bluuebunny/crossref_metadata_2025_split huggingface dataset:
Receptor Cross-Linking on Human Plasmacytoid Dendritic Cells Leads to the Regulation of IFN-α Production
Authors: Fanning Stacey L. , George Thaddeus C. , Feng Di , Feldman Steven B. , Megjugorac Nicholas J. , Izaguirre Alexander G. , Fitzgerald-Bocarsly Patricia 
Published: April 2014

AbstractPlasmacytoid dendritic cells (PDC) are the natural type I IFN-producing cells that produce large amounts of IFN-α in response to viral stimulation. During attempts to isolate PDC from human PBMC, we observed that cross-linking a variety of cell surface receptors, including blood DC Ag (BDCA)-2, BDCA-4, CD4, or CD123 with Abs and immunobeads on PDC leads to inhibition of IFN-α production in response to HSV. To understand the mechanisms involved, a number of parameters were investigated. Cross-linking did not inhibit endocytosis of soluble Ag by PDC. Flow cytometry for annexin V and activated caspase-3 indicated that PDC are not undergoing apoptosis after receptor cross-linking. Cross-linking of CD123, but not the other receptors, caused the up-regulation of costimulatory molecules CD80 and CD86, as well as the down-regulation of CD62L, indicating PDC maturation. Thus, anti-CD123 Ab may be acting similar to the natural ligand, IL-3. Anti-phosphotyrosine Ab, as well as Ab to the IFN regulatory factor, IRF-7, was used in intracellular flow cytometry to elucidate the signaling pathways involved. Tyrosine phosphorylation occurred after cross-linking BDCA-2 and BDCA-4, but not CD4. Cross-linking did not affect IRF-7 levels in PDC, however, cross-linking BDCA-2, BDCA-4, and CD4, but not CD123, inhibited the ability of IRF-7 to translocate to the nucleus. Taken together, these results suggest that cross-linking BDCA-2, BDCA-4, and CD4 on PDC regulates IFN-α production at the level of IRF-7, while the decrease in IFN-α production after CD123 cross-linking is due to stimulation of the IL-3R and induction of PDC maturation.
Ly49B Is Expressed on Multiple Subpopulations of Myeloid Cells
Authors: Gays Frances , Aust Jonathan G. , Reid Delyth M. , Falconer Jane , Toyama-Sorimachi Noriko , Taylor Philip R. , Brooks Colin G. 
Published: April 2014

AbstractUsing a novel mAb specific for mouse Ly49B, we report here that Ly49B, the last remaining member of the C57 Ly49 family to be characterized, is expressed at low levels on ∼1.5% of spleen cells, none which are NK cells or T cells but which instead belong to several distinct subpopulations of myeloid cells defined by expression of CD11b and different levels of Gr1. Much larger proportions of bone marrow and peritoneal cells expressed Ly49B, all being CD11b+ and comprising multiple subpopulations defined by light scatter, F4/80, and Gr1 expression. Costaining for Ly49Q, also expressed on myeloid cells, revealed that Ly49B and Ly49Q were most strongly expressed on nonoverlapping subpopulations, Ly49Qhigh cells being mostly B220+CD4+ and/or CD8+, Ly49B+ cells lacking these markers. Myeloid populations that developed from bone marrow progenitors in vitro frequently coexpressed both Ly49B and Ly49Q, and Ly49B expression could be up-regulated by LPS, α-IFN, and γ-IFN, often independently of Ly49Q. PCR analysis revealed that cultured NK cells and T cells contained Ly49B transcripts, and Ly49B expression could be detected on NK cells cultured in IL-12 plus IL-18, and on an immature NK cell line. Immunohistochemical studies showed that Ly49B expression in tissues overlapped with but was distinct from that of all other myeloid molecules examined, being particularly prominent in the lamina propria and dome of Peyer’s patches, implicating an important role of Ly49B in gut immunobiology. In transfected cells, Ly49B was found to associate with SHP-1, SHP-2, and SHIP in a manner strongly regulated by intracellular phosphorylation events.
Aberrant Phenotype and Function of Myeloid Dendritic Cells in Systemic Lupus Erythematosus
Authors: Ding Dacheng , Mehta Hemal , McCune W. Joseph , Kaplan Mariana J. 
Published: April 2014

AbstractSystemic lupus erythematosus (SLE) is characterized by a systemic autoimmune response with profound and diverse T cell changes. Dendritic cells (DCs) are important orchestrators of immune responses and have an important role in the regulation of T cell function. The objective of this study was to determine whether myeloid DCs from individuals with SLE display abnormalities in phenotype and promote abnormal T cell function. Monocyte-derived DCs and freshly isolated peripheral blood myeloid DCs from lupus patients displayed an abnormal phenotype characterized by accelerated differentiation, maturation, and secretion of proinflammatory cytokines. These abnormalities were characterized by higher expression of the DC differentiation marker CD1a, the maturation markers CD86, CD80, and HLA-DR, and the proinflammatory cytokine IL-8. In addition, SLE patients displayed selective down-regulation of the maturation marker CD83 and had abnormal responses to maturation stimuli. These abnormalities have functional relevance, as SLE DCs were able to significantly increase proliferation and activation of allogeneic T cells when compared with control DCs. We conclude that myeloid DCs from SLE patients display significant changes in phenotype which promote aberrant T cell function and could contribute to the pathogenesis of SLE and organ damage.
Human Plasmacytoid Dendritic Cell Function: Inhibition of IFN-α Secretion and Modulation of Immune Phenotype by Vasoactive Intestinal Peptide
Authors: Fabricius Dorit , O’Dorisio M. Sue , Blackwell Sue , Jahrsdörfer Bernd 
Published: April 2014

AbstractPlasmacytoid dendritic cells (PDC) are considered the main sentinels against viral infections and play a major role in immune tolerance. Vasoactive intestinal peptide (VIP) is a potent immunomodulator, whose role in PDC function is unknown. The present study was designed to investigate whether human PDC express VIP receptors and whether VIP has immunological effects on PDC. Using real-time RT-PCR and immunofluorescence, we demonstrated that VIP receptors VPAC1 and VPAC2 are expressed on PDC. After culturing PDC with VIP and CpG oligodeoxynucleotides for 48 h, expression of surface molecules with significance for PDC-T cell interactions as well as IFN-α secretion were quantified using FACS analysis and ELISA, respectively. For functional assays, CFSE-stained CD4+ T cells were coincubated with differentially treated PDC. T cell proliferation and production of various cytokines were determined by FACS analysis and ELISA. VIP enhanced PDC expression of CD86, MHC II, and CCR7. In contrast, VIP inhibited PDC secretion of IFN-α and expression of Neuropilin-1 and MHC I. The potential of CpG oligodeoxynucleotide-activated PDC to induce proliferation of allogeneic CD4+ T cells was impaired when VIP was present during activation. Furthermore, pretreatment of PDC with VIP resulted in a decrease of the IFN-γ:IL-4 ratio in cocultured T cells, suggesting a modulation of the immune response toward Th2. Taken together, these results strongly suggest that VIP regulates the immunological function of human PDC. VIP may thus be involved in the modulation of immune responses to viral infections as well as in the maintenance of immune tolerance.
Inhibition of Human Tumor-Infiltrating Lymphocyte Effector Functions by the Homophilic Carcinoembryonic Cell Adhesion Molecule 1 Interactions
Authors: Markel Gal , Seidman Rachel , Stern Noam , Cohen-Sinai Tali , Izhaki Orit , Katz Gil , Besser Michal , Treves Avraham J. , Blumberg Richard S. , Loewenthal Ron , Mandelboim Ofer , Orenstein Arie , Schachter Jacob 
Published: April 2014

AbstractEfficient antitumor immune response requires the coordinated function of integrated immune components, but is finally exerted by the differentiated effector tumor-infiltrating lymphocytes (TIL). TIL cells comprise, therefore, an exciting platform for adoptive cell transfer (ACT) in cancer. In this study, we show that the inhibitory carcinoembryonic Ag cell adhesion molecule 1 (CEACAM1) protein is found on virtually all human TIL cells following preparation protocols of ACT treatment for melanoma. We further demonstrate that the CEACAM1 homophilic interactions inhibit the TIL effector functions, such as specific killing and IFN-γ release. These results suggest that CEACAM1 may impair in vivo the antitumor response of the differentiated TIL. Importantly, CEACAM1 is commonly expressed by melanoma and its presence is associated with poor prognosis. Remarkably, the prolonged coincubation of reactive TIL cells with their melanoma targets results in increased functional CEACAM1 expression by the surviving tumor cells. This mechanism might be used by melanoma cells in vivo to evade ongoing destruction by tumor-reactive lymphocytes. Finally, CEACAM1-mediated inhibition may hinder in many cases the efficacy of TIL ACT treatment of melanoma. We show that the intensity of CEACAM1 expression on TIL cells constantly increases during ex vivo expansion. The implications of CEACAM1-mediated inhibition of TIL cells on the optimization of current ACT protocols and on the development of future immunotherapeutic modalities are discussed.
Combined IL-15/IL-15Rα Immunotherapy Maximizes IL-15 Activity In Vivo
Authors: Stoklasek Thomas A. , Schluns Kimberly S. , Lefrançois Leo 
Published: April 2014

AbstractIL-15 has substantial potential as an immunotherapeutic agent for augmenting immune responses. However, the activity of IL-15 is mediated by a unique mechanism in which the cytokine is transpresented by cell-bound high-affinity IL-15Rα to target cells expressing the IL-15Rβ and the common γ-chain. Thus, the efficacy of administered IL-15 alone may be limited by the availability of free IL-15Rα. We now show that administration of soluble IL-15/IL-15Rα complexes greatly enhanced IL-15 half-life and bioavailability in vivo. Treatment of mice with this complex, but not with IL-15 alone, resulted in robust proliferation of memory CD8 T cells, NK cells, and NK T cells. The activity of the complex required IL-15Rβ, but not IL-15Rα, expression by the responding cells and was IL-7-independent. Interestingly, IL-15/IL-15Rα immunotherapy also caused naive CD8 T cell activation and development into effector cells and long-term memory T cells. Lastly, complexed IL-15, as compared with IL-15 alone, dramatically reduced tumor burden in a model of B16 melanoma. These findings hold significant importance for the use of IL-15 as a potential adjuvant/therapeutic and inducer of homeostatic proliferation, without the necessity for prior immunodepletion.
TGFβ Protein Processing and Activity through TCR Triggering of Primary CD8+ T Regulatory Cells
Authors: Ménoret Antoine , Myers Lara M. , Lee Seung-Joo , Mittler Robert S. , Rossi Robert J. , Vella Anthony T. 
Published: April 2014

AbstractIn general, TGFβ is synthesized as a procytokine that requires proteolytic activation, release of the mature cytokine from its noncovalently associated latent-associated peptide, and binding to TGFβRII to mediate suppressive activity. We tracked this process in mice containing primed CD8 regulatory T cells (Tregs) by immunoblotting in primary whole cell lysates for pro-TGFβ, latent-associated peptide and mature TGFβ. Generation of CD8 Tregs promoted processing of the 50 kDa pro-TGFβ protein into a 12.5 kDa mature TGFβ species in vivo. Despite the inability to detect mature TGFβ in the sera of mice with primed CD8 Tregs and in the synthetic culture medium of stimulated CD8 Tregs, we demonstrated engagement of TGFβRII through immunoblotting for Smad2 phosphorylation. This process relied on continual TCR triggering, which also induced Smad3 phosphorylation. To understand the movement of mature TGFβ, we showed that in contrast to IFN-γ, mature TGFβ does not remain a soluble cytokine but is likely to be rapidly adsorbed by neighboring cells. These data show the exquisite local control directed toward TGFβ by the immune system and underscore the fine specificity involved in its detection.
Cell-Associated Double-Stranded RNA Enhances Antitumor Activity through the Production of Type I IFN
Authors: McBride Sara , Hoebe Kasper , Georgel Philippe , Janssen Edith 
Published: April 2014

AbstractThe efficacy of tumor cell vaccination largely depends on the maturation and activation status of the dendritic cell. Here we investigated the ability of soluble and tumor cell-associated dsRNA to serve as an adjuvant in the induction of protective adaptive antitumor responses. Our data showed that cell-associated dsRNA, but not soluble dsRNA, enhanced both tumor-specific CD8+ and CD4+ T cell responses. The cell-associated dsRNA increased the clonal burst of tumor-specific CD8+ T cells and endowed them with an enhanced capacity for expansion upon a secondary encounter with tumor Ags, even when the CD8+ T cells were primed in the absence of CD4+ T cell help. The adjuvant effect of cell-associated dsRNA was fully dependent on the expression of TLR3 by the APCs and their subsequent production of type I IFNs, as the adjuvant effect of cell-associated dsRNA was completely abrogated in mice deficient in TLR3 or type I IFN signaling. Importantly, treatment with dsRNA-associated tumor cells increased the number of tumor-infiltrating lymphocytes and enhanced the survival of tumor-bearing mice. The data from our studies suggest that using cell-associated dsRNA as a tumor vaccine adjuvant may be a suitable strategy for enhancing vaccine efficacy for tumor cell therapy in cancer patients.
CC-Chemokine Ligand 16 Induces a Novel Maturation Program in Human Immature Monocyte-Derived Dendritic Cells
Authors: Cappello Paola , Fraone Tiziana , Barberis Laura , Costa Carlotta , Hirsch Emilio , Elia Angela R. , Caorsi Cristiana , Musso Tiziana , Novelli Francesco , Giovarelli Mirella 
Published: April 2014

AbstractDendritic cells (DCs) are indispensable for initiation of primary T cell responses and a host’s defense against infection. Many proinflammatory stimuli induce DCs to mature (mDCs), but little is known about the ability of chemokines to modulate their maturation. In the present study, we report that CCL16 is a potent maturation factor for monocyte-derived DCs (MoDCs) through differential use of its four receptors and an indirect regulator of Th cell differentiation. MoDCs induced to mature by CCL16 are characterized by increased expression of CD80 and CD86, MHC class II molecules, and ex novo expression of CD83 and CCR7. They produce many chemokines to attract monocytes and T cells and are also strong stimulators in activating allogeneic T cells to skew toward Th1 differentiation. Interestingly, they are still able to take up Ag and express chemokine receptors usually bound by inflammatory ligands and can be induced to migrate to different sites where they capture Ags. Our findings indicate that induction of MoDC maturation is an important property of CCL16 and suggest that chemokines may not only organize the migration of MoDCs, but also directly regulate their ability to prime T cell responses.
The MAPK Scaffold Kinase Suppressor of Ras Is Involved in ERK Activation by Stress and Proinflammatory Cytokines and Induction of Arthritis
Authors: Fusello Angela M. , Mandik-Nayak Laura , Shih Fei , Lewis Robert E. , Allen Paul M. , Shaw Andrey S. 
Published: April 2014

AbstractThe MAPK ERK is required for LPS-induced TNF production by macrophages. Although the scaffold kinase suppressor of Ras (KSR)1 is required for efficient Erk activation by mitogenic stimuli, the role of KSR1 in ERK activation by inflammatory and stress stimuli is unknown. In this study, we examined the effects of KSR deficiency on ERK activation by stress stimuli and show that ERK activation by TNF, IL-1, and sorbitol is attenuated in the absence of KSR1. To determine the significance of this defect in vivo, we tested KSR-deficient mice using a passive transfer model of arthritis. We found that the induction of arthritis is impaired in the absence of KSR. Thus, KSR plays a role in ERK activation during inflammatory and stress responses both in vitro and in vivo.
Platelet-Activating Factor Receptor and Innate Immunity: Uptake of Gram-Positive Bacterial Cell Wall into Host Cells and Cell-Specific Pathophysiology
Authors: Fillon Sophie , Soulis Konstantinos , Rajasekaran Surender , Benedict-Hamilton Heather , Radin Jana N. , Orihuela Carlos J. , El Kasmi Karim C. , Murti Gopal , Kaushal Deepak , Gaber M. Waleed , Weber Joerg R. , Murray Peter J. , Tuomanen Elaine I. 
Published: April 2014

AbstractThe current model of innate immune recognition of Gram-positive bacteria suggests that the bacterial cell wall interacts with host recognition proteins such as TLRs and Nod proteins. We describe an additional recognition system mediated by the platelet-activating factor receptor (PAFr) and directed to the pathogen-associated molecular pattern phosphorylcholine that results in the uptake of bacterial components into host cells. Intravascular choline-containing cell walls bound to endothelial cells and caused rapid lethality in wild-type, Tlr2−/−, and Nod2−/− mice but not in Pafr−/− mice. The cell wall exited the vasculature into the heart and brain, accumulating within endothelial cells, cardiomyocytes, and neurons in a PAFr-dependent way. Physiological consequences of the cell wall/PAFr interaction were cell specific, being noninflammatory in endothelial cells and neurons but causing a rapid loss of cardiomyocyte contractility that contributed to death. Thus, PAFr shepherds phosphorylcholine-containing bacterial components such as the cell wall into host cells from where the response ranges from quiescence to severe pathophysiology.
Vimentin Expressed onMycobacterium tuberculosis-Infected Human Monocytes Is Involved in Binding to the NKp46 Receptor
Authors: Garg Ankita , Barnes Peter F. , Porgador Angel , Roy Sugata , Wu Shiping , Nanda Jagpreet S. , Griffith David E. , Girard William M. , Rawal Nenoo , Shetty Sreerama , Vankayalapati Ramakrishna 
Published: April 2014

AbstractWe previously showed that human NK cells used the NKp46 receptor to lyse Mycobacterium tuberculosis H37Ra-infected monocytes. To identify ligands on H37Ra-infected human mononuclear phagocytes, we used anti-NKp46 to immunoprecipitate NKp46 from NK cells bound to its ligand(s) on H37Ra-infected monocytes. Mass spectrometry analysis identified a 57-kDa molecule, vimentin, as a putative ligand for NKp46. Vimentin expression was significantly up-regulated on the surface of infected monocytes, compared with uninfected cells, and this was confirmed by fluorescence microscopy. Anti-vimentin antiserum inhibited NK cell lysis of infected monocytes, whereas antiserum to actin, another filamentous protein, did not. CHO-K1 cells transfected with a vimentin construct were lysed much more efficiently by NK cells than cells transfected with a control plasmid. This lysis was inhibited by mAb-mediated masking of NKp46 (on NK cells) or vimentin (on infected monocytes). ELISA and Far Western blotting showed that recombinant vimentin bound to a NKp46 fusion protein. These results indicate that vimentin is involved in binding of NKp46 to M. tuberculosis H37Ra-infected mononuclear phagocytes.
The Immediate Early 2 Protein of Human Cytomegalovirus (HCMV) Mediates the Apoptotic Control in HCMV Retinitis through Up-Regulation of the Cellular FLICE-Inhibitory Protein Expression
Authors: Chiou Shih-Hwa , Yang Yi-Ping , Lin Jung-Chun , Hsu Chih-Hung , Jhang Hua-Ci , Yang Yu-Ting , Lee Chen-Hsen , Ho Larry L. T. , Hsu Wen-Ming , Ku Hung-Hai , Chen Shih-Jen , Chen Steve S.-L. , Chang Margaret D. T. , Wu Cheng-Wen , Juan Li-Jung 
Published: April 2014

Abstract
Human CMV (HCMV) is a widespread human pathogen that causes blindness by inducing retinitis in AIDS patients. Previously, we showed that viral immediate early 2 (IE2) protein may allow HCMV to evade the immune control by killing the Fas receptor-positive T lymphocytes attracted to the infected retina with increased secretion of Fas ligand (FasL). In this study, we further demonstrate that the secreted FasL also kills uninfected Fas-rich bystander retinal cells and that IE2 simultaneously protects the infected cells from undergoing apoptotic death, in part, by activating the expression of cellular FLIP (c-FLIP), an antiapoptotic molecule that blocks the direct downstream executer caspase 8 of the FasL/Fas pathway. c-FLIP induction requires the N-terminal 98 residues of IE2 and the c-FLIP promoter region spanning nucleotides −978 to −696. In vivo association of IE2 to this region, IE2-specific c-FLIP activation, and decrease of FasL-up-regulated activities of caspases 8 and 3 were all demonstrated in HCMV-infected human retinal cells. Moreover, c-FLIP up-regulation by IE2 appeared to involve PI3K and might also render cells resistant to TRAIL-mediated death. Finally, enhanced c-FLIP signals were immunohistochemically detected in IE-positive cells in the HCMV-infected lesions of the human retina. Taken together, these data demonstrate specific activation of c-FLIP by HCMV IE2 and indicate a novel role for c-FLIP in the pathogenesis of HCMV retinitis.
Regulatory T Cells Dampen Pulmonary Inflammation and Lung Injury in an Animal Model ofPneumocystisPneumonia
Authors: McKinley Laura , Logar Alison J. , McAllister Florencia , Zheng Mingquan , Steele Chad , Kolls Jay K. 
Published: April 2014

AbstractCD4+CD25+FoxP3+ regulatory T cells are decreased in patients infected with HIV and have been shown to be critical in mediating Ag tolerance in the lung. Because a subset of Pneumocystis-infected individuals develop substantial lung injury, which can be modeled in immune reconstituted scid mice, we used mouse models of Pneumocystis carinii to investigate the role of regulatory T cells in opportunistic infection and immune reconstitution. In this study, we show that CD4+CD25+FoxP3+ cells are part of the host response to Pneumocystis in CD4+ T cell-intact mice. Moreover, lung injury and proinflammatory Th1 and Th2 cytokine levels in the bronchoalveolar lavage fluid and lung homogenate were increased following CD4+CD25− immune reconstitution in Pneumocystis-infected SCID mice but not in CD4+CD25+ T cell-reconstituted animals. The ability of CD4+CD25+ T cells to control inflammation and injury during the course of Pneumocystis was confirmed by treatment of wild-type C57BL/6 mice with anti-CD25 mAb. These data show that CD4+CD25+ T cells control pulmonary inflammation and lung injury associated with Pneumocystis infection both in the setting of immune reconstitution as well as new acquisition of infection.
Anti-HIV State but Not Apoptosis Depends on IFN Signature in CD4+ T Cells
Authors: Audigé Annette , Urosevic Mirjana , Schlaepfer Erika , Walker Russell , Powell Doug , Hallenberger Sabine , Joller Helen , Simon Hans-Uwe , Dummer Reinhard , Speck Roberto F. 
Published: April 2014

Abstract
To gain insights into the molecular mechanisms underlying early host responses to HIV in the CD4+ T cell target population, we examined gene expression in CD4+ T cells isolated 24 h after ex vivo HIV infection of lymphocyte aggregate cultures derived from human tonsils. Gene profiling showed a distinct up-regulation of genes related to immune response and response to virus, notably of IFN-stimulated genes (ISGs), irrespective of the coreceptor tropism of the virus. This mostly IFN-α-dependent gene signature suggested the involvement of plasmacytoid dendritic cells, a principal component of the antiviral immune response. Indeed, depletion of plasmacytoid dendritic cells before HIV inoculation abrogated transcriptional up-regulation of several ISGs and resulted in increased levels of HIV replication. Treatment with a blocking anti-IFN-αR Ab yielded increased HIV replication; conversely, HIV replication was decreased in pDC-depleted cultures treated with IFN-α. Among up-regulated ISGs was also TRAIL, indicating a potential role of the IFN signature in apoptosis. However, a blocking anti-TRAIL Ab did not abrogate apoptosis of CD4+ T cells in CXCR4-tropic HIV-infected cultures, suggesting the involvement of pathways other than TRAIL mediated. We conclude that acute HIV infection of lymphoid tissue results in up-regulation of ISGs in CD4+ T cells, which induces an anti-HIV state but not apoptosis.