bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Distinct Role of Neutrophil Lactoferrin in RelA/p65 Phosphorylation on Ser536 by Recruiting TNF Receptor-Associated Factors to IκB Kinase Signaling Complex
Authors: Oh Sang-Muk , Lee Shin-Hee , Lee Bum-Jin , Pyo Chul-Woong , Yoo Na-Kyung , Lee Soo Young , Kim Jiyoung , Choi Sang-Yun 
Published: April 2014

Abstract
The activation of NF-κB by neutrophil lactoferrin (Lf) is regulated via the IκB kinase (IKK) signaling cascade, resulting in the sequential phosphorylation and degradation of IκB. In this study, we observed that Lf protein augmented p65 phosphorylation at the Ser536, but not the Ser276 residue, and stimulated the translocation of p65 into the nucleus. Lf was also shown to enhance the association between p65 and CREB-binding protein/p300 in vivo. To elucidate the mechanism by which Lf triggers these signaling pathways, we attempted to delineate the roles of the upstream components of the IKK complex, using their dominant-negative mutants and IKKα−/− and IKKβ−/− mouse embryonic cells. We demonstrated that both IKKα and IKKβ as well as NF-κB-inducing kinase are indispensable for Lf-induced p65 phosphorylation. However, MAPK kinase kinase 1 is not essentially required for this activation. We also observed that Lf-induced p65 phosphorylation was either partially or completely abrogated as the result of treatment with the mutant forms of TNFR-associated factor (TRAF) 2, TRAF5, or TRAF6. Moreover, we demonstrated that Lf directly interacted with TRAF5. Expression of the dominant-negative mutant of TRAF5 or its small interfering RNA almost completely abrogated the Lf-induced p65 phosphorylation. These results suggest that signaling pathways, including TRAFs/NF-κB-inducing kinase/IKKs, may be involved in the regulation of Lf-induced p65 activation, thereby resulting in the activation of members of the NF-κB family.
Lymphotoxin Pathway and Aire Influences on Thymic Medullary Epithelial Cells Are Unconnected
Authors: Venanzi Emily S. , Gray Daniel H. D. , Benoist Christophe , Mathis Diane 
Published: April 2014

Abstract
The lymphotoxin pathway is critical for the development and maintenance of peripheral lymphoid organs. Mice with deficiencies in members of this pathway lack lymph nodes and Peyer’s patches and have abnormal spleen architecture. These animals also develop autoantibodies to and lymphocytic infiltrates of multiple organs, provoking speculation that the lymphotoxin pathway may play a role in central tolerance induction. Indeed, a series of reports has claimed that lymphotoxin signals control the expression of Aire, a transcriptional regulator that is expressed in medullary epithelial cells of the thymus, mediates ectopic transcription of genes encoding a variety of peripheral tissue Ags, and promotes clonal deletion of self-reactive thymocytes. However, one report argued that lymphotoxin signals regulate the composition and organization of the thymus, particularly of the medullary epithelial compartment. Herein, we resolve this controversy in favor of the latter view. The expression and function of Aire were unaffected in medullary epithelial cells of mice lacking either lymphotoxin β receptor or the lymphotoxin α-chain, and there was minimal overlap between the sets of genes controlled by Aire and lymphotoxin. Instead, both knockout lines showed abnormal medullary epithelial cell organization, and the line lacking the β receptor had significantly fewer medullary epithelial cells. In short, the lymphotoxin pathway drives the developmental rather than selectional properties of thymic stromal cells.
Sialyl-Lewisx on P-Selectin Glycoprotein Ligand-1 Is Regulated during Differentiation and Maturation of Dendritic Cells: A Mechanism Involving the Glycosyltransferases C2GnT1 and ST3Gal I
Authors: Julien Sylvain , Grimshaw Matthew J. , Sutton-Smith Mark , Coleman Julia , Morris Howard R. , Dell Anne , Taylor-Papadimitriou Joyce , Burchell Joy M. 
Published: April 2014

Abstract
To fulfil their function as APCs, dendritic cells (DC) and their precursors need to travel from blood to the peripheral tissues and, upon activation, migrate from tissues to draining lymph nodes. Because O-glycans play a role in T cell trafficking, we investigated the O-glycosylation profile of human monocyte-derived DC. Sialyl-Lewisx (sLex), a glycan involved in extravasation via selectin binding, was found to be expressed exclusively on P-selectin glycoprotein ligand-1 in monocytes and immature DC. However, sLex was lost from mature DC even though these cells retained expression of P-selectin glycoprotein ligand-1. Maturation of DC led to a rapid change in the expression of glycosyltransferases involved in O-linked glycosylation. A down-regulation of C2GnT1 mRNA and enzymatic activity was observed with a concurrent up-regulation of ST3Gal I and ST6GalNAc II mRNA resulting in a loss of the core 2 structures required for sLex expression as a P-selectin ligand. Interestingly, the early regulation of these glycosyltransferases was mediated by PGE2, which is known to be required for human DC migration. The pattern of O-glycosylation seen in mature cells was very similar to that expressed by naive T cells, which home to lymph nodes. Our data show that the regulation of O-glycosylation controls sLex expression, and also suggest that O-glycans may have a function in DC migration.
Molecular Architecture of the TAP-Associated MHC Class I Peptide-Loading Complex
Authors: Rufer Elke , Leonhardt Ralf M. , Knittler Michael R. 
Published: April 2014

AbstractTapasin organizes the peptide-loading complex (PLC) by recruiting peptide-receptive MHC class I (MHC-I) and accessory chaperones to the N-terminal regions of the TAP subunits TAP1 and TAP2. Despite numerous studies have shown that the formation of the PLC is essential to facilitate proper MHC-I loading, the molecular architecture of this complex is still highly controversial. We studied the stoichiometry of the PLC by blue native-PAGE in combination with Ab-shift assays and found that TAP/tapasin complexes exist at steady state as a mixture of two distinct oligomers of 350 and 450 kDa. Only the higher m.w. complex contains MHC-I and disulfide-linked tapasin/ER60 conjugates. Moreover, we show for the first time to our knowledge that the fully assembled PLC comprises two tapasin, two ER60, but only one complex of MHC-I and calreticulin. Based hereon we postulate that the TAP subunits alternate in the recruitment and loading of a single MHC-I.
Increasing the Survival of Dendritic Cells In Vivo Does Not Replace the Requirement for CD4+ T Cell Help during Primary CD8+ T Cell Responses
Authors: Matthews Kate E. , Qin Jim S. , Yang Jianping , Hermans Ian F. , Palmowski Michael J. , Cerundolo Vincenzo , Ronchese Franca 
Published: April 2014

AbstractThe survival of dendritic cells (DC) in vivo determines the duration of Ag presentation and is critical in determining the strength and magnitude of the resulting T cell response. We used a mouse model to show that Ag-loaded C57BL/6 DC (MHC class II+/+ (MHC II+/+)) that reach the lymph node survived longer than Ag-loaded MHC II−/− DC, with the numbers of C57BL/6 DC being ∼2.5-fold the number of the MHC II−/− DC by day 4 and ∼5-fold by day 7. The differential survival of DC in vivo was not affected by low doses of LPS, but in vitro pretreatment with CD40L or with high doses of LPS increased the numbers of MHC II−/− DC to levels approaching those of C57BL/6 DC. Regardless of their numbers and relative survival in lymph nodes, MHC II−/− DC were profoundly defective in their ability to induce CTL responses against the gp33 peptide epitope, and were unable to induce expansion and optimal cytotoxic activity of CD8+ T cells specific for the male Ag UTY. We conclude that CD4+ T cell help for CD8+ responses involves mechanisms other than the increased survival of Ag-presenting DC in the lymph node.
Allergic Airways Disease Develops after an Increase in Allergen Capture and Processing in the Airway Mucosa
Authors: von Garnier Christophe , Wikstrom Matthew E. , Zosky Graeme , Turner Debra J. , Sly Peter D. , Smith Miranda , Thomas Jennifer A. , Judd Samantha R. , Strickland Deborah H. , Holt Patrick G. , Stumbles Philip A. 
Published: April 2014

AbstractAirway mucosal dendritic cells (AMDC) and other airway APCs continuously sample inhaled Ags and regulate the nature of any resulting T cell-mediated immune response. Although immunity develops to harmful pathogens, tolerance arises to nonpathogenic Ags in healthy individuals. This homeostasis is thought to be disrupted in allergic respiratory disorders such as allergic asthma, such that a potentially damaging Th2-biased, CD4+ T cell-mediated inflammatory response develops against intrinsically nonpathogenic allergens. Using a mouse model of experimental allergic airways disease (EAAD), we have investigated the functional changes occurring in AMDC and other airway APC populations during disease onset. Onset of EAAD was characterized by early and transient activation of airway CD4+ T cells coinciding with up-regulation of CD40 expression exclusively on CD11b− AMDC. Concurrent enhanced allergen uptake and processing occurred within all airway APC populations, including B cells, macrophages, and both CD11b+ and CD11b− AMDC subsets. Immune serum transfer into naive animals recapitulated the enhanced allergen uptake observed in airway APC populations and mediated activation of naive allergen-specific, airway CD4+ T cells following inhaled allergen challenge. These data suggest that the onset of EAAD is initiated by enhanced allergen capture and processing by a number of airway APC populations and that allergen-specific Igs play a role in the conversion of normally quiescent AMDC subsets into those capable of inducing airway CD4+ T cell activation.
Recruitment and Activation of Macrophages by Pathogenic CD4 T Cells in Type 1 Diabetes: Evidence for Involvement of CCR8 and CCL1
Authors: Cantor Joseph , Haskins Kathryn 
Published: April 2014

Abstract
Adoptive transfer of diabetogenic CD4 Th1 T cell clones into young NOD or NOD.scid recipients rapidly induces onset of diabetes and also provides a system for analysis of the pancreatic infiltrate. Although many reports have suggested a role for macrophages in the inflammatory response, there has been little direct characterization of macrophage activity in the pancreas. We showed previously that after migration to the pancreas, diabetogenic CD4 T cell clones produce a variety of inflammatory cytokines and chemokines, resulting in the recruitment of macrophages. In this study, we investigated mechanisms by which macrophages are recruited and activated by T cells. Analysis of infiltrating cells after adoptive transfer by the diabetogenic T cell clone BDC-2.5 indicates that large numbers of cells staining for both F4/80 and CD11b are recruited into the pancreas where they are activated to make IL-1β, TNF-α, and NO, and express the chemokine receptors CCR5, CXCR3, and CCR8. Diabetogenic CD4 T cell clones produce several inflammatory chemokines in vitro, but after adoptive transfer we found that the only chemokine that could be detected ex vivo was CCL1. These results provide the first evidence that CCR8/CCL1 interaction may play a role in type 1 diabetes through macrophage recruitment and activation.
Syndecan-4 Mediates the Coinhibitory Function of DC-HIL on T Cell Activation
Authors: Chung Jin-Sung , Dougherty Irene , Cruz Ponciano D. , Ariizumi Kiyoshi 
Published: April 2014

AbstractReceptor-ligand interactions between APCs and T cells determine whether stimulation of the latter leads to activation or inhibition. Previously, we showed that dendritic cell-associated heparin sulfate proteoglycan-dependent integrin ligand (DC-HIL) on APC can inhibit T cell activation by binding an unknown ligand expressed on activated T cells. Because DC-HIL binds heparin/heparan sulfate and heparin blocks the inhibitory function of DC-HIL, we hypothesized that a heparin/heparan sulfate proteoglycan on activated T cells is the relevant ligand. Screening assays revealed that syndecan-4 (SD-4) is the sole heparan sulfate proteoglycan immunoprecipitated by DC-HIL from extracts of activated T cells and that blocking SD-4 abrogates binding of DC-HIL to activated T cells. Moreover, cell-bound SD-4 ligated by DC-HIL or cross-linked by anti-SD-4 Ab attenuated anti-CD3 responses, whereas knocked-down SD-4 expression led to enhanced T cell response to APC. Blockade of endogenous SD-4 using specific Ab or soluble SD-4 receptor led to augmented T cell reactions to syngeneic and allogeneic stimulation in vitro and exacerbated contact hypersensitivity responses in vivo. We conclude that SD-4 is the T cell ligand through which DC-HIL mediates its negative coregulatory function.
Decay Accelerating Factor Can Control T Cell Differentiation into IFN-γ-Producing Effector Cells via Regulating Local C5a-Induced IL-12 Production
Authors: Lalli Peter N. , Strainic Michael G. , Lin Feng , Medof M. Edward , Heeger Peter S. 
Published: April 2014

AbstractA newly recognized link between the complement system and adaptive immunity is that decay accelerating factor (DAF), a cell surface C3/C5 convertase regulator, exerts control over T cell responses. Extending these results, we show that cultures of Marilyn TCR-transgenic T cells stimulated with DAF-deficient (Daf1−/−) APCs produce significantly more IL-12, C5a, and IFN-γ compared with cultures containing wild-type APCs. DAF-regulated IL-12 production and subsequent T cell differentiation into IFN-γ-producing effectors was prevented by the deficiency of either C3 or C5a receptor (C5aR) in the APC, demonstrating a link between DAF, local complement activation, IL-12, and T cell-produced IFN-γ. Bone marrow chimera experiments verified that bone marrow cell-expressed C5aR is required for optimal differentiation into IFN-γ-producing effector T cells. Overall, our results indicate that APC-expressed DAF regulates local production/activation of C5a following cognate T cell/APC interactions. Through binding to its receptor on APCs the C5a up-regulates IL-12 production, this in turn, contributes to directing T cell differentiation toward an IFN-γ-producing phenotype. The findings have implications for design of therapies aimed at altering pathologic T cell immunity.
Targeting the Wilms Tumor Antigen 1 by TCR Gene Transfer: TCR Variants Improve Tetramer Binding but Not the Function of Gene Modified Human T Cells
Authors: Thomas Sharyn , Xue Shao-An , Cesco-Gaspere Michela , San José Esther , Hart Daniel P. , Wong Vivian , Debets Reno , Alarcon Balbino , Morris Emma , Stauss Hans J. 
Published: April 2014

AbstractWe have previously described the functional activity of a human TCR specific for an HLA-A2-presented peptide derived from the Wilms tumor Ag 1 (WT1). Recent studies showed that the expression and function of human TCR was improved by the introduction of an additional disulfide bond between the α- and β-chains or by the exchange of the human constant region for murine sequences. In this study, we analyzed the functional activity of WT1-TCR variants expressed in Jurkat cells and in primary T cells. The introduction of cysteine residues or murine constant sequences into the WT1-TCR did not result in a global reduction of mispairing with wild-type TCR chains. Instead, the level of mispairing was affected by the variable region sequences of the wild-type TCR chains. The analysis of freshly transduced peripheral blood T cells showed that the transfer of modified TCR constructs generated a higher frequency of Ag-responsive T cells than the transfer of the wild-type TCR. After several rounds of peptide stimulation this difference was no longer observed, as all transduced T cell populations accumulated ∼90% of Ag-responsive T cells. Although the Ag-responsive T cells expressing the modified TCR bound the HLA-A2/WT1 tetramer more efficiently than T cells expressing the wild-type TCR, this did not improve the avidity of transduced T cells nor did it result in a measurable enhancement in IFN-γ production and cytotoxic activity. This indicated that the enhanced tetramer binding of modified WT1-TCR variants was not associated with improved WT1-specific T cell function.
Cognate Memory CD4+ T Cells Generated with Dendritic Cell Priming Influence the Expansion, Trafficking, and Differentiation of Secondary CD8+ T Cells and Enhance Tumor Control
Authors: Hwang Melissa L. , Lukens John R. , Bullock Timothy N. J. 
Published: April 2014

AbstractCD4+ T cells are known to provide support for the activation and expansion of primary CD8+ T cells, their subsequent differentiation, and ultimately their survival as memory cells. However, the importance of cognate memory CD4+ T cells in the expansion of memory CD8+ T cells after re-exposure to Ag has been not been examined in detail. Using bone marrow-derived dendritic cells pulsed with cognate or noncognate MHC class I- and class II-restricted peptides, we examined whether the presence of memory CD4+ T cells with the same Ag specificity as memory CD8+ T cells influenced the quantity and quality of the secondary CD8+ T cell response. After recombinant vaccinia virus-mediated challenge, we demonstrate that, although cognate memory CD4+ T cells are not required for activation of secondary CD8+ T cells, their presence enhances the expansion of cognate memory CD8+ T cells. Cognate CD4+ T cell help results in an approximate 2-fold increase in the frequency of secondary CD8+ T cells in secondary lymphoid tissues, and can be accounted for by enhanced proliferation in the secondary CD8+ T cell population. In addition, cognate memory CD4+ T cells further selectively enhance secondary CD8+ T cell infiltration of tumor-associated peripheral tissue, and this is accompanied by increased differentiation into effector phenotype within the secondary CD8+ T cell population. The consequence of these improvements to the magnitude and phenotype of the secondary CD8+ T cell response is substantial increase in control of tumor outgrowth.
Sphingosine-1 Phosphate Signaling Regulates Positioning of Dendritic Cells within the Spleen
Authors: Czeloth Niklas , Schippers Angela , Wagner Norbert , Müller Werner , Küster Birgit , Bernhardt Günter , Förster Reinhold 
Published: April 2014

AbstractA successful execution and balance of adaptive immune responses requires a controlled positioning and navigation of dendritic cells (DC) into and inside secondary lymphoid organs. Whereas mechanisms were identified governing the migration of DC from peripheral nonlymphoid organs into their draining lymph nodes, little is known about the molecular cues controlling the proper positioning of spleen or lymph node resident DC. In this study, we show that the sphingosine-1 phosphate (S1P) receptor 1 influences the positioning of immature DC inside the murine spleen. Following treatment with FTY720 or SEW2871, drugs known to interfere with S1P1-mediated signaling, the 33D1+ DC subpopulation homogeneously redistributes from the bridging channels to the marginal zone. In contrast, the CD205+ DC subset remains associated with the T cell zone. Upon in vivo LPS treatment, the maturing DC assemble in the T cell zone. The LPS-driven redistribution occurs in the absence of CCR7 and cannot be prevented by FTY720, indicating that guiding mechanisms differ between immature and mature DC. Along with the observed DC subtype-specific S1P receptor expression pattern as well as the profound up-regulation of S1P1 and S1P3 accompanying DC maturation, these results suggest a decisive contribution of S1P signaling to intrasplenic DC motility and migration.
Essential Role of IL-21 in B Cell Activation, Expansion, and Plasma Cell Generation during CD4+ T Cell-B Cell Collaboration
Authors: Kuchen Stefan , Robbins Rachel , Sims Gary P. , Sheng Chen , Phillips Terence M. , Lipsky Peter E. , Ettinger Rachel 
Published: April 2014

AbstractDuring T cell-B cell collaboration, plasma cell (PC) differentiation and Ig production are known to require T cell-derived soluble factors. However, the exact nature of the cytokines produced by activated T cells that costimulate PC differentiation is not clear. Previously, we reported that costimulation of purified human B cells with IL-21 and anti-CD40 resulted in efficient PC differentiation. In this study, we addressed whether de novo production of IL-21 was involved in direct T cell-induced B cell activation, proliferation, and PC differentiation. We found that activated human peripheral blood CD4+ T cells expressed mRNA for a number of cytokines, including IL-21, which was confirmed at the protein level. Using a panel of reagents that specifically neutralize cytokine activity, we addressed which cytokines are essential for B cell activation and PC differentiation induced by anti-CD3-activated T cells. Strikingly, neutralization of IL-21 with an IL-21R fusion protein (IL-21R-Fc) significantly inhibited T cell-induced B cell activation, proliferation, PC differentiation, and Ig production. Inhibition of PC differentiation was observed even when the addition of IL-21R-Fc was delayed until after initial B cell activation and expansion had occurred. Importantly, IL-21 was found to be involved in PC differentiation from both naive and memory B cells. Finally, IL-21R-Fc did not inhibit anti-CD3-induced CD4+ T cell activation, but rather directly blocked T cell-induced B cell activation and PC differentiation. These data are the first to document that B cell activation, expansion, and PC differentiation induced by direct interaction of B cells with activated T cells requires IL-21.
Posttranslational Regulation ofI-Edby Affinity for CLIP
Authors: Rinderknecht Cornelia H. , Belmares Michael P. , Catanzarite Tatiana L. W. , Bankovich Alexander J. , Holmes Tyson H. , Garcia K. Christopher , Nanda Navreet K. , Busch Robert , Kovats Susan , Mellins Elizabeth D. 
Published: April 2014

AbstractSeveral MHC class II alleles linked with autoimmune diseases form unusually low stability complexes with CLIP, leading us to hypothesize that this is an important feature contributing to autoimmune pathogenesis. To investigate cellular consequences of altering class II/CLIP affinity, we evaluated invariant chain (Ii) mutants with varying CLIP affinity for a mouse class II allele, I-Ed, which has low affinity for wild-type CLIP and is associated with a mouse model of spontaneous, autoimmune joint inflammation. Increasing CLIP affinity for I-Ed resulted in increased cell surface and total cellular abundance and half-life of I-Ed. This reveals a post-endoplasmic reticulum chaperoning capacity of Ii via its CLIP peptides. Quantitative effects on I-Ed were less pronounced in DM-expressing cells, suggesting complementary chaperoning effects mediated by Ii and DM, and implying that the impact of allelic variation in CLIP affinity on immune responses will be highest in cells with limited DM activity. Differences in the ability of cell lines expressing wild-type or high-CLIP-affinity mutant Ii to present Ag to T cells suggest a model in which increased CLIP affinity for class II serves to restrict peptide loading to DM-containing compartments, ensuring proper editing of antigenic peptides.