bluuebunny/crossref_metadata_2025_split huggingface dataset:
TNF Enhances CD4+ T Cell Alloproliferation, IFN-γ Responses, and Intestinal Graft-Versus-Host Disease by IL-12-Independent Mechanisms
Authors: Brown Geri R. , Lee Edward L. , Thiele Dwain L. 
Published: April 2014

AbstractInhibition of TNF/TNFR2 interactions ameliorates intestinal graft-vs-host disease (GVHD) and Th1 cytokine responses induced by transfer of B6 CD4+ spleen cells into irradiated MHC class II disparate B6.C-H-2bm12 (bm12) × B6 F1 recipients. The present studies examined whether these effects of TNF are IL-12 dependent. T cell proliferative responses of B6.129S1-IL-12rb2tm1Jm (B6.IL-12R−/−) responder spleen cells were found to be comparable to those of control B6 spleen cells. TNF inhibition reduced T cell proliferation and IFN-γ production in supernatants of MLC using either B6.IL-12R−/− or control B6 responder cells. GVHD induced wasting disease in recipients of B6.IL-12R−/− CD4+ spleen cells that received a TNF inhibitor-encoding adenovirus (5.4 ± 6.5% weight loss (n = 7)) was significantly reduced compared with levels of weight loss observed in recipients that had received a control adenovirus (25.7 ± 12.2% weight loss (n = 11), p = 0.001). Furthermore, TNF inhibition was associated with a reduction in colonic GVHD scores (p = 0.039) and in the percentage of the splenic CD4+ T cells that expressed IFN-γ (16 vs 6%). These findings indicate that TNF promotes CD4+ T cell alloproliferation, IFN-γ responses, and intestinal GVHD by IL-12-independent mechanisms.
A Subset of Human Dendritic Cells in the T Cell Area of Mucosa-Associated Lymphoid Tissue with a High Potential to Produce TNF-α
Authors: de Baey Annegret , Mende Ines , Baretton Gustavo , Greiner Axel , Hartl Wolfgang H. , Baeuerle Patrick A. , Diepolder Helmut M. 
Published: April 2014

Abstract
Recently, a new class of human dendritic cell (DC) precursors has been described in the peripheral blood recognized by the mAb M-DC8. These cells represent ∼1% of PBMC and acquire several characteristics of myeloid DC upon in vitro culture. In this report we show that M-DC8+ monocytes secrete in response to LPS &gt;10 times the amount of TNF-α as M-DC8− monocytes, but produce significantly less IL-10. Consistent with a role in inflammatory responses, we found that M-DC8+ cells localized in the T cell area of inflamed human tonsils and in the subepithelial dome region of Peyer’s patches. In patients with active Crohn’s disease, abundant M-DC8+ cells were detectable in inflamed ileal mucosa, which were entirely depleted after systemic steroid treatment. Our results indicate that M-DC8+ cells are cells of DC phenotype in inflamed mucosa-associated lymphoid tissue that may contribute to the high level of TNF-α production in Crohn’s disease. We infer that selective elimination of M-DC8+ cells in inflammatory diseases has therapeutic potential.
Repertoire Shift in the Humoral Response to Phosphocholine-Keyhole Limpet Hemocyanin: VH Somatic Mutation in Germinal Center B Cells Impairs T15 Ig Function
Authors: Wiens Gregory D. , Brown McKay , Rittenberg Marvin B. 
Published: April 2014

AbstractPhosphocholine (PC) is a naturally occurring Ag common to many pathogenic microorganisms. Early in the primary response to PC conjugated to keyhole limpet hemocyanin (KLH), T15 Id+ Abs constitute &gt;90% of the serum Ig in BALB/c mice. During the late primary and memory response to PC-protein, a shift in the repertoire occurs and T15 Id+ Abs lose dominance. In this study, we use immunohistochemistry and single germinal center microdissection to locate T15 Id+ cells in the spleen in a primary response to PC-KLH. We demonstrate T15 Id+ B cells and VH1-DFL16.1-JH1 and Vκ22-Jκ5 rearrangements in germinal centers early in the immune response; thus loss of T15 dominance is not due to lack of T15 cells within germinal centers. One-hundred thirty one VH1 and 57 Vκ22 rearrangements were cloned and sequenced. Thirty four percent of the VH1 clones and 37% of the Vκ22 clones contained somatic mutations indicating participation in the germinal center response. Six variant T15 H clones were expressed with wild-type T15 L chain in vitro. Two of these Abs were defective in secretion providing the first evidence that mutation occurring in vivo can disrupt Ig assembly and secretion. Of the four secretion-competent Abs, two failed to display binding to PC-protein, while the other two displayed altered carrier recognition. These results indicate that somatic mutation of T15 in vivo can result in the loss of binding and secretion, potentially leading to B cell wastage. The failure of T15 to gain affinity enhancing mutations in the face of these detrimental changes may contribute to repertoire shift.
Prevalent Role of TCR α-Chain in the Selection of the Preimmune Repertoire Specific for a Human Tumor-Associated Self-Antigen
Authors: Dietrich Pierre-Yves , Le Gal Frédérique-Anne , Dutoit Valérie , Pittet Mikäel J. , Trautman Lydie , Zippelius Alfred , Cognet Isabelle , Widmer Valérie , Walker Paul R. , Michielin Olivier , Guillaume Philippe , Connerotte Thierry , Jotereau Francine , Coulie Pierre G. , Romero Pedro , Cerottini Jean-Charles , Bonneville Marc , Valmori Danila 
Published: April 2014

Abstract
The specificity of recognition of pMHC complexes by T lymphocytes is determined by the V regions of the TCR α- and β-chains. Recent experimental evidence has suggested that Ag-specific TCR repertoires may exhibit a more Vα- than Vβ-restricted usage. Whether Vα usage is narrowed during immune responses to Ag or if, on the contrary, restricted Vα usage is already defined at the early stages of TCR repertoire selection, however, has remained unexplored. Here, we analyzed V and CDR3 TCR regions of single circulating naive T cells specifically detected ex vivo and isolated with HLA-A2/melan-A peptide multimers. Similarly to what was previously observed for melan-A-specific Ag-experienced T cells, we found a relatively wide Vβ usage, but a preferential Vα 2.1 usage. Restricted Vα 2.1 usage was also found among single CD8+ A2/melan-A multimer+ thymocytes, indicating that Vα-restricted selection takes place in the thymus. Vα 2.1 usage, however, was independent from functional avidity of Ag recognition. Thus, interaction of the pMHC complex with selected Vα-chains contributes to set the broad Ag specificity, as underlined by preferential binding of A2/melan-A multimers to Vα 2.1-bearing TCRs, whereas functional outcomes result from the sum of these with other interactions between pMHC complex and TCR.
Decreased Binding of Peptides-MHC Class I (pMHC) Multimeric Complexes to CD8 Affects Their Binding Avidity for the TCR But Does Not Significantly Impact on pMHC/TCR Dissociation Rate
Authors: Dutoit Valérie , Guillaume Philippe , Ayyoub Maha , Hesdorffer Charles S. , Luescher Immanuel F. , Valmori Danila 
Published: April 2014

AbstractThe CD8 coreceptor plays a crucial role in both T cell development in the thymus and in the activation of mature T cells in response to Ag-specific stimulation. In this study we used soluble peptides-MHC class I (pMHC) multimeric complexes bearing mutations in the CD8 binding site that impair their binding to the MHC, together with altered peptide ligands, to assess the impact of CD8 on pMHC binding to the TCR. Our data support a model in which CD8 promotes the binding of TCR to pMHC. However, once the pMHC/TCR complex is formed, the TCR dominates the pMHC/TCR dissociation rates. As a consequence of these molecular interactions, under physiologic conditions CD8 plays a key role in complex formation, resulting in the enhancement of CD8 T cell functions whose specificity, however, is determined by the TCR.
Molecular Identification and Functional Expression of μ3, a Novel Alternatively Spliced Variant of the Human μ Opiate Receptor Gene
Authors: Cadet Patrick , Mantione Kirk J. , Stefano George B. 
Published: April 2014

Abstract
Studies from our laboratory have revealed a novel μ opiate receptor, μ3, which is expressed in both vascular tissues and leukocytes. The μ3 receptor is selective for opiate alkaloids and is insensitive to opioid peptides. We now identify the μ3 receptor at the molecular level using a 441-bp conserved region of the μ1 receptor. Sequence analysis of the isolated cDNA suggests that it is a novel, alternatively spliced variant of the μ opiate receptor gene. To determine whether protein expressed from this cDNA exhibits the biochemical characteristics expected of the μ3 receptor, the cDNA clone was expressed in a heterologous system. At the functional level, COS-1 cells transfected with the μ3 receptor cDNA exhibited dose-dependent release of NO following treatment with morphine, but not opioid peptides (i.e., Met-enkephalin). Naloxone was able to block the effect of morphine on COS-1 transfected cells. Nontransfected COS-1 cells did not produce NO in the presence of morphine or the opioid peptides at similar concentrations. Receptor binding analysis with [3H]dihydromorphine further supports the opiate alkaloid selectivity and opioid peptide insensitivity of this receptor. These data suggest that this new μ opiate receptor cDNA encodes the μ3 opiate receptor, since it exhibits biochemical characteristics known to be unique to this receptor (opiate alkaloid selective and opioid peptide insensitive). Furthermore, using Northern blot, RT-PCR, and sequence analysis, we have demonstrated the expression of this new μ variant in human vascular tissue, mononuclear cells, polymorphonuclear cells, and human neuroblastoma cells.
DNA Methylation and Chromatin Structure Regulate T Cell Perforin Gene Expression
Authors: Lu Qianjin , Wu Ailing , Ray Donna , Deng Chun , Attwood John , Hanash Samir , Pipkin Matthew , Lichtenheld Mathias , Richardson Bruce 
Published: April 2014

AbstractPerforin is a cytotoxic effector molecule expressed in NK cells and a subset of T cells. The mechanisms regulating its expression are incompletely understood. We observed that DNA methylation inhibition could increase perforin expression in T cells, so we examined the methylation pattern and chromatin structure of the human perforin promoter and upstream enhancer in primary CD4+ and CD8+ T cells as well as in an NK cell line that expresses perforin, compared with fibroblasts, which do not express perforin. The entire region was nearly completely unmethylated in the NK cell line and largely methylated in fibroblasts. In contrast, only the core promoter was constitutively unmethylated in primary CD4+ and CD8+ cells, and expression was associated with hypomethylation of an area residing between the upstream enhancer at −1 kb and the distal promoter at −0.3 kb. Treating T cells with the DNA methyltransferase inhibitor 5-azacytidine selectively demethylated this area and increased perforin expression. Selective methylation of this region suppressed promoter function in transfection assays. Finally, perforin expression and hypomethylation were associated with localized sensitivity of the 5′ flank to DNase I digestion, indicating an accessible configuration. These results indicate that DNA methylation and chromatin structure participate in the regulation of perforin expression in T cells.
The H4b Minor Histocompatibility Antigen Is Caused by a Combination of Genetically Determined and Posttranslational Modifications
Authors: Yadav Rajwardhan , Yoshimura Yoshitaka , Boesteanu Alina , Christianson Gregory J. , Ajayi Wilfred U. , Shashidharamurthy R. , Stanic Aleksandar K. , Roopenian Derry C. , Joyce Sebastian 
Published: April 2014

AbstractMinor histocompatibility (H) Ag disparities result in graft-vs-host disease and chronic solid allograft rejection in MHC-identical donor-recipient combinations. Minor H Ags are self protein-derived peptides presented by MHC class I molecules. Most arise as a consequence of allelic variation in the bound peptide (p) that results in TCR recognizing the p/MHC as foreign. We used a combinational peptide screening approach to identify the immune dominant H2Kb-restricted epitope defining the mouse H4b minor H Ag. H4b is a consequence of a P3 threonine to isoleucine change in the MHC-bound peptide derived from epithelial membrane protein-3. This allelic variation also leads to phosphorylation of the H4b but not the H4a epitope. Further, ex vivo CD8+ T lymphocytes bind phosphorylated Ag tetramers with high efficiency. Although we document the above process in the minor H Ag system, posttranslational modifications made possible by subtle amino acid changes could also contribute to immunogenicity and immune dominance in tumor immunotherapeutic settings.
Selective Regulation of Mature IgG1 Transcription by CD86 and β2-Adrenergic Receptor Stimulation
Authors: Podojil Joseph R. , Sanders Virginia M. 
Published: April 2014

AbstractStimulation of CD86 and the β2-adrenergic receptor (β2AR) on a B cell, either alone or together, is known to increase the level of IgG1 protein produced by a CD40 ligand/IL-4-activated B cell. It is also known that the mechanism by which CD40 and IL-4R stimulation on a B cell increases the level of IgG1 protein is by increasing germline γ1 transcription, IgG1 class switching, and mature IgG1 transcription, while the molecular mechanism responsible for mediating the CD86- and β2AR-induced effect remains unknown. In the present study using real-time PCR we show that the level of mature IgG1 transcription increases in CD40 ligand/IL-4-activated B cells following stimulation of either CD86 and/or β2AR, and that this increase reflects the increase in IgG1 protein. Furthermore, we show that the CD86- and/or β2AR-induced increase in mature IgG1 transcript is due to an increase in the rate of mature IgG1 transcription, as determined by nuclear run-on analysis. This effect is additive when both receptors are stimulated and is lost when B cells from CD86- and β2AR-deficient mice are used. In contrast, the level of germline γ1 transcription, the stability of mature IgG1 transcript, the number of IgG1-positive B cells, and the number of IgG1-secreting B cells did not change. These results provide the first evidence that CD86 and/or β2AR stimulation on a CD40 ligand/IL-4-activated B cell increases the level of IgG1 protein produced per cell by increasing the rate of mature IgG1 transcription.
The Relative Contribution of IL-4 Receptor Signaling and IL-10 to Susceptibility toLeishmania major
Authors: Noben-Trauth Nancy , Lira Rosalia , Nagase Hisashi , Paul William E. , Sacks David L. 
Published: April 2014

AbstractThe roles of IL-10 and IL-4 receptor signaling were evaluated in a murine model of Leishmania major infection. In previous studies the L. major substrain LV39 caused progressive, nonhealing lesions in BALB/c mice deficient for IL-4R α-chain (IL-4Rα), while substrain IR173 was highly controlled. To explore whether IL-10 is responsible for inducing susceptibility to LV39, wild-type and IL-4Rα−/− mice were treated with anti-IL-10R mAb, and in a genetic approach, the IL-4Rα−/− mice were crossed with BALB/c IL-10−/− mice. In contrast to the lack of resistance conferred by IL-4Rα gene deletion, partial resistance to LV39 was conferred by IL-10 gene deletion or treatment of BALB/c mice with anti-IL-10R mAb. Lesion sizes and LV39 parasite numbers were further and dramatically reduced in both anti-IL-10R-treated IL-4Rα−/− mice and IL-4Rα × IL-10 double knockouts. Anti-IL-10R mAb treatment further suppressed parasite growth in IL-4Rα−/− mice infected with L. major IR173. Production of IFN-γ was only increased relative to wild-type or littermate controls in IL-4Rα−/− mice with complementary defects in IL-10. Comparisons of IFN-γ-treated infected macrophages in vitro indicated that LV39 required 25- to 500-fold greater concentrations of IFN-γ than IR173-infected macrophages to achieve a similar efficiency of parasite killing. These studies suggest that regardless of parasite substrain, IL-10 is as important as IL-4/IL-13 in promoting susceptibility to L. major and even more so for those substrains that are relatively resistant to IFN-γ mediated killing.
Toll-Like Receptor 2 (TLR2) and TLR9 Signaling Results in HIV-Long Terminal RepeatTrans-Activation and HIV Replication in HIV-1 Transgenic Mouse Spleen Cells: Implications of Simultaneous Activation of TLRs on HIV Replication
Authors: Equils Ozlem , Schito Marco L. , Karahashi Hiase , Madak Zeynep , Yarali Ayse , Michelsen Kathrin S. , Sher Alan , Arditi Moshe 
Published: April 2014

AbstractOpportunistic infections are common in HIV-infected patients; they activate HIV replication and contribute to disease progression. In the present study we examined the role of Toll-like receptor 2 (TLR2) and TLR9 in HIV-long terminal repeat (HIV-LTR) trans-activation and assessed whether TLR4 synergized with TLR2 or TLR9 to induce HIV replication. Soluble Mycobacterium tuberculosis factor (STF) and phenol-soluble modulin from Staphylococcus epidermidis induced HIV-LTR trans-activation in human microvessel endothelial cells cotransfected with TLR2 cDNA. Stimulation of ex vivo spleen cells from HIV-1 transgenic mice with TLR4, TLR2, and TLR9 ligands (LPS, STF, and CpG DNA, respectively) induced p24 Ag production in a dose-dependent manner. Costimulation of HIV-1 transgenic mice spleen cells with LPS and STF or CpG DNA induced TNF-α and IFN-γ production in a synergistic manner and p24 production in an additive fashion. In the THP-1 human monocytic cell line stably expressing the HIV-LTR-luciferase construct, LPS and STF also induced HIV-LTR trans-activation in an additive manner. This is the first time that TLR2 and TLR9 and costimulation of TLRs have been shown to induce HIV replication. Together these results underscore the importance of TLRs in bacterial Ag- and CpG DNA-induced HIV-LTR trans-activation and HIV replication. These observations may be important in understanding the role of the innate immune system and the molecular mechanisms involved in the increased HIV replication and HIV disease progression associated with multiple opportunistic infections.
The Toll-Like Receptor 5 Stimulus Bacterial Flagellin Induces Maturation and Chemokine Production in Human Dendritic Cells
Authors: Means Terry K. , Hayashi Fumitaka , Smith Kelly D. , Aderem Alan , Luster Andrew D. 
Published: April 2014

AbstractToll-like receptors (TLRs) are pattern recognition receptors that serve an important function in detecting pathogens and initiating inflammatory responses. Upon encounter with foreign Ag, dendritic cells (DCs) go through a maturation process characterized by an increase in surface expression of MHC class II and costimulatory molecules, which leads to initiation of an effective immune response in naive T cells. The innate immune response to bacterial flagellin is mediated by TLR5, which is expressed on human DCs. Therefore, we sought to investigate whether flagellin could induce DC maturation. Immature DCs were cultured in the absence or presence of flagellin and monitored for expression of cell surface maturation markers. Stimulation with flagellin induced increased surface expression of CD83, CD80, CD86, MHC class II, and the lymph node-homing chemokine receptor CCR7. Flagellin stimulated the expression of chemokines active on neutrophils (IL-8/CXC chemokine ligand (CXCL)8, GRO-α/CXCL1, GRO-β/CXCL2, GRO-γ/CXCL3), monocytes (monocyte chemoattractant protein-1/CC chemokine ligand (CCL)2), and immature DCs (macrophage-inflammatory protein-1α/CCL3, macrophage-inflammatory protein-1β/CCL4), but not chemokines active on effector T cells (IFN-inducible protein-10 kDa/CXCL10, monokine induced by IFN-γ/CXCL9, IFN-inducible T cell α chemoattractant/CXCL11). However, stimulating DCs with both flagellin and IFN-inducible protein-10 kDa, monokine induced by IFN-γ, and IFN-inducible T cell α chemoattractant expression, whereas stimulation with IFN-β or flagellin alone failed to induce these chemokines. In functional assays, flagellin-matured DCs displayed enhanced T cell stimulatory activity with a concomitant decrease in endocytic activity. Finally, DCs isolated from mouse spleens or bone marrows were shown to not express TLR5 and were not responsive to flagellin stimulation. These results demonstrate that flagellin can directly stimulate human but not murine DC maturation, providing an additional mechanism by which motile bacteria can initiate an acquired immune response.
The Induction of HIV Gag-Specific CD8+ T Cells in the Spleen and Gut-Associated Lymphoid Tissue by Parenteral or Mucosal Immunization with RecombinantListeria monocytogenesHIV Gag
Authors: Peters Christian , Peng Xiaohui , Douven Dennis , Pan Zhen-Kun , Paterson Yvonne 
Published: April 2014

AbstractThe induction of mucosal immunity is crucial in controlling viral replication during HIV infection. In this study we compare the ability of a recombinant Listeria monocytogenes that expresses and secretes the HIV Ag Gag to induce CD8+ T cells against this Ag in the spleen, mesenteric lymph nodes, and Peyer’s patches and the ability to provide effector Gag-specific CD8+ T cells to the lamina propria after i.v., oral, or rectal administration of the vaccine. The levels of Ag-specific CD8+-activated T cells were measured ex vivo using intracellular cytokine staining for IFN-γ and H-2Kd Gag peptide tetramer staining. We found that all routes of immunization induced Gag-specific CD8+ T cells in the spleen. After secondary infection, we observed substantial increases in splenic levels of CD8+ T cells, and levels of Gag-specific cells were similar to those against listeriolysin O, the immunodominant Ag of L. monocytogenes. Both primary and secondary oral immunization resulted in abundant Gag-specific CD8+-activated T cells in the lamina propria that constituted ∼35% of the CD8 compartment. However, significant levels of Gag and listeriolysin O-specific CD8+ T cells were observed in mucosal lymphoid tissue only after two immunizations, perhaps because they had already entered the lamina propria compartment after a single immunization. In the context of HIV, a mucosally administered vaccine seems best calculated to prompt an immune response that is capable of preventing infection. The data presented in this report demonstrate that mucosally administered Listeria can prompt such a response and that booster doses can maintain this response.
A Single Heteroclitic Epitope Determines Cancer Immunity After Xenogeneic DNA Immunization Against a Tumor Differentiation Antigen
Authors: Gold Jason S. , Ferrone Cristina R. , Guevara-Patiño Jose A. , Hawkins William G. , Dyall Ruben , Engelhorn Manuel E. , Wolchok Jedd D. , Lewis Jonathan J. , Houghton Alan N. 
Published: April 2014

Abstract
Successful active immunization against cancer requires induction of immunity against self or mutated self Ags. However, immunization against self Ags is difficult. Xenogeneic immunization with orthologous Ags induces cancer immunity. The present study evaluated the basis for immunity induced by active immunization against a melanoma differentiation Ag, gp100. Tumor rejection of melanoma was assessed after immunization with human gp100 (hgp100) DNA compared with mouse gp100 (mgp100). C57BL/6 mice immunized with xenogeneic full-length hgp100 DNA were protected against syngeneic melanoma challenge. In contrast, mice immunized with hgp100 DNA and given i.p. tolerizing doses of the hgp100 Db-restricted peptide, hgp10025–33, were incapable of rejecting tumors. Furthermore, mice immunized with DNA constructs of hgp100 in which the hgp10025–27 epitope was substituted with the weaker Db-binding epitope from mgp100 (mgp10025–27) or a mutated epitope unable to bind Db did not reject B16 melanoma. Mice immunized with a minigene construct of hgp10025–33 rejected B16 melanoma, whereas mice immunized with the mgp10025–33 minigene did not develop protective tumor immunity. In this model of xenogeneic DNA immunization, the presence of an hgp100 heteroclitic epitope with a higher affinity for MHC created by three amino acid (25 to 27) substitutions at predicted minor anchor residues was necessary and sufficient to induce protective tumor immunity in H-2b mice with melanoma.