bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Src Homology Domain 2 (SH2)-Containing Inositol Phosphatase (SHIP), SH2-Containing Phosphotyrosine Phosphatase (SHP)-1, and SHP-2 SH2 Decoy Proteins on FcγRIIB1-Effector Interactions and Inhibitory Functions
Authors: Nakamura Kazuhiro , Brauweiler Anne , Cambier John C. 
Published: April 2014

Abstract
Coaggregation of FcγRIIB1 with B cell Ag receptors (BCR) leads to inhibition of BCR-mediated signaling via recruitment of Src homology domain 2 (SH2)-containing phosphatases. In vitro peptide binding experiments using phosphotyrosine-containing sequences derived from the immunoreceptor tyrosine-based inhibitory motif (ITIM) known to mediate FcγRIIB1 effects suggest that the receptor uses SH2-containing inositol phophatase (SHIP) and SH2-containing phophotyrosine phosphatase (SHP)-1, as well as SHP-2 as effectors. In contrast, coimmunoprecipitation studies of receptor-effector associations suggest that the predominant FcγRIIB1 effector protein is SHIP. However, biologically significant interactions may be lost in such studies if reactants’ dissociation rates (Kd) are high. Thus, it is unclear to what extent these assays reflect the relative recruitment of SHIP, SHP-1, and SHP-2 to the receptor in vivo. As an alternative approach to this question, we have studied the effects of ectopically expressed SHIP, SHP-1, or SHP-2 SH2-containing decoy proteins on FcγRIIB1 signaling. Results demonstrate the SHIP is the predominant intracellular ligand for the phosphorylated FcγRIIB1 ITIM, although the SHP-2 decoy exhibits some ability to bind FcγRIIB1 and block Fc receptor function. The SHIP SH2, while not affecting FcγRIIB1 tyrosyl phosphorylation, blocks receptor-mediated recruitment of SHIP, SHIP phosphorylation, recruitment of p52 Shc, phosphatidylinositol 3,4,5-trisphosphate hydrolysis, inhibition of mitogen-activated protein kinase activation, and, albeit more modestly, FcγRIIB1 inhibition of Ca2+ mobilization. Taken together, results implicate ITIM interactions with SHIP as a major mechanism of FcγRIIB1-mediated inhibitory signaling.
Murine CCR9, a Chemokine Receptor for Thymus-Expressed Chemokine That Is Up-Regulated Following Pre-TCR Signaling
Authors: Norment Anne M. , Bogatzki Lisa Y. , Gantner Ben N. , Bevan Michael J. 
Published: April 2014

Abstract
Chemokines are likely to play an important role in regulating the trafficking of developing T cells within the thymus. By using anti-CD3ε treatment of recombinase-activating gene 2 (Rag2−/−) mice to mimic pre-TCR signaling and drive thymocyte development to the double positive stage, we have identified murine GPR-9-6 as a chemokine receptor whose expression is strongly induced following pre-TCR signaling. GPR-9-6 mRNA is present at high levels in the thymus, and by RT-PCR analysis its expression is induced as normal thymocytes undergo the double negative to double positive transition. Furthermore we show that TECK (thymus-expressed chemokine), a chemokine produced by thymic medullary dendritic cells, is a functional ligand for GPR-9-6. TECK specifically induces a calcium flux and chemotaxis of GPR-9-6-transfected cells. In addition, TECK stimulates the migration of normal double positive thymocytes, as well as Rag2−/− thymocytes following anti-CD3ε treatment. Hence, GPR-9-6 has been designated as CC chemokine receptor 9 (CCR9). Our results suggest that TECK delivers signals through CCR9 important for the navigation of developing thymocytes.
In Vivo CD4+ T Cell Tolerance Induction Versus Priming Is Independent of the Rate and Number of Cell Divisions
Authors: Adler Adam J. , Huang Ching-Tai , Yochum Gregory S. , Marsh David W. , Pardoll Drew M. 
Published: April 2014

Abstract
In vitro studies have suggested that tolerance induction (i.e., anergy) is associated with an inability of T cells to proliferate vigorously upon Ag recognition. In vivo, the relationship between T cell proliferation and tolerance induction is less clear. To clarify this issue, we have been studying a model system in which naive CD4+ T cells specific for the model Ag hemagluttinin (HA) are adoptively transferred into different transgenic founder lines of mice expressing HA as a peripheral self-Ag. When transferred into two lines whose HA expression differs by at least 1000-fold, HA-specific T cells undergo multiple rounds of cell division before reaching a nonresponsive (i.e., tolerant) state. While the proliferative response is more rapid in mice expressing higher levels of HA, the T cells become tolerant regardless of the level of peripheral HA expression. When the T cells encounter HA expressed as a viral Ag, they proliferate at a similar rate and undergo the same number of divisions as with self-HA, but they do not become tolerant. These results indicate that a tolerizing stimulus can induce similar T cell mitotic rates as a priming stimulus. Therefore, CD4+ T cell tolerance induction in vivo is not the result of an insufficient proliferative response elicited upon TCR engagement.
The p55 TNF-α Receptor Plays a Critical Role in T Cell Alloreactivity
Authors: Hill Geoffrey R. , Teshima Takanori , Rebel Vivienne I. , Krijanovski Oleg I. , Cooke Kenneth R. , Brinson Yani S. , Ferrara James L. M. 
Published: April 2014

AbstractTNF-α is known to be an important mediator of tissue damage during allograft rejection and graft-vs-host disease (GVHD), but its role in supporting T cell responses to allogeneic Ags is unclear. We have studied this question by comparing normal mice with those lacking the p55 (p55 TNFR−/−) or p75 (p75 TNFR−/−) TNF-α receptors as donors in well-defined bone marrow transplant (BMT) models. Recipients of p55 TNFR−/− cells had significantly reduced mortality and morbidity from GVHD compared with the other two sources of T cells. In vitro, T cells lacking the p55 (but not the p75) TNF-α receptor exhibited decreased proliferation and production of Th1 cytokines in MLC. This defect was only partially restored by exogenous IL-2 and affected both CD4+ and CD8+ populations. CD8+ p55 TNFR−/− proliferation was impaired independently of IL-2 whereas CTL effector function was impaired in an IL-2-dependent fashion. Inhibition of TNF-α with TNFR:Fc in primary MLC also impaired the proliferation and Th1 differentiation of wild-type T cells. BMT mixing experiments demonstrated that the reduced ability of p55 TNFR−/− donor cells to induce GVHD was due to the absence of the p55 TNFR on T cells rather than bone marrow cells. These data highlight the importance of TNF-α in alloreactive T cell responses and suggest that inhibition of the T cell p55 TNF-α receptor may provide an additional useful therapeutic maneuver to inhibit alloreactive T cell responses following bone marrow and solid organ transplantation.
Blockade of CTLA-4 Signals Inhibits Th2-Mediated Murine Chronic Graft-Versus-Host Disease by an Enhanced Expansion of Regulatory CD8+ T Cells
Authors: Sakurai Jinkyo , Ohata Junko , Saito Kiyoshi , Miyajima Hiroaki , Hirano Takao , Kohsaka Takao , Enomoto Shoji , Okumura Ko , Azuma Miyuki 
Published: April 2014

AbstractCTLA-4 (CD152) is thought to be a negative regulator of T cell activation. Little is known about the function of CTLA-4 in Th2-type immune responses. We have investigated the effect of initial treatment with anti-CTLA-4 mAb on murine chronic graft-vs-host disease. Transfer of parental BALB/c splenocytes into C57BL/6 × BALB/c F1 mice induced serum IgE production, IL-4 expression by donor CD4+ T cells, and host allo-Ag-specific IgG1 production at 6–9 wk after transfer. Treatment with anti-CTLA-4 mAb for the initial 2 wk significantly reduced IgE and IgG1 production and IL-4 expression. Analysis of the splenic phenotype revealed the enhancement of donor T cell expansion, especially within the CD8 subset, and the elimination of host cells early after anti-CTLA-4 mAb treatment. This treatment did not affect early IFN-γ expression by CD4+ and CD8+ T cells and anti-host cytolytic activity. Thus, blockade of CTLA-4 greatly enhanced CD8+ T cell expansion, and this may result in the regulation of consequent Th2-mediated humoral immune responses. These findings suggest a new approach for regulating IgE-mediated allergic immune responses by blockade of CTLA-4 during a critical period of Ag sensitization.
Pathologic Role and Temporal Appearance of Newly Emerging Autoepitopes in Relapsing Experimental Autoimmune Encephalomyelitis
Authors: Vanderlugt Carol L. , Neville Katherine L. , Nikcevich Kelly M. , Eagar Todd N. , Bluestone Jeffrey A. , Miller Stephen D. 
Published: April 2014

Abstract
Relapsing experimental autoimmune encephalomyelitis (R-EAE) is a CD4+ T cell-mediated demyelinating disease model for multiple sclerosis. Myelin destruction during the initial relapsing phase of R-EAE in SJL mice initiated by immunization with the proteolipid protein (PLP) epitope PLP139–151 is associated with activation of T cells specific for the endogenous, non-cross-reactive PLP178–191 epitope (intramolecular epitope spreading), while relapses in R-EAE induced with the myelin basic protein (MBP) epitope MBP84–104 are associated with PLP139–151-specific responses (intermolecular epitope spreading). Here, we demonstrate that T cells specific for endogenous myelin epitopes play the major pathologic role in mediating clinical relapses. T cells specific for relapse-associated epitopes can serially transfer disease to naive recipients and are demonstrable in the CNS of mice with chronic R-EAE. More importantly, induction of myelin-specific tolerance to relapse-associated epitopes, by i.v. injection of ethylene carbodiimide-fixed peptide-pulsed APCs, either before disease initiation or during remission from acute disease effectively blocks the expression of the initial disease relapse. Further, blockade of B7-1-mediated costimulation with anti-B7-1 F(ab) during disease remission from acute PLP139–151-induced disease prevents clinical relapses by inhibiting activation of PLP178–191-specific T cells. The protective effects of anti-B7-1 F(ab) treatment are long-lasting and highly effective even when administered following the initial relapsing episode wherein spreading to a MBP epitope (MBP84–104) is inhibited. Collectively, these data indicate that epitope spreading is B7-1 dependent, plays a major pathologic role in disease progression, and follows a hierarchical order associated with the relative encephalitogenic dominance of the myelin epitopes (PLP139–151 &gt; PLP178–191 &gt; MBP84–104).
Vanadate Induces Calcium Signaling, Ca2+ Release-Activated Ca2+ Channel Activation, and Gene Expression in T Lymphocytes and RBL-2H3 Mast Cells Via Thiol Oxidation
Authors: Ehring George R. , Kerschbaum Hubert H. , Fanger Christopher M. , Eder Claudia , Rauer Heiko , Cahalan Michael D. 
Published: April 2014

Abstract
Using ratiometric Ca2+ imaging and patch-clamp measurement of Ca2+ channel activity, we investigated Ca2+ signaling induced by vanadium compounds in Jurkat T lymphocytes and rat basophilic leukemia cells. In the presence of external Ca2+, vanadium compounds produced sustained or oscillatory Ca2+ elevations; in nominally Ca2+-free medium, a transient Ca2+ rise was generated. Vanadate-induced Ca2+ signaling was blocked by heparin, a competitive inhibitor of the 1,4,5-inositol trisphosphate (IP3) receptor, suggesting that Ca2+ influx is secondary to depletion of IP3-sensitive Ca2+ stores. In Jurkat T cells, vanadate also activated the Ca2+-dependent transcription factor, NF-AT. Intracellular dialysis with vanadate activated Ca2+ influx through Ca2+ release-activated Ca2+ (CRAC) channels with kinetics comparable to those of dialysis with IP3. Neither phosphatase inhibitors nor nonhydrolyzable nucleotide analogues modified CRAC channel activation. The action of vanadate, but not IP3, was prevented by the thiol-reducing agent DTT. In addition, the activation of CRAC channels by vanadate was mimicked by the thiol-oxidizing agent chloramine T. These results suggest that vanadate enhances Ca2+ signaling via thiol oxidation of a proximal element in the signal transduction cascade.
Resting B Lymphocytes as APC for Naive T Lymphocytes: Dependence on CD40 Ligand/CD40
Authors: Evans Dean E. , Munks Michael W. , Purkerson Jeffrey M. , Parker David C. 
Published: April 2014

AbstractAlthough resting B cells as APC are tolerogenic for naive T cells in vivo, we show here that they can provide all the costimulatory signals necessary for naive T cell proliferation in vivo and in vitro. In the absence of an activating signal through the B cell Ag receptor, T cell proliferation after Ag recognition on resting B cells depends on CD40 expression on the B cells, implying that naive T cells use the membrane-bound cytokine, CD40 ligand (CD154), to induce the costimulatory signals that they need. Induction of B7-1 (CD80) and increased or sustained expression of CD44H, ICAM-1 (CD54), and B7-2 (CD86) are dependent on the interaction of CD40 ligand with CD40. Transient expression (12 h) of B7-2 is T cell- and peptide Ag-dependent, but CD40-independent. Only sustained (≥24 h) expression of B7-2 and perhaps increased expression of ICAM-1 could be shown to be functionally important in this system. T cells cultured with CD40-deficient B cells and peptide remain about as responsive as fresh naive cells upon secondary culture with whole splenic APC. Therefore, B cells, and perhaps other APC, may be tolerogenic not because they fail to provide sufficient costimulation for T cell proliferation, but because they are deficient in some later functions necessary for a productive T cell response.
Vaccination with Mouse Mammary Adenocarcinoma Cells Coexpressing B7-1 (CD80) and B7-2 (CD86) Discloses the Dominant Effect of B7-1 in the Induction of Antitumor Immunity
Authors: Martín-Fontecha Alfonso , Moro Monica , Crosti Maria Cristina , Veglia Fabrizio , Casorati Giulia , Dellabona Paolo 
Published: April 2014

Abstract
Nonreplicating TS/A mammary adenocarcinoma cells expressing B7-2 (CD86) (TS/A-2) are more immunogenic than those expressing B7-1 (CD80) (TS/A-1), indicating that B7-1 and B7-2 display nonredundant costimulatory effects in inducing antitumor responses. Whereas transfection of B7-2 cDNA into TS/A-1 cells does not improve their immunogenicity, transfection of B7-1 cDNA into TS/A-2 cells (TS/A-2/1) decreases their immunogenicity in a manner that is directly related to the surface levels of B7-1. Ab blocking of B7-1 on TS/A-2/1 cells before their injection in vivo restores the higher immunogenicity characteristic of single B7-2 transfectants, indicating therefore that B7-1 actively modulates the B7-2-dependent costimulation. The expression of B7-1 also modifies quantitatively the balance of endogenous IFN-γ and IL-4 induced in vivo by TS/A-2 vaccines. In fact, we find that vaccination with TS/A-2/1 cells results in the production of more IFN-γ and less IL-4 than TS/A-2 vaccines, a pattern comparable to that induced by TS/A-1 cells. Thus, in the TS/A model of antitumor response, B7-1 modulates B7-2-dependent costimulatory effects in a dominant, noncompetitive way.
Hierarchical Costimulator Thresholds for Distinct Immune Responses: Application of a Novel Two-Step Fc Fusion Protein Transfer Method
Authors: Chen Aoshuang , Zheng Guoxing , Tykocinski Mark L. 
Published: April 2014

Abstract
Activation of T cells is dependent upon coordinate engagement of Ag and costimulator receptors on their surfaces. In the case of the Ag receptors (TCRs), activation thresholds have been defined, with the number of TCRs that must be triggered to stimulate cytokine secretion by individual activated T cells differing for the various cytokines. In the present study, we have determined whether comparable activation thresholds exist for the costimulator receptors on T cells. To facilitate this type of quantitative costimulator analysis, we developed a novel two-step protein transfer approach that permits delivery of graded amounts of proteins to APC surfaces. By adding a human B7-1 · Fcγ1 (Fc domain of human IgG1) fusion protein to cells precoated with palmitated protein A, fine titration of the B7-1 extracellular domain was achieved. The B7-1 · Fcγ1 reincorporated into cell membranes by this method retained costimulator function, as measured by an in vitro proliferation assay. The degree of proliferation was dependent on the surface density of B7-1 · Fcγ1. Significantly, the threshold B7-1 · Fcγ1 density required for cytokine production differed between IFN-γ and IL-2 and mirrored the hierarchy (IFN-γ &lt; IL-2) described previously for the TCR activation threshold. Hence, this study invokes a novel protein transfer strategy to establish that the levels of surface costimulator on APCs can dictate both the magnitude and the quality of evoked T cell responses. The notion of costimulator receptor activation thresholds emerges.
uPA/uPAR System Is Active in Immature Dendritic Cells Derived from CD14+CD34+ Precursors and Is Down-Regulated upon Maturation
Authors: Ferrero Elisabetta , Vettoretto Katuscia , Bondanza Attilio , Villa Antonello , Resnati Massimo , Poggi Alessandro , Zocchi Maria Raffaella 
Published: April 2014

Abstract
We recently described a subset of peripheral CD14+CD34+ cells able to migrate across endothelial cell monolayers and differentiate into immunostimulatory dendritic cells (DC). In this paper we show that immature DC derived from CD14+CD34+ precursors are also capable of reverse transendothelial migration and extracellular matrix (ECM) invasion using the urokinase plasminogen activator receptor (uPAR). We found that these cells respond to macrophage-inflammatory protein (MIP)-1α, enhancing their ability to invade ECM and supporting the idea that immature DC are selectively recruited at the site of inflammation to expand the pool of APCs. Interestingly, MIP-1α was also capable of preventing the decreased matrix invasion observed by blocking uPAR, suggesting that the uPA/uPAR system and MIP-1α cooperate in driving immature DC migration through the subendothelial matrix. Upon exposure to maturating stimuli, such as TNF-α, CD14+CD34+-derived DC enhance their APC function and decrease the capacity of invading ECM; these changes are accompanied by altered expression and function of uPAR. Moreover, mature DC shift their sensitivity from MIP-1α to MIP-3β, enhancing their transendothelial migration capability in response to the latter chemokine. Our data support the hypothesis that bloodborne DC can move through ECM toward the site of pathogen entry where they differentiate into fully mature APCs with their motility and function regulated by microenvironmental stimuli, including MIP-1α, MIP-3β, and TNF-α.
Effect of Molecular Size on the Ability of Zwitterionic Polysaccharides to Stimulate Cellular Immunity
Authors: Kalka-Moll Wiltrud M. , Tzianabos Arthur O. , Wang Ying , Carey Vincent J. , Finberg Robert W. , Onderdonk Andrew B. , Kasper Dennis L. 
Published: April 2014

Abstract
The large-molecular-sized zwitterionic capsular polysaccharide of the anaerobe Bacteroides fragilis NCTC 9343, designated polysaccharide (PS) A, stimulates T cell proliferation in vitro and induces T cell-dependent protection against abscess formation in vivo. In the present study, we utilized a modification of a recently developed ozonolytic method for depolymerizing polysaccharides to examine the influence of the molecular size of PS A on cell-mediated immunity. Ozonolysis successfully depolymerized PS A into structurally intact fragments. PS A with average molecular sizes of 129.0 (native), 77.8, 46.9, and 17.1 kDa stimulated CD4+-cell proliferation in vitro to the same degree, whereas the 5.0-kDa fragment was much less stimulatory than the control 129.0-kDa PS A. Rats treated with 129.0-kDa, 46.9-kDa, and 17.1-kDa PS A molecules, but not those treated with the 5.0-kDa molecule, were protected against intraabdominal abscesses induced by challenge with viable B. fragilis. These results demonstrate that a zwitterionic polysaccharide as small as 22 repeating units (88 monosaccharides) elicits a T cell-dependent immune response. These findings clearly distinguish zwitterionic T cell-dependent polysaccharides from T cell-independent polysaccharides and give evidence of the existence of a novel mechanism for a polysaccharide-induced immune response.
Soluble Antigen and CD40 Triggering Are Sufficient to Induce Primary and Memory Cytotoxic T Cells
Authors: Lefrançois Leo , Altman John D. , Williams Kristina , Olson Sara 
Published: April 2014

AbstractThe signals directing induction of tolerance rather than immunity are largely unknown. The CD8 T cell response to soluble Ags generally results in deletional tolerance following transient, costimulation-dependent activation. We demonstrated that CD40 signaling reversed the outcome of this response. Adoptive transfer of OVA-specific CD8 T cells followed by soluble OVA immunization resulted in induction of lytic activity and optimal clonal expansion only when CD40 was triggered via an agonistic mAb. Activation of CD8 T cells by CD40 signaling was indirect, because CD40 expression by host cells was required. CD40 signaling along with soluble Ag immunization also induced expansion of secondary lymphoid and intestinal mucosal endogenous OVA-specific CD8 T cells as detected by MHC tetramer reactivity. When CD40 activation was included, long-lived secondary lymphoid and mucosal memory CD8 cells were generated from adoptively transferred and endogenous CD8 T cells. Mucosal and peripheral CD8 memory cells exhibited constitutive Ag-specific lytic activity, with mucosal memory cells being 10-fold more lytic than splenic or lymph node memory cells. These results demonstrated that CD40 signaling during a response to a poorly immunogenic soluble Ag was necessary and sufficient for CTL and memory T cell induction.
Defective Expression of the Monocyte Chemotactic Protein-1 Receptor CCR2 in Macrophages Associated with Human Ovarian Carcinoma
Authors: Sica Antonio , Saccani Alessandra , Bottazzi Barbara , Bernasconi Sergio , Allavena Paola , Gaetano Brancatelli , Fei Francesca , LaRosa Graig , Scotton Chris , Balkwill Frances , Mantovani Alberto 
Published: April 2014

Abstract
Monocyte chemotactic protein-1 (MCP-1, CCL2) is an important determinant of macrophage infiltration in tumors, ovarian carcinoma in particular. MCP-1 binds the chemokine receptor CCR2. Recent results indicate that proinflammatory and anti-inflammatory signals regulate chemokine receptor expression in monocytes. The present study was designed to investigate the expression of CCR2 in tumor-associated macrophages (TAM) from ovarian cancer patients. TAM isolated from ascitic or solid ovarian carcinoma displayed defective CCR2 mRNA (Northern blot and PCR) and surface expression and did not migrate in response to MCP-1. The defect was selective for CCR2 in that CCR1 and CCR5 were expressed normally in TAM. CCR2 gene expression and chemotactic response to MCP-1 were decreased to a lesser extent in blood monocytes from cancer patients. CCR2 mRNA levels and the chemotactic response to MCP-1 were drastically reduced in fresh monocytes cultured in the presence of tumor ascites from cancer patients. Ab against TNF-α restored the CCR2 mRNA level in monocytes cultured in the presence of ascitic fluid. The finding of defective CCR2 expression in TAM, largely dependent on local TNF production, is consistent with previous in vitro data on down-regulation of chemokine receptors by proinflammatory molecules. Receptor inhibition may serve as a mechanism to arrest and retain recruited macrophages and to prevent chemokine scavenging by mononuclear phagocytes at sites of inflammation and tumor growth. In the presence of advanced tumors or chronic inflammation, systemic down-regulation of receptor expression by proinflammatory molecules leaking in the systemic circulation may account for defective chemotaxis and a defective capacity to mount inflammatory responses associated with advanced neoplasia.