bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Determination of T Cell Help in Loss of Tolerance to Nuclear Antigens
Authors: Chen Yifang , Cuda Carla , Morel Laurence 
Published: April 2014

Abstract
Sle1 is a major lupus susceptibility locus in NZM2410 lupus model that is associated with a loss of tolerance to nuclear Ags. At least three genes, Sle1a, Sle1b, and Sle1c contribute to Sle1, and their relative role in lupus pathogenesis is unknown. We show here that Sle1-expressing CD4+ T cells present an activated phenotype associated with increased proliferation and cytokine production. In addition, Sle1 CD4+ T cells provide help to anti-chromatin B cells to produce anti-nuclear antibodies, whether or not these B cells express Sle1. The Sle1a locus alone accounts for all these Sle1 phenotypes, implying that a specific genetic defect in Sle1a is necessary and sufficient to produce autoreactive T cells. However, Sle1c induces intermediate T cell activation and only provides help to Sle1-expressing anti-chromatin-producing B cells, demonstrating the synergic interactions between Sle1c T and Sle1 B cells. Moreover, Sle1a and Sle1c were associated with a significantly reduced level of CD4+CD25+ regulatory T cells that precedes autoantibody production, suggesting a causal relationship with the generation of autoreactive T cells. Our study identifies for the first time that a specific genetic defect is responsible for lupus pathogenesis by inducing autoreactive T cells to break self-tolerance and that this genetic defect is also associated with a decreased number of regulatory T cells.
A Role for c-fos/Activator Protein 1 in B Lymphocyte Terminal Differentiation
Authors: Ohkubo Yusuke , Arima Masafumi , Arguni Eggi , Okada Seiji , Yamashita Kimihiro , Asari Sadaki , Obata Shintaro , Sakamoto Akemi , Hatano Masahiko , O-Wang Jiyang , Ebara Masaaki , Saisho Hiromitsu , Tokuhisa Takeshi 
Published: April 2014

AbstractExpression of B lymphocyte-induced maturation protein 1 (Blimp-1) transcription factor is essential for promoting B cell differentiation into plasma cells. However, a critical transcription factor for Blimp-1 expression in activated B cells is unclear. When splenic B cells were stimulated with CD40 ligand (CD40L) and IL-4, terminal differentiation was induced in the B cells from c-fos transgenic (H2-c-fos) mice but barely in those from control littermates and from c-fos-deficient mice. AP-1 family and Blimp-1 mRNAs were transiently induced in the control B cells, and overexpression of c-Fos induced a sufficient amount of Blimp-1 for terminal differentiation in the H2-c-fos B cells. When normal and c-fos-deficient B cells were stimulated with LPS, a sufficient amount of Blimp-1 for terminal differentiation was induced in those B cells. However, expression of c-fos/AP-1 family mRNAs in LPS-stimulated normal B cells was similar to that of normal B cells stimulated with CD40L and IL-4. EMSA and chromatin immunoprecipitation assays using the AP-1-binding DNA sequence in the murine Blimp-1 promoter region demonstrated that AP-1-binding activity in nuclear protein of LPS-stimulated normal B cells was prolonged more than that in normal B cells stimulated with CD40L and IL-4. Furthermore, the percentage of CD138+ B cells within germinal center B cells in the spleen and the number of Ab-forming cells in the bone marrow of H2-c-fos mice was larger than that of control mice 12 days after immunization. Thus, although c-Fos is not essential for Blimp-1 expression, c-Fos/AP-1 positively regulates Blimp-1 expression and terminal differentiation of activated B cells.
Mouse Endothelial Cells Cross-Present Lymphocyte-Derived Antigen on Class I MHC via a TAP1- and Proteasome-Dependent Pathway
Authors: Bagai Rakesh , Valujskikh Anna , Canaday David H. , Bailey Erin , Lalli Peter N. , Harding Clifford V. , Heeger Peter S. 
Published: April 2014

Abstract
In vivo studies suggest that vascular endothelial cells (ECs) can acquire and cross-present exogenous Ag on MHC-I but the cellular mechanisms underlying this observation remain unknown. We tested whether primary female mouse aortic ECs could cross-present exogenous male Ag to the T cell hybridoma, MHH, specific for HYUty plus Db. MHC-I-deficient male spleen cells provided a source of male Ag that could not directly stimulate the MHH cells. Addition of male but not female MHC-I-deficient spleen cells to wild-type syngeneic female EC induced MHH stimulation, demonstrating EC cross-presentation. Lactacystin treatment of the donor male MHC-I-deficient spleen cells, to inhibit proteasome function, markedly enhanced EC cross-presentation showing that the process is most efficient for intact proteins rather than degraded peptide fragments. Additional experiments revealed that this EC Ag-processing pathway is both proteasome and TAP1 dependent. These studies demonstrate that cultured murine aortic ECs can process and present MHC-I-restricted Ag derived from a separate, live cell, and they offer insight into the molecular requirements involved in this EC Ag presentation process. Through this pathway, ECs expressing cross-presented peptides can participate in the effector phase of T cell-mediated inflammatory responses such as autoimmunity, anti-tumor immunity, and transplant rejection.
IgE Generation and Mast Cell Effector Function in Mice Deficient in IL-4 and IL-13
Authors: Fish Susan C. , Donaldson Debra D. , Goldman Samuel J. , Williams Cara M. M. , Kasaian Marion T. 
Published: April 2014

AbstractIL-4 and IL-13 are potent cytokines that drive production of IgE, which is critical to the development of atopic disease. In this study, we directly compared IgE generation and IgE-dependent mast cell effector function in mouse strains lacking IL-4, IL-13, IL-4 + IL-13, or their common receptor component, IL-4Rα. Although serum IgE was undetectable under resting conditions in most animals deficient in one or both cytokines, peritoneal mast cells from mice lacking IL-4 or IL-13 had only partial reductions in surface IgE level. In contrast, peritoneal mast cells from IL-4/13−/− and IL-4Rα−/− animals were severely deficient in surface IgE, and showed no detectable degranulation following treatment with anti-IgE in vitro. Surprisingly, however, intradermal challenge with high concentrations of anti-IgE Ab induced an ear-swelling response in these strains, implying some capacity for IgE-mediated effector function in tissue mast cells. Furthermore, upon specific immunization with OVA, both IL-4/IL-13−/− and IL-4Rα−/− mice produced detectable levels of serum IgE and Ag-specific IgG1, and generated strong ear-swelling responses to intradermal administration of anti-IgE. These findings suggest that a mechanism for IgE production exists in vivo that is independent of IL-4 or IL-13.
Augmentation of Cutaneous Immune Responses by ATPγS: Purinergic Agonists Define a Novel Class of Immunologic Adjuvants
Authors: Granstein Richard D. , Ding Wanhong , Huang Jing , Holzer Aton , Gallo Richard L. , Di Nardo Anna , Wagner John A. 
Published: April 2014

AbstractExtracellular nucleotides activate ligand-gated P2XR ion channels and G protein-coupled P2YRs. In this study we report that intradermal administration of ATPγS, a hydrolysis-resistant P2 agonist, results in an enhanced contact hypersensitivity response in mice. Furthermore, ATPγS enhanced the induction of delayed-type hypersensitivity to a model tumor vaccine in mice and enhanced the Ag-presenting function of Langerhans cells (LCs) in vitro. Exposure of a LC-like cell line to ATPγS in the presence of LPS and GM-CSF augmented the induction of I-A, CD80, CD86, IL-1β, and IL-12 p40 while inhibiting the expression of IL-10, suggesting that the immunostimulatory activities of purinergic agonists in the skin are mediated at least in part by P2Rs on APCs. In this regard, an LC-like cell line was found to express mRNA for P2X1, P2X7, P2Y1, P2Y2, P2Y4, P2Y9, and P2Y11 receptors. We suggest that ATP, when released after trauma or infection, may act as an endogenous adjuvant to enhance the immune response, and that P2 agonists may augment the efficacy of vaccines.
The Functional Heterogeneity of Type 1 Effector T Cells in Response to Infection Is Related to the Potential for IFN-γ Production
Authors: Mayer Katrin D. , Mohrs Katja , Crowe Sherry R. , Johnson Lawrence L. , Rhyne Paul , Woodland David L. , Mohrs Markus 
Published: April 2014

AbstractThe expression of IFN-γ is a hallmark of Th1 cells and CD8+ effector T cells and is the signature cytokine of type 1 responses. However, it is not known whether T cells are homogeneous in their capacity to produce IFN-γ, whether this potential varies between tissues, and how it relates to the production of other effector molecules. In the present study we used bicistronic IFN-γ-enhanced yellow fluorescent protein (IFN-γ-eYFP) reporter mice (Yeti) and MHC class I tetramers to directly quantify IFN-γ expression at the single cell level. The eYFP fluorescence of Th1 cells and CD8+ effector T cells was broadly heterogeneous even before cell division and correlated with both the abundance of IFN-γ transcripts and the secretion of IFN-γ upon stimulation. CD4+ and CD8+ T cells of influenza-infected mice revealed a similarly heterogeneous IFN-γ expression, and eYFPhigh cells were only found in the infected lung. Ag-specific T cells were in all examined tissues eYFP+, but also heterogeneous in their reporter fluorescence, and eYFPhigh cells were also restricted to the infected lung. A similar heterogeneity was observed in Toxoplasma gondii-infected animals, but eYFPhigh cells were restricted to different tissues. Highly eYFP fluorescent cells produced elevated levels of proinflammatory cytokines and chemokines in addition to IFN-γ, suggesting their coregulated expression as a functional unit in highly differentiated effector T cells.
Iodine and IFN-γ Synergistically Enhance Intercellular Adhesion Molecule 1 Expression on NOD.H2h4 Mouse Thyrocytes
Authors: Sharma Rajni B. , Alegria Judy D. , Talor Monica V. , Rose Noel R. , Caturegli Patrizio , Burek C. Lynne 
Published: April 2014

Abstract
NOD.H2h4 mice spontaneously develop autoimmune lymphocytic thyroiditis that mimics human Hashimoto’s thyroiditis, a disease where iodine, IFN-γ, and adhesion molecules have all been implicated in the pathogenesis. To study how iodine and IFN-γ modulate the expression of ICAM-1, we analyzed NOD.H2h4 thyrocytes in baseline conditions (day 0) and at several time points following supplementation of iodine in the drinking water. On day 0, a small percentage (∼10%) of thyrocytes constitutively expressed ICAM-1. The expression gradually increased to 13, 25, and 41% on days 7, 14 and 28, respectively, returning to baseline (9%) on day 35. The initial ICAM-1 kinetics was paralleled by thyroidal infiltration of CD45+ hemopoietic cells, which increased from an average of 4% on day 0 to an average of 13, 21, and 24% on days 14, 28, and 35, respectively. To distinguish whether the observed ICAM-1 increase was a direct effect of iodine or a consequence of the immune infiltrate, we treated mouse primary thyrocyte cultures with 0.01 mM sodium iodine and showed a 3-fold increased ICAM-1 expression. To assess interaction between IFN-γ and iodine, we analyzed CD45 and ICAM-1expression on thyrocytes from NOD.H2h4 wild-type and NOD.H2h4 thyr-IFN-γ transgenic littermates. Strikingly, IFN-γ interacted synergistically with iodine to enhance ICAM-1 expression on thyrocytes. These findings suggest that iodine and IFN-γ cooperate to promote thyroidal expression of ICAM-1 in this mouse model of thyroiditis, highlighting the complex interplay present in the pathogenesis of Hashimoto’s thyroiditis.
An MHC Class Ib-Restricted TCR That Cross-Reacts with an MHC Class Ia Molecule
Authors: Reed-Loisel Lisa M. , Sullivan Barbara A. , Laur Oskar , Jensen Peter E. 
Published: April 2014

AbstractTCR transgenic 6C5 T cells recognize an insulin B chain epitope presented by the nonclassical class I MHC molecule, Qa-1b. Positive selection of these T cells was shown previously to require Qa-1b. Despite dedicated specificity for Qa-1b, evidence presented in the current study indicates that 6C5 T cells can cross-recognize a classical class I molecule. Clonal deletion was observed unexpectedly in 6C5.H-2bxq mice, which do not express I-E MHC class II molecules and thus should not be subject to superantigen-mediated negative selection. 6C5 T cells were observed to respond in vivo and in vitro to spleen cells from allogeneic H-2q mice, and specificity was mapped to Dq. Evidence was obtained for direct recognition of Dq, rather than indirect presentation of a Dq-derived peptide presented by Qa-1b. Polyclonal CD8+ T cells from class Ia-deficient KbDb−/− mice reacted in vitro to allogeneic spleen cells with an apparent frequency comparable to conventional class Ia-restricted T cells. Our results provide a clear example of a Qa-1-specific TCR that can cross-react with a class Ia molecule and evidence supporting the idea that this may be a common property of T cells selected by class Ib molecules.
Restricted STAT5 Activation Dictates Appropriate Thymic B versus T Cell Lineage Commitment
Authors: Goetz Christine A. , Harmon Ian R. , O’Neil Jennifer J. , Burchill Matthew A. , Johanns Tanner M. , Farrar Michael A. 
Published: April 2014

Abstract
The molecular mechanisms regulating lymphocyte lineage commitment remain poorly characterized. To explore the role of the IL7R in this process, we generated transgenic mice that express a constitutively active form of STAT5 (STAT5b-CA), a key downstream IL7R effector, throughout lymphocyte development. STAT5b-CA mice exhibit a 40-fold increase in pro-B cells in the thymus. As documented by BrdU labeling studies, this increase is not due to enhanced B cell proliferation. Thymic pro-B cells in STAT5b-CA mice show a modest increase in cell survival (∼4-fold), which correlates with bcl-xL expression. However, bcl-xL transgenic mice do not show increases in thymic B cell numbers. Thus, STAT5-dependent bcl-xL up-regulation and enhanced B cell survival are not sufficient to drive the thymic B cell development observed in STAT5b-CA mice. Importantly, thymic pro-B cells in STAT5b-CA mice are derived from early T cell progenitors (ETPs), suggesting that STAT5 acts by altering ETP lineage commitment. Supporting this hypothesis, STAT5 binds to the pax5 promoter in ETPs from STAT5b-CA mice and induces pax5, a master regulator of B cell development. Conversely, STAT5b-CA mice exhibit a decrease in the DN1b subset of ETPs, demonstrating that STAT5 activation inhibits early T cell differentiation or lineage commitment. On the basis of these findings, we propose that the observed expression of the IL-7R on common lymphoid progenitors, but not ETPs, results in differential STAT5 signaling within these distinct progenitor populations and thus helps ensure appropriate development of B cells and T cells in the bone marrow and thymic environments, respectively.
Recombinant Tumor-Associated MUC1 Glycoprotein Impairs the Differentiation and Function of Dendritic Cells
Authors: Rughetti Aurelia , Pellicciotta Ilenia , Biffoni Mauro , Bäckström Malin , Link Thomas , Bennet Eric P. , Clausen Henrik , Noll Thomas , Hansson Gunnar C. , Burchell Joy M. , Frati Luigi , Taylor-Papadimitriou Joyce , Nuti Marianna 
Published: April 2014

Abstract
Tumors exploit several strategies to evade immune recognition, including the production of a large number of immunosuppressive factors, which leads to reduced numbers and impaired functions of dendritic cells (DCs) in the vicinity of tumors. We have investigated whether a mucin released by tumor cells could be involved in causing these immunomodulating effects on DCs. We used a recombinant purified form of the MUC1 glycoprotein, an epithelial associated mucin that is overexpressed, aberrantly glycosylated, and shed during cancer transformation. The O-glycosylation profile of the recombinant MUC1 glycoprotein (ST-MUC1) resembled that expressed by epithelial tumors in vivo, consisting of large numbers of sialylated core 1 (sialyl-T, ST) oligosaccharides. When cultured in the presence of ST-MUC1, human monocyte-derived DCs displayed a modified phenotype with decreased expression of costimulatory molecules (CD86, CD40), Ag-presenting molecules (DR and CD1d), and differentiation markers (CD83). In contrast, markers associated with an immature phenotype, CD1a and CD206 (mannose receptor), were increased. This effect was already evident at day 4 of DC culture and was dose dependent. The modified phenotype of DCs corresponded to an altered balance in IL-12/IL-10 cytokine production, with DC expressing an IL-10highIL-12low phenotype after exposure to ST-MUC1. These DCs were defective in their ability to induce immune responses in both allogeneic and autologous settings, as detected in proliferation and ELISPOT assays. The altered DC differentiation and Ag presentation function induced by the soluble sialylated tumor-associated mucin may represent a mechanism by which epithelial tumors can escape immunosurveillance.
Development of the Expressed Ig CDR-H3 Repertoire Is Marked by Focusing of Constraints in Length, Amino Acid Use, and Charge That Are First Established in Early B Cell Progenitors
Authors: Ivanov Ivaylo I. , Schelonka Robert L. , Zhuang Yingxin , Gartland G. Larry , Zemlin Michael , Schroeder Harry W. 
Published: April 2014

AbstractTo gain insight into the mechanisms that regulate the development of the H chain CDR3 (CDR-H3), we used the scheme of Hardy to sort mouse bone marrow B lineage cells into progenitor, immature, and mature B cell fractions, and then performed sequence analysis on VH7183-containing Cμ transcripts. The essential architecture of the CDR-H3 repertoire observed in the mature B cell fraction F was already established in the early pre-B cell fraction C. These architectural features include VH gene segment use preference, DH family usage, JH rank order, predicted structures of the CDR-H3 base and loop, and the amino acid composition and average hydrophobicity of the CDR-H3 loop. With development, the repertoire was focused by eliminating outliers to what appears to be a preferred repertoire in terms of length, amino acid composition, and average hydrophobicity. Unlike humans, the average length of CDR-H3 increased during development. The majority of this increase came from enhanced preservation of JH sequence. This was associated with an increase in the prevalence of tyrosine. With an accompanying increase in glycine, a shift in hydrophobicity was observed in the CDR-H3 loop from near neutral in fraction C (−0.08 ± 0.03) to mild hydrophilic in fraction F (−0.17 ± 0.02). Fundamental constraints on the sequence and structure of CDR-H3 are thus established before surface IgM expression.
DNA Polymerase η Contributes to Strand Bias of Mutations of A versus T in Immunoglobulin Genes
Authors: Mayorov Vladimir I. , Rogozin Igor B. , Adkison Linda R. , Gearhart Patricia J. 
Published: April 2014

AbstractDNA polymerase (pol) η participates in hypermutation of A:T bases in Ig genes because humans deficient for the polymerase have fewer substitutions of these bases. To determine whether polymerase η is also responsible for the well-known preference for mutations of A vs T on the nontranscribed strand, we sequenced variable regions from three patients with xeroderma pigmentosum variant (XP-V) disease, who lack polymerase η. The frequency of mutations in the intronic region downstream of rearranged JH4 gene segments was similar between XP-V and control clones; however, there were fewer mutations of A:T bases and correspondingly more substitutions of C:G bases in the XP-V clones (p &lt; 10−7). There was significantly less of a bias for mutations of A compared with T nucleotides in the XP-V clones compared with control clones, whereas the frequencies for mutations of C and G were identical in both groups. An analysis of mutations in the WA sequence motif suggests that polymerase η generates more mutations of A than T on the nontranscribed strand. This in vivo data from polymerase η-deficient B cells correlates well with the in vitro specificity of the enzyme. Because polymerase η inserts more mutations opposite template T than template A, it would generate more substitutions of A on the newly synthesized strand.
Deoxyuridine Is Generated Preferentially in the Nontranscribed Strand of DNA from Cells Expressing Activation-Induced Cytidine Deaminase
Authors: Martomo Stella A. , Fu Dongtao , Yang William W. , Joshi Nikhil S. , Gearhart Patricia J. 
Published: April 2014

Abstract
Activation-induced cytidine deaminase (AID) is required for somatic hypermutation and class switch recombination of Ig genes in B cells. Although AID has been shown to deaminate deoxycytidine to deoxyuridine in DNA in vitro, there is no physical evidence for increased uracils in DNA from cells expressing AID in vivo. We used several techniques to detect uracil bases in a gene that was actively transcribed in Escherichia coli cells expressing AID. Plasmid DNA containing the gene was digested with uracil-DNA glycosylase to remove uracil, and apurinic/apryimidinic endonuclease to nick the abasic site. The nicked DNA was first analyzed using alkaline gel electrophoresis, in which there was a 2-fold increase in the linear form of the plasmid after AID induction compared with plasmid from noninduced bacteria. Second, using a quantitative denaturing Southern blot technique, the gene was predominantly nicked in the nontranscribed strand compared with the transcribed strand. Third, using ligation-mediated PCR, the nicks were mapped on the nontranscribed strand and were located primarily at cytosine bases. These data present direct evidence for the presence of uracils in DNA from cells that are induced to express AID, and they are preferentially generated at cytosines in the nontranscribed strand during transcription.
The Influences of Hinge Length and Composition on the Susceptibility of Human IgA to Cleavage by Diverse Bacterial IgA1 Proteases
Authors: Senior Bernard W. , Woof Jenny M. 
Published: April 2014

AbstractThe influences of IgA hinge length and composition on its susceptibility to cleavage by bacterial IgA1 proteases were examined using a panel of IgA hinge mutants. The IgA1 proteases of Streptococcus pneumoniae, Streptococcus sanguis strains SK4 and SK49, Neisseria meningitidis, Neisseria gonorrhoeae, and Haemophilus influenzae cleaved IgA2-IgA1 half hinge, an Ab featuring half of the IgA1 hinge incorporated into the equivalent site in IgA1 protease-resistant IgA2, whereas those of Streptococcus mitis, Streptococcus oralis, and S. sanguis strain SK1 did not. Hinge length reduction by removal of two of the four C-terminal proline residues rendered IgA2-IgA1 half hinge resistant to all streptococcal IgA1 metalloproteinases but it remained sensitive to cleavage by the serine-type IgA1 proteases of Neisseria and Haemophilus spp. The four C-terminal proline residues could be substituted by alanine residues or transferred to the N-terminal extremity of the hinge without affect on the susceptibility of the Ab to cleavage by serine-type IgA1 proteases. However, their removal rendered the Ab resistant to cleavage by all the IgA1 proteases. We conclude that the serine-type IgA1 proteases of Neisseria and Haemophilus require the Fab and Fc regions to be separated by at least ten (or in the case of N. gonorrhoeae type I protease, nine) amino acids between Val222 and Cys241 (IgA1 numbering) for efficient access and cleavage. By contrast, the streptococcal IgA1 metalloproteinases require 12 or more appropriate amino acids between the Fab and Fc to maintain a minimum critical distance between the scissile bond and the start of the Fc.