bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proinflammatory and Th2-Derived Cytokines Modulate CD40-Mediated Expression of Inflammatory Mediators in Airway Epithelia: Implications for the Role of Epithelial CD40 in Airway Inflammation
Authors: Propst Stacie M. , Denson Raquia , Rothstein Emily , Estell Kim , Schwiebert Lisa M. 
Published: April 2014

Abstract
Cytokines produced by activated macrophages and Th2 cells within the lung play a key role in asthma-associated airway inflammation. Additionally, recent studies suggest that the molecule CD40 modulates lung immune responses. Because airway epithelial cells can act as immune effector cells through the expression of inflammatory mediators, the epithelium is now considered important in the generation of asthma-associated inflammation. Therefore, the goal of the present study was to examine the effects of proinflammatory and Th2-derived cytokines on the function of CD40 in airway epithelia. The results show that airway epithelial cells express CD40 and that engagement of epithelial CD40 induces a significant increase in expression of the chemokines RANTES, monocyte chemoattractant protein (MCP-1), and IL-8 and the adhesion molecule ICAM-1. Cross-linking epithelial CD40 had no effect on expression of the adhesion molecule VCAM-1. The proinflammatory cytokines TNF-α and IL-1β and the Th2-derived cytokines IL-4 and IL-13 modulated the positive effects of CD40 engagement on inflammatory mediator expression in airway epithelial cells. Importantly, CD40 ligation enhanced the sensitivity of airway epithelial cells to the effects of TNF-α and/or IL-1β on expression of RANTES, MCP-1, IL-8, and VCAM-1. In contrast, neither IL-4 nor IL-13 modified the effects of CD40 engagement on the expression of RANTES, MCP-1, IL-8, or VCAM-1; however, both IL-4 and IL-13 attenuated the effects of CD40 cross-linking on ICAM-1 expression. Together, these findings suggest that interactions between CD40-responsive airway epithelial cells and CD40 ligand+ leukocytes, such as activated T cells, eosinophils, and mast cells, modulate asthma-associated airway inflammation.
Inhibition of Keratinocyte Apoptosis by IL-15: A New Parameter in the Pathogenesis of Psoriasis?
Authors: Rückert René , Asadullah Khusru , Seifert Martina , Budagian Vadim M. , Arnold Ralf , Trombotto Claudia , Paus Ralf , Bulfone-Paus Silvia 
Published: April 2014

Abstract
Keratinocytes (KC) are important source of and targets for several cytokines. Although KC express IL-15 mRNA, the functional effects of IL-15 on these epithelial cells remain to be dissected. Investigating primary human foreskin KC and HaCaT cells, we show here by semiquantitative RT-PCR and flow cytometric analysis that both translate IL-15 and IL-15R mRNA and express IL-15 and IL-15Rα protein on the cell surface, suggesting that human KC can employ IL-15 for juxtacrine signaling. While IL-15 exerted no significant effect on KC proliferation and IL-6 or IL-8 secretion, IL-15 inhibited both anti-Fas and methylcellulose-induced KC apoptosis in vitro. This is in line with the recognized potent anti-apoptotic effects of IL-15. IL-2, whose receptor shares two components with the IL-15R, failed to inhibit KC apoptosis. Together with the role of IL-15 in sustaining chronic immune reactions, this invited the question of whether a reduction of KC apoptosis by IL-15 may be involved in the pathogenesis of psoriasis, a chronic hyperproliferative inflammatory skin disease characterized by abnormally low KC apoptosis in the epidermis. Remarkably, compared with nonlesional psoriatic skin and skin of healthy volunteers, lesional psoriatic epidermis showed high IL-15 protein expression in the epidermis and enhanced binding activity for IL-15. Therefore, antagonizing the inhibitory effects of IL-15 on KC apoptosis deserves exploration as a novel therapeutic strategy in psoriasis management.
Status of Activation of Circulating Vaccine-Elicited CD8+ T Cells
Authors: Nielsen Mai-Britt , Monsurro Vladia , Migueles Stephen A. , Wang Ena , Perez-Diez Ainhoa , Lee Kang-Hun , Kammula Udai , Rosenberg Steven A. , Marincola Francesco M. 
Published: April 2014

Abstract
Selective blunting of the status of activation of circulating tumor-specific T cells was invoked to explain their paradoxical coexistence with unhampered tumor growth. By analogy, lack of tumor regression in the face of observable melanoma vaccine-induced T cell responses might be attributed to their status of activation. We enumerated with HLA-A*0201/peptide tetramers (tHLA) vaccine-elicited T cell precursor frequency directly in PBMC of patients with melanoma undergoing vaccination with the HLA-A*0201-associated gp100:209–217(210 M) epitope (g209-2 M). Furthermore, we tested by intracellular (IC)-FACS analysis and quantitative real-time PCR (qRT-PCR) the ability of postvaccination PBMC to produce cytokine in response to challenge with vaccine-related epitopes or vaccine-matched (HLA-A*0201) melanoma cells. Vaccine-induced enhancement of T cell precursor frequency could be detected with tHLA in PBMC from six of eight patients studied at frequencies ranging between 0.3 and 2.3% of the total CD8+ population. Stimulation with vaccine-related epitopes induced IFN-γ expression detectable by IC-FACS or qRT-PCR, respectively, in five and six of these patients. Furthermore, down-regulation of tHLA staining was noted upon cognate stimulation that could be utilized as an additional marker of T cell responsiveness. Finally, we observed in six patients an enhancement of reactivity against vaccine-matched tumor targets that was partly independent of documented vaccine-specific immune responses. A strong correlation was noted between tHLA staining of postvaccination PBMC and IFN-γ expression by the same samples upon vaccine-relevant stimulation and assessed either by IC-FACS or qRT-PCR. Thus, blunting of the status of T cell activation on itself cannot easily explain the lack of clinical responses observed with vaccination.
Cutting Edge: DC-SIGN; a Related Gene, DC-SIGNR; and CD23 Form a Cluster on 19p13
Authors: Soilleux Elizabeth J. , Barten Roland , Trowsdale John 
Published: April 2014

AbstractDC-SIGN is a C-type lectin, expressed on a dendritic cell subset. It is able to bind ICAM3 and HIV gp120 in a calcium-dependent manner. Here we report the genomic organization of DC-SIGN and map it to chromosome 19p13 adjacent to the C-type lectin CD23 (FcεRII). We also report a novel, closely linked gene, DC-SIGNR, which shows 73% identity to DC-SIGN at the nucleic acid level and a similar genomic organization. Proteins encoded by both genes have tracts of repeats of 23 aa, predicted to form a coiled coil neck region. They also possess motifs that are known to bind mannose in a calcium-dependent fashion. We show concomitant expression of the two genes in endometrium, placenta, and stimulated KG1 cells (phenotypically similar to monocyte-derived dendritic cells). The existence of a DC-SIGN-related gene calls for reinterpretation of the HIV data to consider possible DC-SIGN/DC-SIGNR hetero-oligomerization.
Amelioration of Experimental Autoimmune Uveoretinitis by Pretreatment with a Pathogenic Peptide in Liposome and Anti-CD40 Ligand Monoclonal Antibody
Authors: Namba Kenichi , Ogasawara Kazumasa , Kitaichi Nobuyoshi , Morohashi Taiki , Sasamoto Yoichi , Kotake Satoshi , Matsuda Hidehiko , Iwabuchi Kazuya , Iwabuchi Chikako , Ohno Shigeaki , Onoé Kazunori 
Published: April 2014

AbstractWe have defined a peptide K2 (ADKDVVVLTSSRTGGV) that corresponds to residues 201–216 of bovine interphotoreceptor retinoid-binding protein and induces experimental autoimmune uveoretinitis (EAU)4 in H-2Ak-carrying mice (H-2Ak mice). In this study, we attempted to ameliorate EAU in the H-2Ak mice without nonspecific suppression of T cell responses. Preceding s.c. administration of liposomes including K2 (liposomal K2) specifically inhibited subsequent generation of T cell response to K2. The same result was obtained with a combination of OVA323–339 peptide and the OVA-specific TCR-transgenic T cells. It was suggested that the inhibition was mainly attributed to peripheral anergy induction of T cells specific for the peptide Ag, although specific cell death might also be involved in the inhibition. Pretreatment with liposomal K2 also considerably abolished IFN-γ production but not IL-4 production. The specific inhibitory effect of the pretreatment with liposomal peptide was augmented by a simultaneous administration of anti-CD40 ligand (anti-CD40L) mAb. Moreover, it was shown that the pretreatment with liposomal K2 reduced both the incidence and severity of the subsequent K2-induced EAU, and the simultaneous administration of anti-CD40L mAb augmented this preventive effect by liposomal K2. Our findings demonstrate that the s.c. administration of liposomal pathogenic peptide and anti-CD40L mAb can be applied to preventing autoimmune diseases without detrimental nonspecific suppression of T cell responses.
Spontaneous Thymocyte Apoptosis Is Regulated by a Mitochondrion-Mediated Signaling Pathway
Authors: Zhang Jian , Mikecz Katalin , Finnegan Alison , Glant Tibor T. 
Published: April 2014

Abstract
Most thymocytes that have not successfully rearranged their TCR genes or that express a receptor with subthreshold avidity for self-Ag/MHC enter a default apoptosis pathway, death by neglect. Spontaneous thymocyte apoptosis (STA), at least in part, may mimic this process in vitro. However, the molecular mechanism(s) by which thymocytes undergo this spontaneous apoptosis remains unknown. Here, we report that caspsase-1 and caspase-3 are activated during STA, but these caspases are dispensable for this apoptotic process. The inhibition of STA by a pan-caspase inhibitor, zVAD, suggests that multiple caspase pathways exist. Importantly, the early release of cytochrome c from mitochondria closely correlates with the degradation of Bcl-2 and Bcl-xL and a decrease in the ratios of Bcl-2 and Bcl-xL to Bax during STA. These findings suggest that the degradation of Bcl-2 and Bcl-xL may favor Bax to induce cytochrome c release from mitochondria, which subsequently activates downstream caspases in STA. Our data provide the first biochemical insight into the molecular mechanism of STA.
EBV Persistence Involves Strict Selection of Latently Infected B Cells
Authors: Joseph Alexandra M. , Babcock Gregory J. , Thorley-Lawson David A. 
Published: April 2014

Abstract
EBV is found preferentially in IgD− B cells in the peripheral blood. This has led to the proposal that the recirculating memory B cell pool is the site of long-lived persistent infection. In this paper we have used CD27, a newly identified specific marker for memory B cells, to test this hypothesis. We show that EBV is tightly restricted in its expression. Less than 1 in 1000 of the infected cells in the peripheral blood are naive (IgD+, CD27−) and &lt;1 in 250 are IgD+ memory cells. Furthermore, EBV was undetectable in the self-renewing peripheral CD5+ or B1 cells, a subset that has not been through a germinal center. No such restriction was observed in tonsillar B cells. Therefore, the virus has access to a range of B cell subsets in the lymph nodes but is tightly restricted to a specific long-lived compartment of B cells, the IgD−, CD27+, and CD5− memory B cells, in the periphery. We suggest that access to this compartment is essential to allow the growth-promoting latent genes to be switched off to create a site of persistent infection that is neither pathogenic nor a target for immunosurveillance.
Activin A Stimulates Type IV Collagenase (Matrix Metalloproteinase-2) Production in Mouse Peritoneal Macrophages
Authors: Ogawa Kenji , Funaba Masayuki , Mathews Lawrence S. , Mizutani Takeo 
Published: April 2014

Abstract
The role of activin, a dimer of inhibin β subunit, in mouse peritoneal macrophages was evaluated. Activin activity in the cultured macrophages was augmented in response to activation by LPS. In Western blot analysis, immunoreactive activin A was detected in the culture medium only when the macrophages were stimulated by LPS. Although mRNA expression of βA subunit was detected, that of α and βB subunit was not found in macrophages by reverse RT-PCR. The activin βA mRNA level was increased in macrophages by LPS, suggesting that the activin production augmented by LPS is regulated at the mRNA level of the βA gene. The mRNAs of four activin receptors (ActRI, ActRIB, ActRII, and ActRIIB) were also detected in the peritoneal macrophages, and the mRNA levels, except for ActRIB, were decreased during the LPS treatment. Exogenous activin A stimulated the mRNA expression and gelatinolytic activity of matrix metalloproteinase-2 (MMP-2) in macrophages in both the presence and the absence of LPS. In contrast, activin did not affect the production of MMP-9 in macrophages. These results suggested that 1) mouse peritoneal macrophages produced activin A; 2) expression of activin A was enhanced with activation of the macrophages; 3) the macrophages also expressed activin receptors; and 4) exogenous activin A stimulated MMP-2 expression and activity, implicating activin A as an positive regulator of MMP-2 expression. Considering that MMP-2 constitutes the rate-limiting proteinase governing the degradation of basement membrane collagens, activin A may be involved in migration and infiltration of macrophages through the basement membrane in an inflammatory state.
TCR Signaling for Initiation and Completion of Thymocyte Positive Selection Has Distinct Requirements for Ligand Quality and Presenting Cell Type
Authors: Yasutomo Koji , Lucas Bruno , Germain Ronald N. 
Published: April 2014

AbstractThymocyte selection involves signaling by TCR engaging diverse self-peptide:MHC molecule ligands on various cell types in the cortex and medulla. Here we separately analyze early and late stages of selection to better understand how presenting cell type, ligand quality, and the timing of TCR signaling contribute to intrathymic differentiation. TCR transgenic CD4+CD8+ thymocytes (double positive (DP)) from MHC-deficient mice were stimulated using various presenting cells and ligands. The resulting CD69high cells were isolated and evaluated for maturation in reaggregate cultures with wild-type or MHC molecule-deficient thymic stroma with or without added hemopoietic dendritic cells (DC). Production of CD4+ T cells required TCR signaling in the reaggregates, indicating that transient recognition of self-ligands by DP is inadequate for full differentiation. DC bearing a potent agonist ligand could initiate positive selection, producing activated thymocytes that matured into agonist-responsive T cells in reaggregates lacking the same ligand. DC could also support the TCR signaling necessary for late maturation. These results argue that despite the negative role assigned to DC in past studies, neither the peptide:MHC molecule complexes present on DC nor any other signals provided by these cells stimulate only thymocyte death. These findings also indicate that unique epithelial ligands are not necessary for positive selection. They provide additional insight into the role of ligand quality in selection events and support the concept that following initiation of maturation from the DP state, persistent TCR signaling is characteristic of and perhaps required by T cells.
The OX40 Costimulatory Receptor Determines the Development of CD4 Memory by Regulating Primary Clonal Expansion
Authors: Gramaglia Irene , Jember Amha , Pippig Susanne D. , Weinberg Andrew D. , Killeen Nigel , Croft Michael 
Published: April 2014

Abstract
The costimulatory receptor OX40 has recently been shown to be involved in primary CD4 responses to several defined Ags. However, to date there has been little information regarding the mechanism of action of OX40, such as whether it regulates T cell numbers, reactivity, or both, and whether it contributes to induction of long-term T cell responses. With an agonist Ab to OX40, and by tracking Ag-specific TCR transgenic T cells in vivo, we show that ligation of OX40 induces clonal expansion and survival of CD4 cells during primary responses, and results in the accumulation of greater numbers of memory cells with time. Significantly, OX40-deficient T cells, from mice generated by gene targeting, secrete IL-2 and proliferate normally during the initial period of activation, but cannot sustain this during the latter phases of the primary response, exhibiting decreased survival over time. Mice lacking OX40 develop only low frequencies of Ag-specific CD4 cells late in primary responses in vivo and generate dramatically lower frequencies of surviving memory cells. These results demonstrate that OX40-OX40L interactions control primary T cell expansion and the ability to retain high numbers of Ag-specific T cells. In this way, OX40 signals promote survival of greater numbers of T cells with time and control the size of the memory T cell pool.
Inhibition of IFN-γ-Induced Janus Kinase-1-STAT1 Activation in Macrophages by Vasoactive Intestinal Peptide and Pituitary Adenylate Cyclase-Activating Polypeptide
Authors: Delgado Mario , Ganea Doina 
Published: April 2014

Abstract
The vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating polypeptide (PACAP), two immunomodulatory neuropeptides that affect both innate and acquired immunity, down-regulate IL-12 p40 and inducible NO synthase expression in LPS/IFN-γ-stimulated macrophages. We showed previously that VIP/PACAP inhibit NF-κB nuclear translocation through the stabilization of IκB and reduce IFN regulatory factor-1 (IRF-1) binding to the regulatory elements found in the IL-12 p40 and inducible NO synthase promoters. In this paper we studied the molecular mechanisms involved in the VIP/PACAP regulation of IRF-1 transactivating activity. Our studies indicate that the inhibition in IRF-1 binding correlates with a reduction in IRF-1 protein and mRNA in IFN-γ-treated Raw 264.7 macrophages. In agreement with the described Janus kinase (Jak)1/Jak2/STAT1/IRF-1 activation pathway, VIP/PACAP inhibit Jak1/Jak2, STAT1 phosphorylation, and the binding of STAT1 to the GAS sequence motif in the IRF-1 promoter. The effects of VIP/PACAP are mediated through the specific VIP/PACAP receptor-1 and the cAMP/protein kinase A (PKA) transduction pathway, but not through the induction of suppressor of cytokine signaling-1 or suppressor of cytokine signaling-3. Because IFN-γ is a major stimulator of innate immune responses in vivo, the down-regulation of IFN-γ-induced gene expression by VIP and PACAP could represent a significant element in the regulation of the inflammatory response by endogenous neuropeptides.
Ceramide-Induced TCR Up-Regulation
Authors: Menné Charlotte , Lauritsen Jens Peter H. , Dietrich Jes , Kastrup Jesper , Wegener Anne-Marie K. , Ødum Niels , Geisler Carsten 
Published: April 2014

Abstract
The TCR is a constitutively recycling receptor meaning that a constant fraction of TCR from the plasma membrane is transported inside the cell at the same time as a constant fraction of TCR from the intracellular pool is transported to the plasma membrane. TCR recycling is affected by protein kinase C activity. Thus, an increase in protein kinase C activity affects TCR recycling kinetics leading to a new TCR equilibrium with a reduced level of TCR expressed at the T cell surface. Down-regulation of TCR expression compromises T cell activation. Conversely, TCR up-regulation is expected to increase T cell responsiveness. The purpose of this study was to identify and characterize potential pathways for TCR up-regulation. We found that ceramide affected TCR recycling dynamics and induced TCR up-regulation in a concentration- and time-dependent manner. Experiments applying phosphatase inhibitors indicated that ceramide-induced TCR up-regulation was most probably mediated by serine/threonine protein phosphatase 2A. Analyses of T cell variants demonstrated that TCR up-regulation was dependent on the presence of an intact CD3γ L-based motif and thus acted on TCR engaged in the recycling pathway. Finally, we showed that TCR up-regulation probably plays a physiological role by increasing T cell responsiveness. Thus, by affecting the TCR recycling kinetics, T cells have the potential both to up- and down-regulate TCR expression and thereby adjust T cell responsiveness.
Thymic Selection Generates T Cells Expressing Self-Reactive TCRs in the Absence of CD45
Authors: Trop Sébastien , Charron Josée , Arguin Chantal , Hugo Patrice 
Published: April 2014

Abstract
The CD45 protein tyrosine phosphatase regulates Ag receptor signaling in T and B cells. In the absence of CD45, TCR coupling to downstream signaling cascades is profoundly reduced. Moreover, in CD45-null mice, the maturation of CD4+CD8+ thymocytes into CD4+CD8− or CD4−CD8+ thymocytes is severely impaired. These findings suggest that thymic selection may not proceed normally in CD45-null mice, and may be biased in favor of thymocytes expressing TCRs with strong reactivity toward self-MHC-peptide ligands to compensate for debilitated TCR signaling. To test this possibility, we purified peripheral T cells from CD45-null mice and fused them with the BWα−β− thymoma to generate hybridomas expressing normal levels of TCR and CD45. The reactivity of these hybridomas to self or foreign MHC-peptide complexes was assessed by measuring the amount of IL-2 secreted upon stimulation with syngeneic or allogeneic splenocytes. A very high proportion (55%) of the hybridomas tested reacted against syngeneic APCs, indicating that the majority of T cells in CD45-null mice express TCRs with high avidity for self-MHC-peptide ligands, and are thus potentially autoreactive. Furthermore, a large proportion of TCRs selected in CD45-null mice (H-2b) were also shown to display reactivity toward closely related MHC-peptide complexes, such as H-2bm12. These results support the notion that modulating the strength of TCR-mediated signals can alter the outcome of thymic selection, and demonstrate that CD45, by molding the window of affinity/avidity for positive and negative selection, directly participates in the shaping of the T cell repertoire.
Critical Relationship Between TCR Signaling Potential and TCR Affinity During Thymocyte Selection
Authors: Love Paul E. , Lee Jan , Shores Elizabeth W. 
Published: April 2014

AbstractWhether a developing thymocyte becomes positively or negatively selected is thought to be determined by the affinity/avidity of its TCR for MHC/peptide ligands expressed in the thymus. Presumably, differences in affinity translate into differences in the potency of the ensuing TCR-mediated signals, and these differences in signal strength determine the outcome of thymocyte selection. However, there is little direct evidence establishing a relationship between TCR-ligand affinity and signal strength during positive and negative selection. The TCR complex contains multiple signaling motifs, known as immunoreceptor tyrosine-based activation motifs (ITAMs) that are required for T cell activation. To examine the effects of TCR signal strength on selection, the signaling potential of the TCR was modified by substituting transgenic TCR ζ-chains containing either three, one, or zero ITAMs for endogenous (3-ITAM) ζ-chain. These ζ-chain variants were then bred into different αβTCR transgenic backgrounds. We report that reductions in TCR signaling potential have distinct effects on the selection of thymocytes expressing different TCRs, and that the requirement for ζ-chain ITAMs critically depends upon the specificity and apparently, affinity, of the TCR for its selecting ligand(s).