-chain molecules associated with protection from the disease. In this study we examined whether a blockade of the programmed death-1 (PD-1)-programmed death ligand-1 (PD-L1) pathway, a major pathway known to control diabetes occurrence, could precipitate T1D in young NOD mice following reconstitution with autologous bone marrow retrovirally transduced with viruses encoding protective MHC class II I-A β-chain molecules. In addition, we examined whether the expression of protective MHC class II alleles in hemopoietic cells could be used to prevent the recurrence of diabetes in mice with pre-existing disease following islet transplantation. Protection from the occurrence of T1D diabetes in young NOD mice by the expression of protective MHC class II I-A β-chain molecules in bone marrow-derived hemopoietic cells was resistant to induction by PD-1-PD-L1 blockade. Moreover, reconstitution of NOD mice with pre-existing T1D autologous hemopoietic stem cells transduced with viruses encoding protective MHC class II I-A β-chains allowed for the successful transplantation of syngeneic islets, resulting in the long-term reversal of T1D. Reversal of diabetes was resistant to induction by PD-1-PDL-1 blockade and depletion of CD25+ T cells. These data suggest that expression of protective MHC class II alleles in bone marrow-derived cells establishes robust self-tolerance to islet autoantigens and is sufficient to prevent the recurrence of autoimmune diabetes following islet transplantation.
JunB Is Required for IgE-Mediated Degranulation and Cytokine Release of Mast Cells
Authors: Textor Björn , Licht Alexander H. , Tuckermann Jan P. , Jessberger Rolf , Razin Ehud , Angel Peter , Schorpp-Kistner Marina , Hartenstein Bettina
Published: April 2014

Mast cells are effector cells of IgE-mediated immune responses frequently found at the vicinity of blood vessels, the margins of diverse tumors and at sites of potential infection and inflammation. Upon IgE-mediated stimulation, mast cells produce and secrete a broad spectrum of cytokines and other inflammatory mediators. Recent work identified JunB, a member of the AP-1 transcription factor family, as critical regulator of basal and induced expression of inflammatory mediators in fibroblasts and T cells. To study the impact of JunB on mast cell biology, we analyzed JunB-deficient mast cells. Mast cells lacking JunB display a normal in vivo maturation, and JunB-deficient bone marrow cells in vitro differentiated to mast cells show no alterations in proliferation or apoptosis. But these cells exhibit impaired IgE-mediated degranulation most likely due to diminished expression of SWAP-70, Synaptotagmin-1, and VAMP-8, and due to impaired influx of extracellular calcium. Moreover, JunB-deficient bone marrow mast cells display an altered cytokine expression profile in response to IgE stimulation. In line with these findings, the contribution of JunB-deficient mast cells to angiogenesis, as analyzed in an in vitro tube formation assay on matrigel, is severely impaired due to limiting amounts of synthesized and secreted vascular endothelial growth factor. Thus, JunB is a critical regulator of intrinsic mast cell functions including cross-talk with endothelial cells.
Targeting IFN-α to B Cell Lymphoma by a Tumor-Specific Antibody Elicits Potent Antitumor Activities
Authors: Huang Tzu-Hsuan , Chintalacharuvu Koteswara R. , Morrison Sherie L.
Published: April 2014

IFN-α, a cytokine crucial for the innate immune response, also demonstrates antitumor activity. However, use of IFN-α as an anticancer drug is hampered by its short half-life and toxicity. One approach to improving IFN-α’s therapeutic index is to increase its half-life and tumor localization by fusing it to a tumor-specific Ab. In the present study, we constructed a fusion protein consisting of anti-HER2/neu-IgG3 and IFN-α (anti-HER2/neu-IgG3-IFN-α) and investigated its effect on a murine B cell lymphoma, 38C13, expressing human HER2/neu. Anti-HER2/neu-IgG3-IFN-α exhibited potent inhibition of 38C13/HER2 tumor growth in vivo. Administration of three daily 1-μg doses of anti-HER2/neu-IgG3-IFN-α beginning 1 day after tumor challenge resulted in 88% of the mice remaining tumor free. Remarkably, anti-HER2/neu-IgG3-IFN-α demonstrated potent activity against established 38C13/HER2 tumors, with complete tumor remission observed in 38% of the mice treated with three daily doses of 5 μg of the fusion protein (p = 0.0001). Ab-mediated targeting of IFN-α induced growth arrest and apoptosis of lymphoma cells contributing to the antitumor effect. The fusion protein also had a longer in vivo half-life than rIFN-α. These results suggest that IFN-α Ab fusion proteins may be effective in the treatment of B cell lymphoma.
The Aryl Hydrocarbon Receptor Is Required for Optimal Resistance to Listeria monocytogenes Infection in Mice
Authors: Shi Lewis Zhichang , Faith Nancy G. , Nakayama Yumi , Suresh Makulasiddappa , Steinberg Howard , Czuprynski Charles J.
Published: April 2014

The aryl hydrocarbon receptor (AhR) is part of a powerful signaling system that is triggered by xenobiotic agents such as polychlorinated hydrocarbons and polycyclic aromatic hydrocarbons. Although activation of the AhR by 2,3,7,8-tetrachlorodibenzo-p-dioxin or certain polycyclic aromatic hydrocarbons can lead to immunosuppression, there is also increasing evidence that the AhR regulates certain normal developmental processes. In this study, we asked whether the AhR plays a role in host resistance using murine listeriosis as an experimental system. Our data clearly demonstrate that AhR null C57BL/6J mice (AhR−/−) are more susceptible to listeriosis than AhR heterozygous (AhR+/−) littermates when inoculated i.v. with log-phase Listeria monocytogenes. AhR−/− mice exhibited greater numbers of CFU of L. monocytogenes in the spleen and liver, and greater histopathological changes in the liver than AhR+/− mice. Serum levels of IL-6, MCP-1, IFN-γ, and TNF-α were comparable between L. monocytogenes-infected AhR−/− and AhR+/− mice. Increased levels of IL-12 and IL-10 were observed in L. monocytogenes-infected AhR−/− mice. No significant difference was found between AhR+/− and AhR−/− macrophages ex vivo with regard to their ability to ingest and inhibit intracellular growth of L. monocytogenes. Intracellular cytokine staining of CD4+ and CD8+ splenocytes for IFN-γ and TNF-α revealed comparable T cell-mediated responses in AhR−/− and AhR+/− mice. Previously infected AhR−/− and AhR+/− mice both exhibited enhanced resistance to reinfection with L. monocytogenes. These data provide the first evidence that AhR is required for optimal resistance but is not essential for adaptive immune response to L. monocytogenes infection.
Resistin-Like Molecule β (RELMβ/FIZZ2) Is Highly Expressed in the Ileum of SAMP1/YitFc Mice and Is Associated with Initiation of Ileitis
Authors: Barnes Sean L. , Vidrich Alda , Wang Mei-Lun , Wu Gary D. , Cominelli Fabio , Rivera-Nieves Jesus , Bamias Giorgos , Cohn Steven M.
Published: April 2014

SAMP1/Fc mice develop spontaneous ileitis that shares many features with human Crohn’s disease. One of the earliest features of ileitis in SAMP1/Fc mice is an increase in the number of ileal goblet and intermediate cells. Resistin-like molecule β (RELMβ) is a goblet cell-specific, cysteine-rich peptide previously shown to function as part of the innate immune response. In this study, we examined the role of expression of RELMβ in the initiation of ileal inflammation in SAMP1/Fc mice. RELMβ was highly induced in the ilea of SAMP1/Fc mice beginning at age 5 wk, coincident with the histological appearance of inflammation. RELMβ was found in ileal goblet cells and some intermediate and Paneth cells. Surprisingly, RELMβ mRNA levels were significantly increased in the ilea of 80% of germ-free SAMP1/Fc mice examined compared with specific pathogen-free AKR control mice of similar age. Ileitis was observed in germfree SAMP1/Fc mice, although it was attenuated relative to specific pathogen-free SAMP1/Fc mice. These data suggest that neither the early induction of RELMβ expression nor ileal inflammation requires the presence of viable intestinal flora. Neither was the induction of RELMβ dependent on the major Th1 or Th2 cytokines. However, RELMβ stimulated naive bone marrow-derived macrophages to secrete significant amounts of TNF-α, IL-6, and RANTES. Our data suggest that RELMβ is involved in the initiation of ileitis in SAMP1/Fc mice and may act through the induction of proinflammatory cytokines from resident immune cells within the mucosa.
IL-17B and IL-17C Are Associated with TNF-α Production and Contribute to the Exacerbation of Inflammatory Arthritis
Authors: Yamaguchi Yumi , Fujio Keishi , Shoda Hirofumi , Okamoto Akiko , Tsuno Nelson H. , Takahashi Koki , Yamamoto Kazuhiko
Published: April 2014

IL-17A is a T cell-derived proinflammatory cytokine that contributes to the pathogenesis of rheumatoid arthritis. Recently, six related molecules have been identified to form the IL-17 family, as follows: IL-17A, IL-17B, IL-17C, IL-17D, IL-17E, and IL-17F. Whereas IL-17A and IL-17F up-regulate IL-6 in synovial fibroblasts, IL-17B and IL-17C are reported to stimulate the release of TNF-α and IL-1β from the monocytic cell line, THP-1 cell. However, their detailed function remains to be elucidated. We report in this study the effects of IL-17 family on the collagen-induced arthritis (CIA) progression by T cell gene transfer and bone marrow chimeric mice. The mRNA expressions of IL-17 family (IL-17A, IL-17B, IL-17C, and IL-17F) and their receptor (IL-17R and IL-17Rh1) genes in the arthritic paws of CIA mice were elevated compared with controls. Although IL-17A and IL-17F were expressed in CD4+ T cells, IL-17B and IL-17C were expressed in the cartilage and in various cell populations in the CIA arthritic paws, respectively. In vitro, IL-17A, IL-17B, IL-17C, and IL-17F induced TNF-α production in mouse peritoneal exudate cells. In vivo, adoptive transfer of IL-17B- and IL-17C-transduced CD4+ T cells evidently exacerbated arthritis. Bone marrow chimeric mice of IL-17B and IL-17C exhibited elevated serum TNF-α concentration and the high arthritis score upon CIA induction. Moreover, neutralization of IL-17B significantly suppressed the progression of arthritis and bone destruction in CIA mice. Therefore, not only IL-17A, but also IL-17B and IL-17C play an important role in the pathogenesis of inflammatory arthritis.
Defects in the Acquisition of CD8 T Cell Effector Function after Priming with Tumor or Soluble Antigen Can Be Overcome by the Addition of an OX40 Agonist
Authors: Redmond William L. , Gough Michael J. , Charbonneau Bridget , Ratliff Timothy L. , Weinberg Andrew D.
Published: April 2014

Several members of the TNFR superfamily, including OX40 (CD134), 4-1BB (CD137), and CD27 provide critical costimulatory signals that promote T cell survival and differentiation in vivo. Although several studies have demonstrated that OX40 engagement can enhance CD4 T cell responses, the mechanisms by which OX40-mediated signals augment CD8 T cell responses are still unclear. Previously, we and others have shown that OX40 engagement on Ag-specific CD8 T cells led to increased CD8 T cell expansion, survival, and the generation of greater numbers of long-lived memory cells. Currently, we demonstrate that provision of an OX40 agonist during the activation of naive CD8 T cells primed in vivo with either soluble or tumor-associated Ag significantly augments granzyme B expression and CD8 T cell cytolytic function through an IL-2-dependent mechanism. Furthermore, augmented CTL function required direct engagement of OX40 on the responding CD8 T cells and was associated with increased antitumor activity against established prostate tumors and enhanced the survival of tumor-bearing hosts. Thus, in the absence of danger signals, as is often the case in a tumor-bearing host, provision of an OX40 agonist can overcome defective CD8 T cell priming and lead to a functional antitumor response in vivo.
Alloimmunity to Human Endothelial Cells Derived from Cord Blood Progenitors
Authors: Suárez Yajaira , Shepherd Benjamin R. , Rao Deepak A. , Pober Jordan S.
Published: April 2014

There is considerable interest in exploiting circulating endothelial progenitor cells (EPCs) for therapeutic organ repair. Such cells may be differentiated into endothelial cells (ECs) in vitro and then expanded for use in tissue engineering. Vessel-derived ECs are variably immunogenic, depending upon tissue source, and it is unknown whether ECs derived from cord blood EPCs are able to initiate an allogeneic response. In this study, we compare the phenotype and alloantigenicity of human cord blood progenitor cell-derived ECs with HUVECs isolated from the same donors. Human cord blood progenitor cell-derived ECs are very similar to HUVECs in the expression of proteins relevant for alloimmunity, including MHC molecules, costimulators, adhesion molecules, cytokines, chemokines, and IDO, and in their ability to initiate allogeneic CD4+ and CD8+ memory T cell responses in vitro and in vivo. These findings have significant implications for the use of cord blood EPCs in regenerative medicine or tissue engineering.
A Hypoallergenic Vaccine Obtained by Tail-to-Head Restructuring of Timothy Grass Pollen Profilin, Phl p 12, for the Treatment of Cross-Sensitization to Profilin
Authors: Westritschnig Kerstin , Linhart Birgit , Focke-Tejkl Margarete , Pavkov Tea , Keller Walter , Ball Tanja , Mari Adriano , Hartl Arnulf , Stöcklinger Angelika , Scheiblhofer Sandra , Thalhamer Josef , Ferreira Fatima , Vieths Stefan , Vogel Lothar , Böhm Alexandra , Valent Peter , Valenta Rudolf
Published: April 2014

Profilins are highly cross-reactive allergens in pollens and plant food. In a paradigmatic approach, the cDNA coding for timothy grass pollen profilin, Phl p 12, was used as a template to develop a new strategy for engineering an allergy vaccine with low IgE reactivity. Non-IgE-reactive fragments of Phl p 12 were identified by synthetic peptide chemistry and restructured (rs) as a new molecule, Phl p 12-rs. It comprised the C terminus of Phl p 12 at its N terminus and the Phl p 12 N terminus at its C terminus. Phl p 12-rs was expressed in Escherichia coli and purified to homogeneity. Determination of secondary structure by circular dichroism indicated that the restructuring process had reduced the IgE-reactive α-helical contents of the protein but retained its β-sheet conformation. Phl p 12-rs exhibited reduced IgE binding capacity and allergenic activity but preserved T cell reactivity in allergic patients. IgG Abs induced by immunization of mice and rabbits with Phl p 12-rs cross-reacted with pollen and food-derived profilins. Recombinant Phl p 12-rs, rPhl p 12-rs, induced less reaginic IgE to the wild-type allergen than rPhl p 12. However, the rPhl p 12-rs-induced IgGs inhibited allergic patients’ IgE Ab binding to profilins to a similar degree as those induced by immunization with the wild type. Phl p 12-rs specific IgG inhibited profilin-induced basophil degranulation. In conclusion, a restructured recombinant vaccine was developed for the treatment of profilin-allergic patients. The strategy of tail-to-head reassembly of hypoallergenic allergen fragments within one molecule represents a generally applicable strategy for the generation of allergy vaccines.
A Critical Role of Protein Kinase Cδ Activation Loop Phosphorylation in Formyl-Methionyl-Leucyl-Phenylalanine-Induced Phosphorylation of p47phox and Rapid Activation of Nicotinamide Adenine Dinucleotide Phosphate Oxidase
Authors: Cheng Ni , He Rong , Tian Jun , Dinauer Mary C. , Ye Richard D.
Published: April 2014

Generation of superoxide by professional phagocytes is an important mechanism of host defense against bacterial infection. Several protein kinase C (PKC) isoforms have been found to phosphorylate p47phox, resulting in its membrane translocation and activation of the NADPH oxidase. However, the mechanism by which specific PKC isoforms regulate NADPH oxidase activation remains to be elucidated. In this study, we report that PKCδ phosphorylation in its activation loop is rapidly induced by fMLF and is essential for its ability to catalyze p47phox phosphorylation. Using transfected COS-7 cells expressing gp91phox, p22phox, p67phox, and p47phox (COS-phox cells), we found that a functionally active PKCδ is required for p47phox phosphorylation and reconstitution of NADPH oxidase. PKCβII cannot replace PKCδ for this function. Characterization of PKCδ/PKCβII chimeras has led to the identification of the catalytic domain of PKCδ as a target of regulation by fMLF, which induces a biphasic (30 and 180 s) phosphorylation of Thr505 in the activation loop of mouse PKCδ. Mutation of Thr505 to alanine abolishes the ability of PKCδ to catalyze p47phox phosphorylation in vitro and to reconstitute NADPH oxidase in the transfected COS-phox cells. A correlation between fMLF-induced activation loop phosphorylation and superoxide production is also established in the differentiated PLB-985 human myelomonoblastic cells. We conclude that agonist-induced PKCδ phosphorylation is a novel mechanism for NADPH oxidase activation. The ability to induce PKCδ phosphorylation may distinguish a full agonist from a partial agonist for superoxide production.
Extensive Characterization of IFN-Induced GTPases mGBP1 to mGBP10 Involved in Host Defense
Authors: Degrandi Daniel , Konermann Carolin , Beuter-Gunia Cornelia , Kresse Alexandra , Würthner Jan , Kurig Stefanie , Beer Sandra , Pfeffer Klaus
Published: April 2014

IFN-γ orchestrates a potent antimicrobial host response. However, the underlying molecular basis for this immunological defense system is largely unknown. In a systematic approach to identify IFN-γ-regulated host effector molecules, a notable number of transcripts with consensus GTP-binding motives were obtained. Further extensive transcriptome and genome analyses identified five novel family members of murine guanylate-binding proteins (mGBPs) now designated mGBP6, 7, 8, 9, and 10. Moreover, in this study, all 10 mGBP members (mGBP1–10) were extensively characterized. mGBPs are selectively up-regulated in vitro by a set of proinflammatory cytokines and TLR agonists as well as in vivo after Listeria monocytogenes and Toxoplasma gondii infection. After IFN-γ stimulation, mGBP1, 2, 3, 6, 7, and 9 are associated with intracellular Toxoplasma parasites and, interestingly, virulent Toxoplasma interfere with mGBP recruitment. Taken together, mGBPs comprise an important set of host defense molecules.
Chemotaxis of Mouse Bone Marrow Neutrophils and Dendritic Cells Is Controlled by ADP-Ribose, the Major Product Generated by the CD38 Enzyme Reaction
Authors: Partida-Sanchez Santiago , Gasser Andreas , Fliegert Ralf , Siebrands Cornelia C. , Dammermann Werner , Shi Guixiu , Mousseau Betty J. , Sumoza-Toledo Adriana , Bhagat Harivadan , Walseth Timothy F. , Guse Andreas H. , Lund Frances E.
Published: April 2014

The ectoenzyme CD38 catalyzes the production of cyclic ADP-ribose (cADPR) and ADP-ribose (ADPR) from its substrate, NAD+. Both products of the CD38 enzyme reaction play important roles in signal transduction, as cADPR regulates calcium release from intracellular stores and ADPR controls cation entry through the plasma membrane channel TRPM2. We previously demonstrated that CD38 and the cADPR generated by CD38 regulate calcium signaling in leukocytes stimulated with some, but not all, chemokines and controls leukocyte migration to inflammatory sites. However, it is not known whether the other CD38 product, ADPR, also regulates leukocyte trafficking In this study we characterize 8-bromo (8Br)-ADPR, a novel compound that specifically inhibits ADPR-activated cation influx without affecting other key calcium release and entry pathways. Using 8Br-ADPR, we demonstrate that ADPR controls calcium influx and chemotaxis in mouse neutrophils and dendritic cells activated through chemokine receptors that rely on CD38 and cADPR for activity, including mouse FPR1, CXCR4, and CCR7. Furthermore, we show that the calcium and chemotactic responses of leukocytes are not dependent on poly-ADP-ribose polymerase 1 (PARP-1), another potential source of ADPR in some leukocytes. Finally, we demonstrate that NAD+ analogues specifically block calcium influx and migration of chemokine-stimulated neutrophils without affecting PARP-1-dependent calcium responses. Collectively, these data identify ADPR as a new and important second messenger of mouse neutrophil and dendritic cell migration, suggest that CD38, rather than PARP-1, may be an important source of ADPR in these cells, and indicate that inhibitors of ADPR-gated calcium entry, such as 8Br-ADPR, have the potential to be used as anti-inflammatory agents.
Cysteinyl Leukotrienes Are Autocrine and Paracrine Regulators of Fibrocyte Function
Authors: Vannella Kevin M. , McMillan Tracy R. , Charbeneau Ryan P. , Wilke Carol A. , Thomas Peedikayil E. , Toews Galen B. , Peters-Golden Marc , Moore Bethany B.
Published: April 2014

Pulmonary fibrosis is characterized by the accumulation of fibroblasts and myofibroblasts. These cells may accumulate from three potential sources: the expansion of resident lung fibroblasts, the process of epithelial-mesenchymal transition, or the recruitment and differentiation of circulating mesenchymal precursors known as fibrocytes. We have previously demonstrated that fibrocytes participate in lung fibrogenesis following administration of FITC to mice. We now demonstrate that leukotriene-deficient 5-LO−/− mice are protected from FITC-induced fibrosis. Both murine and human fibrocytes express both cysteinyl leukotriene receptor (CysLT) 1 and CysLT2. In addition, fibrocytes are capable of producing CysLTs and can be regulated via the autocrine or paracrine secretion of these lipid mediators. Exogenous administration of leukotriene (LT) D4, but not LTC4 induces proliferation of both murine and human fibrocytes in a dose-dependent manner. Consistent with this result, CysLT1 receptor antagonists are able to block the mitogenic effects of exogenous LTD4 on fibrocytes. Endogenous production of CysLTs contributes to basal fibrocyte proliferation, but does not alter fibrocyte responses to basic fibroblast growth factor. Although CysLTs can induce the migration of fibrocytes in vitro, they do not appear to be essential for fibrocyte recruitment to the lung in vivo, possibly due to compensatory chemokine-mediated recruitment signals. However, CysLTs do appear to regulate the proliferation of fibrocytes once they are recruited to the lung. These data provide mechanistic insight into the therapeutic benefit of leukotriene synthesis inhibitors and CysLT1 receptor antagonists in animal models of fibrosis.
Tissue- and Stimulus-Dependent Role of Phosphatidylinositol 3-Kinase Isoforms for Neutrophil Recruitment Induced by Chemoattractants In Vivo
Authors: Pinho Vanessa , de Castro Russo Remo , Amaral Flávio A. , de Sousa Lirlândia P. , Barsante Michele M. , de Souza Danielle G. , Alves-Filho José C. , Cara Denise C. , Hayflick Joel S. , Rommel Christian , Ruckle Thomas , Rossi Adriano G. , Teixeira Mauro M.
Published: April 2014

PI3K plays a fundamental role in regulating neutrophil recruitment into sites of inflammation but the role of the different isoforms of PI3K remains unclear. In this study, we evaluated the role of PI3Kγ and PI3Kδ for neutrophil influx induced by the exogenous administration or the endogenous generation of the chemokine CXCL1. Administration of CXCL1 in PI3Kγ−/− or wild-type (WT) mice induced similar increases in leukocyte rolling, adhesion, and emigration in the cremaster muscle when examined by intravital microscopy. The induction of neutrophil recruitment into the pleural cavity or the tibia-femoral joint induced by the injection of CXCL1 was not significantly different in PI3Kγ−/− or WT mice. Neutrophil influx was not altered by treatment of WT mice with a specific PI3Kδ inhibitor, IC87114, or a specific PI3Kγ inhibitor, AS605240. The administration of IC87114 prevented CXCL1-induced neutrophil recruitment only in presence of the PI3Kγ inhibitor or in PI3Kγ−/− mice. Ag challenge of immunized mice induced CXCR2-dependent neutrophil recruitment that was inhibited by wortmannin or by blockade of and PI3Kδ in PI3Kγ−/− mice. Neutrophil recruitment to bronchoalveolar lavage induced by exogenously added or endogenous production of CXCL1 was prevented in PI3Kγ−/− mice. The accumulation of the neutrophils in lung tissues was significantly inhibited only in PI3Kγ−/− mice treated with IC87114. Neutrophil recruitment induced by exogenous administration of C5a or fMLP appeared to rely solely on PI3Kγ. Altogether, our data demonstrate that there is a tissue- and stimulus-dependent role of PI3Kγ and PI3Kδ for neutrophil recruitment induced by different chemoattractants in vivo.