bluuebunny/crossref_metadata_2025_split huggingface dataset:
IL-7 Administration Alters the CD4:CD8 Ratio, Increases T Cell Numbers, and Increases T Cell Function in the Absence of Activation
Authors: Geiselhart Lisa A. , Humphries Courtney A. , Gregorio Theresa A. , Mou Sherry , Subleski Jeffrey , Komschlies Kristin L. 
Published: April 2014

AbstractIL-7 is vital for the development of the immune system and profoundly enhances the function of mature T cells. Chronic administration of IL-7 to mice markedly increases T cell numbers, especially CD8+ T cells, and enhances T cell functional potential. However, the mechanism by which these effects occur remains unclear. This report demonstrates that only 2 days of IL-7 treatment is needed for maximal enhancement of T cell function, as measured by proliferation, with a 6- to 12-fold increase in the proportion of CD4+ and CD8+ T cells in cell cycle by 18 h of ex vivo stimulation. Moreover, a 2-day administration of IL-7 in vivo increases basal proliferation by 4- and 14-fold in CD4+ and CD8+ T cells, respectively. These effects occur in the absence of cytokine production, increases in most activation markers, and changes in memory markers. This enhanced basal proliferation is the basis for the increase in T cell numbers in that IL-7 induces an additional 60% and 85% of resting CD4+ and CD8+ T cells, respectively, to enter cell cycle in mice given IL-7 for 7 days. These results demonstrate that in vivo administration of IL-7 increases T cell numbers and functional potential via a homeostatic, nonactivating process. These findings may suggest a unique clinical niche for IL-7 in that IL-7 therapy may increase T cell numbers and enhance responses to specific antigenic targets while avoiding a general, nonspecific activation of the T cell population.
Functional Expression of a Costimulatory B7.2 (CD86) Protein on Human Salivary Gland Epithelial Cells that Interacts with the CD28 Receptor, but Has Reduced Binding to CTLA4
Authors: Kapsogeorgou Efstathia K. , Moutsopoulos Haralampos M. , Manoussakis Menelaos N. 
Published: April 2014

AbstractB7 molecules expressed on classic APC play a critical role in the regulation of immune responses by providing activation or inhibitory signals to T cells, through the ligation with CD28 or CTLA4 receptors, respectively. We have recently described the expression of B7 molecules by the salivary gland epithelial cells (SGEC) of patients with Sjögren’s syndrome (also termed autoimmune epithelitis). The role of such expression needs to be clarified. Thus, in the present study, we sought to address the existence and function of B7.2 proteins on cultured nonneoplastic SGEC lines derived from Sjögren’s syndrome patients. The occurrence of B7.2 proteins on SGEC was verified by flow cytometry, immunocytochemistry, immunoprecipitation, and immunoblotting. The assessment of several cell lines in costimulation assays had revealed that the constitutive expression of B7.2 molecules is sufficient to provide costimulatory signals to anti-CD3-stimulated T cells. SGEC-derived costimulation induced IL-2-dependent proliferation of CD4+ T cells, which was associated with low production of IL-2, but probably also with the secretion of yet undefined autocrine T cell growth factor(s). B7.2 proteins expressed by SGEC were found to display distinctive binding properties denoted by the functional interaction with CD28 receptor and reduced binding to CTLA4. Finally, the detection of a functional soluble form of B7.2 protein in cell-free culture supernatants of both SGEC and EBV-transformed B cell lines is demonstrated. These findings imply a critical role for epithelial cells in the regulation of local immune responses in the salivary glands.
Premature TCRαβ Expression and Signaling in Early Thymocytes Impair Thymocyte Expansion and Partially Block Their Development
Authors: Lacorazza H. Daniel , Tuček-Szabo Carolyn , Vasović Ljiljana V. , Remus Kristin , Nikolich-Žugich Janko 
Published: April 2014

AbstractIn thymocyte ontogeny, Tcr-a genes rearrange after Tcr-b genes. TCRαβ transgenic (Tg) mice have no such delay, consequently expressing rearranged TCRαβ proteins early in the ontogeny. Such mice exhibit reduced thymic cellularity and accumulate mature, nonprecursor TCR+CD8−4− thymocytes, believed to be caused by premature Tg TCRαβ expression via unknown mechanism(s). Here, we show that premature expression of TCRαβ on early thymocytes curtails thymocyte expansion and impairs the CD8−4− → CD8+4+ transition. This effect is accomplished by two distinct mechanisms. First, the early formation of TCRαβ appears to impair the formation and function of pre-TCR, consistent with recently published results. Second, the premature TCRαβ contact with intrathymic MHC molecules further pronounces the block in proliferation and differentiation. These results suggest that the benefit of asynchronous Tcr-a and Tcr-b rearrangement is not only to minimize waste during thymopoiesis, but also to simultaneously allow proper expression/function of the pre-TCR and to shield CD8−4− thymocytes from TCRαβ signals that impair thymocyte proliferation and CD8−4− → CD8+4+ transition.
Anergy and not Clonal Ignorance Determines the Fate of B Cells that Recognize a Physiological Autoantigen
Authors: Rojas Mauricio , Hulbert Chrys , Thomas James W. 
Published: April 2014

Abstract
Autoantibodies to insulin arise spontaneously in the insulin autoimmune syndrome and in type I diabetes. In addition, administration of insulin to individuals without autoimmune disease routinely results in Abs that bind autologous hormone. These observations and findings in transgenic models of tolerance led to an inference that physiological levels of hormones and growth factors, such as insulin, are not sufficient to induce tolerance in B cells, a state termed clonal ignorance. In contrast, we have discovered that virtually all conventional B cells expressing a low affinity anti-insulin transgene interact with endogenous insulin and are effectively silenced for Ig production and for T cell-dependent immune responses. A fraction of transgenic B cells escapes silencing and functions autonomously to produce insulin Abs that may lower fasting blood sugars similar to an insulin autoimmune syndrome. These B cells have characteristics of a B1-like subset and are depleted by hypotonic peritoneal lysis. These findings question the concept of clonal ignorance and show that physiological concentrations of Ag may effectively silence conventional B cells even when the affinity for autoantigen is low. Self-reactivity may arise in the repertoire because of compartmental differences that govern the fate of B cells and not as a result of true clonal ignorance.
Oncostatin M-Induced Matrix Metalloproteinase and Tissue Inhibitor of Metalloproteinase-3 Genes Expression in Chondrocytes Requires Janus Kinase/STAT Signaling Pathway
Authors: Li Wen Qing , Dehnade Faramaze , Zafarullah Muhammad 
Published: April 2014

AbstractOncostatin M (OSM), a member of the IL-6 superfamily of cytokines, is elevated in patients with rheumatoid arthritis and, in synergy with IL-1, promotes cartilage degeneration by matrix metalloproteinases (MMPs). We have previously shown that OSM induces MMP and tissue inhibitor of metalloproteinase-3 (TIMP-3) gene expression in chondrocytes by protein tyrosine kinase-dependent mechanisms. In the present study, we investigated signaling pathways regulating the induction of MMP and TIMP-3 genes by OSM. We demonstrate that OSM rapidly stimulated phosphorylation of Janus kinase (JAK) 1, JAK2, JAK3, and STAT1 as well as extracellular signal-regulated kinase (ERK) 1/2, p38, and c-Jun N-terminal kinase 1/2 mitogen-activated protein kinases in primary bovine and human chondrocytes. A JAK3-specific inhibitor blocked OSM-stimulated STAT1 tyrosine phosphorylation, DNA-binding activity of STAT1 as well as collagenase-1 (MMP-1), stromelysin-1 (MMP-3), collagenase-3 (MMP-13), and TIMP-3 RNA expression. In contrast, a JAK2-specific inhibitor, AG490, had no impact on these events. OSM-induced ERK1/2 activation was also not affected by these inhibitors. Similarly, curcumin (diferuloylmethane), an anti-inflammatory agent, suppressed OSM-stimulated STAT1 phosphorylation, DNA-binding activity of STAT1, and c-Jun N-terminal kinase activation without affecting JAK1, JAK2, JAK3, ERK1/2, and p38 phosphorylation. Curcumin also inhibited OSM-induced MMP-1, MMP-3, MMP-13, and TIMP-3 gene expression. Thus, OSM induces MMP and TIMP-3 genes in chondrocytes by activating JAK/STAT and mitogen-activated protein kinase signaling cascades, and interference with these pathways may be a useful approach to block the catabolic actions of OSM.
Eukaryotic Translation Initiation Factor-6 Enhances Histamine and IL-2 Production in Mast Cells
Authors: Oh Chad K. , Filler Scott G. , Cho Seong H. 
Published: April 2014

AbstractEukaryotic translation initiation factor (eIF)-6 is known to be important in ribosome biogenesis. Previously, we have discovered that eIF-6 mRNA is induced in lung in a murine model of asthma. We also found that there was enhanced eIF-6 expression in mast cells stimulated with PMA plus calcium ionophore. Therefore, we hypothesized that the induction of eIF-6 enhances the production of bioactive mediators by mast cells upon allergic stimulation. In the current study, we found that eIF-6 mRNA was rapidly induced in murine mast cells stimulated by FcεRI cross-linking, which is a major physiologic stimulant for mast cells. eIF-6 was also induced in human mast cells upon stimulation. The increase in eIF-6 gene expression in murine mast cells was blocked by therapeutic agents such as dexamethasone and cyclosporin A. To determine the location and function of eIF-6, murine mast cells were transfected with a construct that overexpressed enhanced green fluorescent protein-tagged eIF-6. These experiments demonstrated that eIF-6 was localized predominantly in the nucleolus of the mast cells. Also, overexpression of enhanced green fluorescent protein/eIF-6 enhanced the production of histamine and IL-2, but not IL-4 by stimulated murine mast cells. These results suggest that eIF-6 regulates the production of selected bioactive mediators in allergic diseases. This is the first demonstration of a biologic function of eIF-6 in mammalian cells.
Multiple Antigen-Specific Processing Pathways for Activating Naive CD8+ T Cells In Vivo
Authors: Norbury Christopher C. , Princiotta Michael F. , Bacik Igor , Brutkiewicz Randy R. , Wood Philip , Elliott Tim , Bennink Jack R. , Yewdell Jonathan W. 
Published: April 2014

Abstract
Current knowledge of the processing of viral Ags into MHC class I-associated ligands is based almost completely on in vitro studies using nonprofessional APCs (pAPCs). This is two steps removed from real immune responses to pathogens and vaccines, in which pAPCs activate naive CD8+ T cells in vivo. Rational vaccine design requires answers to numerous questions surrounding the function of pAPCs in vivo, including their abilities to process and present peptides derived from endogenous and exogenous viral Ags. In the present study, we characterize the in vivo dependence of Ag presentation on the expression of TAP by testing the immunogenicity of model Ags synthesized by recombinant vaccinia viruses in TAP1−/− mice. We show that the efficiency of TAP-independent presentation in vitro correlates with TAP-independent activation of naive T cells in vivo and provide the first in vivo evidence for proteolytic processing of antigenic peptides in the secretory pathway. There was, however, a clear exception to this correlation; although the presentation of the minimal SIINFEKL determinant from chicken egg OVA in vitro was strictly TAP dependent, it was presented in a TAP-independent manner in vivo. In vivo presentation of the same peptide from a fusion protein retained its TAP dependence. These results show that determinant-specific processing pathways exist in vivo for the generation of antiviral T cell responses. We present additional findings that point to cross-priming as the likely mechanism for these protein-specific differences.
p62dokNegatively Regulates CD2 Signaling in Jurkat Cells
Authors: Némorin Jean-Guy , Laporte Pierre , Bérubé Geneviève , Duplay Pascale 
Published: April 2014

Abstractp62dok belongs to a newly identified family of adaptor proteins. In T cells, the two members that are predominantly expressed, p56dok and p62dok, are tyrosine phosphorylated upon CD2 or CD28 stimulation, but not upon CD3 ligation. Little is known about the biological role of Dok proteins in T cells. In this study, to evaluate the importance of p62dok in T cell function, we generated Jurkat clones overexpressing p62dok. Our results demonstrate that overexpression of p62dok in Jurkat cells has a dramatic negative effect on CD2-mediated signaling. The p62dok-mediated inhibition affects several biochemical events initiated by CD2 ligation, such as the increase of intracellular Ca2+, phospholipase Cγ1 activation, and extracellular signal-regulated kinase 1/2 activation. Importantly, these cellular events are not affected in the signaling cascade induced by engagement of the CD3/TCR complex. However, both CD3- and CD2-induced NF-AT activation and IL-2 secretion are impaired in p62dok-overexpressing cells. In addition, we show that CD2 but not CD3 stimulation induces p62dok and Ras GTPase-activating protein recruitment to the plasma membrane. These results suggest that p62dok plays a negative role at multiple steps in the CD2 signaling pathway. We propose that p62dok may represent an important negative regulator in the modulation of the response mediated by the TCR.
The NK Cell MHC Class I Receptor Ly49A Detects Mutations on H-2Dd Inside and Outside of the Peptide Binding Groove
Authors: Matsumoto Naoki , Yokoyama Wayne M. , Kojima Somei , Yamamoto Kazuo 
Published: April 2014

Abstract
The NK cell inhibitory receptor Ly49A recognizes the mouse MHC class I molecule H-2Dd and participates in the recognition of missing self. Previous studies indicated that the determinant recognized by Ly49A exists in α1/α2 domain of H-2Dd. Here we have substituted polymorphic as well as conserved residues of H-2Dd α1/α2 domain (when compared with H-2Kd, which does not interact with Ly49A). We then tested the ability of the H-2Dd mutants to interact with Ly49A by soluble Ly49A tetramer binding and NK cell cytotoxicity inhibition assays. Individual introduction of mutations converting the H-2Dd residue into the corresponding H-2Kd residue (N30D, D77S, or A99F) in H-2Dd partially abrogated the interaction between Ly49A and H-2Dd. Introduction of the three mutations into H-2Dd completely abolished Ly49A recognition. Individual introduction of D29N or R35A mutation into the residues of H-2Dd that are conserved among murine MHC class I severely impaired the interaction. The crystal structure of H-2Dd reveals that D77 and A99 are located in the peptide binding groove and that N30, D29, and R35 are in the interface of the three structural domains of MHC class I: α1/α2, α3, and β2-microglobulin. These data suggest that Ly49A can monitor mutations in MHC class I inside and outside of the peptide binding groove and imply that inhibitory MHC class I-specific receptors are sensitive to mutations in MHC class I as well as global loss of MHC class I. Our results also provide insight into the molecular basis of Ly49A to distinguish MHC class I polymorphism.
B Cell-Deficient (μMT) Mice Have Alterations in the Cytokine Microenvironment of the Gut-Associated Lymphoid Tissue (GALT) and a Defect in the Low Dose Mechanism of Oral Tolerance
Authors: Gonnella Patricia A. , Waldner Hans Peter , Weiner Howard L. 
Published: April 2014

Abstract
Peripheral immune tolerance following i.v. administration of Ag has been shown to occur in the absence of B cells. Because different mechanisms have been identified for i.v. vs low dose oral tolerance and B cells are a predominant component of the gut-associated lymphoid tissue (GALT) they may play a role in tolerance induction following oral Ag. To examine the role of B cells in oral tolerance we fed low doses of OVA or myelin oligodendrocyte glycoprotein to B cell-deficient (μMT) and wild-type C57BL/6 mice. Results showed that the GALT of naive wild-type and μMT mice was characterized by major differences in the cytokine microenvironment. Feeding low doses of 0.5 mg OVA or 250 μg myelin oligodendrocyte glycoprotein resulted in up-regulation of IL-4, IL-10, and TGF-β in the GALT of wild-type but not μMT mice. Upon stimulation of popliteal node cells, in vitro induction of regulatory cytokines TGF-β and IL-10 was observed in wild-type but not μMT mice. Greater protection against experimental autoimmune encephalomyelitis was found in wild-type mice. Oral tolerance in μMT and wild-type mice was found to proceed by different mechanisms. Anergy was observed from 0.5 mg to 250 ng in μMT mice but not in wild-type mice. Increased Ag was detected in the lymph of μMT mice. No cytokine-mediated suppression was found following lower doses from 100 ng to 500 pg in either group. These results demonstrate the importance of the B cell for the induction of cytokine-mediated suppression associated with low doses of Ag.
Spontaneous and Continuous Cyclooxygenase-2-Dependent Prostaglandin E2 Production by Stromal Cells in the Murine Small Intestine Lamina Propria: Directing the Tone of the Intestinal Immune Response
Authors: Newberry Rodney D. , McDonough Jacquelyn S. , Stenson William F. , Lorenz Robin G. 
Published: April 2014

Abstract
The mechanisms allowing the gastrointestinal immune system to avoid an inappropriate inflammatory response to nonpathogenic luminal Ags are poorly understood. We have previously described a role for cyclooxygenase (COX)-2-dependent arachidonic acid metabolites produced by the murine small intestine lamina propria in controlling the immune response to a dietary Ag. To better understand the role of COX-2-dependent arachidonic acid metabolites produced by the lamina propria, we examined the pattern of expression and the cellular source of COX-2 and COX-2-dependent PGE2. We now demonstrate that non-bone marrow-derived lamina propria stromal cells have basal COX-2 expression and that COX-2-dependent PGE2 production by these cells is spontaneous and continuous. The other mucosal and nonmucosal lymphoid compartments examined do not share this phenotype. In contrast to the majority of descriptions of COX-2 expression, COX-2 expression by lamina propria stromal cells is not dependent upon exogenous stimuli, including adhesion, LPS signaling via Toll-like receptor 4, or the proinflammatory cytokines TNF-α, IFN-γ, and IL-1β. These findings, in conjunction with the known immunomodulatory capacities of PGs, suggest that COX-2 expression by the small intestine lamina propria is a basal state contributing to the hyporesponsiveness of the intestinal immune response.
GIF Inhibits Th Effector Generation by Acting on Antigen-Presenting B Cells
Authors: Sugie Katsuji , Huang Jianyong 
Published: April 2014

AbstractGlycosylation-inhibiting factor (GIF) is a 13-kDa cytokine secreted from T cells. Administration of bioactive recombinant GIF inhibits IgG1 and IgE Ab responses in vivo. Treatment of B cells with the cytokine reduces the secretion of IgG1 and IgE induced by LPS and IL-4. To examine the effect on cognate T-B interaction, GIF was added to low-density B cells from MD4 transgenic (Tg) mice, which express B cell receptor specific for hen egg lysozyme (HEL). The B cells were subsequently pulsed with HEL-OVA conjugate and cultured with OVA-specific naive CD4 T cells from DO11.10 Tg mice. Treatment of Ag-presenting B cells with GIF reduced expansion and IL-2 secretion of naive T cells and rendered them hyporesponsive to antigenic restimulation, resulting in 50–95% reduction of IL-4 and IFN-γ secretion upon restimulation with Ag. GIF dramatically inhibited Th effector generation when it was added to B cells before pulsing with HEL-OVA, whereas it showed little to no effect when added after B cells were pulsed with Ag. GIF was more effective when B cells from MD4 Tg mice were pulsed with HEL-OVA than when they were pulsed with OVA. This cytokine did not affect Th effector generation when B cells or irradiated splenocytes pulsed with OVA323–339 peptide stimulated naive DO11.10 T cells. Confocal microscopy revealed that GIF inhibited internalization of HEL by B cells from MD4 Tg mice. Therefore, the cytokine may regulate early steps of Ag presentation involving B cell receptors to diminish Th effector generation from naive CD4 T cells.
IFN-γ/TNF-α Synergism as the Final Effector in Autoimmune Diabetes: A Key Role for STAT1/IFN Regulatory Factor-1 Pathway in Pancreatic β Cell Death
Authors: Suk Kyoungho , Kim Sunshin , Kim Yun-Hee , Kim Kyoung-Ah , Chang Inik , Yagita Hideo , Shong Minho , Lee Myung-Shik 
Published: April 2014

AbstractFas ligand (FasL), perforin, TNF-α, IL-1, and NO have been considered as effector molecule(s) leading to β cell death in autoimmune diabetes. However, the real culprit(s) in β cell destruction have long been elusive, despite intense investigation. We and others have demonstrated that FasL is not a major effector molecule in autoimmune diabetes, and previous inability to transfer diabetes to Fas-deficient nonobese diabetic (NOD)-lpr mice was due to constitutive FasL expression on lymphocytes from these mice. Here, we identified IFN-γ/TNF-α synergism as the final effector molecules in autoimmune diabetes of NOD mice. A combination of IFN-γ and TNF-α, but neither cytokine alone, induced classical caspase-dependent apoptosis in insulinoma and pancreatic islet cells. IFN-γ treatment conferred susceptibility to TNF-α-induced apoptosis on otherwise resistant insulinoma cells by STAT1 activation followed by IFN regulatory factor (IRF)-1 induction. IRF-1 played a central role in IFN-γ/TNF-α-induced cytotoxicity because inhibition of IRF-1 induction by antisense oligonucleotides blocked IFN-γ/TNF-α-induced cytotoxicity, and transfection of IRF-1 rendered insulinoma cells susceptible to TNF-α-induced cytotoxicity. STAT1 and IRF-1 were expressed in pancreatic islets of diabetic NOD mice and colocalized with apoptotic cells. Moreover, anti-TNF-α Ab inhibited the development of diabetes after adoptive transfer. Taken together, our results indicate that IFN-γ/TNF-α synergism is responsible for autoimmune diabetes in vivo as well as β cell apoptosis in vitro and suggest a novel signal transduction in IFN-γ/TNF-α synergism that may have relevance in other autoimmune diseases and synergistic anti-tumor effects of the two cytokines.
Nonobese Diabetic Mice Display Elevated Levels of Class II-Associated Invariant Chain Peptide Associated with I-Ag7 on the Cell Surface
Authors: Bhatnagar Aparna , Milburn Peter J. , Lobigs Mario , Blanden Robert V. , Gautam Anand M. 
Published: April 2014

AbstractPeptide presentation by MHC class II molecules plays a pivotal role in determining the peripheral T cell repertoire as a result of both positive and negative selection in the thymus. Homozygous I-Ag7 expression imparts susceptibility to autoimmune diabetes in the nonobese diabetic mouse, and recently, it has been proposed that this arises from ineffectual peptide binding. Following biosynthesis, class II molecules are complexed with class II-associated invariant chain peptides (CLIP), which remain associated until displaced by Ag-derived peptides. If I-Ag7 is a poor peptide binder, then this may result in continued occupation by CLIP to the point of translocation to the cell surface. To test this hypothesis we generated affinity-purified polyclonal antisera that recognized murine CLIP bound to class II molecules in an allele-independent fashion. We have found abnormally high natural levels of cell surface class II occupancy by CLIP on nonobese diabetic splenic B cells. Experiments using I-A-transfected M12.C3 cells showed that I-Ag7 alone was associated with elevated levels of CLIP, suggesting that this was determined solely by the amino acid sequence of the class II molecule. These results indicated that an intrinsic property of I-Ag7 would affect both the quantity and the repertoire of self-peptides presented during thymic selection.