bluuebunny/crossref_metadata_2025_split huggingface dataset:
Four Distinct Patterns of Memory CD8 T Cell Responses to Chronic Murine Cytomegalovirus Infection
Authors: Munks Michael W. , Cho Kathy S. , Pinto Amelia K. , Sierro Sophie , Klenerman Paul , Hill Ann B. 
Published: April 2014

Abstract
CMVs are β herpesviruses that establish lifelong latent infection of their hosts. Acute infection of C57BL/6 mice with murine CMV elicits a very broad CD8 T cell response, comprising at least 24 epitopes from 18 viral proteins. In contrast, we show here that the CD8 T cell response in chronically infected mice was dominated by only five epitopes. Altogether, four distinct CD8 T cell kinetic patterns were evident. Responses to some epitopes, including M45, which dominates the acute response, contracted sharply after day 7 and developed into stable long-term memory. The response to m139 underwent rapid expansion and contraction, followed by a phase of memory inflation, whereas the response to an M38 epitope did not display any contraction phase. Finally, responses against two epitopes encoded by the immediate early gene IE3 were readily detectable in chronically infected mice but near the limit of detection during acute infection. CD8 T cells specific for the noninflationary M45 epitope displayed a classic central memory phenotype, re-expressing the lymph node homing receptor CD62L and homeostatic cytokine receptors for IL-7 and IL-15, and produced low levels of IL-2. Responses to two inflationary epitopes, m139 and IE3, retained an effector memory surface phenotype (CD62Llow, IL-7Rα−, IL-15Rβ−) and were unable to produce IL-2. We suggest that immunological choices are superimposed on altered viral gene expression profiles to determine immunodominance during chronic murine CMV infection.
Impaired Generation of Reactive Oxygen Species during Differentiation of Dendritic Cells (DCs) byMycobacterium tuberculosisSecretory Antigen (MTSA) and Subsequent Activation of MTSA-DCs by Mycobacteria Results in Increased Intracellular Survival
Authors: Sinha Aprajita , Singh Anjana , Satchidanandam Vijaya , Natarajan Krishnamurthy 
Published: April 2014

AbstractWe investigated the role of reactive oxygen species (ROS) in dendritic cell (DC) differentiation by 10-kDa Mycobacterium tuberculosis secretory Ag (MTSA) and survival of mycobacteria therein. Compared with GM-CSF, MTSA induced lower ROS production during DC differentiation from precursors. This result correlated with higher superoxide dismutase 1 expression in MTSA stimulated precursors as compared with GM-CSF stimulation. Furthermore, a negative regulation of protein kinase C (PKC) activation by ROS was observed during DC differentiation. ROS inhibited the rapid and increased phosphorylation of PKCα observed during DC differentiation by MTSA. In contrast, ROS inhibition increased the weak and delayed PKCα phosphorylation by GM-CSF. Similar to DC differentiation, upon activation with either M. tuberculosis cell extract (CE) or live Mycobacterium bovis bacillus Calmette-Guérin (BCG), DCs differentiated with MTSA (MTSA-DCs) generated lower ROS levels when compared with DCs differentiated with GM-CSF (GM-CSF-DCs). Likewise, a negative regulation of PKCα phosphorylation by ROS was once again observed in DCs activated with either M. tuberculosis CE or live M. bovis BCG. However, a reciprocal positive regulation between ROS and calcium was observed. Compared with MTSA-DCs, stimulation of GM-CSF-DCs with M. tuberculosis CE induced a 2-fold higher ROS-dependent calcium influx. However, pretreatment of MTSA-DCs with H2O2 increased calcium mobilization. Finally, lower ROS levels in MTSA-DCs correlated with increased intracellular survival of M. bovis BCG when compared with survival in GM-CSF-DCs. Although inhibiting ROS in GM-CSF-DCs increased M. bovis BCG survival, H2O2 treatment of MTSA-DCs decreased survival of M. bovis BCG. Overall our results suggest that DCs differentiated with Ags such as MTSA may provide a niche for survival and/or growth of mycobacteria following sequestration of ROS.
The Meningococcal Vaccine Candidate GNA1870 Binds the Complement Regulatory Protein Factor H and Enhances Serum Resistance
Authors: Madico Guillermo , Welsch Jo Anne , Lewis Lisa A. , McNaughton Anne , Perlman David H. , Costello Catherine E. , Ngampasutadol Jutamas , Vogel Ulrich , Granoff Dan M. , Ram Sanjay 
Published: April 2014

Abstract
Neisseria meningitidis binds factor H (fH), a key regulator of the alternative complement pathway. A ∼29 kD fH-binding protein expressed in the meningococcal outer membrane was identified by mass spectrometry as GNA1870, a lipoprotein currently under evaluation as a broad-spectrum meningococcal vaccine candidate. GNA1870 was confirmed as the fH ligand on intact bacteria by 1) abrogation of fH binding upon deleting GNA1870, and 2) blocking fH binding by anti-GNA1870 mAbs. fH bound to whole bacteria and purified rGNA1870 representing each of the three variant GNA1870 families. We showed that the amount of fH binding correlated with the level of bacterial GNA1870 expression. High levels of variant 1 GNA1870 expression (either by allelic replacement of gna1870 or by plasmid-driven high-level expression) in strains that otherwise were low-level GNA1870 expressers (and bound low amounts of fH by flow cytometry) restored high levels of fH binding. Diminished fH binding to the GNA1870 deletion mutants was accompanied by enhanced C3 binding and increased killing of the mutants. Conversely, high levels of GNA1870 expression and fH binding enhanced serum resistance. Our findings support the hypothesis that inhibiting the binding of a complement down-regulator protein to the neisserial surface by specific Ab may enhance intrinsic bactericidal activity of the Ab, resulting in two distinct mechanisms of Ab-mediated vaccine efficacy. These data provide further support for inclusion of this molecule in a meningococcal vaccine. To reflect the critical function of this molecule, we suggest calling it fH-binding protein.
The Peptidoglycan-Degrading Property of Lysozyme Is Not Required for Bactericidal Activity In Vivo
Authors: Nash James A. , Ballard Tiffany Nicole S. , Weaver Timothy E. , Akinbi Henry T. 
Published: April 2014

Abstract
Lysozyme is an abundant, cationic antimicrobial protein that plays an important role in pulmonary host defense. Increased concentration of lysozyme in the airspaces of transgenic mice enhanced bacterial killing whereas lysozyme deficiency resulted in increased bacterial burden and morbidity. Lysozyme degrades peptidoglycan in the bacterial cell wall leading to rapid killing of Gram-positive organisms; however, this mechanism cannot account for the protective effect of lysozyme against Gram-negative bacteria. The current study was therefore designed to test the hypothesis that the catalytic activity (muramidase activity) of lysozyme is not required for bacterial killing in vivo. Substitution of serine for aspartic acid at position 53 (D53S) in mouse lysozyme M completely ablated muramidase activity. Muramidase-deficient recombinant lysozyme (LysMD53S) killed both Gram-positive and Gram-negative bacteria in vitro. Targeted expression of LysMD53S in the respiratory epithelium of wild-type (LysM+/+/LysMD53S) or lysozyme Mnull mice (LysM−/−/LysMD53S) resulted in significantly elevated lysozyme protein in the airspaces without any increase in muramidase activity. Intratracheal challenge of transgenic mice with Gram-positive or Gram-negative bacteria resulted in a significant increase in bacterial burden in LysM−/− mice that was completely reversed by targeted expression of LysMD53S. These results indicate that the muramidase activity of lysozyme is not required for bacterial killing in vitro or in vivo.
Stat3 Is Required for Cytoprotection of the Respiratory Epithelium during Adenoviral Infection
Authors: Matsuzaki Yohei , Xu Yan , Ikegami Machiko , Besnard Valérie , Park Kwon-Sik , Hull William M. , Wert Susan E. , Whitsett Jeffrey A. 
Published: April 2014

AbstractThe role of Stat3 in the maintenance of pulmonary homeostasis following adenoviral-mediated lung injury was assessed in vivo. Stat3 was selectively deleted from bronchiolar and alveolar epithelial cells in Stat3ΔΔ mice. Although lung histology and function were unaltered by deletion of Stat3 in vivo, Stat3ΔΔ mice were highly susceptible to lung injury caused by intratracheal administration of AV1-GFP, an early (E) region 1- and E3-deleted, nonproliferative adenovirus. Severe airspace enlargement, loss of alveolar septae, and sloughing of the bronchiolar epithelium were observed in Stat3ΔΔ mice as early as 1 day after exposure to the virus. Although surfactant protein A, B, and C content and surfactant protein-B mRNA expression in Stat3ΔΔ mice were similar, TUNEL staining and caspase-3 were increased in alveolar type II epithelial cells of Stat3ΔΔ mice after exposure to virus. RNA microarray analysis of type II epithelial cells isolated from Stat3ΔΔ mice demonstrated significant changes in expression of numerous genes, including those genes regulating apoptosis, supporting the concept that the susceptibility of Stat3-deficient mice to adenovirus was related to the role of Stat3 in the regulation of cell survival. AV1-Bcl-xL, an E1- and E3-deleted, nonproliferative adenovirus expressing the antiapoptotic protein Bcl-xL, protected Stat3ΔΔ mice from adenoviral-induced lung injury. Adenoviral infection of the lungs of Stat3-deficient mice was associated with severe injury of the alveolar and bronchiolar epithelium. Thus, Stat3 plays a critical cytoprotective role that is required for epithelial cell survival and maintenance of alveolar structures during the early phases of pulmonary adenoviral infection.
Tolerance to Proinsulin-2 Is Due to Radioresistant Thymic Cells
Authors: Faideau Béatrice , Lotton Chantal , Lucas Bruno , Tardivel Isabelle , Elliott John F. , Boitard Christian , Carel Jean-Claude 
Published: April 2014

Abstract
Proinsulin is a key Ag in type 1 diabetes, but the mechanisms regulating proinsulin immune tolerance are unknown. We have shown that preproinsulin-2 gene-deficient mice (proins-2−/−) are intolerant to proinsulin-2. In this study, we analyzed the mechanisms underlying T cell-mediated tolerance to proinsulin-2 in 129/Sv nonautoimmune mice. The expression of one proinsulin-2 allele, whatever its parental origin, was sufficient to maintain tolerance. The site of proinsulin-2 expression relevant to tolerance was evaluated in thymus and bone marrow chimeras. CD4+ T cell reactivity to proinsulin-2 was independent of proinsulin-2 expression in radiation-sensitive bone marrow-derived cells. A wt thymus restored tolerance in proins-2−/− mice. Conversely, the absence of the preproinsulin-2 gene in radioresistant thymic cells was sufficient to break tolerance. Although chimeric animals had proinsulin-2-reactive CD4+ T cells in their peripheral repertoire, they displayed no insulitis or insulin Abs, suggesting additional protective mechanisms. In a model involving transfer to immunodeficient (CD3ε−/−) mice, naive and proinsulin-2-primed CD4+ T cells were not activated, but could be activated by immunization regardless of whether the recipient mice expressed proinsulin-2. Furthermore, we could not identify a role for putative specific T cells regulating proinsulin-2-reactive CD4+ T in transfer experiments. Thus, proinsulin-2 gene expression by radioresistant thymic epithelial cells is involved in the induction of self-tolerance, and additional factors are required to induce islet abnormalities.
SIGIRR Promotes Resistance againstPseudomonas aeruginosaKeratitis by Down-Regulating Type-1 Immunity and IL-1R1 and TLR4 Signaling
Authors: Huang Xi , Hazlett Linda D. , Du Wenjin , Barrett Ronald P. 
Published: April 2014

AbstractPseudomonas aeruginosa keratitis destroys the cornea in susceptible Th1 responder C57BL/6 (B6), but not resistant Th2 responder (BALB/c) mice. To determine whether single Ig IL-1R-related molecule (SIGIRR) played a role in resistance, mRNA and protein expression levels were tested. Both were constitutively expressed in the cornea of the two mouse groups. A disparate mRNA and protein expression pattern was detected in the cornea of BALB/c vs B6 mice after infection. SIGIRR protein decreased significantly in BALB/c over B6 mice at 1 day postinfection. Thus, BALB/c mice were injected with an anti-SIGIRR Ab or IgG control. Anti-SIGIRR Ab over control-treated mice showed increased corneal opacity, stromal damage, and bacterial load. Corneal mRNA levels for IL-1β, MIP-2, IL-1R1, TLR4, IL-18, and IFN-γ and protein levels for IL-1β and MIP-2 also were significantly up-regulated in anti-SIGIRR Ab over control mice, while no changes in polymorphonuclear cell number, IL-4, or IL-10 mRNA expression were detected. To further define the role of SIGIRR, RAW264.7 macrophage-like cells were transiently transfected with SIGIRR and stimulated with heat-killed P. aeruginosa or LPS. SIGIRR transfection significantly decreased mRNA levels for IL-1R1, TLR4, and type 1 immune response-associated cytokines (IL-12, IL-18, and IFN-γ) as well as proinflammatory cytokines IL-1β and MIP-2 protein expression. SIGIRR also negatively regulated IL-1 and LPS, but not poly(I:C)-mediated signaling and NF-κB activation. These data provide evidence that SIGIRR is critical in resistance to P. aeruginosa corneal infection by down-regulating type 1 immunity, and that it negatively regulates IL-1 and TLR4 signaling.
A Mechanism for Neurodegeneration Induced by Group B Streptococci through Activation of the TLR2/MyD88 Pathway in Microglia
Authors: Lehnardt Seija , Henneke Philipp , Lien Egil , Kasper Dennis L. , Volpe Joseph J. , Bechmann Ingo , Nitsch Robert , Weber Joerg R. , Golenbock Douglas T. , Vartanian Timothy 
Published: April 2014

AbstractGroup B Streptococcus (GBS) is a major cause of bacterial meningitis and neurological morbidity in newborn infants. The cellular and molecular mechanisms by which this common organism causes CNS injury are unknown. We show that both heat-inactivated whole GBS and a secreted proteinaceous factor from GBS (GBS-F) induce neuronal apoptosis via the activation of murine microglia through a TLR2-dependent and MyD88-dependent pathway in vitro. Microglia, astrocytes, and oligodendrocytes, but not neurons, express TLR2. GBS as well as GBS-F induce the synthesis of NO in microglia derived from wild-type but not TLR2−/− or MyD88−/− mice. Neuronal death in neuronal cultures complemented with wild-type microglia is NO-dependent. We show for the first time a TLR-mediated mechanism of neuronal injury induced by a clinically relevant bacterium. This study demonstrates a causal molecular relationship between infection with GBS, activation of the innate immune system in the CNS through TLR2, and neurodegeneration. We suggest that this process contributes substantially to the serious morbidity associated with neonatal GBS meningitis and may provide a potential therapeutic target.
Epithelial Inflammation Is Associated with CCL28 Production and the Recruitment of Regulatory T Cells Expressing CCR10
Authors: Eksteen Bertus , Miles Alice , Curbishley Stuart M. , Tselepis Chris , Grant Allister J. , Walker Lucy S. K. , Adams David H. 
Published: April 2014

Abstract
Mucosal tissues require constant immune surveillance to clear harmful pathogens while maintaining tolerance to self Ags. Regulatory T cells (Tregs) play a central role in this process and expression of αEβ7 has been reported to define a subset of Tregs with tropism for inflamed tissues. However, the signals responsible for recruiting Tregs to epithelial surfaces are poorly understood. We have isolated a subset of CCR10-expressing CD25+CD4+Foxp3+ Tregs with potent anti-inflammatory properties from chronically inflamed human liver. The CCR10+ Tregs were detected around bile ducts that expressed increased levels of the CCR10 ligand CCL28. CCL28 was secreted by primary human cholangiocytes in vitro in response to LPS, IL-1β, or bile acids. Exposure of CCR10+ Tregs to CCL28 in vitro stimulated migration and adhesion to mucosal addressin cell adhesion molecule-1 and VCAM-1. Liver-derived CCR10+ Tregs expressed low levels of CCR7 but high levels of CXCR3, a chemokine receptor associated with infiltration into inflamed tissue and contained a subset of αEβ7+ cells. We propose that CXCR3 promotes the recruitment of Tregs to inflamed tissues and CCR10 allows them to respond to CCL28 secreted by epithelial cells resulting in the accumulation of CCR10+ Tregs at mucosal surfaces.
The Src Family Kinases Hck and Fgr Are Dispensable for Inside-Out, Chemoattractant-Induced Signaling Regulating β2 Integrin Affinity and Valency in Neutrophils, but Are Required for β2 Integrin-Mediated Outside-In Signaling Involved in Sustained Adhesion
Authors: Giagulli Cinzia , Ottoboni Linda , Caveggion Elena , Rossi Barbara , Lowell Clifford , Constantin Gabriela , Laudanna Carlo , Berton Giorgio 
Published: April 2014

Abstract
Neutrophil β2 integrins are activated by inside-out signaling regulating integrin affinity and valency; following ligand binding, β2 integrins trigger outside-in signals regulating cell functions. Addressing inside-out and outside-in signaling in hck−/−fgr−/− neutrophils, we found that Hck and Fgr do not regulate chemoattractant-induced activation of β2 integrin affinity. In fact, β2 integrin-mediated rapid adhesion, in static condition assays, and neutrophil adhesion to glass capillary tubes cocoated with ICAM-1, P-selectin, and a chemoattractant, under flow, were unaffected in hck−/−fgr−/− neutrophils. Additionally, examination of integrin affinity by soluble ICAM-1 binding assays and of β2 integrin clustering on the cell surface, showed that integrin activation did not require Hck and Fgr expression. However, after binding, hck−/−fgr−/− neutrophil spreading over β2 integrin ligands was reduced and they rapidly detached from the adhesive surface. Whether alterations in outside-in signaling affect sustained adhesion to the vascular endothelium in vivo was addressed by examining neutrophil adhesiveness to inflamed muscle venules. Intravital microscopy analysis allowed us to conclude that Hck and Fgr regulate neither the number of rolling cells nor rolling velocity in neutrophils. However, arrest of hck−/−fgr−/− neutrophils to &gt;60 μm in diameter venules was reduced. Thus, Hck and Fgr play no role in chemoattractant-induced inside-out β2 integrin activation but regulate outside-in signaling-dependent sustained adhesion.
Adenoviral-Mediated Overexpression of SOCS3 Enhances IgG Immune Complex-Induced Acute Lung Injury
Authors: Gao Hongwei , Hoesel L. Marco , Guo Ren-Feng , Rancilio Nicholas J. , Sarma J. Vidya , Ward Peter A. 
Published: April 2014

AbstractThe lung inflammatory response caused by intratracheal deposition of IgG immune complexes (IC) includes the production of IL-6, which signals through activation of STAT transcription factors. Recently, suppressor of cytokine signaling 3 (SOCS3) has been shown to be a key negative regulator of IL-6/gp130/Jak/STAT3 signal transduction. Although SOCS3 has been implicated in several inflammatory diseases, very little is known regarding its activation and its function in the lung during acute inflammation. Our previous study showed that IL-6/STAT3 activation was triggered in lungs after intrapulmonary deposition of IgG IC in rats. In the current study, we sought to determine whether SOCS3 is playing a regulatory role in the lung inflammatory response. SOCS3 induction occurred during development of inflammation in the IgG IC model of lung injury. Overexpression of SOCS3 in lung using a recombinant adenovirus encoding murine SOCS3 resulted in substantial increases in lung vascular permeability and lung myeloperoxidase, together with enhanced levels of TNF-α, MIP-2, and keratinocyte-activated cytokine in bronchoalveolar lavage fluids. SOCS3 overexpression in lungs led to overproduction of bronchoalveolar lavage IL-6, but not IL-10, in this inflammatory model. We further show that activation of STAT3 was inhibited by SOCS3 overexpression as well as by anti-IL-6 treatment during IgG IC-induced lung injury, as determined by EMSA. In vitro, SOCS3 overexpression abrogated IL-6-induced activation of STAT3 in lung epithelial cells. These findings suggest SOCS3 is an important regulator of lung inflammatory injury after deposition of IgG IC.
Lovastatin-Induced Apoptosis in Macrophages through the Rac1/Cdc42/JNK Pathway
Authors: Liang Shu-Ling , Liu Hongli , Zhou Aimin 
Published: April 2014

Abstract
Statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, have been used successfully in the treatment of hypercholesterolemia for more than a decade. Statins also exhibit overall clinical benefits on cardiovascular diseases independent of their effects on lowering serum cholesterol levels. These beneficial effects of statin therapy are believed to be due, at least in part, to the anti-inflammatory and immunomodulatory roles of statins. Statin treatment reduces the levels of inflammatory markers, decreases the activation and recruitment of immune cells, and delays the progression of atherosclerosis, a chronic inflammatory disease. However, little is known about the direct impact of statins on immune cells, particularly on macrophages. We report that lovastatin, a member of the statin family, effectively induces apoptosis in macrophages. Further investigation of the molecular mechanism has revealed that Rac1 and Cdc42, the small GTPase family members, may play an important role in lovastatin-induced macrophage apoptosis. Moreover, the activation of the JNK pathway may contribute to this event. Our findings provide a better understanding of the molecular basis underlying the anti-inflammatory clinical benefits of statin therapy in cardiovascular diseases.
Identification of a TLR-Independent Pathway forBorrelia burgdorferi-Induced Expression of Matrix Metalloproteinases and Inflammatory Mediators through Binding to Integrin α3β1
Authors: Behera Aruna K. , Hildebrand Ethan , Uematsu Satoshi , Akira Shizuo , Coburn Jenifer , Hu Linden T. 
Published: April 2014

AbstractBorrelia burgdorferi stimulates a robust inflammatory response at sites of localization. Binding of borrelial lipoproteins to TLR-2 is one pathway important in the host response to B. burgdorferi. However, while TLR-2 is clearly important in control of infection, inflammation is actually worsened in the absence of TLR-2 or the shared TLR adapter molecule, MyD88, suggesting that there are alternative pathways regulating inflammation. Integrins are cell surface receptors that play an important role in cell to cell communications and that can activate inflammatory signaling pathways. In this study, we report for the first time that B. burgdorferi binds to integrin α3β1 and that binding of B. burgdorferi to this integrin results in induction of proinflammatory cytokines, chemokines, and end-effector molecules such as matrix metalloproteinases in primary human chondrocyte cells. Expression of these same molecules is not affected by the absence of MyD88 in murine articular cartilage, suggesting that the two pathways act independently in activating host inflammatory responses to B. burgdorferi. B. burgdorferi-induced α3 signaling is mediated by JNK, but not p38 MAPK. In summary, we have identified a new host receptor for B. burgdorferi, integrin α3β1; binding of B. burgdorferi to integrin α3β1 results in the release of inflammatory mediators and is proposed as a TLR-independent pathway for activation of the innate immune response by the organism.