bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Engagement of CD14 and Multiple Toll-Like Receptors by Group B Streptococci
Authors: Henneke Philipp , Takeuchi Osamu , van Strijp Jos A. , Guttormsen Hilde-Kari , Smith Jason A. , Schromm Andra B. , Espevik Terje A. , Akira Shizuo , Nizet Victor , Kasper Dennis L. , Golenbock Douglas T. 
Published: April 2014

AbstractGroup B streptococcus (GBS) imposes a major health threat to newborn infants. Little is known about the molecular basis of GBS-induced sepsis. Both heat-inactivated whole GBS bacteria and a heat-labile soluble factor released by GBS during growth (GBS-F) induce nuclear translocation of NF-κB, the secretion of TNF-α, and the formation of NO in mouse macrophages. Macrophages from mice with a targeted disruption of MyD88 failed to secrete TNF-α in response to both heat-inactivated whole bacteria and GBS-F, suggesting that Toll-like receptors (TLRs) are involved in different aspects of GBS recognition. Immune cell activation by whole bacteria differed profoundly from that by secreted GBS-F. Whole GBS activated macrophages independently of TLR2 and TLR6, whereas a response to the secreted GBS-F was not observed in macrophages from TLR2-deficient animals. In addition to TLR2, TLR6 and CD14 expression were essential for GBS-F responses, whereas TLR1 and TLR4 or MD-2 did not appear to be involved. Heat lability distinguished GBS-F from peptidoglycan and lipoproteins. GBS mutants deficient in capsular polysaccharide or β-hemolysin had GBS-F activity comparable to that of wild-type streptococci. We suggest that CD14 and TLR2 and TLR6 function as coreceptors for secreted microbial products derived from GBS and that cell wall components of GBS are recognized by TLRs distinct from TLR1, 2, 4, or 6.
IFN-γ-Inducible Protein-10 (CXCL10) Is Hepatoprotective During Acute Liver Injury Through the Induction of CXCR2 on Hepatocytes
Authors: Bone-Larson Cynthia L. , Hogaboam Cory M. , Evanhoff Holly , Strieter Robert M. , Kunkel Steven L. 
Published: April 2014

AbstractIFN-γ-inducible protein-10 (IP-10/CXCL10) is a non-ELR-CXC chemokine that is present during various forms of acute and chronic liver injury. The purpose of this study was to explore the role of IP-10 during acute liver injury induced by acetaminophen (APAP). After a 400 mg/kg APAP challenge in fasted CD-1 mice, immunoreactive levels of IP-10 were dramatically elevated in the serum within 8 h. CXCR3, the receptor for IP-10, was up-regulated in the liver. Mice that received an i.v. injection of rIP-10 10 h after APAP challenge exhibited a dramatic reduction in alanine aminotransferase 8 h later. Histologic analysis confirmed that the delayed IP-10 therapy dramatically improved the appearance of the liver when examined 48 h after APAP. The therapeutic effect of IP-10 was associated with a marked increase in CXCR2 expression on hepatocytes. Neutralization of CXCR2 during IP-10 therapy resulted in an abrogation of the hepatoprotective effect of IP-10. Furthermore, IP-10 treatment of cultured hepatocytes stimulated a CXCR2-dependent proliferative response. In conclusion, IP-10 has a hepatoregenerative effect in a murine model of acute liver injury that is dependent on its up-regulation of CXCR2 on hepatocytes.
Disruption of Neutrophil Migration in a Conditional Transgenic Model: Evidence for CXCR2 Desensitization In Vivo
Authors: Wiekowski Maria T. , Chen Shu-Cheng , Zalamea Petronio , Wilburn Brian P. , Kinsley David J. , Sharif Wanda W. , Jensen Kristian K. , Hedrick Joseph A. , Manfra Denise , Lira Sergio A. 
Published: April 2014

AbstractWe developed transgenic mice conditionally expressing the neutrophil chemoattracting chemokine KC and the β-galactosidase gene in multiple tissues. In these transgenic mice, doxycycline treatment induced a strong up-regulation in the expression of KC in several tissues, including heart, liver, kidney, skin, and skeletal muscle. Expression of KC within these tissues led to a rapid and substantial increase in the serum levels of KC (serum KC levels were higher than 200 ng/ml 24 h after treatment). Accordingly, β-galactosidase expression was also detected after injection of doxycycline and was highest in skeletal muscle, pancreas, and liver. Surprisingly, despite expression of KC in multiple tissues, no neutrophil infiltration was observed in any of the tissues examined, including skin. Doxycycline treatment of nontransgenic mice grafted with transgenic skin caused dense neutrophilic infiltration of the grafts, but not the surrounding host skin, indicating that the KC produced in transgenic tissues was biologically active. In separate experiments, neutrophil migration toward a localized source of recombinant KC was impaired in animals overexpressing KC but was normal in response to other neutrophil chemoattractants. Analysis of transgenic neutrophils revealed that high concentrations of KC in transgenic blood had no influence on L-selectin cell surface expression but caused desensitization of the receptor for KC, CXCR2. These results confirm the neutrophil chemoattractant properties of KC and provide a mechanistic explanation for the paradoxical lack of leukocyte infiltration observed in the presence of elevated concentrations of this chemokine.
Genetic Contributions of Nonautoimmune SWR Mice Toward Lupus Nephritis
Authors: Xie Shangkui , Chang SoogHee , Yang Ping , Jacob Chryshanthi , Kaliyaperumal Arunan , Datta Syamal K. , Mohan Chandra 
Published: April 2014

Abstract(SWR × New Zealand Black (NZB))F1 (or SNF1) mice succumb to lupus nephritis. Although several NZB lupus susceptibility loci have been identified in other crosses, the potential genetic contributions of SWR to lupus remain unknown. To ascertain this, a panel of 86 NZB × F1 backcross mice was immunophenotyped and genome scanned. Linkage analysis revealed four dominant SWR susceptibility loci (H2, Swrl-1, Swrl-2, and Swrl-3) and a recessive NZB locus, Nba1. Early mortality was most strongly linked to the H2 locus on chromosome (Chr) 17 (log likelihood of the odds (LOD) = 4.59 − 5.38). Susceptibility to glomerulonephritis was linked to H2 (Chr 17, LOD = 2.37 − 2.70), Swrl-2 (Chr 14, 36 cM, LOD = 2.48 − 2.71), and Nba1 (Chr 4, 75 cM, LOD = 2.15 − 2.23). IgG antinuclear autoantibody development was linked to H2 (Chr 17, LOD = 4.92 − 5.48), Swrl-1 (Chr 1, 86 cM, colocalizing with Sle1 and Nba2, LOD = 2.89 − 2.91), and Swrl-3 (Chr 18, 14 cM, LOD = 2.07 − 2.13). For each phenotype, epistatic interaction of two to three susceptibility loci was required to attain the high penetrance levels seen in the SNF1 strain. Although the SWR contributions H2, Swrl-1, and Swrl-2 map to loci previously mapped in other strains, often linked to very similar phenotypes, Swrl-3 appears to be a novel locus. In conclusion, lupus in the SNF1 strain is truly polygenic, with at least four dominant contributions from the SWR strain. The immunological functions and molecular identities of these loci await elucidation.
Rheumatoid Arthritis (RA)-Associated HLA-DR Alleles Form Less Stable Complexes with Class II-Associated Invariant Chain Peptide Than Non-RA-Associated HLA-DR Alleles
Authors: Patil Namrata S. , Pashine Achal , Belmares Michael P. , Liu Wendy , Kaneshiro Brandy , Rabinowitz Joshua , McConnell Harden , Mellins Elizabeth D. 
Published: April 2014

AbstractCertain HLA-DR alleles confer strong susceptibility to the autoimmune disease rheumatoid arthritis (RA). We compared RA-associated alleles, HLA-DR*0401, HLA-DR*0404, and HLA-DR*0405, with closely related, non-RA-associated alleles, HLA-DR*0402 and HLA-DR*0403, to determine whether they differ in their interactions with the class II chaperone, invariant chain (Ii). Ii binds to class II molecules in the endoplasmic reticulum, inhibits binding of other ligands, and directs class II-Ii complexes to endosomes, where Ii is degraded to class II-associated Ii peptide (CLIP). To evaluate the interaction of Ii and CLIP with these DR4 alleles, we introduced HLA-DR*0401, *0402, and *0404 alleles into a human B cell line that lacked endogenous HLA-DR or HLA-DM molecules. In a similar experiment, we introduced HLA-DR*0403 and *0405 into an HLA-DM-expressing B cell line, 8.1.6, and its DM-negative derivative, 9.5.3. Surface abundance of DR4-CLIP peptide complexes and their susceptibility to SDS-induced denaturation suggested that the different DR4-CLIP complexes had different stabilities. Pulse-chase experiments showed CLIP dissociated more rapidly from RA-associated DR molecules in B cell lines. In vitro assays using soluble rDR4 molecules showed that DR-CLIP complexes of DR*0401 and DR*0404 were less stable than complexes of DR*0402. Using CLIP peptide variants, we mapped the reduced CLIP interaction of RA-associated alleles to the shared epitope region. The reduced interaction of RA-associated HLA-DR4 molecules with CLIP may contribute to the pathophysiology of autoimmunity in RA.
Genetic Control of T and B Lymphocyte Activation in Nonobese Diabetic Mice
Authors: Chiu Priscilla P. L. , Jevnikar Anthony M. , Danska Jayne S. 
Published: April 2014

AbstractType 1 diabetes in nonobese diabetic (NOD) mice is characterized by the infiltration of T and B cells into pancreatic islets. T cells bearing the TCR Vβ3 chain are disproportionately represented in the earliest stages of islet infiltration (insulitis) despite clonal deletion of most Vβ3+ immature thymocytes by the mammary tumor virus-3 (Mtv-3) superantigen (SAg). In this report we showed that a high frequency of NOD Vβ3+ T cells that escape deletion are activated in vivo and that this phenotype is linked to the Mtv-3 locus. One potential mechanism of SAg presentation to peripheral T cells is by activated B cells. Consistent with this idea, we found that NOD mice harbor a significantly higher frequency of activated B cells than nondiabetes-prone strains. These activated NOD B cells expressed cell surface molecules consistent with APC function. At the molecular level, the IgH repertoire of activated B cells in NOD mice was equivalent to resting B cells, suggesting a polyclonal response in vivo. Genetic analysis of the activated B cell phenotype showed linkage to Idd1, the NOD MHC haplotype (H-2g7). Finally, Vβ3+ thymocyte deletion and peripheral T cell activation did not require B cells, suggesting that other APC populations are sufficient to generate both Mtv-3-linked phenotypes. These data provide insight into the genetic regulation of NOD autoreactive lymphocyte activation that may contribute to failure of peripheral tolerance and the pathogenesis of type I diabetes.
Potentiation of Simian Immunodeficiency Virus (SIV)-Specific CD4+ and CD8+ T Cell Responses by a DNA-SIV and NYVAC-SIV Prime/Boost Regimen
Authors: Hel Zdeněk , Tsai Wen-Po , Thornton Arthur , Nacsa Janos , Giuliani Laura , Tryniszewska Elzbieta , Poudyal Monita , Venzon David , Wang Xiaochi , Altman John , Watkins David I. , Lu Wenhong , von Gegerfelt Agneta , Felber Barbara K. , Tartaglia James , Pavlakis George N. , Franchini Genoveffa 
Published: April 2014

AbstractT cell-mediated immune responses play an important role in the containment of HIV-1 replication. Therefore, an effective vaccine against HIV-1 should be able to elicit high frequencies of virus-specific CD8+ and CD4+ T cells. The highly attenuated poxvirus-based vaccine candidate, NYVAC-SIV-gag-pol-env (NYVAC-SIV-gpe), has been shown to induce and/or expand SIV-specific CD4+ and CD8+ T cell responses in both naive and infected macaques. In this study, the immunogenicity of NYVAC-SIV-gpe alone was compared with a combination regimen where priming with an optimized DNA-SIV-gag-env vaccine candidate was followed by a NYVAC-SIV-gpe boost. In macaques immunized with the prime-boost regimen, the extent and durability of CD8+ T cell response to an immunodominant SIV gag epitope was increased and these animals recognized a broader array of subdominant SIV epitopes in the cytolytic assay. In addition, the prime-boost regimen significantly enhanced the proliferative responses to both SIV gag and env proteins. Thus, the combination of these vaccine modalities may represent a valuable strategy in the development of a vaccine for HIV.
Cutting Edge: Neosynthesis Is Required for the Presentation of a T Cell Epitope from a Long-Lived Viral Protein
Authors: Khan Selina , de Giuli Rita , Schmidtke Gunter , Bruns Michael , Buchmeier Michael , van den Broek Maries , Groettrup Marcus 
Published: April 2014

Abstract
CTLs recognize peptide epitopes which are proteolytically generated by the proteasome and presented on MHC class I molecules. According to the defective ribosomal product (DRiP) hypothesis, epitopes originate from newly synthesized polypeptides which are degraded shortly after their translation. The DRiP hypothesis would explain how epitopes can be generated from long-lived proteins. We examined whether neosynthesis is required for presentation of the immunodominant epitope NP118 of the lymphocytic choriomeningitis virus nucleoprotein, which has a half-life of &gt;3 days. Two days after nucleoprotein biosynthesis was terminated in a tetracycline-regulated transfectant, the presentation of the NP118 epitope ceased. This indicates that NP118 epitopes are generated from newly synthesized nucleoproteins rather than from the long-lived pool of nucleoproteins in the cell. Therefore, the lymphocytic choriomeningitis virus nucleoprotein is the first substrate for which a major prediction of the DRiP hypothesis, namely the requirement for neosynthesis, is shown to hold true.
Murine Renal Allografts: Spontaneous Acceptance Is Associated with Regulated T Cell-Mediated Immunity
Authors: Bickerstaff Alice A. , Wang Jiao-Jing , Pelletier Ronald P. , Orosz Charles G. 
Published: April 2014

Abstract
It was shown &gt;20 yr ago that mice will spontaneously accept renal allografts in the absence of immunosuppression, but the mechanism responsible for this is not understood. We transplanted DBA/2 (H-2d) kidneys into nephrectomized C57BL/6 (H-2b) mice, and the allografts were spontaneously accepted for &gt;60 days without immunosuppression. In contrast, nonimmunosuppressed cardiac and skin allografts in the same strain combination are rejected within approximately 10 days. The accepted renal allografts have a prominent leukocytic infiltrate, suggesting an ongoing, local immune response. At 60 days post-transplant, the recipients of accepted renal allografts display DBA/2-reactive alloantibodies. They also display DBA/2-reactive delayed-type hypersensitivity responses that are actively counter-regulated by DBA/2-induced TGF-β production, but not by IL-10 production. These data suggest that a donor-reactive, cell-mediated immune mechanism involving TGF-β is associated with the spontaneous acceptance of renal allografts in mice.
Expression of the Ryanodine Receptor Isoforms in Immune Cells
Authors: Hosoi Eiji , Nishizaki Chiharu , Gallagher Kathleen L. , Wyre Hadley W. , Matsuo Yoshinobu , Sei Yoshitatsu 
Published: April 2014

Abstract
Ryanodine receptor (RYR) is a Ca2+ channel that mediates Ca2+ release from intracellular stores. We have used RT-PCR analysis and examined its expression in primary peripheral mononuclear cells (PBMCs) and in 164 hemopoietic cell lines. In PBMCs, type 1 RYR (RYR1) was expressed in CD19+ B lymphocytes, but less frequently in CD3+ T lymphocytes and in CD14+ monocytes. Type 2 RYR (RYR2) was mainly detected in CD3+ T cells. Induction of RYR1 and/or RYR2 mRNA was found after treatment with stromal cell-derived factor 1, macrophage-inflammatory protein-1α (MIP1α) or TGF-β. Type 3 RYR (RYR3) was not detected in PBMCs. Many hemopoietic cell lines expressed not only RYR1 or RYR2 but also RYR3. The expression of the isoforms was not associated with specific cell lineage. We showed that the RYR-stimulating agent 4-chloro-m-cresol (4CmC) induced Ca2+ release and thereby confirmed functional expression of the RYR in the cell lines expressing RYR mRNA. Moreover, concordant induction of RYR mRNA with Ca2+ channel function was found in Jurkat T cells. In untreated Jurkat T cells, 4CmC (&gt;1 mM) had no effect on Ca2+ release, whereas 4CmC (&lt;400 μM) caused Ca2+ release after the induction of RYR2 and RYR3 that occurred after treatment with stromal cell-derived factor 1, macrophage-inflammatory protein-1α, or TGF-β. Our results demonstrate expression of all three isoforms of RYR mRNA in hemopoietic cells. Induction of RYRs in response to chemokines and TGF-β suggests roles in regulating Ca2+-mediated cellular responses during the immune response.
Melphalan-Induced Expression of IFN-β in MOPC-315 Tumor-Bearing Mice and Its Importance for the Up-Regulation of TNF-α Expression
Authors: Jovasevic Vladimir M. , Mokyr Margalit B. 
Published: April 2014

AbstractWe have previously shown that administration of a low-dose of melphalan (l-phenylalanine mustard; l-PAM) to mice bearing a large s.c. MOPC-315 tumor leads to up-regulation of TNF-α expression, which is first evident at the mRNA level at 24 h after the chemotherapy. In this study, we show accumulation of IFN-β mRNA in the spleen and tumor nodule of such mice as early as 1 h after the chemotherapy followed by elevated production of IFN-β protein. IFN-β protein in turn was found to be important for the l-PAM-induced up-regulation of TNF-α expression, as neutralization of IFN-β inhibited the l-PAM-induced up-regulation of TNF-α mRNA expression in MOPC-315 tumor cells. In addition, l-PAM failed to up-regulate TNF-α expression in spleen cells from mice in which signaling by IFN-β is deficient. Studies into the mechanism through which l-PAM leads to rapid accumulation of IFN-β mRNA revealed that it requires de novo RNA synthesis, indicating that the regulation is at the transcriptional level. However, it did not require de novo protein synthesis, indicating that activation of pre-existing transcription factors is sufficient for IFN-β gene expression. The l-PAM-induced accumulation of IFN-β mRNA was mimicked with H2O2 and was prevented with the antioxidant N-acetyl-l-cysteine, indicating that reactive oxygen species are involved in the transcriptional regulation of l-PAM-induced IFN-β gene expression. Thus, the IFN-β gene is an early response gene that is activated in response to l-PAM via a pathway that involves reactive oxygen species, and IFN-β in turn plays an important role in l-PAM-induced TNF-α up-regulation.
Broad Distribution of Colony-Forming Cells with Erythroid, Myeloid, Dendritic Cell, and NK Cell Potential Among CD34++ Fetal Liver Cells
Authors: Muench Marcus O. , Bárcena Alicia 
Published: April 2014

AbstractThe generation of erythroid, myeloid, and lymphoid cells from human fetal liver progenitors was studied in colony-forming cell (CFC) assays. CD38− and CD38+ progenitors that expressed high levels of CD34 were grown in serum-deprived medium supplemented with kit ligand, flk2/flt3 ligand, GM-CSF, c-mpl ligand, erythropoietin, and IL-15. The resulting colonies were individually analyzed by flow cytometry. CD56+ NK cells were detected in 21.9 and 9.9% of colonies grown from CD38− and CD38+ progenitors, respectively. NK cells were detected in mostly large CD14+/CD15+ myeloid colonies that also, in some cases, contained red cells. NK cells were rarely detected in erythroid colonies, suggesting an early split between the erythroid and the NK cell lineages. CD1a+ dendritic cells were also present in three-quarters of the colonies grown from CD38− and CD38+ progenitors. Multilineage colonies containing erythrocytes, myeloid cells, and NK cells were present in 13.7 and 2.7% of colonies grown from CD38− and CD38+ progenitors, respectively. High proliferative-potential CFCs that generated multilineage colonies were also detected among both populations of progenitors. The total number of high proliferative-potential CFCs with erythroid, myeloid, and NK cell potential was estimated to be 2-fold higher in the CD38+ fraction compared with the CD38− fraction because of the higher frequency of CD38+ cells among CD34++ cells. The broad distribution of multipotent CFCs among CD38− and CD38+ progenitors suggests that the segregation of the erythroid, myeloid, and lymphoid lineages may not always be an early event in hemopoiesis. Alternatively, some stem cells may be present among CD38+ cells.
Phosphorylation by the Protein Kinase CK2 Promotes Calpain-Mediated Degradation of IκBα
Authors: Shen Jian , Channavajhala Padmalatha , Seldin David C. , Sonenshein Gail E. 
Published: April 2014

AbstractRapid IκBα turnover has been implicated in the high basal NF-κB activity in WEHI 231 B immature IgM+ B cells. Here we show that treatment of WEHI 231 cells with apigenin, a selective inhibitor of the protein kinase CK2, decreased the rate of IκBα turnover and nuclear levels of NF-κB. Turnover of IκBα in these cells is mediated in part by the protease calpain. Since both CK2 and calpain target the proline-glutamic acid-serine-threonine (PEST) domain, we investigated the role of CK2 in the degradation of IκBα by calpain using an in vitro phosphorylation/degradation assay. CK2 phosphorylation enhanced μ-calpain-mediated degradation of wild-type IκBα, but not of mutant 3CIκBα, with S283A, T291A, and T299A mutations in phosphorylation sites within the PEST domain. Roles for CK2 and calpain in IκBα turnover were similarly shown in CH31 immature and CH12 mature IgM+ B cells, but not in A20 and M12 IgG+ B cells. These findings demonstrate for the first time that CK2 phosphorylation of serine/threonine residues in the PEST domain promotes calpain-mediated degradation of IκBα and thereby increases basal NF-κB levels in IgM+ B cells.
Microglial Phagocytosis of Apoptotic Inflammatory T Cells Leads to Down-Regulation of Microglial Immune Activation
Authors: Magnus Tim , Chan Andrew , Grauer Oliver , Toyka Klaus V. , Gold Ralf 
Published: April 2014

AbstractApoptotic cell death is an established mechanism to terminate an inflammatory response in rodent or human brains. Microglia, as the resident phagocyte, is a strong candidate for the clearance of apoptotic lymphocytes. Apoptosis was induced in cultured autologous thymocytes and in myelin basic protein (MBP)-specific, encephalitogenic T cells from Lewis rats by the addition of 0.1 μg/ml methylprednisolone. The amount of phagocytosis of apoptotic cells was assessed using an in vitro phagocytosis assay. Supernatants were collected to measure microglial cytokine secretion. The state of immune activation in microglia was investigated by a T cell proliferation assay and by flow cytometric analysis of microglial surface expression of immune molecules. Microglia ingested specifically apoptotic cells (apoptotic thymocytes as well as MBP-specific T cells) in contrast to nonapoptotic control cells (p &lt; 0.0001). Subsequent secretion of the proinflammatory cytokines TNF-α and IL-12 was significantly decreased, while the secretion of IL-10 and TGF-β was not affected. Furthermore, ingestion of apoptotic cells led to increased microglial MHC class II expression without concomitant increase in MHC class I, costimulatory molecules, and ICAM expression. The Ag-specific activation of MBP-specific T cells in cocultures with microglia that had ingested apoptotic cells was significantly less than that of identical T cells that interacted with nonphagocytosing microglia. Together with negative results obtained in a trans-well system, this is in support of a cell contact-mediated effect. Microglia might play an important role in the clearance of apoptotic cells. The uptake of apoptotic cells by microglia is tolerogenic and results in a reduced proinflammatory cytokine production and a reduced activation of encephalitogenic T cells. This might help to restrict an autoimmune inflammation and minimize damage in the inflamed brain.