bluuebunny/crossref_metadata_2025_split huggingface dataset:
L-Selectin Shedding Is Independent of Its Subsurface Structures and Topographic Distribution
Authors: Fors Brian P. , Goodarzi Katayoon , von Andrian Ulrich H. 
Published: April 2014

Abstract
L-selectin (CD62L), a lectin-like adhesion molecule, mediates lymphocyte homing and leukocyte accumulation at sites of inflammation. Its transmembrane (TM) and intracellular (IC) domains confer clustering of L-selectin on microvilli of resting leukocytes, which is important for L-selectin function. Following activation of protein kinase C (PKC) or calmodulin inhibition, the wild-type (WT) protein is rapidly cleaved in its membrane-proximal ectodomain. To examine whether L-selectin topography or TM/IC domains are involved in this shedding process, we used stable transfectants expressing WT L-selectin (on microvilli) or chimeric molecules consisting of the L-selectin ectodomain linked to the TM/IC domains of CD44 (excluded from microvilli) or CD31 (randomly distributed). PKC activation by PMA altered the cells’ surface morphology, but did not induce a redistribution of L-selectin ectodomains. All cell lines shed ectodomains upon PMA activation in a dose-dependent fashion and with similar kinetics. Calmodulin inhibition by trifluoperazine induced shedding in both WT and chimera transfectants. At high trifluoperazine concentrations, shedding of WT L-selectin was significantly more pronounced than that of chimeric molecules. Regardless of the activating stimulus, shedding was blocked by a hydroxamate-based metalloprotease inhibitor, suggesting that ectodomain down-regulation occurred through proteolytic cleavage by identical protease(s). These results show that the recognition site(s) for PKC-induced L-selectin shedding is exclusively contained within the ectodomain; the nature of subsurface structures and surface topography are irrelevant. Shedding induced by calmodulin inhibition has two components: one requires the L-selectin TM/IC domain, and the other is independent of it.
CD84 Functions as a Homophilic Adhesion Molecule and Enhances IFN-γ Secretion: Adhesion Is Mediated by Ig-Like Domain 1
Authors: Martin Margarita , Romero Xavier , de la Fuente Miguel Angel , Tovar Victoria , Zapater Núria , Esplugues Enric , Pizcueta Pilar , Bosch Jaime , Engel Pablo 
Published: April 2014

AbstractCD84 is a member of the CD2 subset of the Ig superfamily of cell surface molecules. Its cytoplasmic tail binds to Src homology 2 domain-containing protein 1A (signaling lymphocytic activation molecule-associated protein), a protein encoded by the X-linked lymphoproliferative disease gene. It is preferentially expressed on B lymphocytes, monocytes, and platelets. We show that it is also expressed on thymocytes and T cells. CD84 was positive on CD4−CD8− thymocytes, and its expression decreased with cell maturation. It is expressed on mature T cells preferentially on CD45RO+. To identify the CD84 ligand, we generated a soluble Ig fusion protein containing the human CD84 extracellular domains (CD84-Ig). Because receptor-ligand interactions occur between several members of this subfamily, we assayed CD84-Ig binding with all members of the CD2 family. CD84-Ig bound to CD84-transfected cells, whereas no binding was detected with cells expressing other CD2 subfamily receptors, showing that CD84 binds to itself. Anti-CD84 mAbs recognizing epitopes wholly within domain 1 of CD84 blocked the binding of the CD84-Ig fusion protein to CD84-transfected cells and platelets. Data from CD84 domain human/mouse chimeras further revealed that only the first extracellular domain of the molecule is involved in the ligand receptor recognition. The CD84-CD84 interaction was independent of its cytoplasmic tail. Finally, concurrent ligation of human CD84 with mAbs or CD84-Ig and CD3 enhanced IFN-γ secretion in human lymphocytes. Thus, CD84 is its own ligand and acts as a costimulatory molecule.
Histamine Polarizes Human Dendritic Cells into Th2 Cell-Promoting Effector Dendritic Cells
Authors: Caron Gersende , Delneste Yves , Roelandts Edith , Duez Catherine , Bonnefoy Jean-Yves , Pestel Joel , Jeannin Pascale 
Published: April 2014

Abstract
Allergic disorders are characterized by allergen-specific Th2-biased responses. Signals controlling Th2 cell polarization, especially those acting by polarizing dendritic cells (DC) into Th2-promoting DC (DC2), are not well known. Histamine, a mediator released by allergen-stimulated mast cells from allergic subjects, has been reported to activate human immature DC. We have therefore tested whether histamine affects DC polarization. We report here that histamine inhibits LPS-induced IL-12 production and polarizes uncommitted maturing DC into effector DC2. DC matured in the presence of histamine fail to produce IL-12 upon subsequent stimulation and prime Th2 responses, even in presence of IFN-γ, a potent DC1-driving factor. All these effects are mediated through both H1 and H2 receptors. These data show that histamine is a potent DC2-polarizing factor and provide evidence for a novel mechanism that explains the initiation and maintenance of a predominant Th2 response in allergic disorders.
Infiltration of Canonical Vγ4/Vδ1 γδ T Cells in an Adriamycin-Induced Progressive Renal Failure Model
Authors: Ando Takashi , Wu Huiling , Watson Debbie , Hirano Tadashi , Hirakata Hideki , Fujishima Masatoshi , Knight John F. 
Published: April 2014

AbstractWe have previously reported an infiltration of renal interstitial γδ T cells in Adriamycin-induced progressive glomerulosclerosis in the rat kidney. The TCR repertoire and sequences used by these γδ T cells have now been studied. Two injections of Adriamycin 14 days apart caused segmental glomerulosclerosis, massive interstitial infiltration of mononuclear cells, and end-stage renal failure. Flow cytometry of lymphocyte subpopulations with Abs to CD3, the γδ TCR, and the αβ TCR showed that γδ T cells as a proportion of CD3+ cells were increased in Adriamycin-treated kidneys (8.5 ± 5.4%), but not in lymph nodes (1.3 ± 0.4%). A semiquantitative score of glomerular damage (r = 0.65; p &lt; 0.01) and creatinine (r = 0.62; p &lt; 0.01) correlated significantly with the presence of γδ T cells. TCR Vγ repertoire analysis by RT-PCR and Southern blotting showed that Vγ2 was the dominant subfamily in lymph nodes, whereas Vγ4 became the predominant subfamily in advanced stages of the rat Adriamycin-treated kidney. Sequencing of the Vγ4-Jγ junctional region showed an invariant sequence. The amino acid sequence of the junctional region of the Vγ4 TCR was the same as the reported mouse canonical Vγ4 TCR sequence. Analysis of the kidney Vδ repertoire showed dominant expression of Vδ1, and sequencing again revealed the selective expression of a canonical Vδ1 gene. Semiquantitative RT-PCR for cytokine gene expression showed that γδ T cells from the kidneys expressed TGF-β, but not IL-4, IL-10, or IFN-γ. These results suggest that the predominant γδ T cells in the Adriamycin kidney use an invariant Vγ4/Vδ1 receptor.
Active Vaccination Against IL-5 Bypasses Immunological Tolerance and Ameliorates Experimental Asthma
Authors: Hertz Marc , Mahalingam Surendran , Dalum Iben , Klysner Steen , Mattes Joerg , Neisig Anne , Mouritsen Søren , Foster Paul S. , Gautam Anand 
Published: April 2014

Abstract
Current therapeutic approaches to asthma have had limited impact on the clinical management and resolution of this disorder. By using a novel vaccine strategy targeting the inflammatory cytokine IL-5, we have ameliorated hallmark features of asthma in mouse models. Delivery of a DNA vaccine encoding murine IL-5 modified to contain a promiscuous foreign Th epitope bypasses B cell tolerance to IL-5 and induces neutralizing polyclonal anti-IL-5 Abs. Active vaccination against IL-5 reduces airways inflammation and prevents the development of eosinophilia, both hallmark features of asthma in animal models and humans. The reduced numbers of inflammatory T cells and eosinophils in the lung also result in a marked reduction of Th2 cytokine levels. Th-modified IL-5 DNA vaccination reduces the expression of IL-5 and IL-4 by ∼50% in the airways of allergen-challenged mice. Most importantly, Th-modified IL-5 DNA vaccination restores normal bronchial hyperresponsiveness to β-methacholine. Active vaccination against IL-5 reduces key pathological events associated with asthma, such as Th2 cytokine production, airways inflammation, and hyperresponsiveness, and thus represents a novel therapeutic approach for the treatment of asthma and other allergic conditions.
The Murine Cytomegalovirus Immune Evasion Protein m4/gp34 Forms Biochemically Distinct Complexes with Class I MHC at the Cell Surface and in a Pre-Golgi Compartment
Authors: Kavanagh Daniel G. , Koszinowski Ulrich H. , Hill Ann B. 
Published: April 2014

Abstract
We have recently demonstrated that the murine CMV (MCMV) gene m4 is an immune evasion gene that protects MCMV-infected targets from some virus-specific CTL clones. m4 encodes m4/gp34, a 34-kDa glycoprotein that binds to major histocompatibility complex class I in the endoplasmic reticulum and forms a detergent-stable complex that is exported to the surface of the cell. To investigate how m4/gp34 promotes CTL evasion, we analyzed the assembly and export of m4/gp34-Kb complexes. We found that 50–70% of Kb exported over the course of MCMV infection was m4/gp34 associated. Because these complexes are present at the cell surface, it is possible that m4 mediates CTL evasion by interfering with contact between class I and receptors on the T cell. In addition, we found that Kb retained by the MCMV immune evasion gene m152 formed a novel type of complex with Endo H-sensitive m4/gp34; these complexes are distinguished from the exported complexes by being stable in 1% digitonin and unstable in 1% Nonidet P-40. Because this association occurs in a pre-Golgi compartment, m4/gp34 might also interfere with Ag presentation by affecting some aspect of class I assembly, such as peptide loading. Although m4/gp34 requires β2-microglobulin to bind class I, there was no significant binding of m4/gp34 to β2-microglobulin in the absence of class I H chain, demonstrating that m4/gp34 forms Nonidet P-40-stable complexes specifically with folded conformations of class I. We conclude that m4/gp34 promotes immune evasion by a novel mechanism involving altered assembly and/or T cell recognition of class I molecules.
Apoptotic Deletion of Th Cells Specific for the 19-kDa Carboxyl-Terminal Fragment of Merozoite Surface Protein 1 During Malaria Infection
Authors: Wipasa Jiraprapa , Xu Huji , Stowers Anthony , Good Michael F. 
Published: April 2014

Abstract
Immunity induced by the 19-kDa fragment of merozoite surface protein 1 is dependent on CD4+ Th cells. However, we found that adoptively transferred CFSE-labeled Th cells specific for an epitope on Plasmodium yoelii 19-kDa fragment of merozoite surface protein 1 (peptide (p)24), but not OVA-specific T cells, were deleted as a result of P. yoelii infection. As a result of infection, spleen cells recovered from infected p24-specific T cell-transfused mice demonstrated reduced response to specific Ag. A higher percentage of CFSE-labeled p24-specific T cells stained positive with annexin and anti-active caspase-3 in infected compared with uninfected mice, suggesting that apoptosis contributed to deletion of p24-specific T cells during infection. Apoptosis correlated with increased percentages of p24-specific T cells that stained positive for Fas from infected mice, suggesting that P. yoelii-induced apoptosis is, at least in part, mediated by Fas. However, bystander cells of other specificities also showed increased Fas expression during infection, suggesting that Fas expression alone is not sufficient for apoptosis. These data have implications for the development of immunity in the face of endemic parasite exposure.
Local Costimulation Reinvigorates Tumor-Specific Cytolytic T Lymphocytes for Experimental Therapy in Mice with Large Tumor Burdens
Authors: Bai Xue-Feng , Bender Jonathan , Liu Jinqing , Zhang Huiming , Wang Yin , Li Ou , Du Peishuang , Zheng Pan , Liu Yang 
Published: April 2014

Abstract
Cytotoxic T cells recognize tumor Ags and destroy cancer cells in vitro. Adoptive transfer studies with transgenic T cells specific for tumor Ags have demonstrated that CTL are effective only in mice with small tumor burdens and thus appear to have limited potential in cancer immunotherapy. Here we used transgenic mice that express the TCR specific for an unmutated tumor Ag P1A and multiple lineages of P1A-expressing tumors to address this critical issue. We found that local costimulation, either by expression of B7-1 on the tumor cells or by local administration of anti-CD28 mAb 37N, reinvigorated the function of CTL specific for the tumor Ag, as it substantially increased the efficacy of CTL therapy for mice with large tumor burdens. Our study suggests that CTL-based immunotherapy can be manipulated to deal with large tumors.
Cutting Edge: IL-17F, a Novel Cytokine Selectively Expressed in Activated T Cells and Monocytes, Regulates Angiogenesis and Endothelial Cell Cytokine Production
Authors: Starnes Trevor , Robertson Michael J. , Sledge George , Kelich Stephanie , Nakshatri Harikrishna , Broxmeyer Hal E. , Hromas Robert 
Published: April 2014

Abstract
A novel secreted cytokine, termed IL-17F, was cloned using nested RACE PCR. This cytokine bears homology to IL-17. IL-17F was expressed only in activated CD4+ T cells and activated monocytes. Recombinant human IL-17F did not stimulate the proliferation of hematopoietic progenitors or the migration of mature leukocytes. However, it markedly inhibited the angiogenesis of human endothelial cells and induced endothelial cells to produce IL-2, TGF-β, and monocyte chemoattractant protein-1.
Cutting Edge: The Absence of C3 Demonstrates a Role for Complement in Th2 Effector Functions in a Murine Model of Pulmonary Allergy
Authors: Drouin Scott M. , Corry David B. , Kildsgaard Jens , Wetsel Rick A. 
Published: April 2014

Abstract
Asthma is a chronic disease of the lung resulting from airway obstruction. Although the initiating causes are not entirely clear, the airway inflammation in asthma is associated with Th2 lymphocytes and their cytokines, particularly IL-4, which play a prominent role in this disease by regulating airway hyperresponsiveness, eosinophil activation, and IgE synthesis. Historically, complement was not thought to contribute to the pathogenesis of asthma. However, using C3-deficient mice in an allergen-induced model of pulmonary allergy, we demonstrate that complement may impact key features of this disease. When challenged with allergen, mice deficient in C3 exhibit diminished airway hyperresponsiveness and lung eosinophilia. Furthermore, these mice also have dramatically reduced numbers of IL-4-producing cells and attenuated Ag-specific IgE and IgG1 responses. Collectively, these results demonstrate that C3-deficient mice have significantly altered allergic lung responses and indicate a role for the complement system in promoting Th2 effector functions in asthma.
Induction of IL-10 and Inhibition of Experimental Arthritis Are Specific Features of Microbial Heat Shock Proteins That Are Absent for Other Evolutionarily Conserved Immunodominant Proteins
Authors: Prakken Berent J. , Wendling Uwe , van der Zee Ruurd , Rutten Victor P. M. G. , Kuis Wietse , van Eden Willem 
Published: April 2014

Abstract
Bacterial heat shock proteins (hsp) are evolutionary conserved immunodominant proteins that manifest amino acid homologies with hsp present in mammalian cells. Preimmunization with mycobacterial hsp65 has been found to protect against various forms of experimental arthritis. As these protective effects have previously been attributed to induction of self homologue cross-reactive T cell responses, the question was raised as to whether this protective effect could be extended to other highly conserved and immunodominant microbial Ags with mammalian homologues. Therefore, we immunized Lewis rats with conserved bacterial Ags (superoxide dismutase, aldolase, GAPDH, and hsp70). Although all Ags appeared highly immunogenic, we only found a protective effect in experimental arthritis after immunization with bacterial hsp70. The protective effect of hsp70 was accompanied with a switch in the subclasses of hsp70-specific Abs, suggesting the induction of Th2-like response. The most striking difference between immunization with hsp70 and all other immunodominant Ags was the expression of IL-10 found after immunization with hsp70. Even more, while immunization with hsp70 led to Ag-induced production of IL-10 and IL-4, immunization with aldolase led to increased production of IFN-γ and TNF-α. Thus, the protective effect of conserved immunodominant proteins in experimental arthritis seems to be a specific feature of hsp. Therefore, hsp may offer unique possibilities for immunological intervention in inflammatory diseases.
Persistence of Dominant T Cell Clones in Accepted Solid Organ Transplants
Authors: Baron Christophe , McMorrow Isabel , Sachs David H , LeGuern Christian 
Published: April 2014

Abstract
Donor/recipient MHC class II matching is beneficial to the survival of allogeneic kidneys in humans and swine. In the latter, tolerance to class I-disparate grafts can be induced by a short course of immunosuppression, a peripheral mechanism that implicates regulatory T cells. Absence of treatment will lead to prompt rejection. Rejected grafts are infiltrated by dominant alloaggressive T cells, whereas there is still speculation on the specificity and function of T cells invading accepted tissues. To characterize the TCR repertoire of graft-infiltrating T cells (GITC) in accepted kidneys, we have used the RT-PCR-based spectratyping technique to assess the length polymorphism of the porcine TCRβ chain complementary-determining region 3 (CDR3). Results show that T cells infiltrating accepted kidneys (n = 5) express a restricted polymorphism of the CDR3 length, whereas PBL from the same animal have the polymorphic distribution of CDR3 lengths found in naive animals; that the skewed Vβ repertoire in accepted grafts involved distinct Vβ subfamilies in otherwise MHC-identical recipient animals; that GITC clonal dominance is not caused by immunosuppression because a second kidney, accepted without drug treatment, exhibits the same TCR Vβ CDR3 profiles than those detected in the first graft; and that intragraft clonal dominance intensifies with time, indicating progressive preeminence of nonaggressive GITC clones. Collectively, these data represent the first example, in a preclinical model, of the emergence of nonaggressive intragraft clones, which may be involved in the induction/maintenance of local tolerance to allogeneic tissues.
Enhancement of Mast Cell Survival: A Novel Function of Some Secretory Phospholipase A2 Isotypes
Authors: Fonteh Alfred N. , Marion Chad R. , Barham Brooke J. , Edens Michelle B. , Atsumi Gen-ichi , Samet James M. , High Kevin P. , Chilton Floyd H. 
Published: April 2014

Abstract
This study tested the hypothesis that certain secretory phospholipase A2 (sPLA2) isotypes act in a cytokine-like fashion through cell surface receptors to influence mast cell survival. Initial experiments revealed that sPLA2 activity and sPLA2 receptor expression are increased, and mast cells lost their capacity to maintain membrane asymmetry upon cytokine depletion. Groups IB and III, but not group IIA PLA2, prevented the loss of membrane asymmetry. Similarly, group IB prevented nucleosomal DNA fragmentation in mast cells. Providing putative products of sPLA2 hydrolysis to cytokine-depleted mast cells did not influence survival. Furthermore, catalytic inactivation of sPLA2 did not alter its capacity to prevent apoptosis. Inhibition of protein synthesis using cycloheximide or actinomycin reversed the antiapoptotic effect of sPLA2. Additionally, both wild-type and catalytically inactive group IB PLA2 induced IL-3 synthesis in mast cells. However, adding IL-3-neutralizing Ab did not change Annexin VFITC binding and only partially inhibited thymidine incorporation in sPLA2-supplemented mast cells. In contrast, IL-3-neutralizing Ab inhibited both Annexin VFITC binding and thymidine incorporation in mast cells maintained with IL-3. sPLA2 enhanced phosphoinositide 3′-kinase activity, and a specific inhibitor of phosphoinositide 3′-kinase reversed the antiapoptotic effects of sPLA2. Likewise, sPLA2 increased the degradation of I-κBα, and specific inhibitors of nuclear factor κ activation (NF-κB) reversed the antiapoptotic effects of sPLA2. Together, these experiments reveal that certain isotypes of sPLA2 enhance the survival of mast cells in a cytokine-like fashion by activating antiapoptotic signaling pathways independent of IL-3 and probably via sPLA2 receptors rather than sPLA2 catalytic products.
Unique Signaling Properties of B Cell Antigen Receptor in Mature and Immature B Cells: Implications for Tolerance and Activation
Authors: Benschop Robert J. , Brandl Erin , Chan Andrew C. , Cambier John C. 
Published: April 2014

Abstract
Immature B cells display increased sensitivity to tolerance induction compared with their mature counterparts. The molecular mechanisms underlying these differences are poorly defined. In this study, we demonstrate unique maturation stage-dependent differences in B cell Ag receptor (BCR) signaling, including BCR-mediated calcium mobilization responses. Immature B cells display greater increases in intracellular calcium concentrations following Ag stimulation. This has consequences for the induction of biologically relevant responses: immature B cells require lower Ag concentrations for activation than mature B cells, as measured by induction of receptor editing and CD86 expression, respectively. BCR-induced tyrosine phosphorylation of CD79a, Lyn, B cell linker protein, and phospholipase Cγ2 is enhanced in immature B cells and they exhibit greater capacitative calcium entry in response to Ag. Moreover, B cell linker protein, Bruton’s tyrosine kinase, and phospholipase Cγ2, which are crucial for the induction of calcium mobilization responses, are present at ∼3-fold higher levels in immature B cells, potentially contributing to increased mobilization of calcium. Consistent with this possibility, we found that the previously reported lack of inositol-1,4,5-triphosphate production in immature B cells may be explained by enhanced inositol-1,4,5-triphosphate breakdown. These data demonstrate that multiple mechanisms guarantee increased Ag-induced mobilization of calcium in immature B cells and presumably ensure elimination of autoreactive B cells from the repertoire.