bluuebunny/crossref_metadata_2025_split huggingface dataset:
Marked Prolongation of Cardiac Allograft Survival by Dendritic Cells Genetically Engineered with NF-κB Oligodeoxyribonucleotide Decoys and Adenoviral Vectors Encoding CTLA4-Ig
Authors: Bonham C. Andrew , Peng Lansha , Liang Xiaoyan , Chen Zongyou , Wang Lianfu , Ma Linlin , Hackstein Holger , Robbins Paul D. , Thomson Angus W. , Fung John J. , Qian Shiguang , Lu Lina 
Published: April 2014

Abstract
Bone marrow-derived dendritic cells (DCs) can be genetically engineered using adenoviral (Ad) vectors to express immunosuppressive molecules that promote T cell unresponsiveness. The success of these DCs for therapy of allograft rejection has been limited in part by the potential of the adenovirus to promote DC maturation and the inherent ability of the DC to undergo maturation following in vivo administration. DC maturation occurs via NF-κB-dependent mechanisms, which can be blocked by double-stranded “decoy” oligodeoxyribonucleotides (ODNs) containing binding sites for NF-κB. Herein, we describe the combined use of NF-κB ODNs and rAd vectors encoding CTLA4-Ig (Ad CTLA4-Ig) to generate stably immature murine myeloid DCs that secrete the potent costimulation blocking agent. These Ad CTLA4-Ig-transduced ODN DCs exhibit markedly impaired allostimulatory ability and promote apoptosis of activated T cells. Furthermore, administration of Ad CTLA4-Ig ODN-treated donor DCs (C57BL10; B10(H-2b)) before transplant significantly prolongs MHC-mismatched (C3HHeJ; C3H(H-2k)) vascularized heart allograft survival, with long-term (&gt;100 days) donor-specific graft survival in 40% of recipients. The mechanism(s) responsible for DC tolerogenicity, which may involve activation-induced apoptosis of alloreactive T cells, do not lead to skewing of intragraft Th cytokine responses. Use of NF-κB antisense decoys in conjunction with rAd encoding a potent costimulation blocking agent offers promise for therapy of allograft rejection or autoimmune disease with minimization of systemic immunosuppression.
Restriction of De Novo Pyrimidine Biosynthesis Inhibits Th1 Cell Activation and Promotes Th2 Cell Differentiation
Authors: Dimitrova Petya , Skapenko Alla , Herrmann Matthias L. , Schleyerbach Rudolf , Kalden Joachim R. , Schulze-Koops Hendrik 
Published: April 2014

AbstractLeflunomide, an inhibitor of de novo pyrimidine biosynthesis, has recently been introduced as a treatment for rheumatoid arthritis in an attempt to ameliorate inflammation by inhibiting lymphocyte activation. Although the immunosuppressive ability of leflunomide has been well described in several experimental animal models, the precise effects of a limited pyrimidine supply on T cell differentiation and effector functions have not been elucidated. We investigated the impact of restricted pyrimidine biosynthesis on the activation and differentiation of CD4 T cells in vivo and in vitro. Decreased activation of memory CD4 T cells in the presence of leflunomide resulted in impaired generation and outgrowth of Th1 effectors without an alteration of Th2 cell activation. Moreover, priming of naive T cells in the presence of leflunomide promoted Th2 differentiation from uncommitted precursors in vitro and enhanced Th2 effector functions in vivo, as indicated by an increase in Ag-specific Th2 cells and in the Th2-dependent Ag-specific Ig responses (IgG1) in immunized mice. The effects of leflunomide on T cell proliferation and differentiation could be antagonized by exogenous UTP, suggesting that they were related to a profound inhibition of de novo pyrimidine biosynthesis. These results indicate that leflunomide might exert its anti-inflammatory activities in the treatment of autoimmune diseases by preventing the generation of proinflammatory Th1 effectors and promoting Th2 cell differentiation. Moreover, the results further suggest that differentiation of CD4 T cells can be regulated at the level of nucleotide biosynthesis.
CD4 T Cell Depletion Is Linked Directly to Immune Activation in the Pathogenesis of HIV-1 and HIV-2 but Only Indirectly to the Viral Load
Authors: Sousa Ana E. , Carneiro Jorge , Meier-Schellersheim Martin , Grossman Zvi , Victorino Rui M. M. 
Published: April 2014

Abstract
The causal relationships among CD4 cell depletion, HIV replication, and immune activation are not well understood. HIV-2 infection, “nature’s experiment” with inherently attenuated HIV disease, provides additional insights into this issue. We report the finding that in HIV-2 and HIV-1 patients with a comparable degree of CD4 depletion the imbalance in the relative sizes of the naive and memory T cell populations and the up-regulation of CD4 and CD8 cell activation markers (HLA-DR, CD38, CD69, Fas molecules) are similar, even though the viral load in the plasma of HIV-2-infected patients is two orders of magnitude lower than in HIV-1 patients and HIV-2 patients are known to have slower rates of CD4 T cell decline and a better clinical prognosis. Moreover, we found a similar increase in the frequency of cycling CD4 T cells (Ki67+), which was in strong correlation with the expression of activation markers. Finally, the level of T cell anergy, as assessed by the proliferative responses to CD3 stimulation and to a panel of microbial Ags, proved to be comparable in HIV-1 and HIV-2 patients with a similar degree of CD4 depletion despite large differences in viral load. Our data are consistent with a direct causal relationship between immune activation and CD4 cell depletion in HIV disease and an only indirect relation of these parameters to the virus replication rate. Invoking the concept of proximal immune activation and virus transmission, which links efficient transmission of virus to local cell activation and proliferation in response to Ags and inflammation, we propose an integrative interpretation of the data and suggest that strongly elevated immune activation induces CD4 cell depletion and not vice versa, with potential implications for the choice of treatment strategies.
Identification of Human Autoantibodies to the DNA Ligase IV/XRCC4 Complex and Mapping of an Autoimmune Epitope to a Potential Regulatory Region
Authors: Lee Kyung-Jong , Dong Xingwen , Wang Jingsong , Takeda Yoshihiko , Dynan William S. 
Published: April 2014

AbstractThe nonhomologous end-joining pathway is the principal mechanism for repair of ionizing radiation-induced, double-strand breaks in mammalian cells. Three polypeptides in this pathway, including the two subunits of Ku protein and the catalytic subunit of the DNA-dependent protein kinase, are known targets of autoantibodies in systemic rheumatic diseases. Here we show that two additional polypeptides in the pathway, DNA ligase IV and XRCC4, are also targets of autoantibodies. These Abs were present in 20% of patients with systemic lupus erythematosus and overlap syndrome. Previous work has shown that XRCC4 is subject to radiation-induced post-translational modification, including phosphorylation by DNA-dependent protein kinase and cleavage by caspase 3. We mapped a major autoimmune epitope in XRCC4 and found that it encompassed a DNA-dependent protein kinase phosphorylation site, which is located at serine 260; that it was adjacent to a site for caspase 3, which cleaves after residue 265; and that it also spanned a site for the inflammatory protease, granzyme B, which cleaves after residue 254. The finding that five different polypeptides in the nonhomologous end-joining pathway are potential targets of autoantibodies together with the observation that one of the autoimmune epitopes in XRCC4 coincides with a sequence that is a nexus for radiation-induced regulatory events suggest that exposure to agents that introduce DNA double-strand breaks may be one of the factors that influences the development of an autoimmune response in susceptible individuals.
Inhibition of Adjuvant Arthritis by a DNA Vaccine Encoding Human Heat Shock Protein 60
Authors: Quintana Francisco J. , Carmi Pnina , Mor Felix , Cohen Irun R. 
Published: April 2014

Abstract
Adjuvant arthritis (AA) is an autoimmune disease inducible in rats involving T cell reactivity to the mycobacterial 65-kDa heat shock protein (HSP65). HSP65-specific T cells cross-reactive with the mammalian 60-kDa heat shock protein (HSP60) are thought to participate in the modulation of AA. In this work we studied the effects on AA of DNA vaccination using constructs coding for HSP65 (pHSP65) or human HSP60 (pHSP60). We found that both constructs could inhibit AA, but that pHSP60 was more effective than pHSP65. The immune effects associated with specific DNA-induced suppression of AA were complex and included enhanced T cell proliferation to a variety of disease-associated Ags. Effective vaccination with HSP60 or HSP65 DNA led paradoxically to up-regulation of IFN-γ secretion to HSP60 and, concomitantly, to down-regulation of IFN-γ secretion to the P180-188 epitope of HSP65. There were also variable changes in the profiles of IL-10 secretion to different Ags. However, vaccination with pHSP60 or pHSP65 enhanced the production of TGFβ1 to both HSP60 and HSP65 epitopes. Our results support a regulatory role for HSP60 autoreactivity in AA and demonstrate that this control mechanism can be activated by DNA vaccination with both HSP60 or HSP65.
T Cell Immunity in Connective Tissue Disease Patients Targets the RNA Binding Domain of the U1-70kDa Small Nuclear Ribonucleoprotein
Authors: Greidinger Eric L. , Foecking Mark F. , Schäfermeyer Kim R. , Bailey Craig W. , Primm Shannon L. , Lee David R. , Hoffman Robert W. 
Published: April 2014

AbstractAlthough the T cell dependence of autoimmune responses in connective tissue diseases has been well established, limited information exists regarding the T cell targeting of self Ags in humans. To characterize the T cell response to a connective tissue disease-associated autoantigen, this study generated T cell clones from patients using a set of peptides encompassing the entire linear sequence of the 70-kDa subunit of U1 snRNP (U1-70kDa) small nuclear ribonucleoprotein. Despite the ability of U1-70kDa to undergo multiple forms of Ag modification that have been correlated with distinct clinical disease phenotypes, a remarkably limited and consistent pattern of T cell targeting of U1-70kDa was observed. All tested T cell clones generated against U1-70kDa were specific for epitopes within the RNA binding domain (RBD) of the protein. High avidity binding of the RBD with U1-RNA was preserved with the disease-associated modified forms of U1-70kDa tested. The high avidity interaction between the U1-RBD on the polypeptide and U1-RNA may be critical in immune targeting of this region in autoimmunity. The T cell autoimmune response to U1-70kDa appears to have less diversity than is seen in the humoral response; and therefore, may be a favorable target for therapeutic intervention.
Impaired Effector Function of Hepatitis C Virus-Specific CD8+ T Cells in Chronic Hepatitis C Virus Infection
Authors: Wedemeyer Heiner , He Xiao-Song , Nascimbeni Michelina , Davis Anthony R. , Greenberg Harry B. , Hoofnagle Jay H. , Liang T. Jake , Alter Harvey , Rehermann Barbara 
Published: April 2014

AbstractThe cellular immune response contributes to clearance of hepatitis C virus (HCV) and persists for decades after recovery from infection. The immunological basis for the inefficiency of the cellular immune response in chronically infected persons is not known. Here, we used four HLA-A2 tetramers, specific for two HCV core and two HCV NS3 epitopes, to investigate at the single-cell level effector function and phenotype of HCV-specific CD8+ T cells in 20 chronically infected and 12 long-term recovered patients. Overall, HCV-specific, tetramer+ T cells were more frequently found in PBMCs of chronically infected patients than in those of recovered patients. However, when compared with HCV-tetramer+ T cells of recovered patients, they displayed an impaired proliferative capacity. As a result of the impaired proliferative capacity, HCV-specific T cell lines derived from chronically infected patients displayed less peptide-specific cytotoxicity than those from recovered patients. In addition, proliferation and ex vivo IFN-γ production of HCV-tetramer+ cells, but not influenza-virus-specific T cells, were defective in chronically infected patients and could not be restored by in vitro stimulation with peptide and IL-2. At least three distinct phenotypes of HCV-specific CD8+ T cells were identified and associated with certain functional characteristics. In addition, impairment of proliferative, cytokine, and cytotoxic effector functions of tetramer+ T cells in viremic patients was associated with weak ex vivo HCV-specific CD4+ T cell responses. Thus, the defective functions of HCV-specific CD8+ T cells might contribute to viral persistence in chronically infected patients, and knowledge on their reversibility may facilitate the development of immunotherapeutic vaccines.
Cutting Edge: CTLA-4 (CD152) Differentially Regulates Mitogen-Activated Protein Kinases (Extracellular Signal-Regulated Kinase and c-Jun N-Terminal Kinase) in CD4+ T Cells from Receptor/Ligand-Deficient Mice
Authors: Schneider Helga , Mandelbrot Didier A. , Greenwald Rebecca J. , Ng Fai , Lechler Robert , Sharpe Arlene H. , Rudd Christopher E. 
Published: April 2014

AbstractAlthough CTLA-4 (CD152) has potent inhibitory effects on T cell function, the signaling events affected by this coreceptor remain to be fully defined. Mitogen-activated protein kinases (MAPK) extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) act as crucial regulators of multiple aspects of cell function. Ab ligation studies have reported an inhibitory effect of CTLA-4 on TCR-induced ERK and JNK activation. In this study, we have re-examined the specificity of CTLA-4 inhibition of MAPKs by using natural ligand with ex vivo-purified CD4+ T cells deficient in CD80 and CD86 (double knockout), or CTLA-4, CD80, and CD86 (triple knockout). Under these conditions, CTLA-4 ligation was found to up-regulate and sustain JNK activation, while inhibiting ERK activity. At the same time, JNK activation could not account for CTLA-4 induction of TGF-β production. Our findings demonstrate that CTLA-4 cosignaling is more complex than previously appreciated, with an ability to differentially regulate members of the MAPK family in T cells.
Fas Resistance of Leukemic Eosinophils Is Due to Activation of NF-κB by Fas Ligation
Authors: Qin Yimin , Camoretti-Mercado Blanca , Blokh Lyubov , Long Catherine G. , Ko Franklin D. , Hamann Kimm J. 
Published: April 2014

Abstract
TNF family receptors can lead to the activation of NF-κB and this can be a prosurvival signal in some cells. Although activation of NF-κB by ligation of Fas (CD95/Apo-1), a member of the TNFR family, has been observed in a few studies, Fas-mediated NF-κB activation has not previously been shown to protect cells from apoptosis. We examined the Fas-induced NF-κB activation and its antiapoptotic effects in a leukemic eosinophil cell line, AML14.3D10, an AML14 subline resistant to Fas-mediated apoptosis. EMSA and supershift assays showed that agonist anti-Fas (CH11) induced nuclear translocation of NF-κB heterodimer p65(RelA)/p50 in these cells in both a time- and dose-dependent fashion. The influence of NF-κB on the induction of apoptosis was studied using pharmacological proteasome inhibitors and an inhibitor of IκBα phosphorylation to block IκBα dissociation and degradation. These inhibitors at least partially inhibited NF-κB activation and augmented CH11-induced cell death. Stable transfection and overexpression of IκBα in 3D10 cells inhibited CH11-induced NF-κB activation and completely abrogated Fas resistance. Increases in caspase-8 and caspase-3 cleavage induced by CH11 and in consequent apoptotic killing were observed in these cells. Furthermore, while Fas-stimulation of resistant control 3D10 cells led to increases in the antiapoptotic proteins cellular inhibitor of apoptosis protein-1 and X-linked inhibitor of apoptosis protein, Fas-induced apoptosis in IκBα-overexpressing cells led to the down-modulation of both of these proteins, as well as that of the Bcl-2 family protein, Bcl-xL. These data suggest that the resistance of these leukemic eosinophils to Fas-mediated killing is due to induced NF-κB activation.
B7-H1 Is Expressed by Human Endothelial Cells and Suppresses T Cell Cytokine Synthesis
Authors: Mazanet Melissa M. , Hughes Christopher C. W. 
Published: April 2014

AbstractHuman endothelial cells (ECs) provide costimulatory signals sufficient to activate resting memory T cells to produce IL-2 and IFN-γ, at least in part through CD58-CD2 interactions. Recently, the B7-like molecule, B7-H1 (PD-L1), was described and shown to regulate T cell activation; however, there are conflicting reports on whether it stimulates or inhibits T cell cytokine synthesis. B7-H1 is not expressed constitutively by ECs; however, it is rapidly induced by IFN-γ, and synergistically by IFN-γ and TNF. In inflamed skin, B7-H1 is expressed by a subset of microvessels, and by keratinocytes, but is barely detectable in normal skin. Blocking the interaction of EC-expressed B7-H1 with its T cell ligand, programmed death-1 (PD-1), using a PD-1-Fc fusion protein, or by blocking B7-H1 expression with morpholino antisense oligonucleotides, augments expression of IL-2 and IFN-γ, implicating B7-H1 as a negative regulator of cytokine synthesis. However, signaling through PD-1 does not affect induction of the activation markers CD25 or CD69 on T cells, suggesting that its effects are specific to cytokine synthesis. The suppressive effects of B7-H1 on cytokine expression are proportional to the strength of the primary stimulus, allowing for B7-H1 to determine the level of T cell activation in response to ECs. Our results demonstrate that B7-H1 negatively regulates cytokine synthesis in T cells activated by ECs.
Morphine Regulates Gene Expression of α- and β-Chemokines and Their Receptors on Astroglial Cells Via the Opioid μ Receptor
Authors: Mahajan Supriya D. , Schwartz Stanley A. , Shanahan Thomas C. , Chawda Ram P. , Nair Madhavan P. N. 
Published: April 2014

AbstractThe brain is a target organ for recreational drugs and HIV-1. Epidemiological data demonstrate that opioid abuse is a risk factor for HIV-1 infection and progression to AIDS. Chemokines and their receptors have been implicated in the neuropathogenesis of HIV-1 infections. However, little is known about the effects of opioids on the expression of chemokines and their receptors (the latter also are HIV-1 coreceptors) by cells of the CNS. Herein we describe the effects of morphine on gene expression of the α- and β-chemokines and their receptors by the astrocytoma cell line U87 and by primary normal human astrocyte (NHA) cultures. U87 cells treated with morphine showed significant down-regulation of IL-8 gene expression, whereas expression of the IL-8 receptor CXCR2 was reciprocally up-regulated as detected by RT-PCR. Treatment of NHAs with morphine suppressed IL-8 and macrophage-inflammatory protein-1β gene expression, whereas expression of their receptor genes, CCR3 and CCR5, was simultaneously enhanced. These morphine-induced effects on U87 and NHA cells were reversed by the opioid μ receptor antagonist β-funaltrexamine. Morphine also enhanced the constitutive expression of the opioid μ receptor on astroglial cells. Our results support the hypothesis that opioids play a significant role in the susceptibility of the CNS to HIV-1 infection and subsequent encephalopathy by inhibiting local production of HIV-1-protective chemokines (IL-8 and macrophage-inflammatory protein-1β) and enhancing expression of HIV-1 entry coreceptor genes (CCR3, CCR5, and CXCR2) within the CNS. These effects of opioids appear to be mediated through the opioid μ receptor that we demonstrated on astroglial cells.
MHC Alloantigens Elicit Secondary, But Not Primary, Indirect In Vitro Proliferative Responses
Authors: Haller Gary W. , Lima Brian , Kunisaki Shaun M. , Germana Sharon , Leguern Christian , Huang Christene A. , Sachs David H. 
Published: April 2014

Abstract
The relative contributions of direct and indirect pathways of allorecognition to graft rejection remain controversial. Recent reports suggest that the indirect pathway may play a prominent role in both acute and chronic allograft rejection. Such studies suggest that MHC-derived allopeptides are more immunogenic than those derived from minor histocompatibility or other nominal Ags. The aim of this study was to characterize the immunogenicity of MHC alloantigens in MHC-defined miniature swine via primary and secondary MLR culture assays. APCs were selectively depleted from either responder or stimulator cell populations to specifically analyze direct and indirect proliferative responses, respectively. Radio-resistant cytokine secretion and subsequent backstimulation of responder cells was eliminated by using stimulators that were either lysed or unresponsive to the responder MHC haplotypes. When the effect of backstimulation was eliminated from MLR culture assays, indirect proliferative responses were not observed among naive responders. Only after in vivo priming of responder animals could indirect proliferation be detected. These data do not refute the potential importance of indirect allorecognition in graft rejection. However, they suggest that MHC-derived alloantigens behave similarly in vitro to minor histocompatibility Ags, with comparable immunogenicity. These data also suggest that the MLR culture assay does not accurately reflect the importance of indirect mechanisms that have previously been reported in experimental models of graft rejection. A greater understanding of the indirect pathway and the associated immunogenicity of MHC allopeptides has the potential benefit of enabling the development of therapeutic interventions to prevent or halt allograft rejection.
μ-Opioid Receptor Mediates Chronic Restraint Stress-Induced Lymphocyte Apoptosis
Authors: Wang Jinghua , Charboneau Richard , Barke Roderick A. , Loh Horace H. , Roy Sabita 
Published: April 2014

Abstract
Psychological stress is associated with immunosuppression in both humans and animals. Although it was well established that psychological stressors stimulate the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system, resulting in the release of various hormones and neurotransmitters, the mechanisms underlying these phenomena are poorly understood. In this study, μ-opioid receptor knockout (MORKO) mice were used to investigate whether the μ-opioid receptor mediates the immunosuppression induced by restraint stress. Our results showed that wild-type (WT) mice subjected to chronic 12-h daily restraint stress for 2 days exhibited a significant decrease in splenocyte number with a substantial increase in apoptosis and CD95 (Fas/APO-1) expression of splenocytes. The effects are essentially abolished in MORKO mice. Furthermore, inhibition of splenic lymphocyte proliferation, IL-2, and IFN-γ production induced by restraint stress in WT mice was also significantly abolished in MORKO mice. Interestingly, both stressed WT and MORKO mice showed a significant elevation in plasma corticosterone and pituitary proopiomelanocortin mRNA expression, although the increase was significantly lower in MORKO mice. Adrenalectomy did not reverse restraint stress-induced immunosuppression in WT mice. These data clearly established that the μ-opioid receptor is involved in restraint stress-induced immune alterations via a mechanism of apoptotic cell death, and that the effect is not mediated exclusively through the glucocorticoid pathway.