bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signal transduction in Jurkat T lymphocytes. Evidence for early Ca2+ movements between the cytoplasm and the nucleoplasm in activated cells
Authors: Gagné Daniféle , Ahnadi Charaf E , Martel Julie , Payet Marcel D , Dupuis Gilles 
Published: January 2018

Abstract
Spatial analyses of the distribution of Ca2+in resting and activated T and B lymphocytes have shown that the bulk of increased [Ca2+]i appears to be associated with the nuclear region. These observations suggest that Ca2+ is released from the perinuclear space or that it diffuses to the nucleoplasm, or both. We have used laser scanning confocal microscopy to assess whether cytoplasmic diffusion of Ca2+ could contribute to the rise in nuclear Ca2+. We found that the activation of individual Jurkat cells by use of an anti-Ti (β-subunit) mAb induced a nucleus-associated increase in [Ca2+]i. In cells loaded with the InsP3 receptor antagonist heparin, the nuclear Ca2+ response was abolished but not the response to thapsigargin. Evidence for a cytoplasmic Ca2+ response was obtained by loading Jurkat cells with a cytoplasm-restricted Ca2+ probe (Calcium Green-1-Dextran). These observations suggested that a process of diffusion of cytoplasmic Ca2+ contributed to the rise of nuclear Ca2+ in Jurkat T cells. This interpretation was supported by the findings (1) that rapid scanning of thapsigargin-released Ca2+ showed an inverse relationship between the levels of cytoplasmic and nuclear Ca2+ and (2) that modulation of the external concentration of Ca2+ in thapsigargin-treated Jurkat cells showed a time-dependent decrease of fluorescence from the nucleoplasm that was reversed by raising the concentration of external Ca2+. We conclude that Ca2+can rapidly diffuse between the cytoplasm and the nucleoplasm in activated Jurkat T lymphocytes and that hydrophilic Ca2+ probes largely partition to the nucleoplasm, thus giving rise to distorted nucleus-to-cytoplasm fluorescence ratios.
Arginine-specific ADP-ribosyltransferases in leukocytes
Authors: Saxty Barbara A , Kefalas Panagiotis , Yadollahi-Farsani Masoud , MacDermot John 
Published: January 2018

Abstract
The posttranslational modification of proteins by the addition of an ADP-ribose group is mediated by ADP-ribosyltransferases, which are expressed widely in many eukaryotic tissues, including leukocytes. DNA encoding arginine-specific ADP-ribosyltransferases has been cloned from both polymorphonuclear neutrophil leukocytes and lymphocytes, and their primary structures are widely conserved, particularly in those domains of the enzyme implicated in NAD+ binding and catalysis. In most cases the enzymes are tethered to the outer aspect of the cell surface or are released directly from the cell surface. The protein substrates of some of the ADP-ribosyltransferases have been identified and the catalytic activity of these enzymes has been implicated in several immune responses as well as white cell chemotaxis. This review describes recent significant advances in this field, and it seems likely that additional leukocyte functions, most particularly those linked to the activity of surface integrins, will be assigned to this class of enzymes.
Subcellular localization of glycosphingolipids in human neutrophils
Authors: Kniep Bernhard , Skubitz Keith M 
Published: January 2018

Abstract
The subcellular distribution of five major glycosphingolipids (GSLs) in human neutrophils was analyzed. The neutrophils were isolated from the blood of six donors and subdivided in three fractions containing the cell membranes, and the primary and the secondary granules, respectively. The separation was confirmed with antibodies detecting established subcellular fraction-specific molecules. The two main neutral GSLs Galβ 1-4Glcβ 1-1 ‘Cer (lactosylceramide, LacCer) and nLc4Cer (paragloboside, PG) and the three gangliosides IV3NeuAcnLc4Cer (2-3SPG), IV6NeuAcnLc4Cer (2-6SPG), and VI3NeuAcnLc6Cer (2-3SnHC) were quantitated using the immunochemical digoxigenin (DIG) staining procedure. Secondary granules contained the highest amount of these GSLs. They are followed by the primary granules and the cell membranes. Based on this quantitation, we conclude that the majority of the GSLs of neutrophils occur intracellularly. These findings are in striking contrast to the general assumption of GSLs being mainly concentrated in the cell membrane.
Novel monoclonal antibodies against membrane structures that are preferentially expressed on IL-2-activated rat NK cells
Authors: Giezeman-Smits Katinka M , Jonges Liesbeth E , Chambers William H , Brisette-Storkus Cynthia S , van Vlierberghe Ronald L P , van Eendenburg Jaap D H , Eggermont Alexander M M , Fleuren Gert Jan , Kuppen Peter J K 
Published: January 2018

Abstract
Interleukin-2 (IL-2)-activated natural killer (NK) cells are known to mediate specific functions such as cytolytic activity and tumor infiltration more efficiently than nonactivated NK cells. To investigate whether these characteristics are associated with induction or up-regulation of expression of membrane structures after IL-2 activation, we selected four hybridomas (mAbs ANK44, ANK66, ANK7, and ANK123) derived from mice immunized with rat IL-2-activated NK cells and compared the expression of the epitopes recognized on IL-2-activated NK cells versus unstimulated NK cells. We found that ANK44-expression was induced after activation with IL-2. The antigens recognized by ANK66, ANK7, and ANK123 were expressed selectively on subsets of nonactivated NK cells. After activation with IL-2 the level of expression of these antigens was increased. Moreover, the majority of NK cells then expressed these antigens after IL-2 activation. Biochemical characterization of the membrane structures recognized on IL-2-activated NK cells showed that they have not previously been described. The precise function of these membrane structures is not yet known, however, the selective nature of their expression implies their involvement in the specific functions of IL-2-activated NK cells.
Salmonella infections in the absence of the major histocompatibility complex II
Authors: Chapes Stephen K , Beharka Alison A 
Published: January 2018

Abstract
We examined the pathogenesis of the facultative intracellular bacterium, Salmonella typhimurium in MHCII-/-, C2D knock-out mice, and wild-type C57BL/6J mice. The MHCII knock-out shortened the kinetics of animal death and reduced the dose of S. typhimurium needed to kill mice. We measured the physiological and cytokine responses of both mouse strains after S. typhimurium injection. Animal weight loss, spleen weights, liver weights, thymus weights, and serum corticosterone concentrations were comparable after injection with several doses of bacteria. The only physiological differences observed between the two strains were observed 3 days after injection of the highest dose of bacteria tested. Serum concentrations of tumor necrosis factor α, interleukin-2, and interleukin-6 increased in a dose-dependent fashion irrespective of mouse MHCII expression. Therefore, even in the absence of MHCII, mice are able to mount relatively normal physiological and immunological responses. Consistent with these normal responses, an increased percentage of MHCII-/-mice, primed with a low dose of bacteria 13 days earlier, were able to survive a lethal challenge of Salmonella compared with unprimed controls. Lastly, C2D mice had significantly higher serum interleukin-10 concentrations than C57BL/6J mice 48 h after infection with all doses of S. typhimurium. C2D macrophages also secreted significantly more IL-10 and less NO and O2–after lipopolysaccharide or phorbol ester stimulation in vitro than wild-type macrophages.
Cationic proteins of neutrophil azurophilic granules: protein-protein interaction and blockade of NADPH oxidase activation
Authors: Tal Tal , Michaela Sharabani , Irit Aviram 
Published: January 2018

Abstract
We have previously reported inhibition of cell-free activation of the neutrophil superoxidegenerating NADPH oxidase by a soluble cationic protein of neutrophil granules and by low concentrations of human defensin. Subcellular fractionation carried out in the current study indicated that the inhibitory substance was derived from azurophilic granules, was released into the medium on cell stimulation, and was resistant to phenylmethylsulfonyl fluoride (PMSF). Phorbol ester was the most effective stimulus for the release of the blocking activity. The possibility was raised that granule protein(s) act in vivo as negative modulators of superoxide production. Gel filtration of granule extract revealed a markedly retarded protein peak exhibiting oxidase-blocking activity and containing lysozyme as the main protein. Because lysozyme did not exert inhibitory effects on oxidase activation, association of the inhibitory protein with lysozyme was assumed. Indeed a column of immobilized lysozyme retained a fraction of the granule extract's oxidase-blocking activity. Elution with a low-pH buffer recovered a component capable of inhibition of the NADPH oxidase in stimulated neutrophils and in the cell-free system. The main 29-kDa protein band in the eluted fraction was identified as proteinase 3, a serine protease of azurophilic granules. Enzymatically active as well as PMSF-blocked conventionally purified proteinase 3 interfered with phorbol myristate acetate-induced superoxide release. These findings support the hypothesis that exocytosed granule constituents may prevent excessive activation of the NADPH oxidase.
Priming induces functional coupling of N-formyl-methionyl-leucyl-phenylalanine receptors in equine neutrophils
Authors: Brazil Timothy J , Rossi Adriano G , Haslett Christopher , McGorum Bruce , Dixon Paddy M , Chilvers Edwin R 
Published: January 2018

Abstract
The synthetic formylpeptide fMLP is widely used as a model chemoattractant and secretagogue for mammalian neutrophils. Despite possessing fMLP receptors, equine neutrophils do not produce superoxide anions in response to fMLP and there is no inflammatory reaction in the horse when fMLP is injected intradermally. The functional capability of these receptors was investigated after pretreatment with recognized priming agents. Purified neutrophils were pretreated with lipopolysaccharide (LPS), platelet-activating factor (PAF), or tumor necrosis factor α (TNF-α) and superoxide anion generation and shape change quantified by lucigenin-dependent chemiluminescence (LDCL) and flow cytometry, respectively. LPS, TNF-α, and PAF pretreatment induced significant LDCL in response to fMLP; similarly LPS pretreatment was a prerequisite for fMLP-stimulated neutrophil polarization in response to fMLP. However, LPS failed to induce fMLP-mediated chemotaxis of equine neutrophils. These data indicate that equine neutrophil fMLP receptors are not vestigial as previously thought but can trigger both respiratory burst activity and cell polarization responses after priming.
Ligation of CR1 attenuates Fc receptor-mediated myeloperoxidase release and HOCl production by neutrophils
Authors: Sambandam Thiagarajan , Chatham W Winn 
Published: January 2018

Abstract
Surface adherent immunoglobulins are potent stimuli for inducing neutrophil release of myeloperoxidase and production of hypochlorous acid (HOCl), an oxidant that promotes activity of neutrophil proteases. Opsonization of surface adherent IgG (SAIgG) by complement results in attenuation of these responses, despite augmenting neutrophil production of superoxide and release of specific granule enzymes. The role of complement receptor ligation in modulating Fc receptor-triggered myeloperoxidase release and HOCl production by neutrophils was determined by incubating neutrophils with SAIgG in the presence of complement receptor ligating antibody reagents. Ligation of CR1 by F(ab)2 derived from CR1 specific monoclonal antibody (mAb 543) resulted in significant attenuation of surface-associated IgG (SAIgG)-induced release of myeloperoxidase and HOCl production but did not result in attenuation of SAIgG-induced superoxide or hydrogen peroxide production; ligation of CR1 by mAb 543 F(ab)2 also attenuated surface adherent IgA-induced myeloperoxidase release and HOCl production. HOCl production was not significantly attenuated when neutrophils were activated with SAIgG in the presence of surface adherent C1q or when CR3 was ligated by F(ab)2 derived from mAb having specificity for the CD11b (mAb M1/70) or CD18 (mAb TS1) subunits of CR3. These results indicate that ligation of CR1 on neutrophils by C3b fixed to IgG may alter signal transduction events linking ligation of neutrophil Fc receptors to cellular events required for release of myeloperoxidase and generation of HOCl.
Inhibition of p130cas tyrosine phosphorylation by calyculin A
Authors: Qiu Wansong , Cobb Ronald R , Scholz Wolfgang 
Published: January 2018

Abstract
P130cas is a dominant tyrosine phosphorylated protein in v-src-and v-crk-transformed cells. Tyrosine phosphorylation also occurs in response to integrin-mediated cell adhesion. P130cas has a unique structure with multiple SH2 and SH3 binding sites, which makes it a candidate docking protein that might be involved in several signal transduction pathways. Little is known about how p130cas itself is regulated. In this report we present evidence that tyrosine phosphorylated p130cas was rapidly dephosphorylated in several lymphatic cell lines after treatment with calyculin A, a serine/ threonine phosphatase inhibitor. A similar result was obtained with okadaic acid, but higher concentrations and longer incubation times were required. Constitutive phosphorylation as well as receptor-cross linking-induced p130cas phosphorylation was inhibited. Furthermore, the p130cas-Crk association was disrupted by treatment of cells with calyculin A. However, the p130cas-Lyn association was not affected. These results suggest that calyculin A specifically affects SH2 domain-mediated protein-protein interactions and that Lyn does not bind to a susceptible SH2 domain. Furthermore, the data presented is consistent with the existence of a calyculin A-sensitive phosphatase or tyrosine kinase that may be a critical regulator of p130cas tyrosine phosphorylation.
Distinct adapter proteins mediate acid versus neutral sphingomyelinase activation through the p55 receptor for tumor necrosis factor
Authors: Adam-Klages Sabine , Schwandner Ralf , Adam Dieter , Kreder Dirk , Bernardo Katussevani , Krönke Martin 
Published: January 2018

Abstract
Ceramide, generated by the enzymatic function of sphingomyelinases (SMases) has emerged as an important signaling pathway transducing diverse biological effects of various cytokine receptors. The 55-kDa receptor for tumor necrosis factor (TNF-R55) activates two types of SMases through distinct cytoplasmic domains. The death domain that is responsible for the initiation of the apoptotic pathway also signals for the activation of an acid SMase (A-SMase). The adapter protein TRADD binds to TNF-R55 in a ligand-dependent manner and serves as anchor for the subsequent recruitment of other proteins into the signaling complex that directly lead to cell death or nuclear factor-κB (NF-κB) induction. Notably, the two proapoptotic adapter proteins TRADD and FADD are also involved in the activation of A-SMase. In contrast, the NF-κB-inducing adapters TRAF2 and RIP do not signal for A-SMase. Thus, activation of A-SMase appears to belong to signals leading to TNF-induced cell death. A second signaling domain (NSD) is located upstream of the death domain and directly links the TNF-R55 to the activation of a neutral SMase (N-SMase). A novel adapter protein, FAN, has been identified that specifically binds to the NSD. FAN contains five WD repeats at its carboxy terminus, while it shows significant sequence homology with the mouse beige protein and its human homolog, the CHS protein, in the center portion of the protein. Overexpression of full-length FAN enhanced N-SMase activity in TNF-treated cells, whereas truncated mutants of FAN produced dominant negative effects. FAN, however, did not interfere with any of the TNF responses signaled for by the death domain. Taken together, our data suggest that distinct cytoplasmic domains of TNF-R55 initiate independent signaling pathways by binding different adapter proteins.
Localization of eosinophil-derived neurotoxin and eosinophil cationic protein in neutrophilic leukocytes
Authors: Sur Sanjiv , Glitz Dohn G , Kita Hirohito , Kujawa Stephen M , Peterson Ellen A , Weiler Deborah A , Kephart Gail M , Wagner Jill M , George Terry J , Gleich Gerald J , Leiferman Kristin M 
Published: January 2018

Abstract
Eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) are generally regarded as eosinophil-specific proteins. We tested whether EDN and ECP are present in mature neutrophils. By indirect immunofluorescence, both eosinophils and neutrophils stained with antibodies to EDN and ECP. Lysates of purified (&lt;0.1% eosinophil contamination) neutrophils contained EDN, 112 ± 4 ng/106 cells, and ECP, 163 ± 2 ng/106 cells, whereas eosinophil major basic protein (MBP) was not detectable. Electron microscopic examination of immunogold-labeled buffy coat cells stained with EDN antibody showed that EDN is localized to neutrophil granules. Finally, EDN mRNA was detected in lysates of highly purified neutrophils (0.001% eosinophil contamination) by the reverse transcription-polymerase chain reaction. We conclude that proteins that are either identical to or immunologically cross-reactive with EDN and ECP are present in neutrophils and that EDN is synthesized and localized to neutrophil granules. Thus, caution must be exercised in interpreting the presence of EDN and ECP as specific markers of eosinophil-associated inflammation in human disease.
Burn-associated Candida albicans infection caused by CD30+ type 2 T cells
Authors: Kobayashi Makiko , Kobayashi Hiroyuki , Herndon David N , Pollard Richard B , Suzuki Fujio 
Published: January 2018

Abstract
Burn injury is associated with the greatly increased susceptibility of thermally injured patients to infection from a variety of pathogens. In this study we investigated the role of burn-associated type 2 T cells on the increased susceptibility of burned patients to Candida albicans infection using SCID mice and peripheral blood lymphocytes (PBL) from thermally injured patients. When SCID mice that were inoculated with PBL from healthy donors were resistant to C. albicans infection, the SCID mice that were inoculated with PBL from burned patients did not show any resistance to the infection. All SCID mice exposed to the pathogen, however, survived after inoculation with patient PBL that were previously depleted of CD30+ cells. The predominance of type 2 T cell responses was demonstrated in PBLs of thermally injured patients. As burn-associated type 2 T cells, CD3+ CD8+ CD30+ IL-4 and IL-10-producing cells were demonstrated in burned patient PBL. These results suggest that burn-associated CD30+ type 2 T cells may play a role on the increased susceptibility of burned patients to C. albicans infection.
Comparative ultrastructure and expression of L-selectin on bovine αβ and γδ T cells
Authors: Leid Jeff G , Speer C A , Jutila Mark A 
Published: January 2018

Abstract
Compared to most αβ T cells, bovine γδ T cells express two to five times the level of L-selectin and have a much higher capacity to roll on monolayers of endothelial cells, platelets, and leukocytes in assays done under physiological flow. To gain additional insight into the basis for these differences, scanning (SEM) and transmission (TEM) electron microscopy were used to compare the cellular ultrastructure of bovine γδ and αβ T cells and to study the expression of L-selectin on these cells. It is interesting that γδ T cells had more than twice as many microvilli and other surface projections on a per cell basis as αβ T cells. This was not due to the γδ T cell being larger; after adhesion and fixation procedures used for the EM studies, γδ T cells averaged 3.9 ± 0.01 μm in diameter, whereas αβ T cells were slightly larger (5.7 ± 0.01 μm in diameter). As previously shown for human neutrophils and lymphocytes, L-selectin was preferentially localized to the tips of the microvilli. In contrast, WC1, a lineage-specific antigen on γδ T cells, was localized on the plasmalemma between the microvilli. Our findings suggest that more effective rolling of γδ T cells in various in vitro flow assays may be due to the greater number of microvilli on γδ T cells leading to a higher number of contact sites during adhesion events. In addition, this physical parameter may explain the increased level of L-selectin expression on γδ versus αβ T cells because L-selectin is clustered at the tips of microvilli. J. Leukoc. Biol. 64: 104–107; 1998.
Blood mononuclear cell production of TNF-α and IL-8: engagement of different signal transduction pathways including the p42 MAP kinase pathway
Authors: Foreback Jami L , Sarma Vidya , Yeager Nicholas R , Younkin Ellen M , Remick Daniel G , Ward Peter A 
Published: January 2018

Abstract
Recent studies of human peripheral blood mononuclear cells (PBMC) stimulated with IgG subclasses have suggested that tumor necrosis factor α (TNF-α) and interleukin-8 (IL-8) production proceed along different signal transduction pathways. To investigate this possibility, inhibitors of signal transduction pathways were employed. Human PBMC were pretreated with various inhibitors before being added to IgG2-coated wells and 4-h supernatant fluids evaluated for cytokine content. The effects of various inhibitors on MAP kinase activation were determined. Inhibitors of protein tyrosine kinases, phosphatases, and phospholipase C decreased TNF-α and IL-8 production, suggesting that all three enzyme pathways are involved in cytokine generation. Inhibitors of G-proteins had differing effects: pertussis toxin inhibited IL-8 but not TNF-α production, whereas cholera toxin inhibited TNF-α but not IL-8 production. Pretreatment of PBMC with pertussis toxin resulted in reduced IgG2-induced calcium mobilization, whereas cholera toxin had no effect, correlating with the effects of pertussis toxin on IL-8 expression. Inhibitors of protein kinase C (PKC) completely blocked TNF-α generation but had no effect on IL-8 production. Gö6976, which inhibits certain isoforms of PKC, inhibited production of both IL-8 and TNF-α. Isoforms of PKC may have opposing effects on cytokine production. PD 98059, a compound that specifically inhibits the activation of mitogen-activated protein kinase kinase (MEK1), inhibited TNF-α production, but had insignificant effects on IL-8 production. Pretreatment of PBMC with either PD 98059 or genistein reduced the extent of phosphorylation of p42 MAP kinase in cells activated on contact with IgG2. These findings suggest distinct signal transduction pathways for cytokine production in PBMC stimulated with IgG2. J. Leukoc. Biol. 64: 124–133; 1998.