bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased Nonobese Diabetic Th1:Th2 (IFN-γ:IL-4) Ratio Is CD4+ T Cell Intrinsic and Independent of APC Genetic Background
Authors: Koarada Syuichi , Wu Yuehong , Olshansky Grace , Ridgway William M. 
Published: April 2014

AbstractAutoreactive CD4+ T cells play a major role in the pathogenesis of autoimmune diabetes in nonobese diabetic (NOD) mice. We recently showed that the non-MHC genetic background controlled enhanced entry into the IFN-γ pathway by NOD vs B6.G7 T cells. In this study, we demonstrate that increased IFN-γ, decreased IL-4, and decreased IL-10 production in NOD T cells is CD4 T cell intrinsic. NOD CD4+ T cells purified and stimulated with anti-CD3/anti-CD28 Abs generated greater IFN-γ, less IL-4, and less IL-10 than B6.G7 CD4+ T cells. The same results were obtained in purified NOD.H2b vs B6 CD4+ T cells, demonstrating that the non-MHC NOD genetic background controlled the cytokine phenotype. Moreover, the increased IFN-γ:IL-4 cytokine ratio was independent of the genetic background of APCs, since NOD CD4+ T cells generated increased IFN-γ and decreased IL-4 compared with B6.G7 CD4+ T cells, regardless of whether they were stimulated with NOD or B6.G7 APCs. Cell cycle analysis showed that the cytokine differences were not due to cycle/proliferative differences between NOD and B6.G7, since stimulated CD4+ T cells from both strains showed quantitatively identical entry into subsequent cell divisions (shown by CFSE staining), although NOD cells showed greater numbers of IFN-γ-positive cells with each subsequent cell division. Moreover, 7-aminoactinomycin D and 5-bromo-2′-deoxyuridine analysis showed indistinguishable entry into G0/G1, S, and G2/M phases of the cell cycle for both NOD and B6.G7 CD4+ cells, with both strains generating IFN-γ predominantly in the S phase. Therefore, the NOD cytokine effector phenotype is CD4+ T cell intrinsic, genetically controlled, and independent of cell cycle machinery.
Rapid Induction of Apoptosis in CD8+ HIV-1 Envelope-Specific Murine CTLs by Short Exposure to Antigenic Peptide
Authors: Takahashi Megumi , Osono Eiichi , Nakagawa Yohko , Wang Jian , Berzofsky Jay A. , Margulies David H. , Takahashi Hidemi 
Published: April 2014

AbstractDuring primary viral infection, in vivo exposure to high doses of virus causes a loss of Ag-specific CD8+ T cells. This phenomenon, termed clonal exhaustion, and other mechanisms by which CTLs are deleted are poorly understood. Here we show evidence for a novel form of cell death in which recently stimulated CD8+ HIV-1 envelope gp160-specific murine CTLs become apoptotic in vitro after brief exposure to free antigenic peptide (P18-I10). Peak apoptosis occurred within 3 h of treatment with peptide, and the level of apoptosis was dependent on both the time after initial stimulation with target cells and the number of targets. Using T cell-specific H-2Dd/P18-I10 tetramers, we observed that the apoptosis was induced by such complexes. Induction of apoptosis was blocked by cyclosporin A, a caspase 3 inhibitor, and a mitogen-activated protein kinase inhibitor, but not by Abs to either Fas ligand or to TNF-α. Thus, these observations suggest the existence of a Fas- or TNF-α-independent pathway initiated by TCR signaling that is involved in the rapid induction of CTL apoptosis. Such a pathway may prove important in the mechanism by which virus-specific CTLs are deleted in the presence of high viral burdens.
Ongoing In Vivo Immunoglobulin Class Switch DNA Recombination in Chronic Lymphocytic Leukemia B Cells
Authors: Cerutti Andrea , Zan Hong , Kim Edmund C. , Shah Shefali , Schattner Elaine J. , Schaffer András , Casali Paolo 
Published: April 2014

Abstract
Chronic lymphocytic leukemia (CLL) results from the expansion of malignant CD5+ B cells that usually express IgD and IgM. These leukemic cells can give rise in vivo to clonally related IgG+ or IgA+ elements. The requirements and modalities of this process remain elusive. Here we show that leukemic B cells from 14 of 20 CLLs contain the hallmarks of ongoing Ig class switch DNA recombination (CSR), including extrachromosomal switch circular DNAs and circle transcripts generated by direct Sμ→Sγ, Sμ→Sα, and Sμ→Sε as well as sequential Sγ→Sα and Sγ→Sε CSR. Similar CLL B cells express transcripts for activation-induced cytidine deaminase, a critical component of the CSR machinery, and contain germline IH-CH and mature VHDJH-CH transcripts encoded by multiple Cγ, Cα, and Cε genes. Ongoing CSR occurs in only a fraction of the CLL clone, as only small proportions of CD5+CD19+ cells express surface IgG or IgA and lack IgM and IgD. In vivo class-switching CLL B cells down-regulate switch circles and circle transcripts in vitro unless exposed to exogenous CD40 ligand and IL-4. In addition, CLL B cells that do not class switch in vivo activate the CSR machinery and secrete IgG, IgA, or IgE upon in vitro exposure to CD40 ligand and IL-4. These findings indicate that in CLL at least some members of the malignant clone actively differentiate in vivo along a pathway that induces CSR. They also suggest that this process is elicited by external stimuli, including CD40 ligand and IL-4, provided by bystander immune cells.
The Role of FcγR Signaling in the K/B × N Serum Transfer Model of Arthritis
Authors: Corr Maripat , Crain Brian 
Published: April 2014

Abstract
Spontaneous arthritis in the KRN transgenic mouse (K/BxN) model is due to the autoreactivity of the transgenic TCR and subsequent induction of autoantibodies directed against glucose-6-phosphate isomerase. These autoantibodies transfer clinically apparent arthritis into most recipient mouse strains and systemic catabolism of the transferred Abs attenuates paw swelling. Although mice deficient in the common γ-chain of the FcγR did not show clinical synovitis after receiving K/BxN sera, erosive lesions in the bone still developed. Further analysis demonstrated that FcγRII−/− mice manifested accelerated arthritis whereas the FcγRIII−/− mice had a more slowly progressing arthritis. Paw swelling required FcγR expression by bone marrow-derived cells and mast cells substantially contributed to the acute phase of paw swelling. In the K/BxN serum transfer model of arthritis, there is a clinically apparent acute phase, which is modulated by FcγRII and FcγRIII, and a subacute component, which results in bone erosion, even in the absence of FcγR signaling.
Rheumatoid Arthritis Synoviocyte Survival Is Dependent on Stat3
Authors: Krause Anja , Scaletta Nicholas , Ji Jong-Dae , Ivashkiv Lionel B. 
Published: April 2014

Abstract
Rheumatoid arthritis (RA) synovial fibroblasts (SFs) are relatively resistant to apoptosis and exhibit dysregulated growth secondary to production of autocrine-acting growth factors and the accumulation of cell-autonomous defects. Many of the cytokines and growth factors expressed during RA synovitis, including IL-6, epidermal growth factor (EGF), and platelet-derived growth factor, activate the transcription factor Stat3 that has been implicated in promoting cell growth and survival. We analyzed the role of Stat3 in mediating the abnormal growth and survival properties of RA synoviocytes using retroviral-mediated gene transfer of a dominant negative mutant of Stat3, termed Stat3-YF. Approximately 3- to 5-fold overexpression of Stat3-YF effectively blocked endogenous Stat3 activation and Stat3-dependent gene expression, including expression of the socs3 and myc genes. Stat3-YF-transduced RA synoviocytes failed to grow in culture, exhibited markedly diminished [3H]thymidine incorporation (&gt;90% decreased), and died spontaneously. Cell death occurred by apoptosis, as confirmed by annexin V staining, propidium iodide exclusion, and identification of cells with subdiploid levels of DNA. In marked contrast to control cells, EGF accelerated death of Stat3-YF-transduced SFs, such that &gt;90% of cells were dead within 24–48 h of transduction. These results indicate that ablation of Stat3 function converts EGF from a growth/survival factor for RA synoviocytes to a death factor. Stat3-YF also induced apoptosis in osteoarthritis synoviocytes, and levels of apoptosis were increased by exogenous EGF. Apoptosis in Stat3-YF-transduced osteoarthritis synoviocytes was suppressed when Stat1 activity was blocked using a dominant negative Stat1 mutant. Our results identify Stat3 as an important molecule for RA SF survival, and suggest that Stat3 may represent a good target for gene therapy.
The Natural Autoantibody Repertoire of Nonobese Diabetic Mice Is Highly Active
Authors: Thomas James W. , Kendall Peggy L. , Mitchell Holly G. 
Published: April 2014

Abstract
Analysis of spontaneous hybridomas generated from nonobese diabetic (NOD) mice indicates that the natural autoantibody repertoire of NOD mice is highly active compared with C57BL/6 and BALB/c mice. This property of increased B cell activity is present early in life (4 wk) and persists in older mice of both sexes. Even when selected for binding to a prototypic β cell Ag, such as insulin, NOD mAb have characteristics of natural autoantibodies that include low avidity and broad specificity for multiple Ags. Analyses of the variable region of Ig H chain (VH) and variable region κ L chain genes expressed by six insulin binding mAb show that V gene segments are often germline encoded and are identical with those used by autoantibodies, especially anti-dsDNA, from systemic autoimmune disease in MRL, NZB/W, and motheaten mice. VH genes used by four mAb are derived from the large J558 family and two mAb use VH7183 and VHQ52 genes. The third complementarity-determining region of Ig H chain of these mAb have limited N segment diversity, and some mAb contain DNA segments indicative of gene replacement. Genetic abnormalities in the regulation of self-reactive B cells may be a feature that is shared between NOD and conventional systemic autoimmune disorders. In NOD, the large pool of self-reactive B cells may fuel autoimmune β cell destruction by facilitating T-B cell interactions, as evidenced by the identification of one mAb that has undergone Ag-driven somatic hypermutation.
Differential MHC Class II-Mediated Presentation of Rheumatoid Arthritis Autoantigens by Human Dendritic Cells and Macrophages
Authors: Tsark Eleanor C. , Wang Wei , Teng Yu-Chin , Arkfeld Daniel , Dodge George R. , Kovats Susan 
Published: April 2014

Abstract
Rheumatoid arthritis is characterized by synovial joint infiltration of activated CD4+ T cells and MHC class II+ APC, and is linked to specific HLA-DR alleles. Candidate autoantigens in synovial fluid and cartilage include type II collagen (CII) and cartilage gp39 (HCgp39). Using preparations of native Ag and T cells derived from Ag-immunized DR4-transgenic mice, we determined that human ex vivo differentiated DR4+ dendritic cells (DC) and macrophages (Mφ) can mediate MHC class II presentation of CII or HCgp39 epitopes. The form of the Ag (soluble, partially degraded, or particulate) delivered to the APC influenced its presentation by DC and Mφ. DC efficiently presented partially degraded, but not native CII α-chains, while Mφ presentation was most efficient after phagocytosis of bead-conjugated CII. Both DC and Mφ presented soluble HCgp39, and activated Mφ from some donors presented epitopes derived from endogenously synthesized HCgp39. When synovial fluid from rheumatoid arthritis patients was used as a source of Ag, DC presentation of HCgp39 and CII epitopes was efficient, indicating that synovial fluid contains soluble forms of CII and HCgp39 amenable to internalization, processing, and presentation. These data support the hypothesis that CII and HCgp39 are autoantigens and that their class II-mediated presentation by DC and Mφ to T cells in vivo has a critical role in the pathogenesis of human rheumatoid arthritis.
Essential Role of NF-κB-Inducing Kinase in T Cell Activation Through the TCR/CD3 Pathway
Authors: Matsumoto Mitsuru , Yamada Takuji , Yoshinaga Steven K. , Boone Tom , Horan Tom , Fujita Shigeru , Li Yi , Mitani Tasuku 
Published: April 2014

Abstract
NF-κB-inducing kinase (NIK) is involved in lymphoid organogenesis in mice through lymphotoxin-β receptor signaling. To clarify the roles of NIK in T cell activation through TCR/CD3 and costimulation pathways, we have studied the function of T cells from aly mice, a strain with mutant NIK. NIK mutant T cells showed impaired proliferation and IL-2 production in response to anti-CD3 stimulation, and these effects were caused by impaired NF-κB activity in both mature and immature T cells; the impaired NF-κB activity in mature T cells was also associated with the failure of maintenance of activated NF-κB. In contrast, responses to costimulatory signals were largely retained in aly mice, suggesting that NIK is not uniquely coupled to the costimulatory pathways. When NIK mutant T cells were stimulated in the presence of a protein kinase C (PKC) inhibitor, proliferative responses were abrogated more severely than in control mice, suggesting that both NIK and PKC control T cell activation in a cooperative manner. We also demonstrated that NIK and PKC are involved in distinct NF-κB activation pathways downstream of TCR/CD3. These results suggest critical roles for NIK in setting the threshold for T cell activation, and partly account for the immunodeficiency in aly mice.
CD40 Ligand and CTLA-4 Are Reciprocally Regulated in the Th1 Cell Proliferative Response Sustained by CD8+ Dendritic Cells
Authors: Fallarino Francesca , Grohmann Ursula , Vacca Carmine , Bianchi Roberta , Fioretti Maria C. , Puccetti Paolo 
Published: April 2014

AbstractSubsets of murine dendritic cells (DCs) from the spleen differ in their ability to induce proliferative responses in both primary and secondary CD4+ T cells. Recent evidence indicates that lymphoid-related CD8+ DCs fail to provide appropriate signals to freshly isolated secondary CD4+ T cells to sustain their proliferation in vitro. In the present study, we examined peptide-pulsed CD8− and CD8+ DCs for ability to stimulate Th1 and Th2 cell clones with the same Ag specificity. Defective ability to induce proliferation was selectively shown by CD8+ DCs presenting Ag to the Th1 clone. The deficiency in CD8+ DCs was overcome by CD40 triggering before peptide pulsing. When exposed to CD8+ DCs in the absence of CD40 activation, the Th1 clone expressed low levels of CD40 ligand and high levels of surface CTLA-4. Neutralization of CTLA-4 during the DC/T cell coculture resulted in increased CD40 ligand expression and proliferation of T cells. Remarkably, the activation of CD40 on DCs under conditions that would increase Th1 cell proliferation, also resulted in down-regulation of surface CTLA-4. These results confirm differential effects of CD8+ and CD8− DCs in the stimulation of Ag-primed Th cells. In addition, they suggest that reciprocal regulation of CD40 ligand and CTLA-4 expression occurs in Th1 cells exposed to CD8+ DCs.
Immune Surveillance and Effector Functions of CCR10+ Skin Homing T Cells
Authors: Hudak Susan , Hagen Michael , Liu Ying , Catron Daniel , Oldham Elizabeth , McEvoy Leslie M. , Bowman Edward P. 
Published: April 2014

AbstractSkin homing T cells carry memory for cutaneous Ags and play an important sentinel and effector role in host defense against pathogens that enter via the skin. CCR10 is a chemokine receptor that is preferentially expressed among blood leukocytes by a subset of memory CD4 and CD8 T cells that coexpress the skin-homing receptor cutaneous lymphocyte Ag (CLA), but not the gut-homing receptor α4β7. Homing and chemokine receptor coexpression studies detailed in this study suggest that the CLA+/CCR10+ memory CD4 T cell population contains members that have access to both secondary lymphoid organ and skin compartments; and therefore, can act as both “central” and “effector” memory T cells. Consistent with this effector phenotype, CLA+/CCR10+ memory CD4 T cells from normal donors secrete TNF and IFN-γ but minimal IL-4 and IL-10 following in vitro stimulation. Interactions of CCR10 and its skin-associated ligand CC ligand 27 may play an important role in facilitating memory T cell entry into cutaneous sites during times of inflammation.
Green Fluorescent Protein-Glucocorticoid Receptor Knockin Mice Reveal Dynamic Receptor Modulation During Thymocyte Development
Authors: Brewer Judson A. , Sleckman Barry P. , Swat Wojciech , Muglia Louis J. 
Published: April 2014

AbstractTo delineate the cellular targets and mechanisms by which glucocorticoids (GCs) exert their actions, we generated mice in which a green fluorescent protein (GFP)-GC receptor (GR) fusion gene is knocked into the GR locus. In these mice, the GFP-GR protein, which is functionally indistinguishable from endogenous GR, allows the tracking and quantitation of GR expression in single living cells. In GFP-GR thymus, GR expression is uniform among embryonic thymocyte subpopulations but gradually matures over a 3-wk period after birth. In the adult, GR is specifically induced to high levels in CD25+CD4−CD8− thymocytes and returns to basal levels in CD4+CD8+ thymocytes of wild-type and positively selecting female HY TCR-transgenic mice, but not negatively selecting male HY TCR-transgenic mice. In GFP-GR/recombinase-activating gene 2−/− thymocytes, GR expression is down-regulated by pre-TCR complex stimulation. Additionally, relative GR expression is dissociated from GC-induced apoptosis in vivo. Results from these studies define differential GR expression throughout ontogeny, suggest pre-TCR activation as a specific mechanism of GR down-regulation, define immature CD8+ thymocytes as novel apoptosis-sensitive GC targets, and separate receptor abundance from susceptibility to apoptosis across thymocyte populations.
Regulation of Class II MHC Expression in APCs: Roles of Types I, III, and IV Class II Transactivator
Authors: Pai Rish K. , Askew David , Boom W. Henry , Harding Clifford V. 
Published: April 2014

AbstractClass II transactivator (CIITA) is necessary for expression of class II MHC (MHC-II) molecules. In mice, CIITA expression is regulated by three promoters (pI, pIII, and pIV), producing types I, III, and IV CIITA. The relative roles of different CIITA types remain unclear. Unstimulated bone marrow-derived macrophages expressed low levels of CIITA mRNA; type I CIITA was nine times more abundant than type IV (type III CIITA was barely detected). Exposure to IFN-γ (6 h) dramatically increased types I and IV CIITA mRNA to similar absolute levels. Type IV CIITA declined over time, but type I was stable for over 72 h. Thus, the dominant form of CIITA evolved with time during activation by IFN-γ, and type I CIITA explained prolonged expression of MHC-II by macrophages. mRNA half-life was shorter for type I than type IV CIITA, suggesting that sustained transcription contributed to stable expression of type I CIITA induced by IFN-γ. Splenic B cells expressed mRNA for type III CIITA but very little for types I or IV. Treatment with IL-4 increased surface expression of MHC-II protein, but mRNA for MHC-II and CIITA (total, I, III, and IV) remained unchanged, suggesting posttranslational regulation. Splenic dendritic cells expressed type I CIITA but little type III or IV; CpG DNA induced their maturation and decreased types I and III CIITA, consistent with decreased MHC-II protein synthesis. CIITA types differ in regulation in various APCs under different stimuli, and the predominant type of CIITA varies at different stages of APC activation.
Critical Role of NK Cells Rather Than Vα14+NKT Cells in Lipopolysaccharide-Induced Lethal Shock in Mice
Authors: Emoto Masashi , Miyamoto Mamiko , Yoshizawa Izumi , Emoto Yoshiko , Schaible Ulrich E. , Kita Eiji , Kaufmann Stefan H. E. 
Published: April 2014

AbstractAlthough macrophages play a central role in the pathogenesis of septic shock, NK1+ cells have also been implicated. NK1+ cells comprise two major populations, namely NK cells and Vα14+NKT cells. To assess the relative contributions of these NK1+ cells to LPS-induced shock, we compared the susceptibility to LPS-induced shock of β2-microglobulin (β2m)−/− mice that are devoid of Vα14+NKT cells, but not NK cells, with that of wild-type (WT) mice. The results show that β2m−/− mice were more susceptible to LPS-induced shock than WT mice. Serum levels of IFN-γ following LPS challenge were significantly higher in β2m−/− mice, and endogenous IFN-γ neutralization or in vivo depletion of NK1+ cells rescued β2m−/− mice from lethal effects of LPS. Intracellular cytokine staining revealed that NK cells were major IFN-γ producers. The Jα281−/− mice that are exclusively devoid of Vα14+NKT cells were slightly more susceptible to LPS-induced shock than heterozygous littermates. Hence, LPS-induced shock can be induced in the absence of Vα14+NKT cells and IFN-γ from NK cells is involved in this mechanism. In WT mice, hierarchic contribution of different cell populations appears likely.
Characterization of Thrombin-Induced Leukocyte Rolling and Adherence: A Potential Proinflammatory Role for Proteinase-Activated Receptor-4
Authors: Vergnolle Nathalie , Derian Claudia K. , D’Andrea Michael R. , Steinhoff Martin , Andrade-Gordon Patricia 
Published: April 2014

Abstract
It is commonly accepted that thrombin exerts its proinflammatory properties through the activation of proteinase-activated receptor (PAR)-1, although two other thrombin receptors have been discovered: PAR-3 and PAR-4. In this study, we have investigated the mechanisms and the receptors involved in thrombin-induced leukocyte/endothelial cell interactions by using selective agonists and antagonists of thrombin receptors in an in vivo intravital microscopy system. Topical addition of selective PAR-1 agonists to rat mesenteric venules failed to reproduce the increased leukocyte rolling and adhesion observed after thrombin topical addition. When added together with the selective PAR-1 antagonist RWJ-56110, thrombin was still able to provoke increased leukocyte rolling and adherence. The thrombin-induced leukocyte rolling and adherence was not affected by pretreatment of rats with an anti-platelet serum. Selective PAR-4-activating peptide was able to reproduce the effects of thrombin on leukocyte rolling and adhesion. Intraperitoneal injection of PAR-4-activating peptide also caused a significant increase in leukocyte migration into the peritoneal cavity. In rat tissues, PAR-4 expression was detected both on endothelium and isolated leukocytes. Taken together, these results showed that in rat mesenteric venules, thrombin exerts proinflammatory properties inducing leukocyte rolling and adherence, by a mechanism independent of PAR-1 activation or platelet activation. However, PAR-4 activation either on endothelial cells or on leukocytes might be responsible for the thrombin-induced effects. These findings suggest that PAR-4 activation could contribute to several early events in the inflammatory reaction, including leukocyte rolling, adherence and recruitment, and that in addition to PAR-1, PAR-4 could be involved in proinflammatory properties of thrombin.