bluuebunny/crossref_metadata_2025_split huggingface dataset:
Apoptosis by Neglect of CD4+ Th Cells in Granulomas: A Novel Effector Mechanism Involved in the Control of Egg-Induced Immunopathology in Murine Schistosomiasis
Authors: Rutitzky Laura I. , Mirkin Gerardo A. , Stadecker Miguel J. 
Published: April 2014

AbstractIn infection with Schistosoma mansoni, parasite eggs precipitate an intrahepatic granulomatous and fibrosing inflammation that is mediated by CD4+ Th cells. Compared with CBA mice, C57BL/6 mice develop smaller granulomas composed of cells that exhibit reduced proliferative responses to schistosome egg Ags. In the present study, we investigated CD4+ T cell apoptosis as a possible mechanism that could account for this subdued response. We found throughout the course of several infection weeks a markedly higher proportion of apoptotic CD4+ T cells in granulomas from C57BL/6 mice than in those from CBA mice ex vivo; the apoptosis further increased upon cell cultivation in vitro. Activation-induced cell death or CD8+ T cells failed to account for the enhanced apoptosis as infected Fas-, Fas ligand,- and CD8-deficient mice exhibited similar apoptosis to that seen in wild-type counterparts. However, a strikingly lower IL-2 production by schistosome egg Ag-stimulated C57BL/6 granuloma and mesenteric lymph node cells suggested the possibility of apoptosis due to growth factor deprivation. Indeed, the CD4+ T cell apoptosis was significantly reversed by addition of rIL-2 in vitro, or by injection of rIL-2 in vivo, which also resulted in significant exacerbation of granulomatous inflammation. These findings indicate that apoptosis by neglect can represent a significant means of controlling CD4+ T cells that mediate the immunopathology in schistosomiasis.
Pathogen-Associated Molecular Patterns Sensitize Macrophages to Fas Ligand-Induced Apoptosis and IL-1β Release
Authors: Fukui Masayuki , Imamura Ryu , Umemura Masayuki , Kawabe Takaya , Suda Takashi 
Published: April 2014

AbstractAntigenic stimulation activates T cells and simultaneously destines them to die by Fas-mediated apoptosis. In this study, we demonstrated that various pathogen-associated molecular patterns up-regulated Fas expression in macrophages and sensitized them specifically to Fas ligand (FasL), but not to other apoptosis-inducing agents such as TNF-α, etoposide (VP-16), and staurosporine. Toll-like receptor, NF-κB, and p38 mitogen-activated protein kinase mediated these responses. LPS stimulation induced the expression of Fas, caspase 8, cellular FLIP Bfl-1/A1, and Bcl-x, but not FasL, TNFR p55, Bak, Bax, and Bad at the transcriptional level. Thus, LPS selectively induced the expression of apoptotic molecules of the Fas death pathway (except for cellular FLIP) and antiapoptotic molecules of the mitochondrial death pathway. However, the kinetics of macrophage disappearance following Escherichia coli-induced peritonitis was similar between wild-type and Fas-deficient mice, suggesting that Fas is not essential for the turnover of activated macrophages in T cell-independent inflammation. In contrast, LPS-activated macrophages produced a large amount of IL-1β upon FasL stimulation. Thus, unlike the activation-induced cell death of T cells, the sensitization of macrophages to FasL by pathogen-associated molecular patterns seems to be a proinflammatory rather than an anti-inflammatory event.
A Catalytically Inactive Form of Protein Kinase C-Associated Kinase/Receptor Interacting Protein 4, a Protein Kinase Cβ-Associated Kinase That Mediates NF-κB Activation, Interferes with Early B Cell Development
Authors: Cariappa Annaiah , Chen Luojing , Haider Khaleda , Tang Mei , Nebelitskiy Eugene , Moran Stewart T. , Pillai Shiv 
Published: April 2014

AbstractProtein kinase C-associated kinase (PKK)/receptor interacting protein 4 (RIP4) is a protein kinase C (PKC) β-associated kinase that links PKC to NF-κB activation. The kinase domain of PKK is similar to that of RIP, RIP2, and RIP3. We show in this study that PKK is expressed early during lymphocyte development and can be detected in common lymphoid progenitor cells. Targeting of a catalytically inactive version of PKK to lymphoid cells resulted in a marked impairment in pro-B cell generation in the bone marrow. Although peripheral B cell numbers were markedly reduced, differentiation into follicular and marginal zone B cells was not defective in these mice. B-1a and B-1b B cells could not be detected in these mice, but this might be a reflection of the overall defect in B cell production observed in these animals. In keeping with a possible link to PKCβ, peripheral B cells in these mice exhibit a defect in anti-IgM-mediated proliferation. These studies suggest that PKK may be required early in B cell development and for BCR-mediated B cell proliferation.
Studies of Structure-Activity Relations of Complement Inhibitor Compstatin
Authors: Soulika Athena M. , Morikis Dimitrios , Sarrias Maria-Rosa , Roy Melinda , Spruce Lynn A. , Sahu Arvind , Lambris John D. 
Published: April 2014

AbstractCompstatin, a 13-mer cyclic peptide, is a novel and promising inhibitor of the activation of the complement system. In our search for a more active analog and better understanding of structure-functions relations, we designed a phage-displayed random peptide library based on previous knowledge of structure activity relations, in which seven amino acids deemed necessary for structure and activity were kept fixed while the remaining six were optimized. Screening of this library against C3 identified four binding clones. Synthetic peptides corresponding to these clones revealed one analog, called acetylated Ile1Leu/His9Trp/Thr13Gly triple replacement analog of compstatin corresponding to clone 640 (Ac-I1L/H9W/T13G), which was more active than compstatin. This newly identified peptide had 4-fold higher activity when compared with the originally isolated form of compstatin and 1.6-fold higher activity when compared with acetylated compstatin (Ac-compstatin). The structures of Ac-I1L/H9W/T13G and Ac-compstatin were studied by nuclear magnetic resonance, compared with the structure of compstatin, and found to be very similar. The binding of Ac-I1L/H9W/T13G and the equally active acetylated analog with His9Ala replacement (Ac-H9A) to C3 was evaluated by surface plasmon resonance, which suggested similarity in their binding mechanism but difference when compared with Ac-compstatin. Compensatory effects of flexibility outside the β-turn and tryptophan ring stacking may be responsible for the measured activity increase in Ac-I1L/H9W/T13G and acetylated analog with His9Ala replacement and the variability in binding mechanism compared with Ac-compstatin. These data demonstrate that tryptophan is a key amino acid for activity. Finally, the significance of the N-terminal acetylation was examined and it was found that the hydrophobic cluster at the linked termini of compstatin is essential for binding to C3 and for activity.
New Programming of IL-4 Receptor Signal Transduction in Activated T Cells: Stat6 Induction and Th2 Differentiation Mediated by IL-4Rα Lacking Cytoplasmic Tyrosines
Authors: Mora Ana L. , Stephenson Linda M. , Enerson Ben , Youn Jeehee , Keegan Achsah D. , Boothby Mark 
Published: April 2014

AbstractSignaling by the IL-4 receptor α-chain (IL-4Rα) is a key determinant of the development of the Th2 lineage of effector T cells. Studies performed in tissue culture cell lines have indicated that tyrosines of the IL-4Rα cytoplasmic tail are necessary for the induction of Stat6, a transcription factor required for Th2 differentiation. Surprisingly, we have found that in activated T cells, IL-4Rα chains lacking all cytoplasmic tyrosines promote induction of this IL-4-specific transcription factor and efficient commitment to the Th2 lineage. Mutagenesis of a tyrosine-free cytoplasmic tail identifies a requirement for the serine-rich ID-1 region in this new program of IL-4R signal transduction observed in activated T cells. Additional findings suggest that an extracellular signal-regulated kinase pathway can be necessary and sufficient for the ability of such tyrosine-free IL-4Rα chains to mediate Stat6 induction. These results provide novel evidence that the molecular mechanisms by which a cytokine specifically induces a Stat transcription factor can depend on the activation state of T lymphoid cells. Furthermore, the data suggest that one pathway by which such new programming may be achieved is mediated by extracellular signal-regulated mitogen-activated protein kinases.
The CD43 Coreceptor Molecule Recruits the ζ-Chain as Part of Its Signaling Pathway
Authors: Cruz-Muñoz Mario Ernesto , Salas-Vidal Enrique , Salaiza-Suazo Norma , Becker Ingeborg , Pedraza-Alva Gustavo , Rosenstein Yvonne 
Published: April 2014

AbstractCD43 is an abundant cell surface sialoglycoprotein implicated in hemopoietic cell adhesion and activation. Cell stimulation through CD43 results in recruitment of different signaling proteins, including members of the Src family kinases, Syk, phospholipase Cγ2, the adapter protein Shc, the guanine nucleotide exchange factor Vav, and activation of protein kinase C. In this study, we report that in human T lymphocytes, the ζ-chain is part of the CD43 signaling pathway. Upon CD43 engagement, the ζ-chain was tyrosine-phosphorylated, generating docking sites for tyrosine-phosphorylated ζ-associated protein of 70 kDa and Vav. In vitro kinase assays suggested that ζ-associated protein of 70 kDa could account for the kinase activity associated with the ζ-chain following CD43 engagement. Cross-linking CD43 on the surface of the Lck-deficient JCaM.1 cells failed to phosphorylate the ζ-chain and associated proteins, suggesting that Lck is a key element in the CD43 signaling pathway leading to ζ phosphorylation. CD43 engagement with beads coated with anti-CD43 mAb resulted in concentration of the ζ-chain toward the bead attachment site, but interestingly, the distribution of the T cell Ag receptor complex remained unaffected. Recruitment of the ζ-chain through CD43-mediated signals was not restricted to T lymphocytes because phosphorylation and redistribution of the ζ-chain was also observed in NK cells. Our results provide evidence that the ζ-chain functions as a scaffold molecule in the CD43 signaling pathway, favoring the recruitment and formation of downstream signaling complexes involved in the CD43-mediated cell activation of T lymphocytes and other leukocytes such as NK cells.
Potential Role of NKG2D/MHC Class I-Related Chain A Interaction in Intrathymic Maturation of Single-Positive CD8 T Cells
Authors: Hüe Sophie , Monteiro Renato C. , Berrih-Aknin Sonia , Caillat-Zucman Sophie 
Published: April 2014

AbstractThe nonclassical MHC class I molecule MHC class I-related chain A (MICA) interacts with the NKG2D receptor expressed at the surface of most peripheral CD8 T cells, γδ T cells, and NK cells. We investigated the role of MICA-NKG2D interactions in the selection or maturation of the T cell repertoire within the thymus using MICA tetramers and anti-MICA mAbs. MICA tetramers identified a small population of late stage CD8 single-positive, CD45RA+ CD62L+ CCR7+ CD69− thymocytes, a phenotype compatible with that of fully mature CD8+ cells ready to emigrate to the periphery as naive cells. MICA molecules were expressed in the outer layer of Hassal’s corpuscles within the medulla of normal thymus. In thymomas, an overexpression of MICA in cortical and medullar epithelial cells was observed. This was associated with a decreased percentage of NKG2D-positive thymocytes, which expressed a less mature phenotype than in normal thymus. These results indicate that CD8+ thymocytes up-regulate NKG2D as they complete their developmental program before leaving the thymic medulla to seed the periphery, and identify NKG2D as a potential regulator of the developmental processes in T cells that are essential for immune homeostasis.
β2-Microglobulin-Free HLA Class I Heavy Chain Epitope Mimicry by Monoclonal Antibody HC-10-Specific Peptide
Authors: Perosa Federico , Luccarelli Grazia , Prete Marcella , Favoino Elvira , Ferrone Soldano , Dammacco Franco 
Published: April 2014

AbstractmAb HC-10 loses its reactivity with HLA class I (HLA-I) H chain (HC) following its association with β2-microglobulin (β2m). Furthermore, the HC-10 defined epitope appears to be involved in the pathogenesis of spondyloarthropathies, because HC-10 reduced their incidence in HLA-B27+β2m°/MHC class II knockout mice. This study has characterized the determinant recognized by HC-10. Panning of a phage display peptide library with HC-10 resulted in isolation of the motif PxxWDR, which could be aligned with P57, W60, D61, and R62 of the first domain of the HLA-I HC allospecificities reactive with HC-10. The 55EGPEYWDR(N/E)T64 (p-1) is the shortest motif-bearing peptide that reacts with HC-10 and inhibits its binding to soluble HLA-B7 HC, irrespective of whether N (p-1a) or E (p-1b) is present at position 63. By contrast, HC-10 did not react with six additional peptides, each bearing motif amino acid substitutions present in HC-10-not-reactive HLA-I allospecificities. The p-1-derived Qp-1, synthesized with the additional conserved Q54, which displays the highest in vitro reactivity with HC-10, was the only one to induce in mice IgG resembling HC-10 in their fine specificity. Mapping of the HC-10-defined determinant suggests that the lack of mAb reactivity with β2m-associated HLA-I HC is caused by blocking by the peptide in the groove of β2m-associated HLA-I HC, though a role of HC conformational changes following its association with β2m cannot be excluded. This information contributes to our understanding of the molecular basis of the antigenic profiles of β2m-free and β2m-associated HLA-I HC and may serve to develop active specific immunotherapy of spondyloarthropathies.
A Novel −66T/C Polymorphism in FcεRI α-Chain Promoter Affecting the Transcription Activity: Possible Relationship to Allergic Diseases
Authors: Hasegawa Masanari , Nishiyama Chiharu , Nishiyama Makoto , Akizawa Yushiro , Mitsuishi Kouichi , Ito Tomonobu , Kawada Hiroshi , Furukawa Susumu , Ra Chisei , Okumura Ko , Ogawa Hideoki 
Published: April 2014

AbstractWe found a novel polymorphism, −66T/C, in the promoter region of human FcεRIα, the specific component of the high affinity receptor for IgE (FcεRI), which is essential for the cell surface expression of FcεRI and the binding of IgE Ab. When the effect of the single nucleotide replacement on the promoter function was analyzed, the transcription activity of the T allele promoter was found to be higher than that of the C allele promoter, and was markedly up-regulated by the overexpression of GATA-1 when compared with the C allele promoter. This is probably because the promoter with T at −66 has an additional GATA-1-binding motif in the region, which may assure higher affinity of the transcription factor to the promoter. In accordance with this, EMSA actually indicated that GATA-1 bound to the T allele probe (−80/−59) with the affinity higher than that to the C allele probe. Statistical analysis suggested that a significant portion of nonallergic individuals has heterozygous −66T/C genotype, while most of allergic individuals have homozygous −66T/T genotype in Japanese population. Our findings for the first time demonstrate the presence of FcεRIα polymorphism related to the allergic diseases.
Recombinant TCR Ligand Induces Early TCR Signaling and a Unique Pattern of Downstream Activation
Authors: Wang Chunhe , Mooney Jeffery L. , Meza-Romero Roberto , Chou Yuan K. , Huan Jianya , Vandenbark Arthur A. , Offner Halina , Burrows Gregory G. 
Published: April 2014

AbstractRecombinant TCR ligands (RTLs) consisting of covalently linked α1 and β1 domains of MHC class II molecules tethered to specific antigenic peptides represent minimal TCR ligands. In a previous study we reported that the rat RTL201 construct, containing RT1.B MHC class II domains covalently coupled to the encephalitogenic guinea pig myelin basic protein (Gp-MBP72–89) peptide, could prevent and treat actively and passively induced experimental autoimmune encephalomyelitis in vivo by selectively inhibiting Gp-MBP72–89 peptide-specific CD4+ T cells. To evaluate the inhibitory signaling pathway, we tested the effects of immobilized RTL201 on T cell activation of the Gp-MBP72–89-specific A1 T cell hybridoma. Activation was exquisitely Ag-specific and could not be induced by RTL200 containing the rat MBP72–89 peptide that differed by a threonine for serine substitution at position 80. Partial activation by RTL201 included a CD3ζ p23/p21 ratio shift, ZAP-70 phosphorylation, calcium mobilization, NFAT activation, and transient IL-2 production. In comparison, anti-CD3ε treatment produced stronger activation of these cellular events with additional activation of NF-κB and extracellular signal-regulated kinases as well as long term increased IL-2 production. These results demonstrate that RTLs can bind directly to the TCR and modify T cell behavior through a partial activation mechanism, triggering specific downstream signaling events that deplete intracellular calcium stores without fully activating T cells. The resulting Ag-specific activation of the transcription factor NFAT uncoupled from the activation of NF-κB or extracellular signal-regulated kinases constitutes a unique downstream activation pattern that accounts for the inhibitory effects of RTL on encephalitogenic CD4+ T cells.
Human Immature Monocyte-Derived Dendritic Cells Express the G Protein-Coupled Receptor GPR105 (KIAA0001, P2Y14) and Increase Intracellular Calcium in Response to its Agonist, Uridine Diphosphoglucose
Authors: Skelton Lisa , Cooper Mike , Murphy Marianne , Platt Adam 
Published: April 2014

AbstractDendritic cells (DC) are essential to the initiation of an immune response due to their unique ability to take-up and process Ag, translocate to lymph nodes, and present processed Ag to naive T cells. Many chemokines, chemokine receptors and other G protein-coupled receptors (GPCRs) are implicated in these various aspects of DC biology. Through microarray analysis, we compared expression levels of chemokines, their cognate receptors, and selected GPCRs in human monocytes and in vitro monocyte-derived immature and mature DC. Hierarchical clustering of gene expression clearly distinguishes the three cell types, most notably highlighting exceptional levels of expression of the GPCR GPR105 within the immature monocyte-derived DC (MDDC) gene cluster. Little or no expression was observed within the monocyte and mature MDDC cluster. Putative functionality of the GPR105 receptor was demonstrated by an observed calcium flux in immature MDDC treated with the potent GPR105 agonist, uridine 5′-diphosphoglucose (UDP-glucose), while no response to the nucleotide sugar was seen in monocytes and mature MDDC. This UDP-glucose-induced calcium response was, at least in part, pertussis toxin-sensitive. Moreover, immature MDDC from some donors treated with UDP-glucose exhibit an increase in expression of the costimulatory molecule CD86, which correlates with the intensity of the UDP-glucose-induced calcium flux. Together, these data demonstrate differential expression of GPR105 on immature and mature MDDC and suggest a role for the receptor and its agonist ligand in DC activation.
Brugia malayiMicrofilariae Induce Cell Death in Human Dendritic Cells, Inhibit Their Ability to Make IL-12 and IL-10, and Reduce Their Capacity to Activate CD4+ T Cells
Authors: Semnani Roshanak Tolouei , Liu Anne Y. , Sabzevari Helen , Kubofcik Joseph , Zhou Jun , Gilden Julia K. , Nutman Thomas B. 
Published: April 2014

AbstractParasite Ag-specific T cell unresponsiveness and diminished IFN-γ production are immunologic hallmarks of patent infection with lymph-dwelling filarial nematodes. Although this diminished responsiveness is directed primarily against the intravascular microfilarial (MF) parasite stage and mediated in part by reduced APC function, the mechanisms involved are not fully understood. In this report, we demonstrate that human dendritic cells (DC) exposed to live MF up-regulate both the cell surface and gene expression of CD54 (ICAM-1). Moreover, live MF result in a 3-fold increase in DC death compared with MF-unexposed DC, primarily due to apoptosis. Notably, microarray and real-time RT-PCR data indicate that live MF concurrently up-regulate mRNA expression of proinflammatory molecules such as IL-8, RANTES, IL-1α, TNF-α, and IL-β in DC, the presence of which is also detected at the protein level, while inhibiting the production of IL-12 (p40 and p70) and IL-10. Soluble excretory-secretory products from live MF diminished IL-12 and IL-10 production and induced DC death, although to a lesser degree. Moreover, exposure of DC to live MF resulted in a decrease in the ability of DC to promote CD4+ T cell production of IFN-γ and IL-5. Our findings clearly suggest that the interaction between live MF and DC is complex but contributes to the hyporesponsiveness and parasite persistence associated with the MF+ state in the infected human. These data further suggest that MF induce an orchestrated response in APC that leads to a diminished capacity to function appropriately, which in turn has significant consequences for CD4+ T cells.
An Anti-Inflammatory Role for Vα14 NK T cells inMycobacterium bovisBacillus Calmette-Guérin-Infected Mice
Authors: Dieli Francesco , Taniguchi Masaru , Kronenberg Mitchell , Sidobre Stephane , Ivanyi Juraj , Fattorini Lanfranco , Iona Elisabetta , Orefici Graziella , De Leo Giacomo , Russo Domenica , Caccamo Nadia , Sireci Guido , Di Sano Caterina , Salerno Alfredo 
Published: April 2014

AbstractThe possible contribution of NKT cells to resistance to Mycobacterium tuberculosis infection remains unclear. In this paper we characterized the Vα14 NKT cell population following infection with Mycobacterium bovis bacillus Calmette-Guérin (BCG). BCG infection determined an early expansion of Vα14 NKT cells in liver, lungs, and spleen, which peaked on day 8 and was sustained until day 30. However, an NK1.1+ Vα14 NKT population preferentially producing IFN-γ predominated at an early stage (day 8), which was substituted by an NK1.1− population preferentially producing IL-4 at later stages (day 30). Despite the fact that Vα14 NKT cell-deficient mice eliminated BCG as did control mice, they had significantly higher numbers of granulomas in liver and lungs. Additionally, while control mice developed organized small granulomas, those in Vα14 NKT-deficient mice had signs of caseation, large cellular infiltrates, and some multinucleated macrophages, suggesting that Vα14 NKT cells may actually work as anti-inflammatory cells by limiting excessive lymphocyte influx and tissue pathology. In agreement, we found an increased spontaneous production and mRNA expression of TNF-α in liver and lungs of Vα14 NKT-deficient mice, whose neutralization in vivo by anti-TNF-α mAbs consistently reduced the number of granulomas in liver and lungs. Together, our results support a regulatory role for Vα14 NKT cells in the course of BCG infection through their ability to limit the extent of inflammatory response and point to an important role for this cell subset as a regulator of the balance between protective responses and immunopathology.