bluuebunny/crossref_metadata_2025_split huggingface dataset:
De Novo Ceramide Synthesis Is Required for N-Linked Glycosylation in Plasma Cells
Authors: Goldfinger Meidan , Laviad Elad L. , Hadar Rivka , Shmuel Miri , Dagan Arie , Park Hyejung , Merrill Alfred H. , Ringel Israel , Futerman Anthony H. , Tirosh Boaz 
Published: May 2009

Abstract
Plasma cells (PCs) are terminally differentiated B lymphocytes responsible for the synthesis and secretion of Igs. The differentiation of B cells into PCs involves a remarkable expansion of both lipid and protein components of the endoplasmic reticulum. Despite their importance in many signal transduction pathways, the role of ceramides, and of complex sphingolipids that are derived from ceramide, in PC differentiation has never been directly studied. To assess their putative role in PC differentiation, we blocked ceramide synthesis with fumonisin B1, a specific inhibitor of ceramide synthase. Under fumonisin B1 treatment, N-linked glycosylation was severely impaired in LPS-activated, but not in naive, B cells. We also show that ceramide synthesis is strongly induced by XBP-1 (X box-binding protein-1). In the absence of ceramide synthesis, ER expansion was dramatically diminished. Our results underscore ceramide biosynthesis as a key metabolic pathway in the process of PC differentiation and reveal a previously unknown functional link between sphingolipids and N-linked glycosylation in PCs.
Human Milk-Derived B Cells: A Highly Activated Switched Memory Cell Population Primed to Secrete Antibodies
Authors: Tuaillon Edouard , Valea Diane , Becquart Pierre , Al Tabaa Yassine , Meda Nicolas , Bollore Karine , Van de Perre Philippe , Vendrell Jean-Pierre 
Published: May 2009

AbstractWhile secretory Abs have been extensively explored in human breast milk, the existence, features, and functions of B lymphocytes remain largely unexplored in this compartment. We analyzed breast milk and blood lymphocytes from 21 lactating women, including 12 HIV-1-infected mothers. Breast milk B cells displayed a phenotype of class-switched memory B cells, with few IgD+ memory and naive B cells. We observed that breast milk B lymphocytes bore a unique profile of adhesion molecules (CD44+, CD62L−, α4β7+/−, α4β1+). Higher percentages of activated B cells (CD38+), large-sized B cells, plasmablasts, and plasma cells (CD19+, CD20low/−, CD27high, CD138+) were found as compared with blood. This indicates that a significant proportion of breast milk B cells underwent terminal plasma cell differentiation. We also observed a higher frequency of cells secreting Ig spontaneously in breast milk. Among these cells, IgG-secreting cells predominated over IgA-secreting cells as measured by Ig ELISPOT assays. Specific Ab-secreting cells were investigated following polyclonal activation using the CD40L ligation. Finally, the detection of anti-HIV-1-secreting cells demonstrates the existence of B cells specific to HIV-1 Ag in breast milk from HIV-1-infected women. Breast milk B cells display a phenotype strikingly different from blood, are primed to secrete Abs, and have a mucosal homing profile similar to B cells located in gut-associated lymphoid tissue.
Hypercostimulation through 4-1BB Distorts Homeostasis of Immune Cells
Authors: Lee Seung-Woo , Salek-Ardakani Shahram , Mittler Robert S. , Croft Michael 
Published: May 2009

Abstract
The deleterious side effects associated with a recent clinical trial with anti-CD28 superagonist Abs have questioned the use of reagents to costimulatory molecules in human therapy. We now show that sustained signaling from an agonist Ab to 4-1BB, a member of the TNFR superfamily, results in detrimental effects on immune cell homeostasis. Repeated anti-4-1BB treatment during the reconstitution of hematopoietic cells in irradiated mice engrafted with bone marrow, or in mice infected with vaccinia virus, induced abnormal apoptosis of premature and immature B cells in the bone marrow, and led to peripheral B cell depletion. Inhibition of B cell development was indirect and due to costimulation of CD8 T cells and dependent on IFN-γ. Moreover, anti-4-1BB also suppressed the development of NK and NKT cells, but in this case independently of T cells and IFN-γ. The altered NK cell homeostasis resulted from activation-induced cell death triggered by anti-4-1BB. These results show that hypercostimulation elicits strong T cell immunity, but it can simultaneously distort immune homeostasis, suggesting that careful attention to activity, dose, and periodicity of treatment will be needed in any immunotherapeutic strategy with agonist Abs to costimulatory molecules.
Interaction of the Hepatitis B Core Antigen and the Innate Immune System
Authors: Lee Byung O. , Tucker Amy , Frelin Lars , Sallberg Matti , Jones Joyce , Peters Cory , Hughes Janice , Whitacre David , Darsow Bryan , Peterson Darrell L. , Milich David R. 
Published: May 2009

Abstract
Previous studies demonstrated that the primary APCs for the hepatitis B core Ag (HBcAg) were B cells and not dendritic cells (DC). We now report that splenic B1a and B1b cells more efficiently present soluble HBcAg to naive CD4+ T cells than splenic B2 cells. This was demonstrated by direct HBcAg-biotin-binding studies and by HBcAg-specific T cell activation in vitro in cultures of naive HBcAg-specific T cells and resting B cell subpopulations. The inability of DC to function as APCs for exogenous HBcAg relates to lack of uptake of HBcAg, not to processing or presentation, because HBcAg/anti-HBc immune complexes can be efficiently presented by DC. Furthermore, HBcAg-specific CD4+ and CD8+ T cell priming with DNA encoding HBcAg does not require B cell APCs. TLR activation, another innate immune response, was also examined. Full-length (HBcAg183), truncated (HBcAg149), and the nonparticulate HBeAg were screened for TLR stimulation via NF-κB activation in HEK293 cells expressing human TLRs. None of the HBc/HBeAgs activated human TLRs. Therefore, the HBc/HBeAg proteins are not ligands for human TLRs. However, the ssRNA contained within HBcAg183 does function as a TLR-7 ligand, as demonstrated at the T and B cell levels in TLR-7 knockout mice. Bacterial, yeast, and mammalian ssRNA encapsidated within HBcAg183 all function as TLR-7 ligands. These studies indicate that innate immune mechanisms bridge to and enhance the adaptive immune response to HBcAg and have important implications for the use of hepadnavirus core proteins as vaccine carrier platforms.
Miltefosine Promotes IFN-γ-Dominated Anti-Leishmanial Immune Response
Authors: Wadhone Pallavi , Maiti Moitrayee , Agarwal Reena , Kamat Vanita , Martin Sunil , Saha Bhaskar 
Published: May 2009

AbstractLeishmania donovani, a protozoan parasite, resides and replicates as amastigotes within macrophages. The parasite inflicts the disease visceral leishmaniasis by suppressing host cell function. Neither a therapeutic vaccine nor an effective anti-leishmanial drug to reverse the immunosuppression is available. Although miltefosine (hexadecylphosphocholine or HPC) is a promising orally bioavailable anti-leishmanial drug, its efficacy is seriously compromised by contra-indications in pregnant women. Further rational redesigning of the drug requires studies on its mechanism of action, which is unknown at present. Because miltefosine is proposed to have immunomodulatory functions, we examined whether miltefosine exerts its anti-leishmanial functions by activating macrophages. We observed that miltefosine’s anti-leishmanial function was significantly compromised in IFN-γ-deficient macrophages suggesting the importance of endogenous IFN-γ in miltefosine-induced anti-leishmanial functions of macrophages. Miltefosine induced IFN-γ, neutralization of which reduced the anti-leishmanial functions of macrophages. IFN-γ responsiveness is reduced in L. donovani-infected macrophages but is significantly restored by miltefosine, as it enhances IFN-γ receptors and IFN-γ induced STAT-1 phosphorylation but reduced activation of SHP-1, the phosphatase implicated in the down-regulation of STAT-1 phosphorylation. Miltefosine induced protein kinase C-dependent and PI3K-dependent p38MAP kinase phosphorylation and anti-leishmanial function. Miltefosine promotes p38MAP kinase-dependent anti-leishmanial functions and IL-12-dependent Th1 response. Leishmania donovani-infected macrophages induced Th2 response but miltefosine treatment reversed the response to Th1-type. Thus, our data define for the first time the mechanistic basis of host cell-dependent anti-leishmanial function of miltefosine.
MHC Class I Dk Locus and Ly49G2+ NK Cells Confer H-2k Resistance to Murine Cytomegalovirus
Authors: Xie Xuefang , Stadnisky Michael D. , Brown Michael G. 
Published: May 2009

Abstract
Essential NK cell-mediated murine CMV (MCMV) resistance is under histocompatibility-2k (H-2k) control in MA/My mice. We generated a panel of intra-H2k recombinant strains from congenic C57L.M-H2k/b (MCMV resistant) mice for precise genetic mapping of the critical interval. Recombination breakpoint sites were precisely mapped and MCMV resistance/susceptibility traits were determined for each of the new lines to identify the MHC locus. Strains C57L.M-H2k(R7) (MCMV resistant) and C57L.M-H2k(R2) (MCMV susceptible) are especially informative; we found that allelic variation in a 0.3-megabase interval in the class I D locus confers substantial difference in MCMV control phenotypes. When NK cell subsets responding to MCMV were examined, we found that Ly49G2+ NK cells rapidly expand and selectively acquire an enhanced capacity for cytolytic functions only in C57L.M-H2k(R7). We further show that depletion of Ly49G2+ NK cells before infection abrogated MCMV resistance in C57L.M-H2k(R7). We conclude that the MHC class I D locus prompts expansion and activation of Ly49G2+ NK cells that are needed in H-2k MCMV resistance.
The Binding of Factor H to a Complex of Physiological Polyanions and C3b on Cells Is Impaired in Atypical Hemolytic Uremic Syndrome
Authors: Ferreira Viviana P. , Herbert Andrew P. , Cortés Claudio , McKee Kristi A. , Blaum Bärbel S. , Esswein Stefan T. , Uhrín Dušan , Barlow Paul N. , Pangburn Michael K. , Kavanagh David 
Published: May 2009

Abstract
Factor H (fH) is essential for complement homeostasis in fluid-phase and on surfaces. Its two C-terminal domains (CCP 19–20) anchor fH to self-surfaces where it prevents C3b amplification in a process requiring its N-terminal four domains. In atypical hemolytic uremic syndrome (aHUS), mutations clustering toward the C terminus of fH may disrupt interactions with surface-associated C3b or polyanions and thereby diminish the ability of fH to regulate complement. To test this, we compared a recombinant protein encompassing CCP 19–20 with 16 mutants. The mutations had only very limited and localized effects on protein structure. Although we found four aHUS-linked fH mutations that decreased binding to C3b and/or to heparin (a model compound for cell surface polyanionic carbohydrates), we identified five aHUS-associated mutants with increased affinity for either or both ligands. Strikingly, these variable affinities for the individual ligands did not correlate with the extent to which all the aHUS-associated mutants were found to be impaired in a more physiological assay that measured their ability to inhibit cell surface complement functions of full-length fH. Taken together, our data suggest that disruption of a complex fH-self-surface recognition process, involving a balance of affinities for protein and physiological carbohydrate ligands, predisposes to aHUS.
Myosin IIA Associates with NK Cell Lytic Granules to Enable Their Interaction with F-Actin and Function at the Immunological Synapse
Authors: Sanborn Keri B. , Rak Gregory D. , Maru Saumya Y. , Demers Korey , Difeo Analisa , Martignetti John A. , Betts Michael R. , Favier Rémi , Banerjee Pinaki P. , Orange Jordan S. 
Published: May 2009

AbstractNK cell cytotoxicity requires the formation of an actin-rich immunological synapse (IS) with a target cell and the polarization of perforin-containing lytic granules toward the IS. Following the polarization of lytic granules, they traverse through the actin-rich IS to join the NK cell membrane in order for directed secretion of their contents to occur. We examined the role of myosin IIA as a candidate for facilitating this prefinal step in lytic NK cell IS function. Lytic granules in and derived from a human NK cell line, or ex vivo human NK cells, were constitutively associated with myosin IIA. When isolated using density gradients, myosin IIA-associated NK cell lytic granules directly bound to F-actin and the interaction was sensitive to the presence of ATP under conditions of flow. In NK cells from patients with a truncation mutation in myosin IIA, NK cell cytotoxicity, lytic granule penetration into F-actin at the IS, and interaction of isolated granules with F-actin were all decreased. Similarly, inhibition of myosin function also diminished the penetration of lytic granules into F-actin at the IS, as well as the final approach of lytic granules to and their dynamics at the IS. Thus, NK cell lytic granule-associated myosin IIA enables their interaction with actin and final transit through the actin-rich IS to the synaptic membrane, and can be defective in the context of naturally occurring human myosin IIA mutation.
The UDP-Glucose Receptor P2RY14 Triggers Innate Mucosal Immunity in the Female Reproductive Tract by Inducing IL-8
Authors: Arase Toru , Uchida Hiroshi , Kajitani Takashi , Ono Masanori , Tamaki Kayoko , Oda Hideyuki , Nishikawa Sayaka , Kagami Maki , Nagashima Takashi , Masuda Hirotaka , Asada Hironori , Yoshimura Yasunori , Maruyama Tetsuo 
Published: May 2009

Abstract
Innate mucosal immune responses, including recognition of pathogen-associated molecular patterns through Toll-like receptors, play an important role in preventing infection in the female reproductive tract (FRT). Damaged cells release nucleotides, including ATP and uridine 5′-diphosphoglucose (UDP-glucose), during inflammation and mechanical stress. We show in this report that P2RY14, a membrane receptor for UDP-glucose, is exclusively expressed in the epithelium, but not the stroma, of the FRT in humans and mice. P2RY14 and several proinflammatory cytokines, such as IL-8, are up-regulated in the endometria of patients with pelvic inflammatory disease. UDP-glucose stimulated IL-8 production via P2RY14 in human endometrial epithelial cells but not stromal cells. Furthermore, UDP-glucose enhanced neutrophil chemotaxis in the presence of a human endometrial epithelial cell line in an IL-8-dependent manner. Administration of UDP-glucose into the mouse uterus induced expression of macrophage inflammatory protein-2 and keratinocyte-derived cytokine, two murine chemokines that are functional homologues of IL-8, and augmented endometrial neutrophil recruitment. Reduced expression of P2RY14 by small interfering RNA gene silencing attenuated LPS- or UDP-glucose-induced leukocytosis in the mouse uterus. These results suggest that UDP-glucose and its receptor P2RY14 are key front line players able to trigger innate mucosal immune responses in the FRT bypassing the recognition of pathogen-associated molecular patterns. Our findings would significantly impact the strategic design of therapies to modulate mucosal immunity by targeting P2RY14.
CD40-Independent Engagement of Mammalian hsp70 by Antigen-Presenting Cells
Authors: Binder Robert J. 
Published: May 2009

Abstract
CD40 has been suggested previously to be a receptor for mammalian murine hsc73 (hsp70). We have examined, in vitro and in vivo, the role of CD40 in the interaction of murine dendritic cells and macrophages with hsp70, using several independent parameters including cell surface binding, translocation of NF-κB, stimulation of release of TNF-α, representation of hsp70-chaperoned peptides, and priming of CD8+ T cells. The various consequences of hsp70-APC interaction were compared between CD40+/+ and CD40−/− mice and were found to be identical in kinetics and magnitude. These data strongly indicate that all known effects of mammalian hsp70 on APCs are mediated in a CD40-independent manner. In light of the earlier demonstration that mycobacterial hsp70 binds murine CD40 and stimulates the APCs through it, our data indicate that CD40 can discriminate between self and mycobacterial hsp70 and is thus a receptor for patterns associated with microbial pathogens.
Induction of Distinct TLR2-Mediated Proinflammatory and Proadhesive Signaling Pathways in Response to Porphyromonas gingivalis Fimbriae
Authors: Hajishengallis George , Wang Min , Liang Shuang 
Published: May 2009

Abstract
The oral pathogen Porphyromonas gingivalis, as well as its purified fimbriae, are known to activate TLR2 and induce proinflammatory and proadhesive effects. The TLR2 proinflammatory pathway induces NF-κB-dependent inflammatory cytokines, whereas the TLR2 proadhesive pathway is characterized by inside-out signaling that transactivates β2 integrin adhesive activities. In this article, using dominant-negative or pharmacological approaches, we show that the two pathways bifurcate and proceed independently downstream of TLR2. Whereas the proinflammatory pathway is dependent on the adaptor molecules Toll/IL-1 receptor domain-containing adaptor protein (also known as Mal) and MyD88, the proadhesive pathway is Toll/IL-1 receptor domain-containing adaptor protein/MyD88-independent and proceeds through PI3K-mediated signaling. Although the Ser/Thr kinase Akt is a major downstream target of PI3K and was activated by P. gingivalis fimbriae in a TLR2- and PI3K-dependent way, Akt was shown not to play a role in the proadhesive patway. In contrast, another PI3K downstream target, cytohesin-1, was shown to mediate P. gingivalis fimbria-induced activation of β2 integrin for ICAM-1 binding. Therefore, P. gingivalis fimbriae activate two distinct TLR2 pathways mediating proinflammatory or proadhesive effects. The delineation of these signaling pathways may provide appropriate targets for selectively inhibiting or enhancing specific activities, depending on whether they undermine or promote the host defense.
Cutting Edge: Highly Alloreactive Dual TCR T Cells Play a Dominant Role in Graft-versus-Host Disease
Authors: Morris Gerald P. , Allen Paul M. 
Published: May 2009

Abstract
Alloreactivity is the response of T cells to MHC molecules not encountered during thymic development. A small population (1–8%) of peripheral T cells in mice and humans express two TCRs due to incomplete allelic exclusion of TCRα, and we hypothesized they are highly alloreactive. FACS analysis of mouse T cell MLR revealed increased dual TCR T cells among alloreactive cells. Quantitative assessment of the alloreactive repertoire demonstrated a nearly 50% reduction in alloreactive T cell frequency among T cells incapable of expressing a secondary TCR. We directly demonstrated expansion of the alloreactive T cell repertoire at the single cell level by identifying a dual TCR T cell with distinct alloreactivities for each TCR. The importance of dual TCR T cells is clearly demonstrated in a parent-into-F1 model of graft-vs-host disease, where dual TCR T cells comprised up to 60% of peripheral activated T cells, demonstrating a disproportionate contribution to disease.
Sodium and Sodium Alloys
Authors: Eggeman Tim ,   Updated by Staff
Published: May 2009

AbstractOf all the alkali metals, sodium has had perhaps the greatest commercial success, owing to its relative ease of manufacture and its important role worldwide in the manufacture of organolead compounds for use as gasoline octane enhancers. The decline of organoleads in North America has greatly affected U.S. production. Other sodium uses exist, but none requiring the massive quantities needed for lead antiknock compounds. Most sodium is made electrolytically. Various electrochemical cells are described.However, sodium is used to make sodium methylate, herbicides, dyes, rubber, fragrances, vitamins, and ibuprophen. In metal manufacture, sodium is used in tantalum, titanium, silicon and refining metallic lead and grain refining. Newer uses include sodium batteries, flue‐gas cleanup, and alloy surface modification. Safe handling of sodium requires special consideration because of its high reactivity. Sodium alloys are also discussed.
Long‐Term Multilayer Adherent Network (MAN) Expansion, Maintenance, and Characterization, Chemical and Genetic Manipulation, and Transplantation of Human Fetal Forebrain Neural Stem Cells
Authors: Wakeman Dustin R. , Hofmann Martin R. , Redmond D. Eugene , Teng Yang D. , Snyder Evan Y. 
Published: May 2009

AbstractHuman neural stem/precursor cells (hNSC/hNPC) have been targeted for application in a variety of research models and as prospective candidates for cell‐based therapeutic modalities in central nervous system (CNS) disorders. To this end, the successful derivation, expansion, and sustained maintenance of undifferentiated hNSC/hNPC in vitro, as artificial expandable neurogenic micro‐niches, promises a diversity of applications as well as future potential for a variety of experimental paradigms modeling early human neurogenesis, neuronal migration, and neurogenetic disorders, and could also serve as a platform for small‐molecule drug screening in the CNS. Furthermore, hNPC transplants provide an alternative substrate for cellular regeneration and restoration of damaged tissue in neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease. Human somatic neural stem/progenitor cells (NSC/NPC) have been derived from a variety of cadaveric sources and proven engraftable in a cytoarchitecturally appropriate manner into the developing and adult rodent and monkey brain while maintaining both functional and migratory capabilities in pathological models of disease. In the following unit, we describe a new procedure that we have successfully employed to maintain operationally defined human somatic NSC/NPC from developing fetal, pre‐term post‐natal, and adult cadaveric forebrain. Specifically, we outline the detailed methodology for in vitro expansion, long‐term maintenance, manipulation, and transplantation of these multipotent precursors.Curr. Protoc. Stem Cell Biol. 9:2D.3.1‐2D.3.77. © 2009 by John Wiley & Sons, Inc.
Functional Analysis of Adult Stem Cells Using Cre‐Mediated Lineage Tracing
Authors: Carlone Diana L. 
Published: May 2009

AbstractLineage‐tracing has been used for decades to establish cell fate maps during development. Recently, with the advent of genetic lineage‐tracing techniques (employing Cre‐lox recombination), it has been possible to permanently mark progenitor/stem cell populations within somatic tissues. In addition, pulse‐chase studies have shown that only stem cells are capable of producing labeled progeny after an extensive period of chase. This unit focuses on the protocols used to target putative adult stem cells in vivo. Using these techniques, one should be able to functionally confirm or deny the stem cell capacity of a given cell population. Curr. Protoc. Stem Cell Biol. 9:5A.2.1‐5A.2.15. © 2009 by John Wiley & Sons, Inc.