bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of Trafficking Receptor Expression in Human Forkhead Box P3+ Regulatory T Cells
Authors: Lim Hyung W. , Broxmeyer Hal E. , Kim Chang H. 
Published: April 2014

AbstractForkhead Box P3+ (FOXP3+) T cells are regulatory cells important for maintaining immune tolerance. While chemokine- and other homing-receptors are important for T cell migration, it has been unclear how they are regulated in FOXP3+ T cells. We thoroughly investigated, ex vivo and in vitro, the regulation of chemokine receptor expression on human FOXP3+ T cells in neonatal cord blood, adult peripheral blood, and tonsils. We found that human FOXP3+ T cells undergo changes in trafficking receptors according to their stages of activation and differentiation. FOXP3+ T cells are divided into CD45RA+ (naive type) and CD45RO+ (memory type) FOXP3+ T cells in neonatal blood, adult blood, and tonsils. CD45RA+FOXP3+ T cells mainly express lymphoid tissue homing receptors (CD62L, CCR7, and CXCR4), while CD45RO+FOXP3+ T cells highly express both Th1 and Th2-associated trafficking receptors along with the lymphoid tissue homing receptors at reduced frequencies. Up-regulation of Th1/Th2-associated trafficking receptors begins with activation of CD45RA+FOXP3+ T cells and is completed after their differentiation to CD45RO+ cells. Some chemokine receptors such as CXCR5 and CXCR6 are preferentially expressed by many FOXP3+ cells at a specific stage (CD69+CD45RO+) in tonsils. Our in vitro differentiation study demonstrated that CD45RA+FOXP3+ T cells indeed undergo chemokine receptor switch from CD45RA+ (secondary lymphoid tissue homing) to CD45RO+ type (lymphoid and nonlymphoid tissue homing). The orderly regulation of trafficking receptors in FOXP3+ T cells according to stages of differentiation and activation is potentially important for their tissue-specific migration and regulation of immune responses in humans.
Characterization of (4-Hydroxy-3-Nitrophenyl)Acetyl (NP)-Specific Germinal Center B Cells and Antigen-Binding B220− Cells after Primary NP Challenge in Mice
Authors: Wolniak Kristy L. , Noelle Randolph J. , Waldschmidt Thomas J. 
Published: April 2014

AbstractPrevious studies examining the primary germinal center (GC) response to SRBC in mice demonstrated a steady ratio of IgM+ to isotype-switched GC B cells and a persistent population of GC B cells with a founder phenotype. These characteristics held true at the inductive, plateau, and dissociative phases of the GC response, suggesting a steady-state environment. To test whether these characteristics apply to the primary response of other T cell-dependent Ags, the present study examined the GC response after challenge with (4-hydroxy-3-nitrophenyl)acetyl (NP) in C57BL/6 mice. Multiparameter flow cytometric analysis was used to assess the phenotype of splenic NP-reactive cells at multiple time points after immunization. Results of these studies demonstrated the characteristics of the SRBC-induced GC reaction to be fully maintained in the NP response. In particular, there was a steady ratio of nonswitched to switched B cells, with the majority of NP-reactive GC B cells displaying IgM. In addition, a substantial frequency of B220− NP-binding cells was observed in the spleen at later time points after NP challenge. Although these cells were IgE+, they were found to express both κ and λ L chains and display the high-affinity IgE Fc (FcεRI) receptor, suggesting that this population is not of B cell origin. Adoptive transfer studies further demonstrated the B220− NP-binding subset to be derived from the myeloid lineage.
TLR7 Ligands Induce Higher IFN-α Production in Females
Authors: Berghöfer Beate , Frommer Ture , Haley Gabriela , Fink Ludger , Bein Gregor , Hackstein Holger 
Published: April 2014

AbstractIFN-α exercises multiple immune modulatory and antiviral activities and has been suggested to play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). Plasmacytoid dendritic cells (pDCs) release IFN-α upon TLR7 and TLR9 ligation. With respect to the nine times higher incidence of SLE in women and the clinical use of synthetic TLR ligands as novel immune adjuvants, we analyzed IFN-α and TNF-α production in healthy human individuals. Blood samples were incubated with synthetic TLR7 and TLR9 ligands. In three independent groups (n1 = 120, n2 = 101, and n3 = 123), analysis revealed a capacity of female PBLs to produce significantly higher IFN-α levels after TLR7 stimulation (p1 &lt; 0.0000001, p2 &lt; 0.0000001, and p3 &lt; 0.0001) compared with male PBLs. In contrast, no sex differences were evident after TLR9 stimulation. TNF-α production after TLR7 stimulation and also total pDC numbers were not different between females and males. X-inactivation escape of the TLR7 gene was investigated in monoclonal B cell lines and, independently, in pDCs after cell sorting and single-cell picking, indicating regular silencing of one TLR7 allele in females. Additionally, exogenous 17β-estrogen and estrogen receptor antagonism did not indicate a significant role on TLR7-induced IFN-α production. Our data reveal for the first time a profound sex-dependent pathway of TLR7-induced IFN-α with higher production in females. These findings may explain the higher prevalence of SLE in females and the reported decreased therapeutic efficacy of synthetic TLR7 ligands in male individuals.
Screening and Identification of Severe Acute Respiratory Syndrome-Associated Coronavirus-Specific CTL Epitopes
Authors: Zhou Minghai , Xu Dongping , Li Xiaojuan , Li Hongtao , Shan Ming , Tang Jiaren , Wang Min , Wang Fu-Sheng , Zhu Xiaodong , Tao Hua , He Wei , Tien Po , Gao George F. 
Published: April 2014

AbstractSevere acute respiratory syndrome (SARS) is a highly contagious and life-threatening disease that emerged in China in November 2002. A novel SARS-associated coronavirus was identified as its principal etiologic agent; however, the immunopathogenesis of SARS and the role of special CTLs in virus clearance are still largely uncharacterized. In this study, potential HLA-A*0201-restricted spike (S) and nucleocapsid protein-derived peptides were selected from an online database and screened for potential CTL epitopes by in vitro refolding and T2 cell-stabilization assays. The antigenicity of nine peptides which could refold with HLA-A*0201 molecules was assessed with an IFN-γ ELISPOT assay to determine the capacity to stimulate CTLs from PBMCs of HLA-A2+ SARS-recovered donors. A novel HLA-A*0201-restricted decameric epitope P15 (S411–420, KLPDDFMGCV) derived from the S protein was identified and found to localize within the angiotensin-converting enzyme 2 receptor-binding region of the S1 domain. P15 could significantly enhance the expression of HLA-A*0201 molecules on the T2 cell surface, stimulate IFN-γ-producing CTLs from the PBMCs of former SARS patients, and induce specific CTLs from P15-immunized HLA-A2.1 transgenic mice in vivo. Furthermore, significant P15-specific CTLs were induced from HLA-A2.1-transgenic mice immunized by a DNA vaccine encoding the S protein; suggesting that P15 was a naturally processed epitope. Thus, P15 may be a novel SARS-associated coronavirus-specific CTL epitope and a potential target for characterization of virus control mechanisms and evaluation of candidate SARS vaccines.
Structurally Distinct Ligand-Binding or Ligand-Independent Notch1 Mutants Are Leukemogenic but Affect Thymocyte Development, Apoptosis, and Metastasis Differently
Authors: Priceputu Elena , Bouallaga Isabelle , Zhang YaoPing , Li Xiujie , Chrobak Pavel , Hanna Zaher S. , Poudrier Johanne , Kay Denis G. , Jolicoeur Paul 
Published: April 2014

AbstractWe previously found that provirus insertion in T cell tumors of mouse mammary tumor virus/c-myc transgenic (Tg) mice induced two forms of Notch1 mutations. Type I mutations generated two truncated molecules, one intracellular (IC) (Notch1IC) and one extracellular (Notch1EC), while in type II mutations Notch1 was deleted of its C terminus (Notch1ΔCT). We expressed these mutants in Tg mice using the CD4 promoter. Both Notch1IC and Notch1ΔCT, but not Notch1EC, Tg mice developed double-positive (DP) thymomas. These disseminated more frequently in Notch1ΔCT Tg mice. Double (Notch1IC × myc) or (Notch1ΔCT × myc) Tg mice developed thymoma with a much shorter latency than single Tg mice, providing genetic evidence of a collaboration between these two oncogenes. FACS analysis of preleukemic thymocytes did not reveal major T cell differentiation anomalies, except for a higher number of DP cells and an accumulation of TCRhighCD2highCD25high DP cells in Notch1IC, and less so in Notch1ΔCT Tg mice. This was associated with enhanced in vivo thymocyte proliferation. However, Notch1IC, but not Notch1ΔCT, DP thymocytes were protected against apoptosis induced in vivo by dexamethasone and anti-CD3 and in vitro by anti-CD3/CD28 Abs. This indicates that the C terminus of Notch1 and/or the conserved regulation by its ligands have a significant impact on the induced T cell phenotype. Therefore, Notch1IC and Notch1ΔCT behave as oncogenes for T cells. Because these two Notch1 mutations are very similar to those described in some forms of human T cell leukemia, these Tg mice may represent relevant models of these human leukemias.
Spi-C Has Opposing Effects to PU.1 on Gene Expression in Progenitor B Cells
Authors: Schweitzer Brock L. , Huang Kelly J. , Kamath Meghana B. , Emelyanov Alexander V. , Birshtein Barbara K. , DeKoter Rodney P. 
Published: April 2014

AbstractThe Ets transcription factor Spi-C, expressed in B cells and macrophages, is closely related to PU.1 and has the ability to recognize the same DNA consensus sequence. However, the function of Spi-C has yet to be determined. The purpose of this study is to further examine Spi-C activity in B cell development. First, using retroviral vectors to infect PU.1−/− fetal liver progenitors, Spi-C was found to be inefficient at inducing cytokine-dependent proliferation and differentiation of progenitor B (pro-B) cells or macrophages relative to PU.1 or Spi-B. Next, Spi-C was ectopically expressed in fetal liver-derived, IL-7-dependent pro-B cell lines. Wild-type (WT) pro-B cells ectopically expressing Spi-C (WT-Spi-C) have several phenotypic characteristics of pre-B cells such as increased CD25 and decreased c-Kit surface expression. In addition, WT-Spi-C pro-B cells express increased levels of IgH sterile transcripts and reduced levels of expression and transcription of the FcγRIIb gene. Gel-shift analysis suggests that Spi-C, ectopically expressed in pro-B cells, can bind PU.1 consensus sites in the IgH intronic enhancer and FcγRIIb promoter. Transient transfection analysis demonstrated that PU.1 functions to repress the IgH intronic enhancer and activate the FcγRIIb promoter, while Spi-C opposes these activities. WT-Spi-C pro-B cells have reduced levels of dimethylation on lysine 9 of histone H3 within the IgH 3′ regulatory region, indicating that Spi-C can contribute to removal of repressive features in the IgH locus. Overall, these studies suggest that Spi-C may promote B cell differentiation by modulating the activity of PU.1-dependent genes.
Vav1 Controls DAP10-Mediated Natural Cytotoxicity by Regulating Actin and Microtubule Dynamics
Authors: Graham Daniel B. , Cella Marina , Giurisato Emanuele , Fujikawa Keiko , Miletic Ana V. , Kloeppel Tracie , Brim Karry , Takai Toshiyuki , Shaw Andrey S. , Colonna Marco , Swat Wojciech 
Published: April 2014

Abstract
The NK cell-activating receptor NKG2D recognizes several MHC class I-related molecules expressed on virally infected and tumor cells. Human NKG2D transduces activation signals exclusively via an associated DAP10 adaptor containing a YxNM motif, whereas murine NKG2D can signal through either DAP10 or the DAP12 adaptor, which contains an ITAM sequence. DAP10 signaling is thought to be mediated, at least in part, by PI3K and is independent of Syk/Zap-70 kinases; however, the exact mechanism by which DAP10 induces natural cytotoxicity is incompletely understood. Herein, we identify Vav1, a Rho GTPase guanine nucleotide exchange factor, as a critical signaling mediator downstream of DAP10 in NK cells. Specifically, using mice deficient in Vav1 and DAP12, we demonstrate an essential role for Vav1 in DAP10-induced NK cell cytoskeletal polarization involving both actin and microtubule networks, maturation of the cytolytic synapse, and target cell lysis. Mechanistically, we show that Vav1 interacts with DAP10 YxNM motifs through the adaptor protein Grb2 and is required for activation of PI3K-dependent Akt signaling. Based on these findings, we propose a novel model of ITAM-independent signaling by Vav downstream of DAP10 in NK cells.
B7RP-1-ICOS Interactions Are Required for Optimal Infection-Induced Expansion of CD4+ Th1 and Th2 Responses
Authors: Wilson Emma H. , Zaph Colby , Mohrs Markus , Welcher Andy , Siu Jerry , Artis David , Hunter Christopher A. 
Published: April 2014

AbstractAlthough initial reports linked the costimulatory molecule ICOS preferentially with the development of Th2 cells, there is evidence that it is not required for protective type 2 immunity to helminths and that it contributes to Th1 and Th2 responses to other parasites. To address the role of ICOS in the development of infection-induced polarized Th cells, ICOS−/− mice were infected with Trichuris muris or Toxoplasma gondii. Wild-type mice challenged with T. muris developed Th2 responses and expelled these helminths by day 18 postinfection, whereas ICOS−/− mice failed to clear worms and produced reduced levels of type 2 cytokines. However, by day 35 postinfection, ICOS−/− mice were able to mount an effective Th2 response and worms were expelled. This delay in protective immunity was associated with a defect in infection-induced increases in the number of activated and proliferating CD4+ T cells. Similarly, following challenge with T. gondii ICOS was required for optimal proliferation by CD4+ T cells. However, the reduced number of activated CD4+ T cells and associated defect in the production of IFN-γ did not result in increased susceptibility to T. gondii, but rather resulted in decreased CNS pathology during the chronic phase of this infection. Taken together, these data are consistent with a model in which ICOS is not involved in dictating polarity of the Th response but rather regulates the expansion of these subsets.
B Cells Expressing a Natural Polyreactive Autoantibody Have a Distinct Phenotype and Are Overrepresented in Immunoglobulin Heavy Chain Transgenic Mice
Authors: Tian Qi , Beardall Michael , Xu Yang , Li Ju , Parker David C. , Casanova Nina , Bakke Anthony C. , Chen Ching 
Published: April 2014

AbstractDespite stringent regulation of disease-associated autoantibodies, a substantial proportion of circulating Abs in sera of healthy individuals exhibit self-reactivity. These Abs are referred to as naturally occurring or natural autoantibodies (NAAs). To understand the origin and function of NAAs, we have generated a new site-directed transgenic mouse model in which a prerearranged VDJ gene coding for the H chain of a typical polyreactive NAA, ppc1-5, is inserted into the IgH locus. This H chain, when combined with its original L chain, the λ1 L chain, yields a NAA that characteristically binds a variety of self and non-self Ags including ssDNA, actin, ubiquitin, and nitrophenyl phosphocholine. Despite their autoreactivity, B cells expressing ppc1-5H/λ1 NAA are not negatively selected, but rather are overrepresented in the transgenic mice. The shift toward λ1 expression mainly occurs during the transition of immature to mature B cells in the spleen, suggesting a BCR selection process. The ppc1-5H/λ1 B cells exhibit a phenotype that is different from those of the known mature B cell populations, and they are located predominantly in the lymphoid follicles of the spleen and the lymph nodes. These B cells are functionally active, producing high levels of Abs in vivo and responding well to BCR stimulation in vitro. The findings indicate that the ppc1-5/λ1 natural autoantibodies originate from a distinct B cell subset that may be positively selected by virtue of its poly/autoreactivity.
Structure-Activity Profiles of Ab-Derived TNF Fusion Proteins
Authors: Bauer Stefan , Adrian Nicole , Fischer Eliane , Kleber Sascha , Stenner Frank , Wadle Andreas , Fadle Natalie , Zoellner Andy , Bernhardt Rita , Knuth Alexander , Old Lloyd J. , Renner Christoph 
Published: April 2014

AbstractTNF application in humans is limited by severe side effects, including life-threatening symptoms of shock. Therefore, TNF can be successfully applied as a tumor therapeutic reagent only under conditions that prevent its systemic action. To overcome this limitation, genetic fusion of TNF to tumor-selective Abs is a favored strategy to increase site-specific cytokine targeting. Because wild-type TNF displays its bioactivity as noncovalently linked homotrimer, the challenge is to define structural requirements for a TNF-based immunokine format with optimized structure-activity profile. We compared toxicity and efficacy of a dimerized CH2/CH3 truncated IgG1-TNF fusion protein and a single-chain variable fragment-coupled TNF monomer recognizing fibroblast-activating protein. The former construct preserves its dimeric structure stabilized by the natural disulfide bond IgG1 hinge region, while the latter trimerizes under native conditions. Analysis of complex formation of wild-type TNF and of both fusion proteins with TNFR type 1 (TNF-R1) using surface plasmon resonance correlated well with in vitro and in vivo toxicity data. There is strong evidence that TNF subunits in a trimeric state display similar toxicity profiles despite genetic fusion to single-chain variable fragment domains. However, LD50 of either immunodeficient BALB/c nu/nu or immunocompetent BALB/c mice was significantly decreased following administration of TNF in the formation of IgG1-derived dimeric fusion protein. Reduction of unspecific peripheral complexation of TNF-R1 resulted in higher anticancer potency by immunotargeting of fibroblast-activating protein-expressing xenografts. The broader therapeutic window of the IgG1-derived TNF fusion protein favors the dimeric TNF-immunokine format for systemic TNF-based tumor immunotherapy.
Conserved Functions of Ikaros in Vertebrate Lymphocyte Development: Genetic Evidence for Distinct Larval and Adult Phases of T Cell Development and Two Lineages of B Cells in Zebrafish
Authors: Schorpp Michael , Bialecki Mike , Diekhoff Dagmar , Walderich Brigitte , Odenthal Jörg , Maischein Hans-Martin , Zapata Agustin G. ,   Tübingen 2000 Screen Consortium,   Freiburg Screening Group, Boehm Thomas 
Published: April 2014

Abstract
Zebrafish has been advocated as an alternative animal model to study lymphocyte development, although the similarities in the genetic requirements of lymphopoiesis between fish and mammals have not yet been investigated. In this study, we examine the role of the transcription factor Ikaros in zebrafish lymphopoiesis. In fish larvae homozygous for an ikaros allele predicted to lack the C-terminal zinc fingers, T lymphopoiesis is absent; the presence of VHDμJμ rearrangements in adolescent fish is delayed in mutants. In adolescent mutant fish, T cells expressing tcrb and tcrd and B cells expressing igm are formed with low efficiency and display an oligoclonal Ag receptor repertoire. By contrast, B cells expressing the igz isotype do not develop, providing genetic evidence for two separate B cell lineages in zebrafish. Thus, Ikaros appears to play similar roles in fish and mammalian lymphopoiesis.
Autoantibodies from Synovial Lesions in Chronic, Antibiotic Treatment-Resistant Lyme Arthritis Bind Cytokeratin-10
Authors: Ghosh Srimoyee , Seward Robert , Costello Catherine E. , Stollar B. David , Huber Brigitte T. 
Published: April 2014

AbstractAlthough the causative agent of Lyme disease is definitively known to be the tick-borne spirochete, Borrelia burgdorferi, the etiology of chronic joint inflammation that ensues in a subset of patients remains less well understood. Persistence of arthritis after apparent eradication of the spirochete suggests an autoimmune reaction downstream of the original bacterial infection. We have generated recombinant Ab probes from synovial lesions within affected arthritic joints in an attempt to recapitulate disease-relevant Ag-binding specificities at the site of injury. Using this panel of intra-articular probes, as well as Ab fragments derived from patient peripheral blood, we have identified cytokeratin 10, present in synovial microvascular endothelium, as a target ligand and a putative autoantigen in chronic, antibiotic treatment-resistant Lyme arthritis. Furthermore, there is cross-reactivity between cytokeratin 10 and a prominent B. burgdorferi Ag, outer surface protein A. Release of the self protein in the context of inflammation-induced tissue injury and the resulting in situ response to it could set in motion a feed-forward loop, which amplifies the inflammatory process, thereby rendering it chronic and self-perpetuating, even in the absence of the inciting pathogen.
CD46 (Membrane Cofactor Protein) Acts as a Human Epithelial Cell Receptor for Internalization of Opsonized Uropathogenic Escherichia coli
Authors: Li Ke , Feito Maria Jose , Sacks Steven H. , Sheerin Neil S. 
Published: April 2014

Abstract
Escherichia coli is a common urinary pathogen whose uptake into epithelial cells is mediated by attachment through type 1 fimbriae. In this study, we show by using using human urinary tract epithelial cells that maximal internalization of E. coli is achieved only when bacteria are opsonized with complement. The concentrations of complement proteins in the urine rise sufficiently during infection to allow bacterial opsonization. The complement regulatory protein, CD46 (membrane cofactor protein), acts in cohort with fimbrial adhesion to promote the uptake of pathogenic E. coli. This uptake is inhibited by RNA interference to lower the expression of CD46 and by soluble CD46 that will competitively inhibit opsonized bacteria binding to cell surface CD46. We propose that efficient internalization of uropathogenic E. coli by the human urinary tract depends on cooperation between fimbrial-mediated adhesion and C3 receptor (CD46)–ligand interaction. Complement receptor–ligand interaction could pose a new target for interrupting the cycle of reinfection due to intracellular bacteria.