bluuebunny/crossref_metadata_2025 huggingface dataset:
Dendritic Cell Function Can Be Modulated through Cooperative Actions of TLR Ligands and Invariant NKT Cells
Authors: Hermans Ian F. , Silk Jonathan D. , Gileadi Uzi , Masri S. Hajar , Shepherd Dawn , Farrand Kathryn J. , Salio Mariolina , Cerundolo Vincenzo
Published: April 2014

The quality of signals received by dendritic cells (DC) in response to pathogens influences the nature of the adaptive response. We show that pathogen-derived signals to DC mediated via TLRs can be modulated by activated invariant NKT (iNKT) cells. DC maturation induced in vivo with any one of a variety of TLR ligands was greatly improved through simultaneous administration of the iNKT cell ligand α-galactosylceramide. DC isolated from animals treated simultaneously with TLR and iNKT cell ligands were potent stimulators of naive T cells in vitro compared with DC from animals treated with the ligands individually. Injection of protein Ags with both stimuli resulted in significantly improved T cell and Ab responses to coadministered protein Ags over TLR stimulation alone. Ag-specific CD8+ T cell responses induced in the presence of the TLR4 ligand monophosphoryl lipid A and α-galactosylceramide showed faster proliferation kinetics, and increased effector function, than those induced with either ligand alone. Human DC exposed to TLR ligands and activated iNKT cells in vitro had enhanced expression of maturation markers, suggesting that a cooperative action of TLR ligands and iNKT cells on DC function is a generalizable phenomenon across species. These studies highlight the potential for manipulating the interactions between TLR ligands and iNKT cell activation in the design of effective vaccine adjuvants.
Epigenetic and Transcriptional Programs Lead to Default IFN-γ Production by γδ T Cells
Authors: Chen Liang , He Weifeng , Kim Sean T. , Tao Jian , Gao Yunfei , Chi Hongbo , Intlekofer Andrew M. , Harvey Bohdan , Reiner Steven L. , Yin Zhinan , Flavell Richard A. , Craft Joe
Published: April 2014

γδ T cells have unique features and functions compared with αβ T cells and have been proposed to bridge the innate and adaptive immune responses. Our earlier studies demonstrated that splenic γδ T cells predominantly produce IFN-γ upon activation in vitro, which is partially due to the expression of the Th1-specific transcription factor T-bet. In this study we have explored the epigenetic and transcriptional programs that underlie default IFN-γ production by γδ T cells. We show that the kinetics of IFN-γ transcription is faster in γδ T cells compared with CD4+ and CD8+ T cells and that γδ T cells produce significantly greater amounts of IFN-γ in a proliferation-independent manner when compared with other T cell subsets. By analyzing the methylation pattern of intron 1 of the ifn-γ locus, we demonstrate that this region in naive γδ T cells is hypomethylated relative to the same element in naive CD4+ and CD8+ T cells. Furthermore, naive γδ T cells constitutively express eomesodermin (Eomes), a transcription factor important for IFN-γ production in CD8+ T cells, and Eomes expression levels are enhanced upon activation. Retroviral transduction of activated γδ T cells from both wild-type and T-bet-deficient mice with a dominant negative form of Eomes significantly reduced IFN-γ production, indicating a critical role for this transcription factor in mediating IFN-γ production by γδ T cells in a T-bet-independent manner. Our results demonstrate that both epigenetic and transcriptional programs contribute to the early vigorous IFN-γ production by γδ T cells.
Gag-Specific CD8+ T Lymphocytes Recognize Infected Cells before AIDS-Virus Integration and Viral Protein Expression
Authors: Sacha Jonah B. , Chung Chungwon , Rakasz Eva G. , Spencer Sean P. , Jonas Anna K. , Bean Alexander T. , Lee Wonhee , Burwitz Benjamin J. , Stephany Jason J. , Loffredo John T. , Allison David B. , Adnan Sama , Hoji Akihiko , Wilson Nancy A. , Friedrich Thomas C. , Lifson Jeffrey D. , Yang Otto O. , Watkins David I.
Published: April 2014

CD8+ T cells are a key focus of vaccine development efforts for HIV. However, there is no clear consensus as to which of the nine HIV proteins should be used for vaccination. The early proteins Tat, Rev, and Nef may be better CD8+ T cell targets than the late-expressed structural proteins Gag, Pol, and Env. In this study, we show that Gag-specific CD8+ T cells recognize infected CD4+ T lymphocytes as early as 2 h postinfection, before proviral DNA integration, viral protein synthesis, and Nef-mediated MHC class I down-regulation. Additionally, the number of Gag epitopes recognized by CD8+ T cells was significantly associated with lower viremia (p = 0.0017) in SIV-infected rhesus macaques. These results suggest that HIV vaccines should focus CD8+ T cell responses on Gag.
Efficient Activation of Vα14 Invariant NKT Cells by Foreign Lipid Antigen Is Associated with Concurrent Dendritic Cell-Specific Self Recognition
Authors: Cheng Lu , Ueno Aito , Cho Suzanne , Im Jin S. , Golby Susanne , Hou Sheng , Porcelli Steven A. , Yang Yang
Published: April 2014

A burst release of cytokines by Vα14 invariant NKT (iNKT) cells upon their TCR engagement critically regulates innate and adaptive immune responses. However, it remains unclear in vivo why iNKT cells respond efficiently to microbial or intracellular lipid Ags that are at low levels or that possess suboptimal antigenicity. We found that dendritic cells (DCs) potentiated iNKT cells to respond to a minimal amount of ligand α-galactosylceramide (αGalCer) through CD1d-dependent autoreactive responses that require endosomal processing and CD1d trafficking. The ability of potentiation of NKT cells was DC specific and did not depend on costimulatory signals and IL-12 production by DCs. However, DCs that failed to synthesize a major endogenous lipid Ag isoglobotrihexosylceramide were unable to potentiate NKT cells for efficient activation. Further analysis showed that differences in the level and pattern of endogenous lipid Ag presentation differentiate DCs and B cells for effective potentiation and subsequent activation of iNKT cells in the presence of an exogenous Ag. Thus, CD1d-dependent potentiation by DCs may be crucial for iNKT cell-mediated immunity against infectious agents.
Dendritic Cells Infiltrating Human Non-Small Cell Lung Cancer Are Blocked at Immature Stage
Authors: Perrot Ivan , Blanchard Dominique , Freymond Nathalie , Isaac Sylvie , Guibert Benoît , Pachéco Yves , Lebecque Serge
Published: April 2014

The efficacy of immune response to control human cancer remains controversial. It is particularly debated whether and to what extent the capacity of tumor-infiltrating dendritic cells (DC) to drive immunization can be turned off by transformed cells, leading to tumor-specific tolerance rather than immunization. To address this issue, we have characterized the DC isolated from human non-small cell lung cancer (NSCLC). These biopsy specimens contained CD11chigh myeloid DC (mDC), but also CD11c− plasmacytoid DC (pDC) and a third DC subset expressing intermediate level of CD11c. Compared with peripheral blood, CD11chigh tumor-infiltrating DC (TIDC) displayed a “semi-mature” phenotype, and TLR4 or TLR8 stimulation drove them to mature partially and to secrete limited amounts of cytokines. In contrast, most tumor-infiltrating pDC were immature but underwent partial maturation after TLR7 activation, whereas TLR9 ligation triggered low secretion of IFN-α. CD11cint mDC represented ∼25% of total DC in tumoral and peritumoral tissues and expressed low levels of costimulatory molecules contrasting with high levels of the immunoinhibitory molecule B7-H1. Finally, the poor APC function of total TIDC even after TLR stimulation and the migratory response of both tumor-infiltrating mDC and pDC toward CCL21 and SDF-1 in vitro suggested their ability to compromise the tumor-specific immune response in draining lymph nodes in vivo. Further studies will be required to establish the specific role of the three TIDC subsets in tumor immunity and to draw conclusions for the design of therapeutic strategies.
Regulation of Suppressor of Cytokine Signaling 3 (SOCS3) mRNA Stability by TNF-α Involves Activation of the MKK6/p38MAPK/MK2 Cascade
Authors: Ehlting Christian , Lai Wi S. , Schaper Fred , Brenndörfer Erwin D. , Matthes Raphaela-Jessica , Heinrich Peter C. , Ludwig Stephan , Blackshear Perry J. , Gaestel Matthias , Häussinger Dieter , Bode Johannes G.
Published: April 2014

The potential of some proinflammatory mediators to inhibit gp130-dependent STAT3 activation by enhancing suppressor of cytokine signaling (SOCS) 3 expression represents an important molecular mechanism admitting the modulation of the cellular response toward gp130-mediated signals. Thus, it is necessary to understand the mechanisms involved in the regulation of SOCS3 expression by proinflammatory mediators. In this study, we investigate SOCS3 expression initiated by the proinflammatory cytokine TNF-α. In contrast to IL-6, TNF-α increases SOCS3 expression by stabilizing SOCS3 mRNA. Activation of the MAPK kinase 6 (MKK6)/p38MAPK-cascade is required for TNF-α-mediated stabilization of SOCS3 mRNA and results in enhanced SOCS3 protein expression. In fibroblasts or macrophages deficient for MAPK-activated protein kinase 2 (MK2), a downstream target of the MKK6/p38MAPK cascade, basal SOCS3-expression is strongly reduced and TNF-α-induced SOCS3-mRNA stabilization is impaired, indicating that MK2 is crucial for the control of SOCS3 expression by p38MAPK-dependent signals. As a target for SOCS3 mRNA stability-regulating signals, a region containing three copies of a pentameric AUUUA motif in close proximity to a U-rich region located between positions 2422 and 2541 of the 3′ untranslated region of SOCS3 is identified. One factor that could target this region is the zinc finger protein tristetraprolin (TTP), which is shown to be capable of destabilizing SOCS3 mRNA via this region. However, data from TTP-deficient cells suggest that TTP does not play an irreplaceable role in the regulation of SOCS3 mRNA stability by TNF-α. In summary, these data indicate that TNF-α regulates SOCS3 expression on the level of mRNA stability via activation of the MKK6/p38MAPK cascade and that the activation of MK2, a downstream target of p38MAPK, is important for the regulation of SOCS3 expression.
IL-21 Is Produced by NKT Cells and Modulates NKT Cell Activation and Cytokine Production
Authors: Coquet Jonathan M. , Kyparissoudis Konstantinos , Pellicci Daniel G. , Besra Gurdyal , Berzins Stuart P. , Smyth Mark J. , Godfrey Dale I.
Published: April 2014

The common γ-chain cytokine, IL-21, is produced by CD4+ T cells and mediates potent effects on a variety of immune cells including NK, T, and B cells. NKT cells express the receptor for IL-21; however, the effect of this cytokine on NKT cell function has not been studied. We show that IL-21 on its own enhances survival of NKT cells in vitro, and IL-21 increases the proliferation of NKT cells in combination with IL-2 or IL-15, and particularly with the CD1d-restricted glycosphingolipid Ag α-galactosylceramide. Similar to its effects on NK cells, IL-21 enhances NKT cell granular morphology, including granzyme B expression, and some inhibitory NK receptors, including Ly49C/I and CD94. IL-21 also enhanced NKT cell cytokine production in response to anti-CD3/CD28 in vitro. Furthermore, NKT cells may be subject to autocrine IL-21-mediated stimulation because they are potent producers of this cytokine following in vitro stimulation via CD3 and CD28, particularly in conjunction with IL-12 or following in vivo stimulation with α-galactosylceramide. Indeed, NKT cells produced much higher levels of IL-21 than conventional CD4 T cells in this assay. This study demonstrates that NKT cells are potentially a major source of IL-21, and that IL-21 may be an important factor in NKT cell-mediated immune regulation, both in its effects on NK, T, and B cells, as well as direct effects on NKT cells themselves. The influence of IL-21 in NKT cell-dependent models of tumor rejection, microbial clearance, autoimmunity, and allergy should be the subject of future investigations.
Tumor Evasion of the Immune System by Converting CD4+CD25− T Cells into CD4+CD25+ T Regulatory Cells: Role of Tumor-Derived TGF-β
Authors: Liu Victoria C. , Wong Larry Y. , Jang Thomas , Shah Ali H. , Park Irwin , Yang Ximing , Zhang Qiang , Lonning Scott , Teicher Beverly A. , Lee Chung
Published: April 2014

CD4+CD25+ T regulatory (Treg) cells were initially described for their ability to suppress autoimmune diseases in animal models. An emerging interest is the potential role of Treg cells in cancer development and progression because they have been shown to suppress antitumor immunity. In this study, CD4+CD25− T cells cultured in conditioned medium (CM) derived from tumor cells, RENCA or TRAMP-C2, possess similar characteristics as those of naturally occurring Treg cells, including expression of Foxp3, a crucial transcription factor of Treg cells, production of low levels of IL-2, high levels of IL-10 and TGF-β, and the ability to suppress CD4+CD25− T cell proliferation. Further investigation revealed a critical role of tumor-derived TGF-β in converting CD4+CD25− T cells into Treg cells because a neutralizing Ab against TGF-β, 1D11, completely abrogated the induction of Treg cells. CM from a nontumorigenic cell line, NRP-152, or irradiated tumor cells did not convert CD4+CD25− T cells to Treg cells because they produce low levels of TGF-β in CM. Finally, we observed a reduced tumor burden in animals receiving 1D11. The reduction in tumor burden correlated with a decrease in tumor-derived TGF-β. Treatment of 1D11 also reduced the conversion of CD4+ T cells into Treg cells and subsequent Treg cell-mediated suppression of antitumor immunity. In summary, we have demonstrated that tumor cells directly convert CD4+CD25− T cells to Treg cells through production of high levels of TGF-β, suggesting a possible mechanism through which tumor cells evade the immune system.
Augmentation of Signaling through BCR Containing IgE but not That Containing IgA Due to Lack of CD22-Mediated Signal Regulation
Authors: Sato Motohiko , Adachi Takahiro , Tsubata Takeshi
Published: April 2014

The B cell membrane molecules CD22 and CD72 contain ITIMs in their cytoplasmic portion, and negatively regulate signaling through BCR. Various lines of evidence suggest that ligation of BCR containing IgG (IgG-BCR) transmits augmented signaling due to lack of CD22-mediated signal regulation. However, the signaling capacities of BCR containing IgA and IgE remain largely undefined. In this study, we demonstrate that both IgE-BCR and IgG-BCR, but not IgA-BCR, transmit augmented signaling compared with IgM-BCR. Ligation of IgE-BCR does not induce signaling events required for CD22-mediated signal inhibition, and restoration of these signaling events by coligation of CD22 with BCR abrogates signal augmentation. Furthermore, the cytoplasmic portion of IgE but not that of IgA is sufficient for suppressing CD22-mediated signal inhibition. These findings strongly suggest that the cytoplasmic portion of IgE but not that of IgA reverses CD22-mediated signal inhibition, leading to augmentation of signaling through IgE-BCR but not IgA-BCR. Augmented IgE-BCR signaling appears to play a role in production of large amounts of IgE during helminth infection, whereas regulated signaling through IgA-BCR may be crucial for constitutive production of IgA for mucosal immunity.
Fitness of Cell-Mediated Immunity Independent of Repertoire Diversity
Authors: AbuAttieh Mouhammed , Rebrovich Michelle , Wettstein Peter J. , Vuk-Pavlovic Zvezdana , Limper Andrew H. , Platt Jeffrey L. , Cascalho Marilia
Published: April 2014

Fitness of cell-mediated immunity is thought to depend on TCR diversity; however, this concept has not been tested formally. We tested the concept using JH−/− mice that lack B cells and have TCR Vβ diversity <1% that of wild-type mice and quasimonoclonal (QM) mice with oligoclonal B cells and TCR Vβ diversity 7% that of wild-type mice. Despite having a TCR repertoire contracted >99% and defective lymphoid organogenesis, JH−/− mice rejected H-Y-incompatible skin grafts as rapidly as wild-type mice. JH−/− mice exhibited T cell priming by peptide and delayed-type hypersensitivity, although these responses were less than normal owing either to TCR repertoire contraction or defective lymphoid organogenesis. QM mice with TCR diversity contracted >90%, and normal lymphoid organs rejected H-Y incompatible skin grafts as rapidly as wild type mice and exhibited normal T cell priming and normal delayed-type hypersensitivity reactions. QM mice also resisted Pneumocystis murina like wild-type mice. Thus, cell-mediated immunity can function normally despite contractions of TCR diversity >90% and possibly >99%.
Targeting of Antigen to Dendritic Cells with Poly(γ-Glutamic Acid) Nanoparticles Induces Antigen-Specific Humoral and Cellular Immunity
Authors: Uto Tomofumi , Wang Xin , Sato Katsuaki , Haraguchi Misako , Akagi Takami , Akashi Mitsuru , Baba Masanori
Published: April 2014

Nanoparticles are considered to be efficient tools for inducing potent immune responses by an Ag carrier. In this study, we examined the effect of Ag-carrying biodegradable poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) on the induction of immune responses in mice. The NPs were efficiently taken up by dendritic cells (DCs) and subsequently localized in the lysosomal compartments. γ-PGA NPs strongly induced cytokine production, up-regulation of costimulatory molecules, and the enhancement of T cell stimulatory capacity in DCs. These maturational changes of DCs involved the MyD88-mediated NF-κB signaling pathway. In vivo, γ-PGA NPs were preferentially internalized by APCs (DCs and macrophages) and induced the production of IL-12p40 and IL-6. The immunization of mice with OVA-carrying NPs induced Ag-specific CTL activity and Ag-specific production of IFN-γ in splenocytes as well as potent production of Ag-specific IgG1 and IgG2a Abs in serum. Furthermore, immunization with NPs carrying a CD8+ T cell epitope peptide of Listeria monocytogenes significantly protected the infected mice from death. These results suggest that Ag-carrying γ-PGA NPs are capable of inducing strong cellular and humoral immune responses and might be potentially useful as effective vaccine adjuvants for the therapy of infectious diseases.
Anti-Nuclear Antibody Production and Autoimmunity in Transgenic Mice That Overexpress the Transcription Factor Bright
Authors: Shankar Malini , Nixon Jamee C. , Maier Shannon , Workman Jennifer , Farris A. Darise , Webb Carol F.
Published: April 2014

The B cell-restricted transcription factor, B cell regulator of IgH transcription (Bright), up-regulates Ig H chain transcription 3- to 7-fold in activated B cells in vitro. Bright function is dependent upon both active Bruton’s tyrosine kinase and its substrate, the transcription factor, TFII-I. In mouse and human B lymphocytes, Bright transcription is down-regulated in mature B cells, and its expression is tightly regulated during B cell differentiation. To determine how Bright expression affects B cell development, transgenic mice were generated that express Bright constitutively in all B lineage cells. These mice exhibited increases in total B220+ B lymphocyte lineage cells in the bone marrow, but the relative percentages of the individual subpopulations were not altered. Splenic immature transitional B cells were significantly expanded both in total cell numbers and as increased percentages of cells relative to other B cell subpopulations. Serum Ig levels, particularly IgG isotypes, were increased slightly in the Bright-transgenic mice compared with littermate controls. However, immunization studies suggest that responses to all foreign Ags were not increased globally. Moreover, 4-wk-old Bright-transgenic mice produced anti-nuclear Abs. Older animals developed Ab deposits in the kidney glomeruli, but did not succumb to further autoimmune sequelae. These data indicate that enhanced Bright expression results in failure to maintain B cell tolerance and suggest a previously unappreciated role for Bright regulation in immature B cells. Bright is the first B cell-restricted transcription factor demonstrated to induce autoimmunity. Therefore, the Bright transgenics provide a novel model system for future analyses of B cell autoreactivity.
Aire-Dependent Alterations in Medullary Thymic Epithelium Indicate a Role for Aire in Thymic Epithelial Differentiation
Authors: Gillard Geoffrey O. , Dooley James , Erickson Matthew , Peltonen Leena , Farr Andrew G.
Published: April 2014

The prevalent view of thymic epithelial differentiation and Aire activity holds that Aire functions in terminally differentiated medullary thymic epithelial cells (MTECs) to derepress the expression of structural tissue-restricted Ags, including pancreatic endocrine hormones. An alternative view of these processes has proposed that Aire functions to regulate the differentiation of immature thymic epithelial cells, thereby affecting tissue-restricted Ag expression and negative selection. In this study, we demonstrate that Aire impacts several aspects of murine MTECs and provide support for this second model. Expression of transcription factors associated with developmental plasticity of progenitor cells, Nanog, Oct4, and Sox2, by MTECs was Aire dependent. Similarly, the transcription factors that regulate pancreatic development and the expression of pancreatic hormones are also expressed by wild-type MTECs in an Aire-dependent manner. The altered transcriptional profiles in Aire-deficient MTECs were accompanied by changes in the organization and composition of the medullary epithelial compartment, including a reduction in the medullary compartment defined by keratin (K) 14 expression, altered patterns of K5 and K8 expression, and more prominent epithelial cysts. These findings implicate Aire in the regulation of MTEC differentiation and the organization of the medullary thymic compartment and are compatible with a role for Aire in thymic epithelium differentiation.
Genomic Organization of the Chicken CD8 Locus Reveals a Novel Family of Immunoreceptor Genes
Authors: Liaw Hung-Jiun , Chen Wei-Ru , Huang Yu-Chia , Tsai Chung-Wei , Chang King-Chan , Kuo Chia-Lam
Published: April 2014

The genomic organization of the chicken CD8α gene was investigated to determine the basis of its polymorphism. Contiguous to the CD8α gene we identified multiple DNA blocks possessing sequences homologous to CD8α. Gene conversions and recombination over evolutionary time among CD8α and these CD8α homologous genes seem to account for the observed polymorphism. Furthermore, these CD8α-like DNAs encode a distinct multigene family of immunoreceptors that have a charged or polar residue in place of the interspecies-conserved CD8α transmembrane proline residue and a short cytoplasmic tail nonhomologous to CD8α. The identification of this novel multigene family with an organization reminiscent of human killer Ig-like receptors raises compelling questions on their evolutionary relationship among immunoreceptors.
Early Growth Response Transcriptional Regulators Are Dispensable for Macrophage Differentiation
Authors: Carter John H. , Tourtellotte Warren G.
Published: April 2014

Early growth response (Egr) proteins comprise a family of transcriptional regulators (Egr1–4) that modulate gene expression involved in the growth and differentiation of many cell types. In particular, Egr1 is widely believed to have an essential role in regulating monocyte/macrophage differentiation. However, Egr1-deficient mice have normal numbers of functional macrophages, an observation that has led to the hypothesis that other Egr proteins may compensate for Egr1 function in vivo. We examined whether other Egr transcription factors have a functionally redundant role in monocyte/macrophage differentiation. Egr1 and Egr3 expression was found to be induced in myeloid cells when they were differentiated into macrophages by treatment with M-CSF, whereas Egr2 was minimally induced and Egr4 was not detected. In either Egr1/Egr3 or Egr1/Egr2 double homozygous mutant mice, macrophage differentiation and function remained unimpaired. Additionally, the expression of molecules that broadly inhibit Egr function failed to block commitment to the monocytic lineage or inhibit the maturation of monocyte precursors. Finally, several hemopoietic growth factors were found to induce Egr gene expression, indicating that Egr gene expression is not cell lineage specific. Taken together, these results demonstrate that Egr transcription factors are neither essential for nor specific to monocyte/macrophage differentiation.
17β-Estradiol Induces IL-1α Gene Expression in Rheumatoid Fibroblast-Like Synovial Cells through Estrogen Receptor α (ERα) and Augmentation of Transcriptional Activity of Sp1 by Dissociating Histone Deacetylase 2 from ERα
Authors: Itoh Yuka , Hayashi Hidetoshi , Miyazawa Keiji , Kojima Soichi , Akahoshi Tohru , Onozaki Kikuo
Published: April 2014

Rheumatoid arthritis (RA) occurs four times more frequently in women than in men, although the mechanistic basis of the gender difference is unknown. RA is characterized by the overproliferation of synoviocytes producing proinflammatory cytokines such as IL-1, implicated in the pathogenesis of the disease. In this study we examined whether 17β-estradiol (E2) induced IL-1α mRNA expression in the rheumatoid fibroblast-like cell line MH7A, as well as in primary synovial cells from RA patients, and investigated the underlying molecular mechanisms. E2 induced IL-1α mRNA expression in both cell types in an estrogen receptor-dependent manner. In MH7A cells ERα but not ERβ mediated the effects of E2. Deletion and mutation analysis revealed that a GC-rich region within the IL-1α gene promoter was responsible for the response to E2. EMSAs showed that Sp1 and Sp3 bound to the GC-rich region and that the transcriptional activity of Sp1 was up-regulated by the treatment with E2. Sp1 and ERα interacted physically regardless of the presence of E2. Physical interaction was also observed between ERα and histone deacetylase 2 (HDAC2), and E2 induced the dissociation of HDAC2 from ERα. These results suggest that E2 induces the dissociation of corepressor HDAC2 from ERα, which leads to the augmentation of Sp1 transcriptional activity through the GC-rich region within the IL-1α gene promoter.
A Novel Antibody-Dependent Cellular Cytotoxicity Mechanism Involved in Defense against Malaria Requires Costimulation of Monocytes FcγRII and FcγRIII
Authors: Jafarshad Ali , Dziegiel Morten H. , Lundquist Rasmus , Nielsen Leif K. , Singh Subhash , Druilhe Pierre L.
Published: April 2014

Clinical experiments have shown that the Ab-dependent cell-mediated inhibition of Plasmodium falciparum is a major mechanism controlling malaria parasitemia and thereby symptoms. In this study, we demonstrate that a single merozoite per monocyte (MN) is sufficient to trigger optimal antiparasitic activity. Using particulate Ag as pseudomerozoites, we show that only Ags, and no other parasite-derived factor, are required to trigger MN activation and that a single Ag is as potent as the complex combination of Ags constituting the merozoite surface. Moreover, we found that soluble Ags binding at least two Abs are as effective as the parasite at stimulating MN and that nonmalarial Ags are as efficient provided they are targeted by cytophilic Abs. Indeed, only cytophilic IgGs are potent and, in agreement with immunoepidemiological findings, IgG3 is superior to IgG1. Very low Ab concentrations (>700 pM), i.e., in the range of molecules having a hormonal effect, are effective, in contrast to Abs having a direct, neutralizing effect. Finally, Ab-dependent cell-mediated inhibition proved to require the synergistic activation of both FcγRIIa and FcγRIIIa which both distinguish it from other Ab-dependent cellular cytotoxicity and implies that all MN are not equally effective. These findings have both fundamental and practical implications, particularly for vaccine discovery.
Dectin-1 Stimulation by Candida albicans Yeast or Zymosan Triggers NFAT Activation in Macrophages and Dendritic Cells
Authors: Goodridge Helen S. , Simmons Randi M. , Underhill David M.
Published: April 2014

Innate immune pattern recognition receptors play critical roles in pathogen detection and initiation of antimicrobial responses. We and others have previously demonstrated the importance of the β-glucan receptor Dectin-1 in the recognition of pathogenic fungi by macrophages and dendritic cells and have elucidated some of the mechanisms by which Dectin-1 signals to coordinate the antifungal response. While Dectin-1 signals alone are sufficient to trigger phagocytosis and Src-Syk-mediated induction of antimicrobial reactive oxygen species, collaboration with TLR2 signaling enhances NF-κB activation and regulates cytokine production. In this study we demonstrate that Dectin-1 signaling can also directly modulate gene expression via activation of NFAT. Dectin-1 ligation by zymosan particles or live Candida albicans yeast triggers NFAT activation in macrophages and dendritic cells. Dectin-1-triggered NFAT activation plays a role in the induction of early growth response 2 and early growth response 3 transcription factors, and cyclooxygenase-2. Furthermore, we show that NFAT activation regulates IL-2, IL-10 and IL-12 p70 production by zymosan-stimulated dendritic cells. These data establish NFAT activation in myeloid cells as a novel mechanism of regulation of the innate antimicrobial response.
Type I IFN Signaling Is Crucial for Host Resistance against Different Species of Pathogenic Bacteria
Authors: Mancuso Giuseppe , Midiri Angelina , Biondo Carmelo , Beninati Concetta , Zummo Sebastiana , Galbo Roberta , Tomasello Francesco , Gambuzza Maria , Macrì Giancarlo , Ruggeri Alessia , Leanderson Tomas , Teti Giuseppe
Published: April 2014

It is known that host cells can produce type I IFNs (IFN-αβ) after exposure to conserved bacterial products, but the functional consequences of such responses on the outcome of bacterial infections are incompletely understood. We show in this study that IFN-αβ signaling is crucial for host defenses against different bacteria, including group B streptococci (GBS), pneumococci, and Escherichia coli. In response to GBS challenge, most mice lacking either the IFN-αβR or IFN-β died from unrestrained bacteremia, whereas all wild-type controls survived. The effect of IFN-αβR deficiency was marked, with mortality surpassing that seen in IFN-γR-deficient mice. Animals lacking both IFN-αβR and IFN-γR displayed additive lethality, suggesting that the two IFN types have complementary and nonredundant roles in host defenses. Increased production of IFN-αβ was detected in macrophages after exposure to GBS. Moreover, in the absence of IFN-αβ signaling, a marked reduction in macrophage production of IFN-γ, NO, and TNF-α was observed after stimulation with live bacteria or with purified LPS. Collectively, our data document a novel, fundamental function of IFN-αβ in boosting macrophage responses and host resistance against bacterial pathogens. These data may be useful to devise alternative strategies to treat bacterial infections.
Toll/IL-1 Receptor Domain-Containing Adaptor Inducing IFN-β (TRIF)-Mediated Signaling Contributes to Innate Immune Responses in the Lung during Escherichia coli Pneumonia
Authors: Jeyaseelan Samithamby , Young Scott K. , Fessler Michael B. , Liu Yuhong , Malcolm Kenneth C. , Yamamoto Masahiro , Akira Shizuo , Worthen G. Scott
Published: April 2014

Bacterial pneumonia remains a serious disease and is associated with neutrophil recruitment. Innate immunity is pivotal for the elimination of bacteria, and TLRs are essential in this process. Toll/IL-1R domain-containing adaptor inducing IFN-β (TRIF) is an adaptor for TLR3 and TLR4, and is associated with the MyD88-independent cascade. However, the importance of TRIF in immune responses against pulmonary bacterial pathogens is not well understood. We investigated the involvement of TRIF in a murine model of Escherichia coli pneumonia. TRIF−/− mice infected with E. coli display attenuated neutrophil migration; NF-κB activation; and TNF-α, IL-6, and LPS-induced C-X-C chemokine production in the lungs. In addition, E. coli-induced phosphorylation of JNK, ERK, and p38 MAPK was detected in bone marrow-derived macrophages (BMMs) of TRIF+/+ mice, but attenuated in BMMs of TRIF−/− mice. Furthermore, E. coli-induced TNF-α and IL-6 production was attenuated in BMMs of TRIF−/− mice. E. coli LPS-induced late MAPK activation, and TNF-α and IL-6 production were abolished in BMMs of TRIF−/− mice. Moreover, TRIF is not required for LPS-induced neutrophil influx, and keratinocyte cell-derived chemokine, MIP-2, and LPS-induced C-X-C chemokine production in the lungs. Using TLR3−/− mice, we ruled out the role of TLR3-mediated TRIF-dependent neutrophil influx during E. coli pneumonia. A TLR4-blocking Ab inhibited E. coli-induced TNF-α and IL-6 in BMMs of both TRIF−/− and TRIF+/+ mice, suggesting that TRIF-mediated signaling involves TLR4. We also found that TRIF is critical to control E. coli burden in the lungs and E. coli dissemination. Thus, rapid activation of TRIF-dependent TLR4-mediated signaling cascade serves to augment pulmonary host defense against a Gram-negative pathogen.
A Role of Toll-IL-1 Receptor Domain-Containing Adaptor-Inducing IFN-β in the Host Response to Pseudomonas aeruginosa Lung Infection in Mice
Authors: Power Melanie R. , Li Bo , Yamamoto Masahiro , Akira Shizuo , Lin Tong-Jun
Published: April 2014

Toll-IL-1R domain-containing adaptor-inducing IFN-β (TRIF) is an adaptor molecule that mediates a distinct TLR signaling pathway. Roles of TRIF in the host defense have been primarily associated with virus infections owing to the induction of IFN-αβ. In this study, we investigated a role of TRIF in Pseudomonas aeruginosa infection. In vitro, TRIF-deficient mouse alveolar and peritoneal macrophages showed a complete inhibition of RANTES (CCL5) production, severely impaired TNF and KC (CXCL1) production, and reduced NF-κB activation in response to P. aeruginosa stimulation. In vivo, TRIF-deficient mice showed a complete inhibition of RANTES production, a severely impaired TNF and KC production, and an efficient MIP-2 and IL-1β production in the lung following P. aeruginosa infection. This outcome was associated with a delayed recruitment of neutrophils into the airways. These results suggest that TRIF mediates a distinct cytokine/chemokine profile in response to P. aeruginosa infection. P. aeruginosa-induced RANTES production is completely dependent on TRIF pathway in mice. Importantly, TRIF deficiency leads to impaired clearance of P. aeruginosa from the lung during the initial 24–48 h of infection. Thus, TRIF represents a novel mechanism involved in the development of host response to P. aeruginosa infection.
TLR9 Expression and Function Is Abolished by the Cervical Cancer-Associated Human Papillomavirus Type 16
Authors: Hasan Uzma A. , Bates Elizabeth , Takeshita Fumihiko , Biliato Alexandra , Accardi Rosita , Bouvard Veronique , Mansour Mariam , Vincent Isabelle , Gissmann Lutz , Iftner Thomas , Sideri Mario , Stubenrauch Frank , Tommasino Massimo
Published: April 2014

Cervical cancer development is linked to the persistent infection by high-risk mucosal human papillomaviruses (HPVs) types. The E6 and E7 major oncoproteins from this dsDNA virus play a key role in the deregulation of the cell cycle, apoptosis, and adaptive immune surveillance. In this study, we show for the first time that HPV type 16 (HPV16), the most carcinogenic type among the high-risk subgroup, interferes with innate immunity by affecting the expression of TLRs. Infection of human primary keratinocytes with HPV16 E6 and E7 recombinant retroviruses inhibits TLR9 transcription and hence functional loss of TLR9-regulated pathways. Similar findings were achieved in HPV16-positive cancer-derived cell lines and primary cervical cancers, demonstrating that this event occurs also in an in vivo context. Interestingly, E6 and E7 from the low-risk HPV type 6 are unable to down-regulate the TLR9 promoter. In addition, E6 and E7 from the high-risk HPV type 18, which are known to persist less competently in the host than HPV16, have reduced efficiency compared with HPV16 in inhibiting TLR9 transcription. Furthermore, a CpG motif derived from the HPV16 E6 DNA sequence activated TLR9, indicating this virus is able to initiate innate responses via the receptor it later down-regulates. This study reveals a novel mechanism used by HPV16 to suppress the host immune response by deregulating the TLR9 transcript, providing evidence that abolishing innate responses may be a crucial step involved in the carcinogenic events mediated by HPVs.
HIV-Specific IL-10-Positive CD8+ T Cells Suppress Cytolysis and IL-2 Production by CD8+ T Cells
Authors: Elrefaei Mohamed , Ventura Florence L. , Baker Chris A. R. , Clark Richard , Bangsberg David R. , Cao Huyen
Published: April 2014

IL-10 producing T cells inhibit Ag-specific CD8+ T cell responses and may play a role in the immune dysregulation observed in HIV infection. We have previously observed the presence of HIV-specific IL-10-positive CD8+ T cells in advanced HIV disease. In this study, we examined the suppressive function of the Gag-specific IL-10-positive CD8+ T cells. Removal of these IL-10-positive CD8+ T cells resulted in increased cytolysis and IL-2, but not IFN-γ, production by both HIV- and human CMV-specific CD8+ T cells. In addition, these IL-10-positive CD8+ T cells mediated suppression through direct cell-cell contact, and had a distinct immunophenotypic profile compared with other regulatory T cells. We describe a new suppressor CD8+ T cell population in advanced HIV infection that may contribute to the immune dysfunction observed in HIV infection.
Expression Profile of FcγRIIb on Leukocytes and Its Dysregulation in Systemic Lupus Erythematosus
Authors: Su Kaihong , Yang Hengxuan , Li Xinrui , Li Xiaoli , Gibson Andrew W. , Cafardi John M. , Zhou Tong , Edberg Jeffrey C. , Kimberly Robert P.
Published: April 2014

FcγRIIb (CD32B, Online Mendelian Inheritance in Man 604590), an IgG FcR with a tyrosine-based inhibitory motif, plays a critical role in the balance of tolerance and autoimmunity in murine models. However, the high degree of homology between FcγRIIb and FcγRIIa in humans and the lack of specific Abs to differentiate them have hampered study of the normal expression profile of FcγRIIb and its potential dysregulation in autoimmune diseases such as systemic lupus erythematosus (SLE). Using our newly developed anti-FcγRIIb mAb 4F5 which does not react with FcγRIIa, we found that FcγRIIb is expressed on the cell surface of circulating B lymphocytes, monocytes, neutrophils, myeloid dendritic cells (DCs), and at very low levels on plasmacytoid DCs from some donors. Normal donors with the less frequent 2B.4 promoter haplotype have higher FcγRIIb expression on monocytes, neutrophils, and myeloid DCs similar to that reported for B lymphocytes, indicating that FcγRIIb expression on both myeloid and lymphoid cells is regulated by the naturally occurring regulatory single nucleotide polymorphisms in the FCGR2B promoter. FcγRIIb expression in normal controls is up-regulated on memory B lymphocytes compared with naive B lymphocytes. In contrast, in active SLE, FcγRIIb is significantly down-regulated on both memory and plasma B lymphocytes compared with naive and memory/plasma B lymphocytes from normals. Similar down-regulation of FcγRIIb on myeloid-lineage cells in SLE was not seen. Our studies demonstrate the constitutive regulation of FcγRIIb by natural gene polymorphisms and the acquired dysregulation in SLE autoimmunity, which may identify opportunities for using this receptor as a therapeutic target.
Aberrant Expression of the Insulin-Like Growth Factor-1 Receptor by T Cells from Patients with Graves’ Disease May Carry Functional Consequences for Disease Pathogenesis
Authors: Douglas Raymond S. , Gianoukakis Andrew G. , Kamat Shweta , Smith Terry J.
Published: April 2014

Graves’ disease (GD), an autoimmune process involving thyroid and orbital tissue, is associated with lymphocyte abnormalities including expansion of memory T cells. Insulin-like growth factor receptor-1 (IGF-1R)-bearing fibroblasts overpopulate connective tissues in GD. IGF-1R on fibroblasts, when ligated with IgGs from these patients, results in the expression of the T cell chemoattractants, IL-16 and RANTES. We now report that a disproportionately large fraction of peripheral blood T cells express IGF-1R (CD3+IGF-R+). CD3+IGF-1R+ T cells comprise 48 ± 4% (mean ± SE; n = 33) in patients with GD compared with 15 ± 3% (n = 21; p < 10−8) in controls. This increased population of IGF-1R+ T cells results, at least in part, from an expansion of CD45RO+ T cells expressing the receptor. In contrast, the fraction of CD45RA+IGF-1R+ T cells is similar in GD and controls. T cells harvested from affected orbital tissues in GD reflect similar differences in the proportion of IGF-1R+CD3+ and IGF-1R+CD4+CD3+ cells as those found in the peripheral circulation. GD-derived peripheral T cells express durable, constitutive IGF-1R expression in culture and receptor levels are further up-regulated following CD3 complex activation. IGF-1 enhanced GD-derived T cell incorporation of BrdU (p < 0.02) and inhibited Fas-mediated apoptosis (p < 0.02). These findings suggest a potential role for IGF-1R displayed by lymphocytes in supporting the expansion of memory T cells in GD.
Phenotype and Effector Function of CC Chemokine Receptor 9-Expressing Lymphocytes in Small Intestinal Crohn’s Disease
Authors: Saruta Masayuki , Yu Qi T. , Avanesyan Armine , Fleshner Phillip R. , Targan Stephan R. , Papadakis Konstantinos A.
Published: April 2014

CCL25/CCR9 chemokine ligand/receptor pair has been reported to play an important role in small bowel (SB) immunity and inflammation. We have previously reported an aberrant SB expression of CCL25 in Crohn’s disease (CD) and an increased frequency of CCR9+ T cells in the peripheral blood of patients with SB inflammatory diseases such as CD and celiac disease. In this study, we have characterized the phenotype and effector function of CCR9+ T cells in mucosal lymphoid tissues in CD. We show that CCR9+ T cells isolated from mesenteric lymph nodes (MLN) draining CD SB express a more activated phenotype compared with MLN draining normal SB. Stimulation of CCR9+ T cells isolated from CD SB lamina propria produced more IFN-γ and IL-17 in response to anti-CD3 or IL-12/IL-18 stimulation compared with those isolated from normal SB. The addition of TL1A to the cytokine combination markedly augmented the secretion of IFN-γ, but not IL-17, by CD lamina propria CCR9+ T cells. CCL25 incubation of CD SB lamina propria lymphocytes and MLN lymphocytes increased their adhesion to VCAM-1/Fc in vitro. Finally, the TCRVβ analysis of CCR9+ T cells revealed a diverse TCRVβ repertoire among MLN CCR9+ T cells in patients with SB CD. Our data indicate that CCR9+ T cells in SB CD are proinflammatory and support the rationale for the use of CCR9 antagonists for the treatment of human SB CD.
Enhanced Antitumor Responses Elicited by Combinatorial Protein Transfer of Chemotactic and Costimulatory Molecules
Authors: Liu Shanrong , Breiter Deborah R. , Zheng Guoxing , Chen Aoshuang
Published: April 2014

Thus far, immunotherapies based on one or a few immunostimulatory molecules have shown limited antitumor efficacy. This highlights the need to use multiple immunostimulatory molecules, to target different immune cells, including immunosuppressive cells, simultaneously. Consequently, in this study, we delivered intratumorally via protein transfer four molecules, including the chemotactic molecules secondary lymphoid tissue chemokine and Fas ligand and the costimulatory molecules 4-1BBL and TNF-related activation-induced cytokine. Secondary lymphoid tissue chemokine and Fas ligand together can attract an array of immune cells and induce apoptosis in CD4+CD25+ regulatory T cells (Treg), whereas 4-1BBL and TRANCE together can stimulate T cells and dendritic cells (DCs). We show that the transfer of all four molecules increases tumor-infiltrating neutrophils, DCs, and CD4+ and CD8+ T cells and decreases intratumoral Treg. We show that the treatment favors the generation of a Th1 cytokine milieu at the tumor site, which is attributed not only to an increase in IL-12-producting DCs and IFN-γ-producing CD8+ T cells, but also to a decrease in IL-10-producing Treg. Importantly, in the L5178Y lymphoma model, we show that compared with transfer of the chemotactic molecules alone or the costimulatory molecules alone, transfer of all four molecules demonstrates stronger antitumor responses against established tumors. Furthermore, we show that the antitumor responses elicited by transfer of all four molecules are mediated by long-term, systemic antitumor immunity. Hence, this study demonstrates for the first time that combinatorial use of chemotactic and costimulatory molecules provides a useful strategy for enhancing antitumor responses.
Cancer/Testis Genes in Multiple Myeloma: Expression Patterns and Prognosis Value Determined by Microarray Analysis
Authors: Condomines Maud , Hose Dirk , Raynaud Pierre , Hundemer Michael , De Vos John , Baudard Marion , Moehler Thomas , Pantesco Véronique , Moos Marion , Schved Jean-François , Rossi Jean-François , Rème Thierry , Goldschmidt Hartmut , Klein Bernard
Published: April 2014

Cancer-testis (CT) Ags are expressed in testis and malignant tumors but rarely in nongametogenic tissues. Due to this pattern, they represent attractive targets for cancer vaccination approaches. The aims of the present study are: 1) to assess the expression of CT genes on a pangenomic base in multiple myeloma (MM); 2) to assess the prognosis value of CT gene expression; and 3) to provide selection strategies for CT Ags in clinical vaccination trials. We report the expression pattern of CT genes in purified MM cells (MMC) of 64 patients with newly diagnosed MM and12 patients with monoclonal gammopathy of unknown significance, in normal plasma cell and B cell samples, and in 20 MMC lines. Of the 46 CT genes interrogated by the Affymetrix HG-U133 set arrays, 35 are expressed in the MMC of at least one patient. Of these, 25 are located on chromosome X. The expression of six CT genes is associated with a shorter event-free survival. The MMC of 98% of the patients express at least one CT gene, 86% at least two, and 70% at least three CT genes. By using a set of 10 CT genes including KM-HN-1, MAGE-C1, MAGE-A3/6/12, MAGE-A5, MORC, DDX43, SPACA3, SSX-4, GAGE-1–8, and MAGE-C2, a combination of at least three CT genes—desirable for circumventing tumor escape mechanisms—is obtained in the MMC of 67% of the patients. Provided that the immunogenicity of the products of these 10 CT genes is confirmed, gene expression profiling could be useful in identifying which CT Ags could be used to vaccinate a given patient.