bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential Binding of Cross-Reactive Anti-DNA Antibodies to Mesangial Cells: The Role of α-Actinin
Authors: Zhao Zeguo , Deocharan Bisram , Scherer Philipp E. , Ozelius Laurie J. , Putterman Chaim 
Published: April 2014

Abstract
Target Ag display is a necessary requirement for the expression of certain immune-mediated kidney diseases. We previously had shown that anti-DNA Abs that cross-react with α-actinin may be important in the pathogenesis of murine and human lupus nephritis; in murine models, we had found that a significant proportion of pathogenic serum and kidney-deposited Igs are α-actinin reactive. Furthermore, a pathogenic anti-DNA/α-actinin Ab showed enhanced binding to immortalized mesangial cells (MCs) derived from a lupus prone MRL-lpr/lpr mouse as compared with MCs from BALB/c mice which are not susceptible to spontaneous lupus, suggesting that kidney α-actinin expression may be contributing to nephritis. In the current study, we established that two isoforms of α-actinin that are present in the kidney, α-actinin 1 and α-actinin 4, can both be targeted by anti-α-actinin Abs. We found novel sequence polymorphisms between MRL-lpr/lpr and BALB/c in the gene for α-actinin 4. Moreover, α-actinin 4 and a splice variant of α-actinin 1 were both expressed at significantly higher levels (mRNA and protein) in MCs from the lupus prone MRL-lpr/lpr strain. Significantly, we were able to confirm these differences in intact kidney by examining glomerular Ig deposition of anti-α-actinin Abs. We conclude that enhanced α-actinin expression may determine the extent of Ig deposition in the Ab-mediated kidney disease in lupus. Modulation of Ag expression may be a promising approach to down-regulate immune complex formation in the target organ in individuals with circulating pathogenic Abs.
Peripheral Blood Neutrophil Activation Patterns Are Associated with Pulmonary Inflammatory Responses to Lipopolysaccharide in Humans
Authors: Abraham Edward , Nick Jerry A. , Azam Tania , Kim Soo Hyun , Mira Jean-Paul , Svetkauskaite Daiva , He Qianbin , Zamora Marty , Murphy James , Park Jong Sung , Overdier Katherine , Dinarello Charles A. 
Published: April 2014

AbstractIncreased nuclear accumulation of NF-κB in LPS-stimulated peripheral blood neutrophils has been shown to be associated with more severe clinical course in patients with infection associated acute lung injury. Such observations suggest that differences in neutrophil response may contribute to the pulmonary inflammation induced by bacterial infection. To examine this question, we sequentially measured LPS-induced DNA binding of NF-κB in neutrophils collected from healthy humans on at least three occasions, each separated by at least 2 wk, and then determined pulmonary inflammatory responses after instillation of LPS into the lungs. Consistent patterns of peripheral blood neutrophil responses, as determined by LPS-induced NF-κB DNA binding, were present in volunteers, with a &gt;80-fold difference between individuals in the mean area under the curve for NF-κB activation. The number of neutrophils recovered from bronchoalveolar lavage after exposure to pulmonary LPS was significantly correlated with NF-κB activation in peripheral blood neutrophils obtained over the pre-LPS exposure period (r = 0.65, p = 0.009). DNA binding of NF-κB in pulmonary neutrophils also was associated with the mean NF-κB area under the curve for LPS-stimulated peripheral blood neutrophils (r = 0.63, p = 0.01). Bronchoalveolar lavage levels of IL-6 and TNFRII were significantly correlated with peripheral blood neutrophil activation patterns (r = 0.75, p = 0.001 for IL-6; and r = 0.48, p = 0.049 for TNFRII. These results demonstrate that stable patterns in the response of peripheral blood neutrophils to LPS exist in the human population and correlate with inflammatory response following direct exposure to LPS in the lung.
Secreted Proteins fromMycobacterium tuberculosisGain Access to the Cytosolic MHC Class-I Antigen-Processing Pathway
Authors: Lewinsohn David M. , Grotzke Jeff E. , Heinzel Amy S. , Zhu LiQing , Ovendale Pamela J. , Johnson Mark , Alderson Mark R. 
Published: April 2014

AbstractCD8+ T cells play an important role in the host response to infection with Mycobacterium tuberculosis (Mtb). Mtb resides in an arrested phagosome that is phenotypically similar to an early endosome. The mechanisms by which Mtb-derived Ags gain access to the HLA-I-processing pathway are incompletely characterized. Studies with CD8+ T cell lines have suggested that Mtb Ags gain access to the HLA-I pathway in an alternate vacuolar pathway that is both brefeldin A (BFA) and TAP independent. To define the requirements of entry of Ag into the HLA-I pathway, we have used human CD8+ T cell clones specific for the secreted Mtb Ag CFP10. Human monocyte-derived dendritic cells were pulsed with CFP10 expressed in a recombinant adenovirus, surface adsorbed to microspheres, or in its native form by Mtb. When delivered by adenovirus, processing and presentation of CFP10 were blocked by both BFA and the proteasomal blocker lactacystin. In contrast, processing of CFP10 adsorbed to the surface of microspheres was not affected by either of these Ag-processing inhibitors. BFA, lactacystin, and TAP inhibition blocked the recognition of Mtb-infected dendritic cells, suggesting that processing was via a cytosolic pathway for this secreted protein Ag. We conclude that secreted proteins from Mtb can be processed in a BFA- and proteasome-dependent manner, consistent with egress of Ag into the cytosol and subsequent loading of proteasomally derived peptides.
PneumocystisCell Wall β-Glucans Induce Dendritic Cell Costimulatory Molecule Expression and Inflammatory Activation through a Fas-Fas Ligand Mechanism
Authors: Carmona Eva M. , Vassallo Robert , Vuk-Pavlovic Zvezdana , Standing Joseph E. , Kottom Theodore J. , Limper Andrew H. 
Published: April 2014

AbstractRespiratory failure during Pneumocystis pneumonia is mainly a consequence of exaggerated inflammatory responses to the organism. Dendritic cells (DCs) are the most potent APCs in the lung and are key to the regulation of innate and adaptive immune responses. However, their participation in the inflammatory response directed against Pneumocystis infection has not been fully elucidated. Therefore, we studied the role of Pneumocystis carinii, as well as Saccharomyces cerevisiae, cell wall-derived β-glucans, in DC costimulatory molecule expression. We further studied the impact of β-glucans on subsequent T cell activation. Because cytokine secretion by DCs has recently been shown to be regulated by Fas ligand (FasL), its role in β-glucan activation of DCs was also investigated. β-Glucan-induced DC activation occurred in part through dectin-1 receptors. We demonstrated that DC activation by β-glucans elicits T cell activation and polarization into a Th1 patterned response, but with the conspicuous absence of IL-12. These observations differed from LPS-driven T cell polarization, suggesting that β-glucans and LPS signal DC activation through different mechanisms. We additionally determined that IL-1β and TNF-α secretion by β-glucan-stimulated DCs was partially regulated by Fas-FasL. This suggests that dysregulation of FasL could further enhance exuberant and prolonged cytokine production by DCs following DC-T cell interactions, further promoting lung inflammation typical of Pneumocystis pneumonia.
Transcellular Secretion of Group V Phospholipase A2 from Epithelium Induces β2-Integrin-Mediated Adhesion and Synthesis of Leukotriene C4 in Eosinophils
Authors: Muñoz Nilda M. , Meliton Angelo Y. , Lambertino Anissa , Boetticher Evan , Learoyd Jonathan , Sultan Faraz , Zhu Xiangdong , Cho Wonhwa , Leff Alan R. 
Published: April 2014

AbstractWe examined the mechanism by which secretory group V phospholipase A2 (gVPLA2) secreted from stimulated epithelial cells activates eosinophil adhesion to ICAM-1 surrogate protein and secretion of leukotriene (LT)C4. Exogenous human group V PLA2 (hVPLA2) caused an increase in surface CD11b expression and focal clustering of this integrin, which corresponded to increased β2 integrin-mediated adhesion. Human IIaPLA2, a close homolog of hVPLA2, or W31A, an inactive mutant of hVPLA2, did not affect these responses. Exogenous lysophosphatidylcholine but not arachidonic acid mimicked the β2 integrin-mediated adhesion caused by hVPLA2 activation. Inhibition of hVPLA2 with MCL-3G1, a mAb against gVPLA2, or with LY311727, a global secretory phospholipase A2 (PLA2) inhibitor, attenuated the activity of hVPLA2; trifluoromethylketone, an inhibitor of cytosolic group IVA PLA2 (gIVA-PLA2), had no inhibitory effect on hVPLA2-mediated adhesion. Activation of β2 integrin-dependent adhesion by hVPLA2 did not cause ERK1/2 activation and was independent of gIVA-PLA2 phosphorylation. In other studies, eosinophils cocultured with epithelial cells were stimulated with FMLP/cytochalasin B (FMLP/B) and/or endothelin-1 (ET-1) before LTC4 assay. FMLP/B alone caused release of LTC4 from eosinophils, which was augmented by coculture with epithelial cells activated with ET-1. Addition of MCL-3G1 to cocultured cells caused ∼50% inhibition of LTC4 secretion elicited by ET-1, which was blocked further by trifluoromethylketone. Our data indicate that hVPLA2 causes focal clustering of CD11b and β2 integrin adhesion by a novel mechanism that is independent of arachidonic acid synthesis and gIVA-PLA2 activation. We also demonstrate that gVPLA2, endogenously secreted from activated epithelial cells, promotes secretion of LTC4 in cocultured eosinophils.
Proinflammatory Role of Glucocorticoid-Induced TNF Receptor-Related Gene in Acute Lung Inflammation
Authors: Cuzzocrea Salvatore , Nocentini Giuseppe , Di Paola Rosanna , Agostini Massimiliano , Mazzon Emanuela , Ronchetti Simona , Crisafulli Concetta , Esposito Emanuela , Caputi Achille P. , Riccardi Carlo 
Published: April 2014

AbstractGlucocorticoid-induced TNFR-related gene (GITR) participates in the immune/inflammatory response. Because GITR expression has been described in cells other than T lymphocytes, we investigated whether it also modulates acute inflammatory response. Using GITR-deficient (GITR−/−) mice, we analyzed the role of GITR in the development of carrageenan-induced lung inflammation (pleurisy) by studying several proinflammatory markers 2–8 h after carrageenan injection. When compared with GITR+/+, GITR−/− mice exhibited decreased production of turbid exudate containing a lower number of leukocytes. This was correlated with the reduction of inflammatory markers (including TNF-α, IL-1β, myeloperoxidase, inducible NO synthase, and cyclooxygenase 2) in the pleural exudate and/or in the lung. Moreover, endothelial cells expressed lower levels of adhesion molecules. In lungs of GITR+/+ mice, GITR ligand expression was not modulated during pleurisy, while that of GITR increased, as a consequence of increased infiltration by GITR-expressing cells and of GITR up-regulation in macrophages and endothelial cells. Finally, cotreatment of GITR+/+ mice with carrageenan and Fc-GITR fusion protein decreased the number of inflammatory cells (pleural macrophages and lung neutrophils) as compared with carrageenan treatment alone, confirming that GITR plays a role in the modulation of pleurisy.
Homozygosity for the IgG2 Subclass Allotype G2M(n) Protects against Severe Infection in Hereditary C2 Deficiency
Authors: Jönsson Göran , Oxelius Vivi-Anne , Truedsson Lennart , Braconier Jean Henrik , Sturfelt Gunnar , Sjöholm Anders G. 
Published: April 2014

AbstractHomozygous C2 deficiency (C2D) is the most common deficiency of the classical complement pathway in Western countries. It is mostly found in patients with autoimmune disease or susceptibility to bacterial infections and in healthy persons. We wished to assess to what extent other immunological factors might explain differences of susceptibility to infections in C2D. For this reason, 44 Swedish patients with C2D were stratified with regard to the severity of documented infections. Investigations of IgG subclass levels, IgG subclass-specific GM allotypes, concentrations of factor B, properdin, and factor H, and polymorphisms of mannan-binding lectin and the Fc receptors FcγRIIa and FcγRIIIb were performed. Homozygosity for the G2M*n allele, which is known to promote Ab responses to polysaccharide Ags, was strongly associated with the absence of severe infections (p &lt; 0.001) in the patients, suggesting a major protective role. The combination of mannan (or mannose)-binding lectin and C2 deficiency was found to be a minor susceptibility factor for invasive infection (p = 0.03). Low concentrations of IgG2 and factor B might sometimes contribute to susceptibility to infection. Other factors investigated did not appear to be important. In conclusion, the findings indicated that efficient Ab responses to polysaccharides are protective against severe infection in C2D. Implications with regard to vaccination should be considered.
Detailed Analysis of Intrahepatic CD8 T Cells in the Normal and Hepatitis C-Infected Liver Reveals Differences in Specific Populations of Memory Cells with Distinct Homing Phenotypes
Authors: Heydtmann Mathis , Hardie Debbie , Shields Philip L. , Faint Jeff , Buckley Christopher D. , Campbell James J. , Salmon Michael , Adams David H. 
Published: April 2014

AbstractIn hepatitis C virus (HCV) infection the immune response is ineffective, leading to chronic hepatitis and liver damage. Primed CD8 T cells are critical for antiviral immunity and subsets of circulating CD8 T cells have been defined in blood but these do not necessarily reflect the clonality or differentiation of cells within tissue. Current models divide primed CD8 T cells into effector and memory cells, further subdivided into central memory (CCR7+, L-selectin+), recirculating through lymphoid tissues and effector memory (CCR7−, L-selectin−) mediating immune response in peripheral organs. We characterized CD8 T cells derived from organ donors and patients with end-stage HCV infection to show that: 1) all liver-infiltrating CD8 T cells express high levels of CD11a, indicating the effective absence of naive CD8 T cells in the liver. 2) The liver contains distinct subsets of primed CD8+ T cells including a population of CCR7+ L-selectin− cells, which does not reflect current paradigms. The expression of CCR7 by these cells may be induced by the hepatic microenvironment to facilitate recirculation. 3) The CCR7 ligands CCL19 and CCL21 are present on lymphatic, vascular, and sinusoidal endothelium in normal liver and in patients with HCV infection. We suggest that the recirculation of CCR7+/L-selectin− intrahepatic CD8 T cells to regional lymphoid tissue will be facilitated by CCL19 and CCL21 on hepatic sinusoids and lymphatics. This centripetal pathway of migration would allow restimulation in lymph nodes, thereby promoting immune surveillance in normal liver and renewal of effector responses in chronic viral infection.
Immature CD4+CD8+ Thymocytes and Mature T Cells Regulate Nur77 Distinctly in Response to TCR Stimulation
Authors: Cunningham Nicole R. , Artim Stephen C. , Fornadel Christen M. , Sellars MacLean C. , Edmonson Samuel G. , Scott Grant , Albino Frank , Mathur Akriti , Punt Jennifer A. 
Published: April 2014

AbstractThe orphan steroid receptor, Nur77, is thought to be a central participant in events leading to TCR-mediated clonal deletion of immature thymocytes. Interestingly, although both immature and mature murine T cell populations rapidly up-regulate Nur77 after TCR stimulation, immature CD4+CD8+ thymocytes respond by undergoing apoptosis, whereas their mature descendants respond by dividing. To understand these developmental differences in susceptibility to the proapoptotic potential of Nur77, we compared its regulation and compartmentalization and show that mature, but not immature, T cells hyperphosphorylate Nur77 in response to TCR signals. Nur77 resides in the nucleus of immature CD4+CD8+ thymocytes throughout the course of its expression and is not found in either the organellar or cytoplasmic fractions. However, hyperphosphorylation of Nur77 in mature T cells, which is mediated by both the MAPK and PI3K/Akt pathways, shifts its localization from the nucleus to the cytoplasm. The failure of immature CD4+CD8+ thymocytes to hyperphosphorylate Nur77 in response to TCR stimulation may be due in part to decreased Akt activity at this developmental stage.
Glutamate Released by Dendritic Cells as a Novel Modulator of T Cell Activation
Authors: Pacheco Rodrigo , Oliva Harold , Martinez-Navío José M. , Climent Núria , Ciruela Francisco , Gatell José M. , Gallart Teresa , Mallol Josefa , Lluis Carmen , Franco Rafael 
Published: April 2014

Abstract
Adaptive immune responses begin after productive immunosynaptic contacts formation established in secondary lymphoid organs by dendritic cells (DC) presenting the Ag to T lymphocytes. Despite its resemblance to the neurosynapse, the participation of soluble small nonpeptidic mediators in the intercellular cross-talk taking place during T cell–DC interactions remains poorly studied. In this study, we show that human DC undergoing maturation and in contact with T cells release significant amounts of glutamate, which is the main excitatory neurotransmitter in mammalians. The release of glutamate is nonvesicular and mediated by the DC-expressed Xc− cystine/glutamate antiporter. DC-derived glutamate stimulating the constitutively expressed metabotropic glutamate receptor 5 impairs T cell activation. However, after productive Ag presentation, metabotropic glutamate receptor 1 is expressed in T cells to mediate enhanced T cell proliferation and secretion of Th1 and proinflammatory cytokines. These data suggest that, during T cell–DC interaction, glutamate is a novel and highly effective regulator in the initiation of T cell-mediated immune responses.
Human Bone Marrow: A Reservoir for “Enhanced Effector Memory” CD8+ T Cells with Potent Recall Function
Authors: Zhang Xiaoyu , Dong Haidong , Lin Wei , Voss Stephen , Hinkley Lucinda , Westergren Melissa , Tian Guoliang , Berry Daniel , Lewellen David , Vile Richard G. , Chen Lieping , Farber Donna L. , Strome Scott E. 
Published: April 2014

Abstract
The role of human bone marrow (BM) CD8+ T cells in the immune response to viral Ags is poorly defined. We report here the identification and characterization of a functionally enhanced effector memory CD8+ T cell population (TEM) in the BM of patients undergoing total joint replacement for osteoarthritis. These BM-derived TEM differ strikingly from correlate cells in peripheral blood (PB), expressing elevated levels of CD27, HLA-DR, CD38, CD69, and unique patterns of chemokine receptors. Interestingly, while BM TEM have low levels of resting perforin and granzyme B, these molecules evidence profound up-regulation in response to TCR stimulation resulting in enhanced cytotoxic potential. Moreover, compared with the TEM subset in PB, BM CD8+ TEM cells demonstrate a more vigorous recall response to pooled viral Ags. Our results reveal that human BM serves as a repository for viral Ag-specific TEM with great therapeutic potential in vaccine development.
Activin A Functions as a Th2 Cytokine in the Promotion of the Alternative Activation of Macrophages
Authors: Ogawa Kenji , Funaba Masayuki , Chen Yan , Tsujimoto Masafumi 
Published: April 2014

Abstract
Activin A, a member of the TGF-β superfamily, is a pluripotent growth and differentiation factor. In this study, we report that murine Th cells produce activin A upon activation. Activin activity in the cultured CD4+ T cells was induced by anti-CD3 cross-linking. Activin βA mRNA level was increased in response to activation, indicating that activin production in CD4+ T cells is regulated at the mRNA level. Activin production was detected exclusively in CD4+CD25− T cells, but not in CD4+CD25+ regulatory T cells. When CD4+ T cells were differentiated into Th cell subsets, higher activin secretion was detected when cultured under Th2-skewing conditions. The mRNA level of activin βA was abundant in Th2, but not in Th1 cells. Furthermore, secretion of activin was significantly higher in activated Th2 clones than in Th1 clones. The activin βA-proximal promoter contains a binding site for c-Maf, a Th2-specific transcriptional factor, at close proximity with an NF-AT binding site. c-Maf was able to synergize with NF-AT to transactivate activin βA gene, and both factors are implicated in activin βA transcription in Th2 cells. Activin A induced macrophages to express arginase-1 (M-2 phenotype), whereas it inhibited inducible NO synthase expression (M-1 phenotype) induced by IFN-γ. Taken together, these observations suggest that activin A is a novel Th2 cytokine that promotes differentiation of macrophages toward the M-2 phenotype.
TIRC7 Inhibits T Cell Proliferation by Modulation of CTLA-4 Expression
Authors: Bulwin Grit-Carsta , Heinemann Thomas , Bugge Volker , Winter Michael , Lohan Anke , Schlawinsky Mirko , Schulze Anke , Wälter Stephanie , Sabat Robert , Schülein Ralf , Wiesner Burkhard , Veh Rüdiger W. , Löhler Jürgen , Blumberg Richard S. , Volk Hans-Dieter , Utku Nalân 
Published: April 2014

Abstract
Ab targeting of TIRC7 has been shown previously to inhibit T cell proliferation and Th1 lymphocyte-associated cytokine production. In this study, we demonstrate that Ab targeting of TIRC7 induces early cell surface expression of CTLA-4. The majority of stimulated CD4+ and CD8+ human T cells coexpress CTLA-4 and TIRC7. Similar to CTLA-4, TIRC7 rapidly accumulates at the site of Ag adhesion upon T cell activation. TIRC7 seems to colocalize with CTLA-4 in human T cells, and both molecules are associated with clathrin-coated vesicles, indicating they share intracellular transport systems. Moreover, Ab targeting of TIRC7 results in an early activation of CTLA-4 transcription. The inhibition of cell proliferation mediated by TIRC7 is dependent on CTLA-4 expression because the TIRC7-mediated inhibitory effects on cell proliferation and cytokine expression are abolished by Ab blockade of CTLA-4. Splenocytes obtained from CTLA-4-deficient mice are not responsive to TIRC7 Ab targeting. Thus, TIRC7 acts as an upstream regulatory molecule of CTLA-4 expression.
Microbial Immune Suppression Mediated by Direct Engagement of Inhibitory Fc Receptor
Authors: Monari Claudia , Kozel Thomas R. , Paganelli Francesca , Pericolini Eva , Perito Stefano , Bistoni Francesco , Casadevall Arturo , Vecchiarelli Anna 
Published: April 2014

Abstract
A microbial polysaccharide (glucuronoxylomannan (GXM)) exerts potent immunosuppression by direct engagement to immunoinhibitory receptor FcγRIIB. Activation of FcγRIIB by GXM leads to the recruitment and phosphorylation of SHIP that prevents IκBα activation. The FcγRIIB blockade inhibits GXM-induced IL-10 production and induces TNF-α secretion. GXM quenches LPS-induced TNF-α release via FcγRIIB. The addition of mAb to GXM reverses GXM-induced immunosuppression by shifting recognition from FcγRIIB to FcγRIIA. These findings indicate a novel mechanism by which microbial products can impair immune function through direct stimulation of an inhibitory receptor. Furthermore, our observations provide a new mechanism for the ability of specific Ab to reverse the immune inhibitory effects of certain microbial products.