bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative Contribution of CD1 on the Development of CD4+ and CD8+ T Cell Compartments
Authors: Wang Bin , Chun Taehoon , Wang Chyung-Ru 
Published: April 2014

AbstractCD1 molecules are MHC class I-like glycoproteins whose expression is essential for the development of a unique subset of T cells, the NK T cells. To evaluate to what extent CD1 contributes to the development of CD4+ and CD8+ T cells, we generated CD1oIIo and CD1oTAPo mice and compared the generation of T cells in these double-mutant mice and IIo or TAPo mice. FACS analysis showed that the number of CD4+ T cells in CD1oIIo mice was reduced significantly compared with the corresponding population in IIo mice. Both CD4+ NK1.1+ and the CD4+ NK1.1− population were reduced in CD1oIIo mice, suggesting that CD1 can select not only CD4+ NK1.1+ T cells but also some NK1.1− CD4+ T cells. Functional analysis showed that the residual CD4+ cells in CD1oIIo can secrete large amounts of IFN-γ and a significant amount of IL-4 during primary stimulation with anti-CD3, suggesting that this population may be enriched for NK T cells restricted by other class I molecules. In contrast to the CD4+ population, no significant differences in the CD8+ T cell compartment can be detected between TAPo and CD1oTAPo mice in all lymphoid tissues tested, including intestinal intraepithelial lymphocytes. Our data suggest that, unlike other MHC class I molecules, CD1 does not contribute in a major way to the development of CD8+ T cells.
α4β1 Integrin/VCAM-1 Interaction Activates αLβ2 Integrin-Mediated Adhesion to ICAM-1 in Human T Cells
Authors: Chan Jason R. , Hyduk Sharon J. , Cybulsky Myron I. 
Published: April 2014

Abstract
Modulation of integrin affinity and/or avidity provides a regulatory mechanism by which leukocyte adhesion to endothelium is strengthened or weakened at different stages of emigration. In this study, we demonstrate that binding of high-affinity α4β1 integrins to VCAM-1 strengthens αLβ2 integrin-mediated adhesion. The strength of adhesion of Jurkat cells, a human leukemia T cell line, or MnCl2-treated peripheral blood T cells to immobilized chimeric human VCAM-1/Fc, ICAM-1/Fc, or both was quantified using parallel plate flow chamber leukocyte detachment assays in which shear stress was increased incrementally (0.5–30 dynes/cm2). The strength of adhesion to VCAM-1 plus ICAM-1, or to a 40-kDa fragment of fibronectin containing the CS-1 exon plus ICAM-1, was greater than the sum of adhesion to each molecule alone. Treatment of Jurkat or blood T cells with soluble cross-linked VCAM-1/Fc or HP2/1, a mAb to α4, significantly increased adhesion to ICAM-1. These treatments induced clustering of αLβ2 integrins, but not the high-affinity β2 integrin epitope recognized by mAb 24. Up-regulated adhesion to ICAM-1 was abolished by cytochalasin D, an inhibitor of cytoskeletal rearrangement. Taken together, our data suggest that the binding of VCAM-1 or fibronectin to α4β1 integrins initiates a signaling pathway that increases β2 integrin avidity but not affinity. A role for the cytoskeleton is implicated in this process.
The Multidrug Resistance Protein 1: A Functionally Important Activation Marker for Murine Th1 Cells
Authors: Prechtl Stefan , Roellinghoff Martin , Scheper Rik , Cole Susan P. C. , Deeley Roger G. , Lohoff Michael 
Published: April 2014

Abstract
Previously, we described the expression of an energy-dependent pump in resting murine Th2 (but not resting Th1) cells which extruded the fluorescent dye Fluo-3. After stimulation with Ag and APCs, Th1 cells also expressed this pump. Furthermore, expression of the murine multidrug resistance protein 1 (mrp1) correlated with the presence of the pump. In this study, we report that Fluo-3 is indeed transported by murine mrp1 or its human ortholog MRP1, as revealed by transfection of HEK 293 cells with mrp1 or MRP1 cDNA. Like antigenic activation, IL-2 dose-dependently enhanced the Fluo-3-extruding activity in murine Th1 cells. Although TNF-α and IL-12 by themselves only weakly enhanced Fluo-3 extrusion, each of them did so in strong synergism with IL-2. An Ab directed against mrp1 was used to quantify the expression of mrp1 protein in T cells at the single-cell level. Like the Fluo-3 pump, mrp1 protein expression was enhanced by IL-2. Immunohistochemical studies using confocal laser microscopy indicated that mrp1 is localized mainly at the plasma membrane. In addition, protein expression of mrp1 was induced in Vβ8+CD4+ T cells 12 h after in vivo application of Staphylococcal enterotoxin B. Finally, mrp1 was functionally relevant during the activation process of Th1 cells, because T cell activation could be suppressed by exposure of cells to the mrp1 inhibitor MK571. Thus, we present mrp1 as a novel, functionally important activation marker for Th1 cells and short-term in vivo activated CD4+ T cells, whereas its expression seems to be constitutive in Th2 cells.
Autocrine Production of IL-10 Mediates Defective IL-12 Production and NF-κB Activation in Tumor-Associated Macrophages
Authors: Sica Antonio , Saccani Alessandra , Bottazzi Barbara , Polentarutti Nadia , Vecchi Annunciata , Damme Jo Van , Mantovani Alberto 
Published: April 2014

Abstract
IL-12 is a central cytokine in the activation of inflammation and immunity and in the generation of Th1-type responses. Tumor-associated macrophages (TAM) from mouse and human tumors showed defective production of IL-12. Defective IL-12 production was associated with lack of p50/p65 NF-κB activation. TAM produced increased amounts of the immunosuppressive cytokine IL-10. Abs against IL-10 restored the defective capacity of TAM to produce IL-12. Our data suggest that during tumor growth an IL-10-dependent pathway of diversion of macrophage function can be activated into the tumor microenvironment and results in the promotion of the IL-10+ IL-12− phenotype of TAM. Blocking IL-10, as well as other immunosuppressive cytokines present in the tumor microenvironment, such as TGF-β, may complement therapeutic strategies aimed at activating type I antitumor immune responses.
Antiviral B Cell Memory in the Absence of Mature Follicular Dendritic Cell Networks and Classical Germinal Centers in TNFR1−/− Mice
Authors: Karrer U. , López-Macías C. , Oxenius A. , Odermatt B. , Bachmann M. F. , Kalinke U. , Bluethmann H. , Hengartner H. , Zinkernagel R. M. 
Published: April 2014

Abstract
TNFR1−/− mice have been shown to lack networks of mature follicular dendritic cells (FDCs) and they do not form germinal centers. With nonreplicating Ags, IgG titers were inefficiently induced and not maintained. In this study, the neutralizing Ab response and the establishment of B cell memory in TNFR1−/− mice after infection with vesicular stomatitis virus (VSV) were analyzed histologically and functionally. Immunization with VSV-derived protein Ags without adjuvant induced only IgM but no IgG Abs in TNFR1−/− mice, whereas VSV glycoprotein emulsified in CFA or IFA induced IgM and IgG responses that were short-lived and of moderate titer. However, infection with live VSV induced excellent neutralizing IgM and IgG responses in TNFR1−/− mice, and adoptively transferable B cell memory was generated and persisted for more than 300 days. In contrast, IgG levels and Ab-forming cells in the bone marrow declined within 300 days by 90–95% compared with controls. These findings suggest that 1) increased Ag dose and time of Ag availability can substitute for FDC-stored Ab-complexed Ag in the induction of efficient IgG responses in TNFR1−/− mice devoid of classical germinal centers; 2) the induction and maintenance of adoptively transferable B cell memory can occur in the absence of Ag bound to mature FDCs; and 3) the long-term maintenance of elevated IgG titers is largely dependent on FDC-associated persisting Ag. However, about 5–10% of the Ab production remained in the absence of detectable persisting Ag in TNFR1−/− mice, probably either due to immature FDCs being partially functional and/or due to long-lived plasma cells.
IFN-γ Is Necessary But Not Sufficient for Anti-CD40 Antibody-Mediated Inhibition of the Th2 Response to Schistosoma mansoni Eggs
Authors: Martin Diana L. , King Christopher L. , Pearlman Eric , Strine Ellen , Heinzel Frederick P. 
Published: April 2014

Abstract
The injection of Schistosoma mansoni eggs into the footpads of mice results in a localized Th2 cytokine response and tissue eosinophilia. We examined whether treatment with CD40-activating Abs would block the development of Th2 cytokine responses and eosinophilic tissue pathology in this model. Seven days after C57BL/6 mice were injected with eggs and the FGK45 anti-CD40 Ab, Ag-specific synthesis of IL-4, IL-5, and IL-13 in lymph node culture was reduced (&gt;10-fold) relative to control mice treated with eggs and rat IgG. In contrast, IFN-γ and IL-12 were increased in both culture supernatants and in the serum. Similar changes in lymph node cytokine mRNA were observed in vivo, and tissue eosinophilia was reduced nearly 20-fold. Th2 cytokine responses in anti-CD40-treated IFN-γ−/− and IL-12 p40−/− C57BL/6 mice were unaffected, although anti-CD40 induced high levels of systemic and local IFN-γ production in both wild-type and IL-12 p40−/− mice. We conclude that CD40-activating treatments strongly reverse the immune phenotype generated in response to a classic, Th2-biasing stimulus and stimulate IFN-γ through a novel IL-12-independent pathway. This model for Th1-deviating immune therapy may have relevance to the treatment of Th2-dependent diseases in general.
Modulation of Renal Disease in MRL/lpr Mice Genetically Deficient in the Alternative Complement Pathway Factor B
Authors: Watanabe Hiroshi , Garnier Gérard , Circolo Antonella , Wetsel Rick A. , Ruiz Phil , Holers V. Michael , Boackle Susan A. , Colten Harvey R. , Gilkeson Gary S. 
Published: April 2014

Abstract
In systemic lupus erythematosus, the renal deposition of complement-containing immune complexes initiates an inflammatory cascade resulting in glomerulonephritis. Activation of the classical complement pathway with deposition of C3 is pathogenic in lupus nephritis. Although the alternative complement pathway is activated in lupus nephritis, its role in disease pathogenesis is unknown. To determine the role of the alternative pathway in lupus nephritis, complement factor B-deficient mice were backcrossed to MRL/lpr mice. MRL/lpr mice develop a spontaneous lupus-like disease characterized by immune complex glomerulonephritis. We derived complement factor B wild-type (B+/+), homozygous knockout (B−/−), and heterozygous (B+/−) MRL/lpr mice. Compared with B+/− or B+/+ mice, MRL/lpr B−/− mice developed significantly less proteinuria, less glomerular IgG deposition, and decreased renal scores as well as lower IgG3 cryoglobulin production and vasculitis. Serum C3 levels were normal in the B−/− mice compared with significantly decreased levels in the other two groups. These results suggest that: 1) factor B plays an important role in the pathogenesis of glomerulonephritis and vasculitis in MRL/lpr mice; and 2) activation of the alternative pathway, either by the amplification loop or by IgA immune complexes, has a prominent effect on serum C3 levels in this lupus model.
Comparison of Mouse and Rabbit Eiκ Enhancers Indicates That Different Elements Within the Enhancer May Mediate Activation of Transcription and Recombination
Authors: Coquilleau Isabelle , Cavelier Patricia , Rougeon François , Goodhardt Michele 
Published: April 2014

AbstractThe intronic Ig κ-light chain enhancer (Eiκ) has been implicated in regulation of transcription and Vκ-Jκ recombination at the κ locus. To identify sequences within the Eiκ enhancer which are involved in control of recombination, we have made use of the finding that the Eiκ element from the rabbit b9 κ locus is capable of inducing rearrangement, but not transcription of κ genes in mouse lymphoid cells. We have therefore compared the binding of murine nuclear proteins to the mouse and rabbit Eiκ elements. DNase I footprinting and gel mobility shift assays indicate that only the κB, κE1, and κE2 sites of the rabbit enhancer are able to interact with murine trans-acting factors. Moreover, although the rabbit κB site binds murine NF-κB p50/p50 and p50/p65 complexes with high affinity, this site is not capable of mediating transcriptional activation of transient transfection reporter constructs in mouse B lineage cells. These results therefore suggest that, in contrast to the maintenance of κ enhancer transcription which requires all of the Eiκ sites, only the κB, κE1, and κE2 sites may be necessary for the recombinational activity of the enhancer. Furthermore, NF-κB-mediated effects on transcription and recombination appear to involve separate downstream activation pathways.
Human Cytomegalovirus Gene Products US3 and US6 Down-Regulate Trophoblast Class I MHC Molecules
Authors: Jun Youngsoo , Kim Eunok , Jin Mirim , Sung Ha Chin , Han Hoon , Geraghty Daniel E. , Ahn Kwangseog 
Published: April 2014

AbstractThe epidemiological correlation between human CMV (HCMV) infection and spontaneous fetal loss has been suggested, but the underlying mechanism is not well understood. Fetal cytotrophoblasts, which are in direct contact with the maternal immune system in the uterus during pregnancy, do not express HLA-A and HLA-B, but express the nonclassical class I HLA-G and HLA-C. It has been shown that both HLA-G and HLA-C are capable of inhibiting NK-mediated cell lysis. In our present study, using human trophoblast cell lines as well as other cell lines stably transfected with the human class I genes, we have demonstrated that HCMV US3 and US6 down-regulate the cell-surface expression of both HLA-G and HLA-C by two different mechanisms. HCMV US3 physically associates with both trophoblast class I MHC species, retaining them in the endoplasmic reticulum. In contrast, HCMV US6 inhibits peptide transport by TAP and thus specifically the intracellular trafficking of class I molecules. Therefore, these findings suggest for the first time a possible molecular mechanism underlying HCMV-related spontaneous pregnancy loss.
High-Level Rearrangement and Transcription of Yeast Artificial Chromosome-Based Mouse Igκ Transgenes Containing Distal Regions of the Contig
Authors: Li Shuyu , Hammer Robert E. , George-Raizen Julia B. , Meyers Katherine C. , Garrard William T. 
Published: April 2014

Abstract
The mouse Igκ L chain gene locus has been extensively studied, but to date high-level expression of germline transgenes has not been achieved. Reasoning that each end of the locus may contain regulatory elements because these regions are not deleted upon Vκ-Jκ joining, we used yeast artificial chromosome-based techniques to fuse distal regions of the contig to create transgene miniloci. The largest minilocus (290 kb) possessed all members of the upstream Vκ2 gene family including their entire 5′ and 3′ flanking sequences, along with one member of a downstream Vκ21 gene family. In addition, again using yeast artificial chromosome-based technology, we created Igκ miniloci that contained differing lengths of sequences 5′ of the most distal Vκ2 gene family member. In transgenic mice, Igκ miniloci exhibited position-independent and copy number-dependent germline transcription. Igκ miniloci were rearranged in tissue and developmental stage-specific manners. The levels of rearrangement and transcription of the distal and proximal Vκ gene families were similar to their endogenous counterparts and appeared to be responsive to allelic exclusion, but were differentially sensitive to numerous position effects. The minilocus that contained the longest 5′ region exhibited significantly greater recombination of the upstream Vκ2 genes but not the downstream Vκ21 gene, providing evidence for a local recombination stimulating element. These results provide evidence that our miniloci contain nearly all regulatory elements required for bona fide Igκ gene expression, making them useful substrates for functional analyses of cis-acting sequences in the future.
Glucocorticoids Inhibit Calcium- and Calcineurin-Dependent Activation of the Human IL-4 Promoter
Authors: Chen Rongbing , Burke Thomas F. , Cumberland John E. , Brummet Mary , Beck Lisa A. , Casolaro Vincenzo , Georas Steve N. 
Published: April 2014

Abstract
The mechanism by which glucocorticoids (GC) inhibit IL-4 gene expression is currently unknown. In T lymphocytes, IL-4 gene expression is regulated at the level of transcription by increases in intracellular calcium concentration and by the calcium-activated phosphatase calcineurin. In this paper we report that dexamethasone (Dex) inhibits calcium ionophore-induced activation of the human IL-4 promoter in transiently transfected Jurkat T cells. Inhibition of the promoter by Dex is dependent on expression of the GC receptor (GR), because it does not occur in GR-deficient cells. Dex also represses activation of the promoter induced by cotransfecting cells with a constitutively active mutant of calcineurin. Using a series of deletion constructs, we show that the proximal 95 bp of the IL-4 promoter contain a Dex-sensitive regulatory element. This region contains the P1 sequence, a proximal binding site for NF-AT. A calcium-induced but Dex-inhibited nuclear complex containing NF-AT binds to the P1 element in EMSA. Using immunoprecipitation under nondenaturing conditions, we found that the GRα isoform coprecipitates with NF-ATc in nuclear extracts of calcium ionophore- and Dex-treated cells. Taken together, our results show that GC inhibit IL-4 gene expression by interfering with NF-AT-dependent transactivation of the proximal human IL-4 promoter.
Human CD8β, But Not Mouse CD8β, Can Be Expressed in the Absence of CD8α as a ββ Homodimer
Authors: Devine Lesley , Kieffer Lynda J. , Aitken Victoria , Kavathas Paula B. 
Published: April 2014

Abstract
The T cell coreceptor CD8 exists on mature T cells as disulfide-linked homodimers of CD8α polypeptide chains and heterodimers of CD8α- and CD8β-chains. The function of the CD8α-chain for binding to MHC class I and associating with the tyrosine kinase p56lck was demonstrated with CD8αα homodimers. CD8αβ functions as a better coreceptor, but the actual function of CD8β is less clear. Addressing this issue has been hampered by the apparent inability of CD8β to be expressed without CD8α. This study demonstrates that human, but not mouse, CD8β can be expressed on the cell surface without CD8α in both transfected COS-7 cells and murine lymphocytes. By creating chimeric proteins, we show that the murine Ig domain of CD8β is responsible for the lack of expression of murine CD8ββ dimers. In contrast to CD8αα, CD8ββ is unable to bind MHC class I in a cell-cell adhesion assay. Detection of this form of CD8 should facilitate studies on the function of the CD8 β-chain and indicates that caution should be used when interpreting studies on CD8 function using chimeric protein with the murine CD8ββ Ig domain. In addition, we demonstrate that the Ig domains of CD8α are also involved in controlling the ability of CD8 to be expressed. Mutation of B- and F-strand cysteine residues in CD8α reduced the ability of the protein to fold properly and, therefore, to be expressed.
Disparate Intracellular Processing of Human IL-12 Preprotein Subunits: Atypical Processing of the P35 Signal Peptide
Authors: Murphy Finbarr J. , Hayes Mark P. , Burd Parris R. 
Published: April 2014

Abstract
IL-12 is a heterodimeric cytokine produced by APC that critically regulates cell-mediated immunity. Because of its crucial function during immune responses, IL-12 production is stringently regulated, in part through transcriptional control of its p35 subunit, which requires the differentiative effects of IFN-γ for expression. To determine whether post-transcriptional aspects of IL-12 production might be regulated, we examined intracellular protein processing of each subunit. We report here that p40 and p35 subunits are processed by disparate pathways. Whereas processing of p40 conforms to the cotranslational model of signal peptide removal concomitant with translocation into the endoplasmic reticulum (ER), processing of p35 does not. Translocation of the p35 preprotein into the ER was not accompanied by cleavage of the signal peptide; rather, removal of the p35 signal peptide occurred via two sequential cleavages. The first cleavage took place within the ER, and the cleavage site localized to the middle of the hydrophobic region of the signal peptide. Although the preprotein was glycosylated upon entry into the ER, its glycosylation status did not affect primary cleavage. Subsequently, the remaining portion of the p35 signal peptide was removed by a second cleavage, possibly involving a metalloprotease, concomitant with additional glycosylation and secretion. Secretion could be inhibited by mutation of the second cleavage site or by inhibition of glycosylation with tunicamycin. In contrast, p40 secretion was not affected by inhibition of glycosylation. Our findings demonstrate that IL-12 subunits are processed by disparate pathways and suggest new modalities for regulation of IL-12 production.
The Cytoplasmic Tyrosine Motifs in Full-Length Glycoprotein 130 Have Different Roles in IL-6 Signal Transduction
Authors: Schmitz Jochen , Dahmen Heike , Grimm Carsten , Gendo Cornelia , Müller-Newen Gerhard , Heinrich Peter C. , Schaper Fred 
Published: April 2014

Abstract
The function of the signal-transducing receptor subunit glycoprotein 130 (gp130) in the IL-6-receptor complex has previously been studied using carboxyl-terminal deletion mutants or a truncated molecule of ∼60 membrane-proximal amino acids (containing box 1 and box 2) linked to the individual gp130 tyrosine motifs. However, the redundancy of the tyrosine motifs within the cytoplasmic part of gp130 has been neglected. Here we describe the analysis of the function of the individual cytoplasmic tyrosine residues of gp130 in the context of the full-length receptor protein in IL-6 signaling as measured by STAT activation, acute phase protein induction, and stimulation of proliferation. Add-back receptor mutants containing only one cytoplasmic tyrosine have been generated and tested for their efficiency in IL-6 signal transduction. Our studies revealed that tyrosine motifs which have been described to recruit STAT proteins are not equivalent with respect to their potential to activate STAT factors and acute phase protein gene promoters: the two distal tyrosines, Tyr905 and Tyr915, of gp130 were more potent than Tyr767 and Tyr814. Surprisingly, Tyr905 and Tyr915 mediate acute phase protein gene promoter activation stronger than the wild-type receptor containing all six cytoplasmic tyrosine residues. In contrast, Ba/F3 cells stably transfected with add-back receptors containing Tyr767 or Tyr905 were more sensitive to IL-6-induced proliferation than cells expressing the other add-back receptor mutants. Thus, the tyrosine residues in the cytoplasmic part of gp130 were found to contribute differentially to IL-6 signal transduction in the full- length gp130 protein.