bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Activation of the Formyl Peptide Receptor by a New Endogenous Ligand in Human Lung A549 Cells
Authors: Rescher Ursula , Danielczyk Antje , Markoff Arseni , Gerke Volker 
Published: April 2014

Abstract
The formyl peptide receptor (FPR), a heptahelical G protein-coupled receptor on phagocytic leukocytes, can be triggered by bacterially derived oligopeptides of the prototype fMLP. Although FPR expression and activation have been associated with cells of myeloid origin and bacterial inflammation, the receptor has recently been identified in nonmyeloid cells, thus suggesting additional physiological functions and the existence of an endogenous agonist. In this study, we demonstrate the presence and functional activation of the FPR in the human lung cell line A549, which represents an extrahepatic model for the regulation of acute-phase proteins. Activation of the FPR in A549 cells cannot only be triggered by fMLP, but also by an agonistic peptide of the recently identified endogenous FPR ligand, annexin 1. In addition to inducing changes in the F-actin content, annexin 1-mediated triggering of the FPR results in an increased expression of acute-phase proteins. Hence, activation of nonmyeloid FPR by its endogenous ligand annexin 1 could participate in the regulation of acute-phase responses, e.g., during inflammation and/or wound healing.
Intrathecal Fas Ligand Infusion Strengthens Immunoprivilege of Central Nervous System and Suppresses Experimental Autoimmune Encephalomyelitis
Authors: Zhu Bing , Luo Liqing , Chen Yongliang , Paty Donald W. , Cynader Max S. 
Published: April 2014

AbstractFas ligand (FasL) is an essential molecule strongly expressed in some immunoprivileged sites, but is expressed at very low levels in normal CNS. In this study, acute experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats with guinea pig myelin basic protein. Intrathecal infusion of recombinant FasL before EAE onset dose dependently suppressed acute EAE and alleviated pathological inflammation in lumbosacral spinal cord. This treatment greatly increased apoptosis in CNS inflammatory cells, but did not inhibit systemic immune response to myelin basic protein. Systemic administration of a similar dose of rFasL was ineffective. In vitro, encephalitogenic T cells were highly sensitive to rFasL-induced cell death, and activated macrophages were also susceptible. In addition, in vitro rFasL treatment potentiated the immunosuppressive property of rat cerebrospinal fluid. We conclude that intrathecal infusion of rFasL eliminated the initial wave of infiltrating T cells and macrophages, and therefore blocked the later recruitment of inflammatory cells into CNS. Although Fas receptor expression was observed on spinal cord neurons, astrocytes, and oligodendrocytes, no damage to these cells or to the myelin structure was detected after rFasL infusion.
Interacting Quantitative Trait Loci Control Loss of Peripheral Tolerance and Susceptibility to Autoimmune Ovarian Dysgenesis After Day 3 Thymectomy in Mice
Authors: Roper Randall J. , Ma Runlin Z. , Biggins Julia E. , Butterfield Russell J. , Michael Sandra D. , Tung Kenneth S. K. , Doerge Rebecca W. , Teuscher Cory 
Published: April 2014

AbstractDay 3 thymectomy (D3Tx) results in a loss of peripheral tolerance mediated by CD4+CD25+ T cells and the development of autoimmune ovarian dysgenesis (AOD) in A/J and (C57BL/6J × A/J)F1 (B6AF1) hybrids but not in C57BL/6J mice. Quantitative trait loci (QTL) linkage analysis using a B6AF1 × C57BL/6J backcross population verified Aod1 and Aod2 that were previously mapped as qualitative traits. Additionally, three new QTL intervals, Aod3, Aod4, and Aod5, on chromosomes 1, 2, and 7, respectively, influencing specific subphenotypes of AOD were identified. QTL linkage analysis using the A × B and B × A recombinant inbred lines verified Aod3 and confirmed linkage to H2. Aod5 colocalized with Mater, an ovarian-specific autoantigen recognized by anti-ovarian autoantibodies in the sera of D3Tx mice. Sequence analysis of Mater identified allelic, strain-specific splice variants between A/J and C57BL/6J mice making it an attractive candidate gene for Aod5. Interaction analysis revealed significant epistatic effects between Aod1–5 and Gasa2, a locus associated with susceptibility to D3Tx-induced autoimmune gastritis, as well as with H2. These results indicate that the QTL controlling D3Tx-induced autoimmune phenomenon are both organ specific and more generalized in their effects with respect to the genesis and activity of the immunoregulatory mechanisms maintaining peripheral tolerance.
Cutting Edge: A Murine, IL-12-Independent Pathway of IFN-γ Induction by Gram-Negative Bacteria Based on STAT4 Activation by Type I IFN and IL-18 Signaling
Authors: Freudenberg Marina A. , Merlin Thomas , Kalis Christoph , Chvatchko Yolande , Stübig Hella , Galanos Chris 
Published: April 2014

AbstractIFN-αβ is a potent immunoregulatory cytokine involved in the defense against viral and bacterial infections. In this study, we describe an as yet undefined IFN-αβ-dependent pathway of IFN-γ induction in mice. This pathway is based on a synergism of IFN-αβ and IL-18, and is independent of IL-12 signaling yet dependent on STAT4. In contradiction to current dogma, we show further that IFN-αβ alone induces tyrosine phosphorylation of STAT4 in murine splenocytes of different mouse strains. This pathway participates in the induction of IFN-γ by Gram-negative bacteria and is therefore expected to play a role whenever IFN-α or IFN-β and IL-18 are produced concomitantly during bacterial, viral, or other infections.
Messenger RNA Electroporation of Human Monocytes, Followed by Rapid In Vitro Differentiation, Leads to Highly Stimulatory Antigen-Loaded Mature Dendritic Cells
Authors: Ponsaerts Peter , Van den Bosch Glenn , Cools Nathalie , Van Driessche Ann , Nijs Griet , Lenjou Marc , Lardon Filip , Van Broeckhoven Christine , Van Bockstaele Dirk R. , Berneman Zwi N. , Van Tendeloo Viggo F. I. 
Published: April 2014

AbstractDendritic cells (DC) are professional Ag-capturing and -presenting cells of the immune system. Because of their exceptional capability of activating tumor-specific T cells, cancer vaccination research is now shifting toward the formulation of a clinical human DC vaccine. We developed a short term and serum-free culture protocol for rapid generation of fully mature, viable, and highly stimulatory CD83+ DC. Human monocytes were cultured for 24 h in serum-free AIM-V medium, followed by 24-h maturation by polyriboinosinic polyribocytidylic acid (polyI:C). Short term cultured, polyI:C-maturated DC, far more than immature DC, showed typical mature DC markers and high allogeneic stimulatory capacity and had high autologous stimulatory capacity in an influenza model system using peptide-pulsed DC. Electroporation of mRNA as an Ag-loading strategy in these cells was optimized using mRNA encoding the enhanced green fluorescent protein (EGFP). Monocytes electroporated with EGFP mRNA, followed by short term, serum-free differentiation to mature DC, had a phenotype of DC, and all showed positive EGFP fluorescence. Influenza matrix protein mRNA-electroporated monocytes cultured serum-free and maturated with polyI:C showed high stimulatory capacity in autologous T cell activation experiments. In conclusion, the present short term and serum-free ex vivo DC culture protocol in combination with mRNA electroporation at the monocyte stage imply an important reduction in time and consumables for preparation of Ag-loaded mature DC compared with classical DC culture protocols and might find application in clinical immunotherapy settings.
Cytokine Control of Memory B Cell Homing Machinery
Authors: Roy Meenakshi P. , Kim Chang H. , Butcher Eugene C. 
Published: April 2014

AbstractThe germinal center (GC) is a pivotal site for the development of B cell memory. Whereas GC B cells do not chemotax to most chemokines and do not express the adhesion receptors L-selectin, α4β7, and cutaneous lymphocyte Ag (CLA), memory B cells respond to various chemotactic signals and express adhesion receptors. In this study, we show that CD40 ligand, IL-2, and IL-10 together drive this transition of GC B cells to memory phenotype in vitro, up-regulating memory B cell markers, chemotactic responses to CXC ligand (CXCL)12, CXCL13, and CCL19, and expression of adhesion receptors L-selectin, α4β7, and CLA. Moreover, addition of IL-4 modulates this transition, preventing chemotactic responses to CXCL12 and CXCL13 (but not to CCL19), and inhibiting the re-expression of L-selectin, but not of CLA or α4β7. CCR7 expression, responsiveness to CCL19, and L-selectin/α4β7 phenotype are coordinately regulated. Thus, IL-2/IL-10 and IL-4 play important and distinctive roles in developing the migratory capacities of memory B cells.
IL-17 Selectively Down-Regulates TNF-α-Induced RANTES Gene Expression in Human Colonic Subepithelial Myofibroblasts
Authors: Andoh Akira , Fujino Sanae , Bamba Shigeki , Araki Yoshio , Okuno Takafumi , Bamba Tadao , Fujiyama Yoshihide 
Published: April 2014

Abstract
IL-17 enhances the TNF-α-induced IL-6 and IL-8 secretion in human colonic subepithelial myofibroblasts. In this study, we investigated how IL-17 modulates RANTES secretion in these cells. TNF-α potently induced RANTES secretion, but IL-17 dose-dependently inhibited the TNF-α-induced RANTES secretion. This was also observed at the mRNA level. Even after pretreatment with TNF-α for 12 h, the inhibitory effect of IL-17 was detectable. IL-17 did not affect the TNF-α-induced stability of the RANTES gene. IL-17 significantly decreased the TNF-α-induced increase in RANTES promoter activity, and IL-17 actually blocked the TNF-α-induced RANTES gene transcription. EMSAs demonstrated that IL-17 did not modulate the TNF-α-induced NF-κB DNA-binding activity, but markedly decreased TNF-α-induced IFN regulatory factor-1 (IRF-1) DNA-binding activity. Because cooperation between NF-κB and IRF-1 is important in the TNF-α-induced RANTES gene expression, the major mechanism mediating the inhibitory effect of IL-17 may be achieved by the inhibition of IRF-1 DNA-binding activity.
Mature Dendritic Cell Generation Promoted by Lysophosphatidylcholine
Authors: Coutant Frédéric , Perrin-Cocon Laure , Agaugué Sophie , Delair Thierry , André Patrice , Lotteau Vincent 
Published: April 2014

Abstract
During the acute phase response, the interplay between high density lipoproteins and low density lipoproteins (LDL) favors transient generation of oxidized LDL with proinflammatory activities. We hypothesized that oxidative modification of LDL is an endogenous signal for the immune system, and we have shown that oxidized LDL promotes mature dendritic cell transition from monocyte, therefore linking the nonspecific acute phase response to adaptive immunity. Lysophosphatidylcholine (LPC) is a major lipid component of oxidized LDL with reported proinflammatory activities. We now report that LPC acts through G protein-coupled receptors on differentiating monocytes to generate mature dendritic cells with the ability to stimulate IL-2 and IFN-γ production by allogeneic T lymphocytes. LPC is most effective in lipoprotein-deprived serum and can be inhibited by an excess of native LDLs reflecting normal plasma conditions. Therefore, by controlling the balance between native and oxidized lipoproteins and the resulting production of LPC, the acute phase reactants may provide a context of Ag presentation that is transiently favorable to immune activation. Intralipid, a therapeutic lipid emulsion for parenteral nutrition with unexplained immunomodulatory properties, also blocked LPC activity. This opens perspectives for the understanding and treatment of acute and chronic inflammatory diseases.
IL-4 Promotes Stat6-Dependent Survival of Autoreactive B Cells In Vivo Without Inducing Autoantibody Production
Authors: Morris Suzanne C. , Dragula Nanette L. , Finkelman Fred D. 
Published: April 2014

AbstractPersistent cross-linking of hen egg lysozyme (HEL)-specific B cell membrane Ig (mIg) in double transgenic mice that express soluble HEL as a self Ag (HEL-Ig mice) decreases B cell mIgM expression, responsiveness, and life span. Because in vitro treatment with IL-4 inhibits T cell apoptosis through a Stat6-independent mechanism, increases mIg expression, and suppresses activation-induced B cell death, we studied IL-4 effects on B cell mIg expression, survival, and Ab secretion in Stat6-sufficient and deficient HEL-Ig mice. IL-4 treatment nearly normalized B cell number and greatly increased the percentage of mature B cells in HEL-Ig mice, but failed to normalize mIgM expression or spontaneous LPS-induced IgM secretion. IL-4 effects on B cell survival and maturation were CD4+ T cell independent, but Stat6 dependent, and did not involve receptor editing. IL-4 had to be present while B cells were generated to have a detectable effect on autoreactive B cell survival; however, the survival of B cells generated in the presence of IL-4 was substantially increased even after IL-4 was withdrawn. These observations suggest that: 1) activation-induced B cell death and anergy are independent processes; 2) B cells that survive to maturity develop increased resistance to Ag-induced deletion; and 3) IL-4 promotes B and T cell survival through different mechanisms.
TCR/CD3 Down-Modulation and ζ Degradation Are Regulated by ZAP-70
Authors: Dumont Céline , Blanchard Nicolas , Di Bartolo Vincenzo , Lezot Nathalie , Dufour Evelyne , Jauliac Sébastien , Hivroz Claire 
Published: April 2014

AbstractTCR down-modulation following binding to MHC/peptide complexes is considered to be instrumental for T cell activation because it allows serial triggering of receptors and the desensitization of stimulated cells. We studied CD3/TCR down-modulation and ζ degradation in T cells from two ZAP-70-immunodeficient patients. We show that, at high occupancy of the TCR, down-modulation of the CD3/TCR is comparable whether T cells express or do not express ZAP-70. However, if TCR occupancy was low, we found that CD3/TCR was down-regulated to a lesser extent in ZAP-70-negative than in ZAP-70-positive T cells. We studied CD3/TCR down-modulation in P116 (a ZAP-70-negative Jurkat cell-derived clone) and in P116 transfected with genes encoding the wild-type or a kinase-dead form of ZAP-70. Down-modulation of the TCR at high occupancy did not require ZAP-70, whereas at low TCR occupancy down-modulation was markedly reduced in the absence of ZAP-70 and in cells expressing a dead kinase mutant of ZAP-70. Thus, the presence of ZAP-70 alone is not sufficient for down-modulation; the kinase activity of this molecule is also required. The degradation of ζ induced by TCR triggering is also severely impaired in T cells from ZAP-70-deficient patients, P116 cells, and P116 cells expressing a kinase-dead form of ZAP-70. This defect in TCR-induced ζ degradation is observed at low and high levels of TCR occupancy. Our results identify ZAP-70, a tyrosine kinase known to be crucial for T cell activation, as a key player in TCR down-modulation and ζ degradation.
Thymocyte Development in Early Growth Response Gene 1-Deficient Mice
Authors: Bettini Matthew , Xi Hongkang , Milbrandt Jeffrey , Kersh Gilbert J. 
Published: April 2014

Abstract
Early growth response gene 1 (Egr1) codes for a transcriptional regulator that contains a zinc-finger DNA binding domain. Egr1 expression is induced by a variety of extracellular stimuli including TCR-ligand interactions. Its pattern of expression in the thymus and dependence on ERK activation have led to speculation that it has a role in T cell development, but the exact nature of this role has been undefined. To more clearly define the role of Egr1 in thymocyte development, we have analyzed thymocytes from Egr1-deficient mice. We find that thymuses from Egr1-deficient mice contain twice as many cells as age-matched controls, and the increase in thymocyte number is apparent at the early CD4/CD8 double negative stage of development. Subsequent maturation to the CD4/CD8 double positive stage and survival of the double positive cells both appear normal in Egr1-deficient animals. We also find that Egr1 promotes positive selection of both CD4 and CD8 single positive cells without playing a major role in negative selection. Egr1 influences positive selection by enhancing expression of the helix-loop-helix inhibitor Id3 and the anti-apoptosis molecule bcl-2. Thus, Egr1 translates developmental signals into appropriate changes in gene expression at multiple stages of thymocyte development.
Aberrant DAP12 Signaling in the 129 Strain of Mice: Implications for the Analysis of Gene-Targeted Mice
Authors: McVicar Daniel W. , Winkler-Pickett Robin , Taylor Lynn S. , Makrigiannis Andrew , Bennett Michael , Anderson Stephen K. , Ortaldo John R. 
Published: April 2014

AbstractNK cells are implicated in antiviral responses, bone marrow transplantation and tumor immunosurveillance. Their function is controlled, in part, through the Ly49 family of class I binding receptors. Inhibitory Ly49s suppress signaling, while activating Ly49s (i.e., Ly49D) activate NK cells via the DAP12 signaling chain. Activating Ly49 signaling has been studied primarily in C57BL/6 mice, however, 129 substrains are commonly used in gene-targeting experiments. In this study, we show that in contrast to C57BL/6 NK cells, cross-linking of DAP12-coupled receptors in 129/J mice induces phosphorylation of DAP12 but not calcium mobilization or cytokine production. Consistent with poor-activating Ly49 function, 129/J mice reject bone marrow less efficiently than C57BL/6 mice. Sequence analysis of receptors and DAP12 suggests no structural basis for inactivity, and both the 129/J and C57BL/6 receptors demonstrate normal function in a reconstituted receptor system. Most importantly, reconstitution of Ly49D in 129/J NK cells demonstrated that the signaling deficit is within the NK cells themselves. These unexpected findings bring into question any NK analysis of 129/J, 129Sv, or gene-targeted mice derived from these strains before complete backcrossing, and provide a possible explanation for the differences observed in the immune response of 129 mice in a variety of models.
Editing Autoreactive TCR Enables Efficient Positive Selection
Authors: Santori Fabio R. , Arsov Ivica , Lili Mirjana , Vukmanović Stanislav 
Published: April 2014

AbstractAllelic exclusion is inefficient at the TCRα locus, allowing a sizeable portion of T cells to carry two functional TCRs. The potential danger of dual TCR expression is a rescue of autoreactive TCRs during selection in the thymus and subsequent development of autoimmunity. In this study, we examine the reason(s) for replacing an autoreactive TCR and for allowing the survival of cells carrying two TCRs. We compared development of TCR transgenic CD4+CD8− thymocytes in the presence or absence of MHC class II autoantigen that does not induce deletion of thymocytes. Contrary to the expected negative effect of the presence of autoantigen, ∼100% more CD4+CD8− thymocytes were found in the presence of MHC class II autoantigen than in the neutral background. A further increase in the strength of autoantigenic signal via expression of a human CD4 transgene led to an additional increase in the numbers of CD4+CD8− thymocytes. Thus, editing autoreactive TCR results in more efficient positive selection, and this may be both a reason and a reward for risking autoimmunity.
The Unique Antigen Receptor Signaling Phenotype of B-1 Cells Is Influenced by Locale but Induced by Antigen
Authors: Chumley Michael J. , Dal Porto Joseph M. , Cambier John C. 
Published: April 2014

AbstractNormal animals contain an autoreactive B lymphocyte subset, the B-1 subset, which is controlled by undefined mechanisms to prevent autoimmunity. Using a VH11Vκ9 Ig transgenic mouse, with a specificity prototypic of the subset, we have explored conditions responsible for the previously reported Ag hyporesponsiveness of these cells. We report that peritoneal VH11Vκ9 B cells exhibit typical B-1 behavior with high basal intracellular free Ca2+ and negligible receptor-mediated calcium mobilization. However, splenic B cells from this mouse, while phenotypically similar to their peritoneal counterparts, including expression of CD5, mount robust B-2-like responses to Ag as measured by calcium influx and altered tyrosine phosphorylation responses. When these splenic cells are adoptively transferred to the peritoneal cavity and encounter their cognate self-Ag, they acquire a B-1 signaling phenotype. The ensuing hyporesponsiveness is characterized by increases in both basal intracellular calcium and resting tyrosyl phosphorylation levels and is highlighted by a marked abrogation of B cell receptor-mediated calcium mobilization. Thus, we show that self-Ag recognition in specific microenvironments such as the peritoneum, and we would propose other privileged sites, confers a unique form of anergy on activated B cells. This may explain how autoreactive B-1 cells can exist while autoimmunity is avoided.
Role of B7 Costimulatory Molecules in the Adjuvant Activity of the Heat-Labile Enterotoxin ofEscherichia coli
Authors: Martin Michael , Sharpe Arlene , Clements John D. , Michalek Suzanne M. 
Published: April 2014

AbstractMuch interest has been directed at understanding the adjuvant properties of the heat-labile enterotoxin of Escherichia coli (LT). In this study, we have assessed how LT compared with the nonenzymatic mutant LT (E112K) affect the level of B7-1 and B7-2 expression on APCs, and we determined how these costimulatory molecules influence their adjuvant properties. Analysis of B7-1 and B7-2 expression on B cells revealed that LT enhanced B7-2 but not B7-1, while LT (E112K) had no effect on the expression of either costimulatory molecule. Treatment of macrophage or dendritic cells with LT resulted in a predominant enhancement of B7-2, while LT (E112K) induced mainly B7-1 expression. Analysis of LT- and LT (E112K)-treated B cells, macrophage, and dendritic cells also revealed significant differences in their ability to enhance anti-CD3-stimulated CD4+ T cell proliferative responses via B7-1 and B7-2. Furthermore, the ability of LT to enhance both Ab and CD4+ T cell responses to a coadministered Ag was severely abrogated in B7-2- but not B7-1-deficient mice. In contrast, the in vivo adjuvant properties of LT (E112K) appeared to be mediated by both B7-1 and B7-2 for optimal CD4+ T cell responses, while B7-1 appeared to be the predominant B7 molecule involved in the ability of LT (E112K) to augment Ab responses to a coadministered Ag. These findings demonstrate distinct differences in the ability of LT and LT (E112K) to enhance B7-1 and B7-2 on APC, as well as a dependence upon these costimulatory molecules for their adjuvant properties.