bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Basis of Reduced Potency of Underacylated Endotoxins
Authors: Teghanemt Athmane , Zhang DeSheng , Levis Erika N. , Weiss Jerrold P. , Gioannini Theresa L. 
Published: April 2014

Abstract
Potent TLR4-dependent cell activation by Gram-negative bacterial endotoxins depends on sequential endotoxin-protein and protein-protein interactions with LPS-binding protein, CD14, myeloid differentiation protein 2 (MD-2), and TLR4. Previous studies have suggested that reduced agonist potency of underacylated endotoxins (i.e., tetra- or penta- vs hexa-acylated) is determined by post-CD14 interactions. To better define the molecular basis of the differences in agonist potency of endotoxins differing in fatty acid acylation, we compared endotoxins (lipooligosaccharides (LOS)) from hexa-acylated wild-type (wt), penta-acylated mutant msbB meningococcal strains as well as tetra-acylated LOS generated by treatment of wt LOS with the deacylating enzyme, acyloxyacylhydrolase. To facilitate assay of endotoxin:protein and endotoxin:cell interactions, the endotoxins were purified after metabolic labeling with [3H]- or [14C]acetate. All LOS species tested formed monomeric complexes with MD-2 in an LPS-binding protein- and CD14-dependent manner with similar efficiency. However, msbB LOS:MD-2 and acyloxyacylhydrolase-treated LOS:MD-2 were at least 10-fold less potent in inducing TLR4-dependent cell activation than wt LOS:MD-2 and partially antagonized the action of wt LOS:MD-2. These findings suggest that underacylated endotoxins produce decreased TLR4-dependent cell activation by altering the interaction of the endotoxin:MD-2 complex with TLR4 in a way that reduces receptor activation. Differences in potency among these endotoxin species is determined not by different aggregate properties, but by different properties of monomeric endotoxin:MD-2 complexes.
Inflammatory Responses to Pneumovirus Infection in IFN-αβR Gene-Deleted Mice
Authors: Garvey Tara L. , Dyer Kimberly D. , Ellis John A. , Bonville Cynthia A. , Foster Barbara , Prussin Calman , Easton Andrew J. , Domachowske Joseph B. , Rosenberg Helene F. 
Published: April 2014

Abstract
Pneumonia virus of mice (PVM; family Paramyxoviridae) is a natural pathogen of rodents that reproduces important clinical features of severe respiratory syncytial virus infection in humans. As anticipated, PVM infection induces transcription of IFN antiviral response genes preferentially in wild-type over IFN-αβR gene-deleted (IFN-αβR−/−) mice. However, we demonstrate that PVM infection results in enhanced expression of eotaxin-2 (CCL24), thymus and activation-regulated chemokine (CCL17), and the proinflammatory RNase mouse eosinophil-associated RNase (mEar) 11, and decreased expression of monocyte chemotactic protein-5, IFN-γ-inducible protein-10, and TLR-3 in lung tissue of IFN-αβR−/− mice when compared with wild type. No differential expression of chemokines MIP-1α or MIP-2 or Th2 cytokines IL-4 or IL-5 was observed. Differential expression of proinflammatory mediators was associated with distinct patterns of lung pathology. The widespread granulocytic infiltration and intra-alveolar edema observed in PVM-infected, wild-type mice are replaced with patchy, dense inflammatory foci localized to the periphery of the larger blood vessels. Bronchoalveolar lavage fluid from IFN-αβR−/− mice yielded 7- to 8-fold fewer leukocytes overall, with increased percentages of eosinophils, monocytes, and CD4+ T cells, and decreased percentage of CD8+ T cells. Differential pathology is associated with prolonged survival of the IFN-αβR−/− mice (50% survival at 10.8 ± 0.6 days vs the wild type at 9.0 ± 0.3 days; p &lt; 0.02) despite increased virus titers. Overall, our findings serve to identify novel transcripts that are differentially expressed in the presence or absence of IFN-αβR-mediated signaling, further elucidating interactions between the IFN and antiviral inflammatory responses in vivo.
HIV-Specific CD8+ Lymphocytes in Semen Are Not Associated with Reduced HIV Shedding
Authors: Sheth Prameet M. , Danesh Ali , Shahabi Kamnoosh , Rebbapragada Anuradha , Kovacs Colin , Dimayuga Rowena , Halpenny Roberta , MacDonald Kelly S. , Mazzulli Tony , Kelvin David , Ostrowski Mario , Kaul Rupert 
Published: April 2014

AbstractSexual contact with HIV-infected semen is a major driving force behind the global HIV pandemic. Little is known regarding the immune correlates of virus shedding in this compartment, although HIV-1-specific CD8+ T cells are present in semen. We collected blood and semen from 27 chronically HIV-infected, therapy-naive men without common sexually transmitted infections or urethral inflammation and measured HIV-1 RNA viral load and cytokine/chemokine levels in both compartments. HIV-1 RNA levels were 10-fold higher in blood than semen, but discordantly high semen shedding was associated with higher semen levels of the proinflammatory cytokines IL-6, IL-8, IL-12, and IFN-γ. Virus-specific CD8+ T cell epitopes were mapped in blood by IFN-γ ELISPOT, using an overlapping HIV-1 clade B peptide matrix, and blood and semen CD8+ T cell responses were then assayed ex vivo using intracellular IFN-γ staining. HIV-specific CD8+ responses were detected in 70% of semen samples, and their frequency was similar to or higher than blood. There was no correlation between the presence of virus-specific CD8+ T cells in semen and levels of HIV-1 RNA shedding. Among participants with detectable CD8+ IFN-γ semen responses, their relative frequency was not associated with reduced HIV-1 RNA shedding, and their absolute number was correlated with higher levels of HIV-1 RNA semen shedding (r = 0.6; p = 0.03) and of several proinflammatory cytokines. Neither the presence nor the frequency of semen HIV-specific CD8+ T cell IFN-γ responses in semen correlated with reduced levels of HIV RNA in semen.
Role of CXC Chemokine Ligand 13, CC Chemokine Ligand (CCL) 19, and CCL21 in the Organization and Function of Nasal-Associated Lymphoid Tissue
Authors: Rangel-Moreno Javier , Moyron-Quiroz Juan , Kusser Kim , Hartson Louise , Nakano Hideki , Randall Troy D. 
Published: April 2014

Abstract
Nasal-associated lymphoid tissue (NALT) orchestrates immune responses to Ags in the upper respiratory tract. Unlike other lymphoid organs, NALT develops independently of lymphotoxin-α (LTα). However, the structure and function of NALT are impaired in Ltα−/− mice, suggesting a link between LTα and chemokine expression. In this study we show that the expression of CXCL13, CCL19, CCL21, and CCL20 is impaired in the NALT of Ltα−/− mice. We also show that the NALT of Cxcl13−/− and plt/plt mice exhibits some, but not all, of the structural and functional defects observed in the NALT of Ltα−/− mice. Like the NALT of Ltα−/− mice, the NALT in Cxcl13−/− mice lacks follicular dendritic cells, BP3+ stromal cells, and ERTR7+ lymphoreticular cells. However, unlike the NALT of Ltα−/− mice, the NALT of Cxcl13−/− mice has peripheral node addressin+ high endothelial venules (HEVs). In contrast, the NALT of plt/plt mice is nearly normal, with follicular dendritic cells, BP3+ stromal cells, ERTR7+ lymphoreticular cells, and peripheral node addressin+ HEVs. Functionally, germinal center formation and switching to IgA are defective in the NALT of Ltα−/− and Cxcl13−/− mice. In contrast, CD8 T cell responses to influenza are impaired in Ltα−/− mice and plt/plt mice. Finally, the B and T cell defects in the NALT of Ltα−/− mice lead to delayed clearance of influenza from the nasal mucosa. Thus, the B and T cell defects in the NALT of Ltα−/− mice can be attributed to the impaired expression of CXCL13 and CCL19/CCL21, respectively, whereas impaired HEV development is directly due to the loss of LTα.
Killer Cell Ig-Like Receptor-Dependent Signaling by Ig-Like Transcript 2 (ILT2/CD85j/LILRB1/LIR-1)
Authors: Kirwan Sheryl E. , Burshtyn Deborah N. 
Published: April 2014

Abstract
Inhibitory killer cell Ig-like receptors (KIR) signal by recruitment of the tyrosine phosphatase Src homology region 2 domain-containing phosphatase-1 to ITIM. In the present study, we show that, surprisingly, KIR lacking ITIM are able to signal and inhibit in the human NK cell line NK92, but not in mouse NK cells. Signaling by mutant KIR is weaker than the wild-type receptor, does not require the transmembrane or cytoplasmic tail of KIR, and is blocked by overexpression of a catalytically inactive Src homology region 2 domain-containing phosphatase-1 molecule. We also demonstrate that mutant KIR signaling is blocked by Abs, which disrupt the interaction between KIR and human leukocyte Ag-C or Abs, which block the interaction between Ig-like transcript 2 (ILT2) and the α3 domain of HLA class I molecules. Thus, although ILT2 expressed in NK92 is insufficient to signal in response to human leukocyte Ag-C alone, ILT2 can signal in a KIR-dependent manner revealing functional cooperation between receptors encoded by two distinct inhibitory receptor families.
Heterogeneity of Flt3-Expressing Multipotent Progenitors in Mouse Bone Marrow
Authors: Lai Anne Y. , Lin Simon M. , Kondo Motonari 
Published: April 2014

Abstract
Mechanisms of lymphoid and myeloid lineage choice by hemopoietic stem cells remain unclear. In this study we show that the multipotent progenitor (MPP) population, which is immediately downstream of hemopoietic stem cells, is heterogeneous and can be subdivided in terms of VCAM-1 expression. VCAM-1+ MPPs were fully capable of differentiating into both lymphoid and myeloid lineages. In contrast, VCAM-1− MPPs gave rise to lymphocytes predominately in vivo. T and B cell development from VCAM-1− MPPs was 1 wk faster than that from VCAM-1+ MPPs. Furthermore, VCAM-1+ MPPs gave rise to common myeloid progenitors and VCAM-1− MPPs in vivo, indicating that VCAM-1− MPPs are progenies of VCAM-1+ MPPs. VCAM-1− MPPs, in turn, developed into lymphoid lineage-restricted common lymphoid progenitors. These results establish a hierarchy of developmental relationship between MPP subsets and lymphoid and myeloid progenitors. In addition, VCAM-1+ MPPs may represent the branching point between the lymphoid and myeloid lineages.
Rapid Production of TNF-α following TCR Engagement of Naive CD8 T Cells
Authors: Brehm Michael A. , Daniels Keith A. , Welsh Raymond M. 
Published: April 2014

Abstract
The acquisition of effector functions by naive CD8 T cells following TCR engagement is thought to occur sequentially with full functionality being gained only after the initiation of division. We show that naive CD8 T cells are capable of immediate effector function following TCR engagement, which stimulates the rapid production of TNF-α. Stimulation of splenocytes from naive mice of differing genetic backgrounds with anti-CD3ε mAb resulted in significant production of TNF-α by naive CD8 T cells within 5 h. Moreover, naive lymphocytic choriomeningitis virus-specific TCR-transgenic CD8 T cells stimulated with either their cognate peptide ligand or virus-infected cells produced TNF-α as early as 2 h poststimulation, with production peaking by 4 h. Naive CD8 T cells produced both membrane-bound and soluble TNF-α. Interfering with TNF-α activity during the initial encounter between naive CD8 T cells and Ag loaded dendritic cells altered the maturation profile of the APC and diminished the overall viability of the APC population. These findings suggest that production of TNF-α by naive CD8 T cells immediately after TCR engagement may have an unappreciated impact within the local environment where Ag presentation is occurring and potentially influence the development of immune responses.
Both Regulatory T Cells and Antitumor Effector T Cells Are Primed in the Same Draining Lymph Nodes during Tumor Progression
Authors: Hiura Toru , Kagamu Hiroshi , Miura Satoru , Ishida Akira , Tanaka Hiroshi , Tanaka Junta , Gejyo Fumitake , Yoshizawa Hirohisa 
Published: April 2014

Abstract
The peripheral tolerance mechanism prevents effective antitumor immunity, even though tumor cells possess recognizable tumor-associated Ags. Recently, it has been elucidated that regulatory T cells (Treg) play a critical role in maintaining not only self-tolerance, but also tolerance of tumor cells. However, because the Treg that maintain self-tolerance arise naturally in the thymus and are thought to be anergic in peripheral, it is still unclear where and when Treg for tumor cells are generated. In this study we analyze tumor-draining lymph nodes (LNs) and demonstrate that both antitumor effector T cells and Treg capable of abrogating the antitumor reactivity of the effector T cells are primed in the same LNs during tumor progression. The regulatory activity generated in tumor-draining LNs exclusively belonged to the CD4+ T cell subpopulation that expresses both CD25 and a high level of CD62L. Forkhead/winged helix transcription factor gene expression was detected only in the CD62LhighCD4+CD25+ T cells. CD62LhighCD4+CD25+ Treg and CD62LlowCD4+CD25+ T cells, which possess effector T cell functions, had comparable expression of LFA-1, VLA-4, CTLA-4, lymphocyte activation gene-3, and glucocorticoid-induced TNFR. Thus, only CD62L expression could distinguish regulatory CD4+CD25+ cells from effector CD4+CD25+ cells in draining LNs as a surface marker. The Treg generated in tumor-draining LNs possess the same functional properties as the Treg that arise naturally in the thymus but recognize tumor-associated Ag. CD62LhighCD4+CD25+ Treg contained a subpopulation that expressed CD86. Blocking experiments revealed that ligation of CTLA-4 on effector T cells by CD86 on Treg plays a pivotal role in regulating CD4+ effector T cells.
Treatment of Mice with the Suppressor of Cytokine Signaling-1 Mimetic Peptide, Tyrosine Kinase Inhibitor Peptide, Prevents Development of the Acute Form of Experimental Allergic Encephalomyelitis and Induces Stable Remission in the Chronic Relapsing/Remitting Form
Authors: Mujtaba Mustafa G. , Flowers Lawrence O. , Patel Chintak B. , Patel Ravi A. , Haider Mohammad I. , Johnson Howard M. 
Published: April 2014

Abstract
We have previously characterized a novel tyrosine kinase inhibitor peptide (Tkip) that is a mimetic of suppressor of cytokine signaling 1 (SOCS-1) and inhibits JAK2 phosphorylation of the transcription factor STAT1α. We show in this study that Tkip protects mice against experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis. Mice are immunized with myelin basic protein (MBP) for induction of disease. Tkip (63 μg) administered every other day suppressed the development of acute EAE in 75% of New Zealand White (NZW) mice. Furthermore, Tkip completely protected SJL/J mice, which where induced to get the relapsing/remitting form of EAE, against relapses compared with control groups in which &gt;70% of the mice relapsed after primary incidence of disease. Protection of mice by Tkip was similar to that seen with the type I IFN, IFN-τ. Protection of mice correlated with lower MBP Ab titers in Tkip-treated groups as well as suppression of MBP-induced proliferation of splenocytes taken from EAE-afflicted mice. Cessation of Tkip and IFN-τ administration resulted in SJL/J mice relapsing back into disease. Prolonged treatment of mice with Tkip produced no evidence of cellular toxicity or weight loss. Consistent with its JAK2 inhibitory function, Tkip also inhibited the activity of the inflammatory cytokine TNF-α, which uses the STAT1α transcription factor. The data presented in this study show that Tkip, like the type I IFN, IFN-τ, inhibits both the autoreactive cellular and humoral responses in EAE and ameliorates both the acute and chronic relapsing/remitting forms of EAE.
BMP Signaling Is Required for Normal Thymus Development
Authors: Bleul Conrad C. , Boehm Thomas 
Published: April 2014

Abstract
The microenvironment of the thymus fosters the generation of a diverse and self-tolerant T cell repertoire from a pool of essentially random specificities. Epithelial as well as mesenchymal cells contribute to the thymic stroma, but little is known about the factors that allow for communication between the two cells types that shape the thymic microenvironment. In this study, we investigated the role of bone morphogenetic protein (BMP) signaling in thymus development. Transgenic expression of the BMP antagonist Noggin in thymic epithelial cells under the control of a Foxn1 promoter in the mouse leads to dysplastic thymic lobes of drastically reduced size that are ectopically located in the neck at the level of the hyoid bone. Interestingly, the small number of thymocytes in these thymic lobes develops with normal kinetics and shows a wild-type phenotype. Organ initiation of the embryonic thymic anlage in these Noggin transgenic mice occurs as in wild-type mice, but the tight temporal and spatial regulation of BMP4 expression is abrogated in subsequent differentiation stages. We show that transgenic Noggin blocks BMP signaling in epithelial as well as mesenchymal cells of the thymic anlage. Our data demonstrate that BMP signaling is crucial for thymus development and that it is the thymic stroma rather than developing thymocytes that depends on BMP signals.
Discovery and Pharmacological Characterization of a Novel Rodent-Active CCR2 Antagonist, INCB3344
Authors: Brodmerkel Carrie M. , Huber Reid , Covington Maryanne , Diamond Sharon , Hall Leslie , Collins Robert , Leffet Lynn , Gallagher Karen , Feldman Patricia , Collier Paul , Stow Mark , Gu Xiaomei , Baribaud Frederic , Shin Niu , Thomas Beth , Burn Tim , Hollis Greg , Yeleswaram Swamy , Solomon Kim , Friedman Steve , Wang Anlai , Xue Chu Biao , Newton Robert C. , Scherle Peggy , Vaddi Kris 
Published: April 2014

Abstract
This report describes the characterization of INCB3344, a novel, potent and selective small molecule antagonist of the mouse CCR2 receptor. The lack of rodent cross-reactivity inherent in the small molecule CCR2 antagonists discovered to date has precluded pharmacological studies of antagonists of this receptor and its therapeutic relevance. In vitro, INCB3344 inhibits the binding of CCL2 to mouse monocytes with nanomolar potency (IC50 = 10 nM) and displays dose-dependent inhibition of CCL2-mediated functional responses such as ERK phosphorylation and chemotaxis with similar potency. Against a panel of G protein-coupled receptors that includes other CC chemokine receptors, INCB3344 is at least 100-fold selective for CCR2. INCB3344 possesses good oral bioavailability and systemic exposure in rodents that allows in vivo pharmacological studies. INCB3344 treatment results in a dose-dependent inhibition of macrophage influx in a mouse model of delayed-type hypersensitivity. The histopathological analysis of tissues from the delayed-type hypersensitivity model demonstrates that inhibition of CCR2 leads to a substantial reduction in tissue inflammation, suggesting that macrophages play an orchestrating role in immune-based inflammatory reactions. These results led to the investigation of INCB3344 in inflammatory disease models. We demonstrate that therapeutic dosing of INCB3344 significantly reduces disease in mice subjected to experimental autoimmune encephalomyelitis, a model of multiple sclerosis, as well as a rat model of inflammatory arthritis. In summary, we present the first report on the pharmacological characterization of a selective, potent and rodent-active small molecule CCR2 antagonist. These data support targeting this receptor for the treatment of chronic inflammatory diseases.
A Genetic Basis for IFN-γ Production and T-bet Expression in Humans
Authors: Höhler Thomas , Reuss Esther , Adams Petra , Bartsch Brigitte , Weigmann Benno , Wörns Markus , Galle Peter R. , Victor Anja , Neurath Markus F. 
Published: April 2014

Abstract
Th1 and Th2 cytokines secreted by polarized effector T cells play a pivotal role in the development of autoimmune and allergic diseases. However, the genetic basis of cytokine production by T lymphocytes in humans is poorly understood. In this study, we investigated the genetic contribution to cytokine production and regulation of T cell-specific transcription factors in a prospective twin study. We found a substantial genetic contribution to the production of Th1 cytokines such as IFN-γ and TNF-α with heritabilities of 0.85 (95% confidence intervals, 0.74–0.95) and 0.72 (0.50–0.93), respectively, whereas no genetic influence on production of the Th2 signature cytokine IL-4 was observed. Furthermore, the intrapair variability in IFN-γ production by isolated T cells was lower in monozygotic than in dizygotic twins. In contrast to GATA-3, NFAT, and NF-κB, intrapair variability of T-bet, the master transcription factor of Th1 cells, was very low among monozygotic and high among dizygotic twins, indicative of a strong genetic influence on T-bet (heritability 0.93, 95% confidence interval, 0.84–1.0). Our data provide novel insights into the genetic regulation of human Th cell polarization. These data suggest that signature cytokines and cytokine signaling events of Th1 rather than Th2 cells are genetically determined and implicate that Th2-associated diseases in humans might be due to genetic variations in Th1 cytokine regulation via T-bet. This concept is highlighted by the recent finding that inactivation of the T-bet gene in mice results in development of clinical hallmark features of asthma.
Cutting Edge: MyD88 Controls Phagocyte NADPH Oxidase Function and Killing of Gram-Negative Bacteria
Authors: Laroux F. Stephen , Romero Xavier , Wetzler Lee , Engel Pablo , Terhorst Cox 
Published: April 2014

Abstract
MyD88 is an adaptor protein for the TLR family of proteins that has been implicated as a critical mediator of innate immune responses to pathogen detection. In this study, we report that MyD88 plays a crucial role in killing Gram-negative bacteria by primary macrophages via influencing NADPH oxidase function. Peritoneal macrophages from MyD88−/− mice exhibited a marked inability to kill Escherichia coli (F18) or an attenuated strain of Salmonella typhimurium (sseB) in vitro. This defect in killing was due to diminished NADPH oxidase-mediated production of superoxide anion in response to bacteria by MyD88−/− phagocytes as a consequence of defective NADPH oxidase assembly. Defective oxidase assembly in MyD88-deficient macrophages resulted from impaired p38 MAPK activation and subsequent phosphorylation of p47phox. Together these data demonstrate a pivotal role for MyD88 in killing Gram-negative bacteria via modulation of NADPH oxidase activity in phagocytic cells.
Cutting Edge: CpG Oligonucleotides Induce Splenic CD19+ Dendritic Cells to Acquire Potent Indoleamine 2,3-Dioxygenase-Dependent T Cell Regulatory Functions via IFN Type 1 Signaling
Authors: Mellor Andrew L. , Baban Babak , Chandler Phillip R. , Manlapat Anna , Kahler David J. , Munn David H. 
Published: April 2014

Abstract
CpG oligodeoxynucleotides (CpG-ODNs) stimulate innate and adaptive immunity by binding to TLR9 molecules. Paradoxically, expression of the immunoregulatory enzyme indoleamine 2,3-dioxygenase (IDO) is induced following i.v. CpG-ODN administration to mice. CpG-ODNs induced selective IDO expression by a minor population of splenic CD19+ dendritic cells (DCs) that did not express the plasmacytoid DC marker 120G8. Following CpG-ODN treatment, CD19+ DCs acquired potent IDO-dependent T cell suppressive functions. Signaling through IFN type I receptors was essential for IDO up-regulation, and CpG-ODNs induced selective activation of STAT-1 in CD19+ DCs. Thus, CpG-ODNs delivered systemically at relatively high doses elicited potent T cell regulatory responses by acting on a discrete, minor population of splenic DCs. The ability of CpG-ODNs to induce both stimulatory and regulatory responses offers novel opportunities for using them as immunomodulatory reagents but may complicate therapeutic use of CpG-ODNs to stimulate antitumor immunity in cancer patients.