bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Role for Toll-Like Receptor 4 in Dendritic Cell Activation and Cytolytic CD8+ T Cell Differentiation in Response to a Recombinant Heat Shock Fusion Protein
Authors: Palliser Deborah , Huang Qian , Hacohen Nir , Lamontagne Steven P. , Guillen Eduardo , Young Richard A. , Eisen Herman N. 
Published: April 2014

Abstract
Recombinant heat shock fusion proteins (Hsfp) injected into mice without added adjuvants can stimulate production of CD8 cytolytic T cells. Because initiation of productive immune responses generally requires dendritic cell (DC) activation, the question arises as to whether the Hsfp can activate DC independently of contaminating LPS. Using microarray analyses of DC from LPS-insensitive mice having a point mutation in Toll-like receptor 4 (Tlr4) (C3H/HeJ), or lacking Tlr4 (B10/ScNCr), we show here that unlike a LPS standard, Hsfp activated DC from HeJ mice almost as well as DC from wild-type mice. Consistent with the microarray analysis, the Hsfp’s ability to activate DC was not eliminated by polymyxin B but was destroyed by proteinase K. The Hsfp did not, however, stimulate DC from mice lacking Tlr4. In vivo the CD8 T cell response to the Hsfp in mice lacking Tlr4 was impaired: the responding CD8 cells initially proliferated vigorously but their development into cytolytic effector cells was diminished. Overall, the results indicate that this Hsfp can activate DC independently of LPS but still requires Tlr4 for an optimal CD8 T cell response.
Different Potentials of γδ T Cell Subsets in Regulating Airway Responsiveness: Vγ1+ Cells, but Not Vγ4+ Cells, Promote Airway Hyperreactivity, Th2 Cytokines, and Airway Inflammation
Authors: Hahn Youn-Soo , Taube Christian , Jin Niyun , Sharp Laura , Wands J. M. , Aydintug M. Kemal , Lahn Michael , Huber Sally A. , O’Brien Rebecca L. , Gelfand Erwin W. , Born Willi K. 
Published: April 2014

Abstract
Allergic airway inflammation and hyperreactivity are modulated by γδ T cells, but different experimental parameters can influence the effects observed. For example, in sensitized C57BL/6 and BALB/c mice, transient depletion of all TCR-δ+ cells just before airway challenge resulted in airway hyperresponsiveness (AHR), but caused hyporesponsiveness when initiated before i.p. sensitization. Vγ4+ γδ T cells strongly suppressed AHR; their depletion relieved suppression when initiated before challenge, but not before sensitization, and they suppressed AHR when transferred before challenge into sensitized TCR-Vγ4−/−/6−/− mice. In contrast, Vγ1+ γδ T cells enhanced AHR and airway inflammation. In normal mice (C57BL/6 and BALB/c), enhancement of AHR was abrogated only when these cells were depleted before sensitization, but not before challenge, and with regard to airway inflammation, this effect was limited to C57BL/6 mice. However, Vγ1+ γδ T cells enhanced AHR when transferred before challenge into sensitized B6.TCR-δ−/− mice. In this study Vγ1+ cells also increased levels of Th2 cytokines in the airways and, to a lesser extent, lung eosinophil numbers. Thus, Vγ4+ cells suppress AHR, and Vγ1+ cells enhance AHR and airway inflammation under defined experimental conditions. These findings show how γδ T cells can be both inhibitors and enhancers of AHR and airway inflammation, and they provide further support for the hypothesis that TCR expression and function cosegregate in γδ T cells.
A Novel Anti-Inflammatory Role of Simvastatin in a Murine Model of Allergic Asthma
Authors: McKay Anne , Leung Bernard P. , McInnes Iain B. , Thomson Neil C. , Liew Foo Y. 
Published: April 2014

Abstract
Statins, the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, are effective serum cholesterol-lowering agents in clinical practice, and they may also have anti-inflammatory properties. Asthma is characterized by chronic eosinophilic inflammation in the airways, which is thought to be regulated by the activity of T lymphocytes. We therefore examined the anti-inflammatory activity of simvastatin in a murine model of allergic asthma. In mice previously sensitized to OVA, simvastatin treatment, either orally or i.p., reduced the total inflammatory cell infiltrate and eosinophilia in bronchoalveolar lavage fluid in response to inhaled OVA challenge. Simvastatin therapy i.p. was also associated with a reduction in IL-4 and IL-5 levels in bronchoalveolar lavage fluid and, at higher doses, a histological reduction in inflammatory infiltrates in the lungs. OVA-induced IL-4, IL-5, IL-6, and IFN-γ secretion was reduced in thoracic lymph node cultures from simvastatin-treated mice. Simvastatin treatment did not alter serum total IgE or OVA-specific IgG1 and IgG2a levels. These data demonstrate the therapeutic potential of statin-sensitive pathways in allergic airways disease.
IL-12 Inhibits Thymic Involution by Enhancing IL-7- and IL-2-Induced Thymocyte Proliferation
Authors: Li Lina , Hsu Hui-Chen , Stockard Cecil R. , Yang PingAr , Zhou Juling , Wu Qi , Grizzle William E. , Mountz John D. 
Published: April 2014

Abstract
IL-12 has been reported to affect thymic T cell selection, but the role of IL-12 in thymic involution has not been studied. We found that in vivo, IL-12b knockout (IL-12b−/−) mice exhibited accelerated thymic involution compared with wild-type (WT) B6 mice. This is characterized by an increase in thymocytes with the early development stage phenotype of CD25−CD44+CD4−CD8− in aged IL-12b−/− mice. Histologically, there were accelerated degeneration of thymic extracellular matrix and blood vessels, a significantly decreased thymic cortex/medulla ratio, and increased apoptotic cells in aged IL-12b−/− mice compared with WT mice. There was, however, no apparent defect in thymic structure and thymocyte development in young IL-12−/− mice. These results suggest the importance of IL-12 in maintaining thymic integrity and function during the aging process. Surprisingly, in WT B6 mice, there was no age-related decrease in the levels of IL-12 produced from thymic dendritic cells. Stimulation of thymocytes with IL-12 alone also did not enhance the thymocyte proliferative response in vitro. IL-12, however, provided a strong synergistic effect to augment the IL-7 or IL-2 induced thymocyte proliferative response, especially in aged WT and IL-12b−/− mice. Our data strongly support the role of IL-12 as an enhancement cytokine, which acts through its interactions with other cytokines to maintain thymic T cell function and development during aging.
Differential Segmental Flexibility and Reach Dictate the Antigen Binding Mode of Chimeric IgD and IgM: Implications for the Function of the B Cell Receptor
Authors: Løset Geir Å. , Roux Kenneth H. , Zhu Ping , Michaelsen Terje E. , Sandlie Inger 
Published: April 2014

Abstract
Mature, naive B cells coexpress IgD and IgM with identical binding sites. In this study, the binding properties of such IgM and IgD are compared to determine how size and shape may influence their ability to bind Ag and thus function as receptors. To dissect their intrinsic binding properties, recombinant IgM and IgD were produced in soluble form as monomers of the basic H2L2 Ab architecture, each with two Ag binding sites. Since these sites are connected with a hinge region in IgD and structural Ig domains in IgM, the two molecules differ significantly in this region. The results show that IgD exhibited the larger angle and longer distance between its binding sites, as well as having the greater flexibility. Relative functional affinity was assessed on two antigenic surfaces with high or low epitope density, respectively. At high epitope density, IgM had a higher functional affinity for the Ag compared with IgD. The order was reversed at low epitope density due to a decrease in the functional affinity of IgM. Studies of binding kinetics showed similar association rates for both molecules. The dissociation rate, however, was slower for IgM at high epitope density and for IgD at low epitope density. Taken together, the results show that IgM and IgD with identical Ag binding regions have different Ag binding properties.
Posttranscriptional Inhibition of Gene Expression byMycobacterium tuberculosisOffsets Transcriptional Synergism with IFN-γ and Posttranscriptional Up-Regulation by IFN-γ
Authors: Qiao Yaming , Prabhakar Savita , Canova Antony , Hoshino Yoshihiko , Weiden Michael , Pine Richard 
Published: April 2014

AbstractHost defense against Mycobacterium tuberculosis requires the cytokine IFN-γ and IFN regulatory factor 1 (IRF-1), a transcription factor that is induced to high levels by IFN-γ. Therefore, we chose to study regulation of IRF-1 expression as a model for effects of M. tuberculosis on response to IFN-γ. We found that IRF-1 mRNA abundance increased far more than transcription rate in human monocytic THP-1 cells stimulated by IFN-γ, but less than transcription rate in cells infected by M. tuberculosis. IFN-γ stimulation of infected cells caused a synergistic increase in IRF-1 transcription, yet IRF-1 mRNA abundance was similar in uninfected and infected cells stimulated by IFN-γ, as was the IRF-1 protein level. Comparable infection by Mycobacterium bovis bacillus Calmette-Guérin failed to induce IRF-1 expression and had no effect on the response to IFN-γ. We also examined the kinetics of transcription, the mRNA t1/2, and the distribution of IRF-1 transcripts among total nuclear RNA, poly(A) nuclear RNA, and poly(A) cytoplasmic RNA pools in cells that were infected by M. tuberculosis and/or stimulated by IFN-γ. Our data suggest that infection by M. tuberculosis inhibits RNA export from the nucleus. Moreover, the results indicate that regulated entry of nascent transcripts into the pool of total nuclear RNA affects IRF-1 expression and that this process is stimulated by IFN-γ and inhibited by M. tuberculosis. The ability of infection by M. tuberculosis to limit the increase in IRF-1 mRNA expression that typically follows transcriptional synergism may contribute to the pathogenicity of M. tuberculosis.
Toward a Definition of Self: Proteomic Evaluation of the Class I Peptide Repertoire
Authors: Hickman Heather D. , Luis Angela D. , Buchli Rico , Few Steven R. , Sathiamurthy Muthuraman , VanGundy Rodney S. , Giberson Christopher F. , Hildebrand William H. 
Published: April 2014

Abstract
MHC class I molecules present host- and pathogen-derived peptides for immune surveillance. Much attention is given to the search for viral and tumor nonself peptide epitopes, yet the question remains, “What is self?” Analyses of Edman motifs and of small sets of individual peptides suggest that the class I self repertoire consists of thousands of different peptides. However, there exists no systematic characterization of this self-peptide backdrop, causing the definition of class I-presented self to remain largely hypothetical. To better understand the breadth and nature of self proteins sampled by class I HLA, we sequenced &gt;200 endogenously loaded HLA-B*1801 peptides from a human B cell line. Peptide-source proteins, ranging from actin-related protein 6 to zinc finger protein 147, possessed an assortment of biological and molecular functions. Major categories included binding proteins, catalytic proteins, and proteins involved in cell metabolism, growth, and maintenance. Genetically, peptides encoded by all chromosomes were presented. Statistical comparison of proteins presented by class I vs the human proteome provides empiric evidence that the range of proteins sampled by class I is relatively unbiased, with the exception of RNA-binding proteins that are over-represented in the class I peptide repertoire. These data show that, in this cell line, class I-presented self peptides represent a comprehensive and balanced summary of the proteomic content of the cell. Importantly, virus- and tumor-induced changes in virtually any cellular compartment or to any chromosome can be expected to be presented by class I molecules for immune recognition.
All Known In Vivo Functions of the Oct-2 Transcription Factor Require the C-Terminal Protein Domain
Authors: Corcoran Lynn M. , Koentgen Frank , Dietrich Wendy , Veale Margaret , Humbert Patrick O. 
Published: April 2014

Abstract
Oct-2, a transcription factor expressed in the B lymphocyte lineage and in the developing CNS, functions through of a number of discrete protein domains. These include a DNA-binding POU homeodomain flanked by two transcriptional activation domains. In vitro studies have shown that the C-terminal activation domain, a serine-, threonine- and proline-rich sequence, possesses unique qualities, including the ability to activate transcription from a distance in a B cell-specific manner. In this study, we describe mice in which the endogenous oct-2 gene has been modified through gene targeting to create a mutated allele, oct-2ΔC, which encodes Oct-2 protein isoforms that lack all sequence C-terminal to the DNA-binding domain. Surprisingly, despite the retention of the DNA-binding domain and the glutamine-rich N-terminal activation domain, the truncated protein(s) encoded by the oct-2ΔC allele are unable to rescue any of the previously described defects exhibited by oct-2 null mice. Homozygous oct-2ΔC/ΔC mice die shortly after birth, and B cell maturation, B-1 cell self renewal, serum Ig levels, and B lymphocyte responses to in vitro stimulation are all reduced or absent, to a degree equivalent to that seen in oct-2 null mice. We conclude that the C-terminal activation domain of Oct-2 is required to mediate the unique and indispensable functions of the Oct-2 transcription factor in vivo.
Relevance of Posttranslational Modifications for the Arthritogenicity of Type II Collagen
Authors: Myers Linda K. , Myllyharju Johanna , Nokelainen Minna , Brand David D. , Cremer Michael A. , Stuart John M. , Bodo Michael , Kivirikko Kiri I. , Kang Andrew H. 
Published: April 2014

Abstract
To establish the role of posttranslational modification in modulating the immune response to collagen, recombinant human type II collagen (rCII) was produced using a yeast expression system (rCIIpic) and a baculovirus expression system (rCIIbac). The biosynthesis of CII requires extensive posttranslational modification including the hydroxylation of prolyl and lysyl residues and glycosylation of selected hydroxylysyl residues. Amino acid analyses indicated that the rCIIbac was adequately hydroxylated at prolyl residues but underhydroxylated at lysyl residues and underglycosylated compared with tissue-derived CII, whereas rCIIpic was adequately hydroxylated at prolyl residues but unhydroxylated at lysyl residues and had no glycosylation. When DBA/1 mice were immunized with rCII, rCIIpic induced a lower incidence of arthritis than tissue-derived CII, whereas rCIIbac induced an intermediate level of arthritis. The severity of the arthritis was significantly lower in mice immunized with rCIIpic compared with mice immunized with tissue-derived CII, whereas that of rCIIbac was intermediate. These data indicate that the degree of lysine hydroxylation and glycosylation plays a role in the induction of arthritis. The recombinant collagens were then compared with tissue-derived CII when given as i.v. or oral tolerogens to suppress arthritis. Both recombinant collagens were less potent than tissue-derived CII, and this decrease in arthritis was associated with a decrease in Ab response to CII. These data suggest that the degree of glysosylation affects the immune response to CII, so that underglycosylated CII is less effective in the induction of arthritis and in its ability to suppress collagen-induced arthritis.
The Ig-Like Domain of Tapasin Influences Intermolecular Interactions
Authors: Turnquist Heth R. , Petersen Jason L. , Vargas Shanna E. , McIlhaney Mary M. , Bedows Elliott , Mayer Werner E. , Grandea Andres G. , Van Kaer Luc , Solheim Joyce C. 
Published: April 2014

Abstract
Presentation of antigenic peptides to T lymphocytes by MHC class I molecules is regulated by events involving multiple endoplasmic reticulum proteins, including tapasin. By studying the effects of substitutions in the tapasin Ig-like domain, we demonstrated that H-2Ld/tapasin association can be segregated from reconstitution of folded Ld surface expression. This finding suggests that peptide acquisition by Ld is influenced by tapasin functions that are independent of Ld binding. We also found that the presence of a nine-amino acid region in the Ig-like domain of mouse or human tapasin is required for association with Ld, and certain point substitutions in this sequence abrogate human, but not mouse, tapasin association with Ld. These data are consistent with a higher overall affinity between Ld and mouse tapasin compared with human tapasin. In addition, we found that other point mutations in the same region of the tapasin Ig-like domain affect MHC class I surface expression and Ag presentation. Finally, we showed that the cysteine residues in the Ig-like domain of tapasin influence tapasin’s stability, its interaction with the MHC class I H chain, and its stabilization of TAP. Mutagenesis of these cysteines decreases tapasin’s electrophoretic mobility, suggesting that these residues form an intramolecular disulfide bond. Taken together, these results reveal a critical role for the tapasin Ig-like domain in tapasin function.
Toxoplasma gondii Interferes with Lipopolysaccharide-Induced Mitogen-Activated Protein Kinase Activation by Mechanisms Distinct from Endotoxin Tolerance
Authors: Kim Leesun , Butcher Barbara A. , Denkers Eric Y. 
Published: April 2014

Abstract
We show in this study that Toxoplasma gondii infection induces rapid activation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase 1/2, and stress-activated protein kinase/c-Jun N-terminal kinase MAPK, followed promptly by their deactivation in mouse macrophages. Nevertheless, when infected cells were subsequently subjected to LPS triggering, MAPK activation was severely defective, in particular in the case of p38 MAPK, which is required for LPS-triggered TNF-α and IL-12 production. Similar effects occurred during endotoxin tolerance, but the phenomena were distinct. LPS pretriggering failed to activate the major p38 MAPK kinase, MAPK kinase 3/6. Toxoplasma infection, in contrast, resulted in sustained activation of this kinase. Furthermore, endotoxin pre-exposure blocked IκBα degradation upon subsequent LPS triggering, but this was not the case for Toxoplasma preinfection. Endotoxin-mediated down-regulation of the LPS receptor, Toll-like receptor 4, has been suggested as one possible mechanism contributing to tolerance, and we found in this study that LPS down-modulated Toll-like receptor 4 expression. In contrast, Toxoplasma infection induced up-regulation of this pattern recognition receptor. Our results show that T. gondii blocks LPS-triggered cytokine production in part through MAPK inactivation, and that this occurs through pathways distinct from endotoxin-induced tolerance.
Essential Involvement of IFN-γ in Clostridium difficile Toxin A-Induced Enteritis
Authors: Ishida Yuko , Maegawa Tsuneo , Kondo Toshikazu , Kimura Akihiko , Iwakura Yoichiro , Nakamura Shinichi , Mukaida Naofumi 
Published: April 2014

Abstract
Clostridium difficile has emerged as the important causative agent of antibiotics-associated pesudomembranous colitis; especially its toxin A is presumed to be responsible for the colitis. We examined the pathophysiological roles of IFN-γ in toxin A-induced enteritis using IFN-γ knockout (KO) mice. When toxin A of C. difficile was injected into the ileal loops of BALB/c wild-type (WT) mice, massive fluid secretion, disruption of intestinal epithelial structure, and massive neutrophil infiltration developed within 4 h after the injection. IFN-γ protein was faintly detected in some CD3-positive lymphocytes in the lamina propria and submucosa of the ileum of untreated WT mice. On the contrary, at 2 and 4 h after toxin A injection, IFN-γ protein was detected in infiltrating neutrophils and to a lesser degree in CD3-positive lymphocytes. In the ileum of WT mice, toxin A treatment markedly enhanced the gene expression of TNF-α, macrophage inflammatory protein-1α and -2, KC, and ICAM-1 &gt;2 h after treatment. In contrast, the histopathological changes were marginal, without enhanced fluid secretion in the ileum of toxin A-treated IFN-γ KO mice. Moreover, toxin A-induced gene expression of TNF-α, neutrophil chemotactic chemokines, and ICMA-1 was remarkably attenuated in IFN-γ KO mice. Furthermore, pretreatment of WT mice with a neutralizing anti-IFN-γ Ab prevented toxin A-induced enteritis. These observations indicate that IFN-γ is the crucial mediator of toxin A-induced acute enteritis and suggest that IFN-γ is an important molecular target for the control of C. difficile-associated pseudomembranous colitis.
NK Cells, but Not NKT Cells, Are Involved in Pseudomonas aeruginosa Exotoxin A-Induced Hepatotoxicity in Mice
Authors: Mühlen Katrin A. , Schümann Jens , Wittke Frederick , Stenger Steffen , van Rooijen Nico , van Kaer Luc , Tiegs Gisa 
Published: April 2014

Abstract
Pseudomonas aeruginosa exotoxin A (PEA) causes T cell- and Kupffer cell (KC)-dependent liver injury in mice. TNF-α as well as IL-18 and perforin are important mediators of liver damage following PEA injection. In this study, we focus on the role of NK and NKT cells in PEA-induced liver toxicity. Depletion of both NK and NKT cells by injection of anti-NK1.1 Ab as well as depletion of NK cells alone by anti-asialo GM1 Ab protected mice from PEA-induced hepatotoxicity, whereas mice lacking only NKT cells were susceptible. Additionally, we observed infiltration of NK cells, T cells, and neutrophils into liver parenchyma after injection of PEA. The number of NKT cells, however, remained unchanged. The increase in intrahepatic NK cells depended on KCs and the TNF-α-dependent up-regulation of the adhesion molecule VCAM-1 in the liver, but not on NKT cells. PEA also augmented the cytotoxicity of hepatic NK cells against typical NK target cells (YAC-1 cells). This effect depended on KCs, but not on TNF-α or NKT cells. Furthermore, only weak expression of MHC class I was detected on hepatocytes, which was further down-regulated in PEA-treated mice. This could explain the susceptibility of hepatocytes to NK cell cytolytic activity in this model. Our results demonstrate that NK cells, activated and recruited independently of NKT cells, contribute to PEA-induced T cell-dependent liver injury in mice.