bluuebunny/crossref_metadata_2025_split huggingface dataset:
CXC Chemokine Receptor-2 Ligands Are Required for Neutrophil-Mediated Host Defense in Experimental Brain Abscesses
Authors: Kielian Tammy , Barry Brenda , Hickey William F. 
Published: April 2014

Abstract
We have developed a mouse brain abscess model by using Staphylococcus aureus, one of the main etiologic agents of brain abscesses in humans. Direct damage to the blood-brain barrier was observed from 24 h to 7 days after S. aureus exposure as demonstrated by the accumulation of serum IgG in the brain parenchyma. Evaluation of brain abscesses by immunohistochemistry and flow cytometry revealed a prominent neutrophil infiltrate. To address the importance of neutrophils in the early containment of S. aureus infection in the brain, mice were transiently depleted of neutrophils before implantation of bacteria-laden beads. Neutrophil-depleted animals consistently demonstrated more severe brain abscesses and higher CNS bacterial burdens compared with control animals. S. aureus led to the induction of numerous chemokines in the brain, including macrophage-inflammatory protein (MIP)-1α/CCL3, MIP-1β/CCL4, MIP-2/CXCL1, monocyte chemoattractant protein-1/CCL2, and TCA-3/CCL1, within 6 h after bacterial exposure. These chemokines also were expressed by both primary cultures of neonatal mouse microglia and astrocytes exposed to heat-inactivated S. aureus in vitro. Because neutrophils constitute the majority of the cellular infiltrate in early brain abscess development, subsequent analysis focused on MIP-2 and KC/CXCL1, two neutrophil-attracting CXC chemokines. Both MIP-2 and KC protein levels were significantly elevated in the brain after S. aureus exposure. Neutrophil extravasation into the brain parenchyma was impaired in CXCR2 knockout mice and was associated with increased bacterial burdens. These studies demonstrate the importance of the CXCR2 ligands MIP-2 and KC and neutrophils in the acute host response to S. aureus in the brain.
The α4β1 (Very Late Antigen (VLA)-4, CD49d/CD29) and α5β1 (VLA-5, CD49e/CD29) Integrins Mediate β2 (CD11/CD18) Integrin-Independent Neutrophil Recruitment to Endotoxin-Induced Lung Inflammation
Authors: Burns J. Adam , Issekutz Thomas B. , Yagita Hideo , Issekutz Andrew C. 
Published: April 2014

Abstract
The β2 integrin cell adhesion molecules (CAM) mediate polymorphonuclear leukocyte (PMNL) emigration in most inflamed tissues, but, in the lung, other yet to be identified CAMs appear to be involved. In Lewis rats, the intratracheal injection of Escherichia coli-LPS induced acute (6-h) PMNL accumulation in the lung parenchyma (280 × 106 by myeloperoxidase assay; PBS control = 35 × 106) and bronchoalveolar lavage fluid (BALF = 27 × 106; PBS = 0.1 × 106). Parenchymal accumulation was not inhibited by a blocking Ab to β2 integrins and only minimally inhibited (20.5%; p &lt; 0.05) in BALF. We examined the role of α4β1 and α5β1 integrins and of selectins in this PMNL recruitment. Treatment with mAbs to α4β1 or α5β1, even in combination, had no effect on PMNL accumulation induced by intratracheal LPS. However, anti-α4 combined with anti-β2 mAbs inhibited PMNL recruitment to the parenchyma by 56% (p &lt; 0.001) and to BALF by 58% (p &lt; 0.01). The addition of anti-α5 mAb to β2 plus α4 blockade inhibited PMNL accumulation further (by 79%; p &lt; 0.05). In contrast, blockade of L-, P-, and E-selectins in combination or together with β2, α4, and α5 integrins had no effect. LPS-induced BALF protein accumulation was not inhibited by treatment with anti-β2 plus α4 mAbs, but was prevented when α5β1 was also blocked. Thus, while selectins appear to play no role, α4β1 and α5β1 function as major alternate CAMs to the β2 integrins in mediating PMNL migration to lung and to pulmonary vascular and epithelial permeability.
Human Leukocyte Subpopulations from Inflamed Gut Bind to Joint Vasculature Using Distinct Sets of Adhesion Molecules
Authors: Salmi Marko , Jalkanen Sirpa 
Published: April 2014

Abstract
Reactive arthritis can be triggered by inflammatory bowel diseases. We hypothesized that migration of mucosal immune cells from inflamed gut to joints could contribute to the development of reactive arthritis. Here we isolated gut-derived leukocytes from patients with Crohn’s disease and ulcerative colitis. Using function-blocking mAbs and in vitro frozen section adhesion assays we studied whether these cells bind to synovial vessels and which molecules mediate the interaction. The results showed that mucosal leukocytes from inflammatory bowel diseased gut bind well to venules in synovial membrane. Small intestinal lymphocytes adhered to synovial vessels using multiple homing receptors and their corresponding endothelial ligands (CD18-ICAM-1, α4β7/α4β1-integrin-VCAM-1, L-selectin-peripheral lymph node addressins, and CD44). Of these, only ICAM-1 significantly supported binding of immunoblasts. In contrast, P-selectin glycoprotein ligand-1-P-selectin interaction accounted for practically all synovial adherence of mucosal macrophages. In addition, blocking of vascular adhesion protein-1 significantly inhibited binding of all these leukocyte subsets to joint vessels. We conclude that different leukocyte populations derived from inflamed gut bind avidly to synovial vessels using distinct repertoire of adhesion molecules, suggesting that their recirculation may contribute to the development of reactive arthritis in inflammatory bowel diseases.
Lipopolysaccharide Activates Akt in Human Alveolar Macrophages Resulting in Nuclear Accumulation and Transcriptional Activity of β-Catenin
Authors: Monick Martha M. , Carter A. Brent , Robeff Pamela K. , Flaherty Dawn M. , Peterson Michael W. , Hunninghake Gary W. 
Published: April 2014

Abstract
Exposure of human alveolar macrophages to bacterial LPS results in activation of a number of signal transduction pathways. An early event after the alveolar macrophage comes in contact with LPS is activation of the phosphatidylinositol 3 kinase (PI 3-kinase). This study evaluates the downstream effects of that activation. We observed that LPS exposure results in phosphorylation of Akt (serine 473). We found this using both phosphorylation-specific Abs and also by in vivo phosphorylation with 32P-loaded cells. AKT activation resulted in the phosphorylation-dependent inactivation of glycogen synthase kinase (GSK-3) (serine 21/9). We found that both of these events were linked to PI 3-kinase because the PI 3-kinase inhibitors, wortmannin and LY294002, inhibited LPS-induced phosphorylation of both AKT and GSK-3. Inactivation of GSK-3 has been shown to reduce the ubiquitination of β-catenin, resulting in nuclear accumulation and transcriptional activity of β-catenin. Consistent with this, we found that LPS caused an increase in the amounts of PI 3-kinase-dependent nuclear β-catenin in human alveolar macrophages and expression of genes that require nuclear β-catenin for their activation. This is the first demonstration that LPS exposure activates AKT, inactivates GSK-3, and causes accumulation and transcriptional activity of β-catenin in the nucleus of any cell, including alveolar macrophages.
Requirement ofA1-afor Bacillus Calmette-Guérin-Mediated Protection of Macrophages Against Nitric Oxide-Induced Apoptosis
Authors: Kausalya Santhanam , Somogyi Robert , Orlofsky Amos , Prystowsky Michael B. 
Published: April 2014

AbstractThe role of apoptosis in regulating the course of intracellular microbial infection is not well understood. We studied the relationship between apoptotic regulation and bacillus Calmette-Guérin (BCG) treatment in murine peritoneal exudate macrophages (PEM) and the J774 macrophage cell line. In both PEM and J774 cells, mRNA expression of the anti-apoptotic gene, A1, was selectively induced by BCG treatment as compared with other bcl2 family members (bcl-w, bcl-2, bcl-xl, bcl-xs, bax, bak, bad). In PEM, A1 expression was maximal by 8 h postinfection and was abrogated by the proteasomal inhibitor MG-132. The induction was independent of protein synthesis as well as the p38 mitogen-activated protein kinase and phosphatidylinositol 3-kinase pathways and did not require live organism. Three genes encoding closely related isoforms of A1 were all expressed; however, the A1-a isoform displayed the greatest fold induction in PEM. BCG-induced A1 expression was associated with protection of host macrophages from NO-mediated apoptosis in both PEM and J774 cells. BCG-mediated protection was abrogated in PEM derived from A1-a−/− mice, indicating a requirement of A1-a for survival of inflammatory macrophages.
Reduced Early Alcohol-Induced Liver Injury in CD14-Deficient Mice
Authors: Yin Ming , Bradford Blair U. , Wheeler Michael D. , Uesugi Takehiko , Froh Matthias , Goyert Sanna M. , Thurman Ronald G. 
Published: April 2014

Abstract
Activation of Kupffer cells by gut-derived endotoxin is associated with alcohol-induced liver injury. Recently, it was shown that CD14-deficient mice are more resistant to endotoxin-induced shock than wild-type controls. Therefore, this study was designed to investigate the role of CD14 receptors in early alcohol-induced liver injury using CD14 knockout and wild-type BALB/c mice in a model of enteral ethanol delivery. Animals were given a high-fat liquid diet continuously with ethanol or isocaloric maltose-dextrin as control for 4 wk. The liver to body weight ratio in wild-type mice (5.8 ± 0.3%) was increased significantly by ethanol (7.3 ± 0.2%) but was not altered by ethanol in CD14-deficient mice. Ethanol elevated serum alanine aminotransferase levels nearly 3-fold in wild-type mice, but not in CD14-deficient mice. Wild-type and knockout mice given the control high-fat diet had normal liver histology, whereas ethanol caused severe liver injury (steatosis, inflammation, and necrosis; pathology score = 3.8 ± 0.4). In contrast, CD14-deficient mice given ethanol showed minimal hepatic changes (score = 1.6 ± 0.3, p &lt; 0.05). Additionally, NF-κB, TGF-β, and TNF-α were increased significantly in wild-type mice fed ethanol but not in the CD14 knockout. Thus, chronic ethanol feeding caused more severe liver injury in wild-type than CD14 knockouts, supporting the hypothesis that endotoxin acting via CD14 plays a major role in the development of early alcohol-induced liver injury.
Frequencies of Neuroantigen-Specific T Cells in the Central Nervous System Versus the Immune Periphery During the Course of Experimental Allergic Encephalomyelitis
Authors: Targoni Oleg S. , Baus Jan , Hofstetter Harald H. , Hesse Maike D. , Karulin Alexey Y. , Boehm Bernhard O. , Forsthuber Thomas G. , Lehmann Paul V. 
Published: April 2014

AbstractDirect measurements of the frequency and the cytokine signature of the neuroantigen-specific effector cells in experimental allergic encephalomyelitis (EAE) are a continuing challenge. This is true for lymphoid tissues, and more importantly, for the CNS itself. Using enzyme-linked immunospot analysis (ELISPOT) assays, we followed proteolipid protein (PLP) 139–151-specific T cells engaged by active immunization of SJL mice. The total numbers of PLP139–151-specific CD4 cells were highest before disease onset. At this time, these cells resided in lymphoid and nonlymphoid tissues, but were not detected in the CNS. While the PLP139–151-specific cells reached high frequencies in the CNS during clinical EAE, in absolute numbers, less than 20% of them were present in the target organ, with the majority residing in the periphery throughout all stages of the disease. The numbers of PLP139–151-specific cells gradually declined in both compartments with time. While eventually this first wave of effector cells completely disappeared from the CNS, PLP178–191-specific cells became engaged, being detected first in the CNS. These data suggest that throughout all stages of EAE, the effector cells in the CNS are recruited from a vast peripheral reservoir, and that the second wave of effector cells is engaged while the first wave undergoes exhaustion.
Persistence of Pathogenic CD4+ Th1-Like Cells In Vivo in the Absence of IL-12 but in the Presence of Autoantigen
Authors: Hong Kenneth , Berg Ellen L. , Ehrhardt Rolf O. 
Published: April 2014

AbstractDespite recent successful treatment of murine autoimmune disease with anti-IL-12 mAb, it has not yet been addressed whether anti-IL-12 mAb can also be effective in late stages of disease and whether it can provide lasting protection against recurrence, especially during continued presence of autoantigen. We used a newly developed psoriasis model in scid/scid mice, which allows easy tracking of pathogenic T cells, to show that when anti-IL-12 mAb is given for 2 wk (1 mg/wk) in the late stage of severe disease, inflammation is greatly reduced, as measured by ear thickness and histology (scores, 1.1 ± 0.1 vs 2.0 ± 0.4). Moreover, prolonged treatment (4 wk) of chronic psoriatic mice with high doses of mAb (1 mg/wk; prolonged active anti-inflammatory treatment (PAAIT)) results in the almost complete resolution of lesions (scores, 0.3 ± 0.1 vs 2.7 ± 0.2). Surprisingly, however, despite these significant treatment results, the psoriasis-like lesions return soon after the anti-IL-12 mAb treatment is discontinued. This rapid relapse of disease may be attributed to large populations of activated CD4+ T cells present in the lymph nodes of PAAIT animals still expressing an effector/memory phenotype (CD45RBlow, L-selectinlow). Upon stimulation in vitro such PAAIT lymph node cells secrete high amounts of IFN-γ (129 ng/ml); when transferred into naive scid/scid animals they are able to rapidly induce disease without costimulation. Our data indicates an alternative IL-12-independent pathway for pathogenic Th-1-like cells in vivo during the chronic phase of disease that allows these cells to persist and maintain their pathogenicity in the draining lymph tissue of the autoimmune site.
Cutting Edge: Recombinant Adenoviruses Induce CD8 T Cell Responses to an Inserted Protein Whose Expression Is Limited to Nonimmune Cells
Authors: Prasad Shiv A. , Norbury Christopher C. , Chen Weisan , Bennink Jack R. , Yewdell Jonathan W. 
Published: April 2014

Abstract
CD8 T cells (TCD8+) play a crucial role in immunity to viruses. Current understanding of activation of naive T cells entails Ag presentation by professional APCs (pAPCs). What happens, however, when viruses evolve to avoid infecting pAPCs? We have studied the consequences of this strategy by generating recombinant adenoviruses that express influenza A virus nucleoprotein under the control of tissue-specific promoters. We show that the immunogenicity of such viruses requires their delivery to organs capable of expressing nucleoprotein. This indicates that infection of pAPCs is not required for adenoviruses to elicit a TCD8+ response, probably due to a cross-priming via pAPCs. While this bodes well for recombinant adenoviruses as vaccines, it dims their prospects as gene therapy vectors.
Cutting Edge: Characterization of Allorestricted and Peptide-Selective Alloreactive T Cells Using HLA-Tetramer Selection
Authors: Moris Arnaud , Teichgräber Volker , Gauthier Laurent , Bühring Hans-Jörg , Rammensee Hans-Georg 
Published: April 2014

Abstract
The vast majority of alloreactive T cells recognize foreign MHC molecules in a peptide-dependent manner. A subpopulation of these peptide-dependent alloreactive T cells is peptide-specific and contains T cells that are of interest for tumor immunotherapy. Allorestricted T cells (i.e., peptide-specific and alloreactive) specific for tumor-associated Ags can be raised in vitro. However, it is technically difficult to distinguish between peptide-specific and peptide-nonspecific alloreactive T cells by functional assays in vitro. Here we show for the first time that allorestricted T cells specifically bind HLA-peptide tetrameric complexes, as nominal Ag-specific T cells would do. In consequence, fluorescent HLA-peptide tetrameric complexes can be used for sorting and cloning of allorestricted CTLs specific for a peptide of interest. We also show by the mean of HLA-peptide tetramers the existence of peptide-selective alloreactive T cells that recognize a conformation on the foreign-MHC brought about by some but not all peptides bound.
Transgenic Expression of IL-10 in T Cells Facilitates Development of Experimental Myasthenia Gravis
Authors: Ostlie Norma S. , Karachunski Peter I. , Wang Wei , Monfardini Cristina , Kronenberg Mitchell , Conti-Fine Bianca M. 
Published: April 2014

Abstract
Ab to the acetylcholine receptor (AChR) cause experimental myasthenia gravis (EMG). Th1 cytokines facilitate EMG, whereas Th2 cytokines might be protective. IL-10 inhibits Th1 responses but facilitates B cell proliferation and Ig production. We examined the role of IL-10 in EMG by using wild-type (WT) C57BL/6 mice and transgenic (TG) C57BL/6 mice that express IL-10 under control of the IL-2 promoter. We immunized the mice with doses of AChR that cause EMG in WT mice or with low doses ineffective at causing EMG in WT mice. After low-dose AChR immunization, WT mice did not develop EMG and had very little anti-AChR serum Ab, which were mainly IgG1, whereas TG mice developed EMG and had higher levels of anti-AChR serum Ab, which were mainly IgG2, in addition to IgG1. At the higher doses, TG mice developed EMG earlier and more frequently than WT mice and had more serum anti-AChR Ab. Both strains had similar relative serum concentrations of anti-AChR IgG subclasses and IgG and complement at the muscle synapses. CD8+-depleted splenocytes from all AChR-immunized mice proliferated in the presence of AChR and recognized a similar epitope repertoire. CD8+-depleted splenocytes from AChR-immunized TG mice stimulated in vitro with AChR secreted significantly more IL-10, but less of the prototypic Th1 cytokine IFN-γ, than those from WT mice. They secreted comparable amounts of IL-4 and slightly but not significantly reduced amounts of IL-2. This suggests that TG mice had reduced activation of anti-Torpedo AChR Th1 cells, but increased anti-AChR Ab synthesis, that likely resulted from IL-10-mediated stimulation of anti-AChR B cells. Thus, EMG development is not strictly dependent on Th1 cell activity.
Unique Functions of CD11b+, CD8α+, and Double-Negative Peyer’s Patch Dendritic Cells
Authors: Iwasaki Akiko , Kelsall Brian L. 
Published: April 2014

AbstractWe have recently demonstrated the presence of three populations of dendritic cells (DC) in the murine Peyer’s patch. CD11b+/CD8α− (myeloid) DCs are localized in the subepithelial dome, CD11b−/CD8α+ (lymphoid) DCs in the interfollicular regions, and CD11b−/CD8α− (double-negative; DN) DCs at both sites. We now describe the presence of a novel population of intraepithelial DN DCs within the follicle-associated epithelium and demonstrate a predominance of DN DCs only in mucosal lymphoid tissues. Furthermore, we demonstrate that all DC subpopulations maintain their surface phenotype upon maturation in vitro, and secrete a distinct pattern of cytokines upon exposure to T cell and microbial stimuli. Only myeloid DCs from the PP produce high levels of IL-10 upon stimulation with soluble CD40 ligand− trimer, or Staphylococcus aureus and IFN-γ. In contrast, lymphoid and DN, but not myeloid DCs, produce IL-12p70 following microbial stimulation, whereas no DC subset produces IL-12p70 in response to CD40 ligand trimer. Finally, we show that myeloid DCs from the PP are particularly capable of priming naive T cells to secrete high levels of IL-4 and IL-10, when compared with those from nonmucosal sites, while lymphoid and DN DCs from all tissues prime for IFN-γ production. These findings thus suggest that DC subsets within mucosal tissues have unique immune inductive capacities.
IL-12 Alone and in Synergy with IL-18 Inhibits Osteoclast Formation In Vitro
Authors: Horwood Nicole J. , Elliott Jan , Martin T. John , Gillespie Matthew T. 
Published: April 2014

Abstract
IL-12, like IL-18, was shown to potently inhibit osteoclast formation in cultures of cocultures of murine osteoblast and spleen cells, as well as in adult spleen cells treated with M-CSF and receptor activator of NF-κB ligand (RANKL). Neither IL-12 nor IL-18 was able to inhibit RANKL-induced osteoclast formation in cultured RAW264.7 cells, demonstrating that IL-12, like IL-18, was unable to act directly on osteoclastic precursors. IL-12, like IL-18, was found to act by T cells, since depletion of T cells from the adult spleen cell cultures ablated the inhibitory action of IL-12 and addition of either CD4 or CD8 T cells from C57BL/6 mice to RANKL-stimulated RAW264.7 cultures permitted IL-12 or IL-18 to be inhibitory. Additionally, IL-12 was still able to inhibit osteoclast formation in cocultures with osteoblasts and spleen cells from either GM-CSF R−/− mice or IFN-γ R−/− mice, indicating that neither GM-CSF nor IFN-γ was mediating osteoclast inhibition in these cultures. Combined, IL-18 and IL-12 synergistically inhibited osteoclast formation at concentrations 20- to 1000-fold less, respectively, than when added individually. A candidate inhibitor could not be demonstrated using neutralizing Abs to IL-4, IL-10, or IL-13 or from mRNA expression profiles among known cytokine inhibitors of osteoclastogenesis in response to IL-12 and IL-18 treatment, although the unknown inhibitory molecule was determined to be secreted from T cells.
CD99 Signals Caspase-Independent T Cell Death
Authors: Pettersen Rolf D. , Bernard Ghislaine , Olafsen Mette Kløvstad , Pourtein Monique , Lie Sverre O. 
Published: April 2014

Abstract
Death signaling by Fas and TNF receptors plays a major role in the control of activated mature T cells. However, the nature of the death receptors, which may be used by the immune system to control T cells that have not acquired susceptibility to Fas ligand or TNF, is not established. In this study, we demonstrate that engagement of distinct epitopes on CD99 rapidly induces T cell death by a novel caspase-independent pathway. A new mAb to these CD99 epitopes, Ad20, induces programmed cell death of transformed T cells as determined by morphological changes, phosphatidylserine exposure on the cell surface, and uptake of propidium iodide. In general, ligation of CD99 induced kinetically faster and more profound death responses as compared with the impact of anti-Fas and TNF-related apoptosis-inducing ligand (TRAIL). Ad20-induced programmed cell death was observed with seven of eight T cell lines examined, and notably, only two of these were distinctly responsive to anti-Fas and TRAIL. CD99-mediated death signaling proceeded independently of functional CD3, CD4, CD45, and p56lck, revealed distinctions from CD47-mediated T cell death responses, and was not influenced by interference with CD47 signaling. In contrast to the effect on transformed T cell lines, Ad20-induced death responses were not observed with normal peripheral T cells. Thus, our data suggest that CD99 is linked to a novel death pathway that may have biologic relevance in control of early T cells.