bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monitoring of neutrophil priming in whole blood by antibodies isolated from a synthetic phage antibody library
Authors: Koenderman Leo , Kanters Deon , Maesen B , Raaijmakers Jan , Lammers Jan-Willem J , de Kruif John , Logtenberg Ton 
Published: September 2022

AbstractNeutrophil activation is a multistep process. In vitro activation of neutrophils with semiphysiological activators is optimal only after preactivation or priming with cytokines, chemotaxins, and/or bacterial products. Until now, no antibodies have been developed that can distinguish between resting and (cytokine) primed neutrophils with a sufficient dynamic range necessary for screening clinical samples. We have isolated two human phage antibodies, designated MoPhab A17 and A27, from a synthetic bacteriophage antibody library. These phage antibodies recognize epitopes that are upregulated on neutrophils present in whole blood treated with low priming concentrations of cytokines, such as GM-CSF and TNF-α. This induction was time- and concentration-dependent and optimal at concentrations that are sufficient for priming functional responses in neutrophils: GM-CSF (10 pM) and TNF-α (100 IU/ml). PMNs, isolated from the peripheral blood of chronic obstructive pulmonary disease (COPD) patients with a clinical exacerbation, exhibited a partial in vivo primed phenotype. These antibodies promise to be an ideal tool to monitor disease activity in whole blood of patients with inflammatory diseases.
Innate and adaptive immunity in Candida albicans infections and saprophytism
Authors: Romani Luigina 
Published: September 2022

Abstract
Underlying acquired immunity to the fungus Candida albicans is usually present in adult immunocompetent individuals and is presumed to prevent mucosal colonization progressing to symptomatic infection. Exploration of immunological events leading to Candida resistance or susceptibility has indicated the central role of the innate and adaptive immune systems, the relative contribution of which may vary depending on the site of the primary infection. Nevertheless, acquired resistance to infection results from the development of Th1 responses. Cytokines produced by Th1 cells activate phagocytic cells to a candidacidal state. In contrast, cytokines produced by Th2 cells inhibit Th1 development and deactivate phagocytic effector cells. Because reciprocal influences have been recognized between innate and adaptive Th immunity, it appears that an integrated immune response determines the life-long commensalism of the fungus at the mucosal level, as well as the transition from mucosal saprophyte to pathogen.
HIV-1 can be recovered from a variety of cells including peripheral blood monocytes of patients receiving highly active antiretroviral therapy: a further obstacle to eradication
Authors: Crowe Suzanne M , Sonza Secondo 
Published: September 2022

Abstract
During highly active antiretroviral therapy (HAART), HIV-1 can still persist in circulating, resting CD4+ T lymphocytes, lymph node mononuclear cells, and seminal cells of patients despite sustained suppression of plasma viremia to undetectable levels. Sanctuary sites where antiretroviral drug penetration is not optimal may allow local HIV-1 infection of cells within and passing through these tissues. Factors such as imperfect drug adherence due to complicated drug regimens may also result in tissue compartments with suboptimal drug concentrations allowing viral replication. We have examined blood monocytes from HIV-1-infected subjects being effectively treated with HAART to determine virus carriage in these cells. Monocytes were purified from peripheral blood of patients with plasma HIV-1 RNA below 50 copies/mL and who had maintained levels of plasma RNA below detection for 3 months or more. Replication-competent virus could be recovered from the majority of monocyte populations by co-culture with CD8-depleted, PHA-activated, peripheral blood mononuclear cells. Sequencing of the reverse transcriptase and protease genes of the recovered viruses did not reveal resistance to both reverse transcriptase and protease inhibitors. Continued new infection of this transitory, circulating population of cells even during prolonged, effective HAART most likely reflects ongoing, low-level HIV-1 replication within cellular reservoirs and sanctuary sites in the body.
Osteopontin augments CD3-mediated interferon-γ and CD40 ligand expression by T cells, which results in IL-12 production from peripheral blood mononuclear cells
Authors: O’Regan Anthony W , Hayden Jason M , Berman Jeffrey S 
Published: September 2022

Abstract
Osteopontin is an RGD-containing bone matrix protein with cytokine-like functions that is associated with early stages of Th1-mediated diseases. Although the function of osteopontin in these responses is unknown, it is expressed by activated T cells and macrophages and can costimulate T cell proliferation. Studies have demonstrated that early IL-12 and IFN-γ expression is required to induce a protective response to many intracellular pathogens. Herein, we demonstrate that osteopontin stimulation augments the ability of anti-CD3 monoclonal antibody to induce CD40 ligand (CD40L) and IFN-γ expression on human T cells, resulting in CD40L- and IFN-γ-dependent IL-12 productionin vitro. These findings suggest a functional role for osteopontin in early Th1 responses, namely regulation of T cell-dependent IL-12 production. Further, osteopontin up-regulation of CD40L provides mechanistic support for the association of osteopontin with polyclonal B cell proliferation and humoral autoimmune disease.
Bleomycin-induced pulmonary fibrosis is independent of eosinophils
Authors: Hao Huiqing , Cohen Donald A , Jennings C Darrell , Bryson J Scott , Kaplan Alan M 
Published: September 2022

Abstract
Eosinophils have been shown to increase in tissues during many fibrotic conditions and consequently have been suggested to contribute to the development of fibrosis. This study tested the hypothesis that eosinophils are essential in the development of lung fibrosis in mice in response to bleomycin (BLM). Anti-IL-5 antibody was administered intraperitoneally into mice 2 h prior to endotracheal BLM inoculation and thereafter, every other day. Lung eosinophilia was evaluated by measurement of eosinophil peroxidase activity and confirmed by eosinophil counts in histologic sections. Lung fibrosis was evaluated by hydroxyproline content and confirmed by collagen staining in histological sections. Results demonstrated that BLM induced pronounced lung eosinophilia, which was maximal 7 days after BLM treatment and remained elevated through day 14, in C57Bl/6 SCID mice and CBA/J mice. In contrast, eosinophilia was a minor component in the lungs of wildtype C57Bl/6 mice after BLM treatment, although lung fibrosis developed similarly in all three strains of mice. Treatment with anti-IL-5 completely abrogated eosinophilia but failed to block pulmonary fibrosis induced by BLM in all mouse strains, including C57Bl/6 SCID, wildtype C57Bl/6 mice, and CBA/J mice. Analysis of cytokine mRNA by RNase-protection assay in C57Bl/6 SCID mice indicated that BLM treatment caused enhanced expression of the cytokines, TNF-α, and IL-6 at days 3, 7, and 14 post-BLM inoculation, regardless of whether eosinophils were depleted by anti-IL-5. Finally, the importance of eosinophils in lung fibrosis was examined in IL-5 gene knockout mice (IL-5tm1Kopf). BLM treatment induced significant lung fibrosis in IL-5 knockout mice in the absence of eosinophilia. These findings indicate that eosinophils are not an absolute requirement for BLM-induced pulmonary fibrosis in the mouse.
Dynamics of rab5 activation in endocytosis and phagocytosis
Authors: Roberts R L , Barbieri M A , Ullrich J , Stahl P D 
Published: September 2022

Abstract
Fluid-phase endocytosis is stimulated by H-ras-linked growth factor receptors and this stimulation requires activation of rab5. We utilized a GFP-rab5a:wt fusion protein to monitor GFP-rab5a:wt activation in living fibroblasts and in J774 macrophages. Control CHO cells that expressed GFP-rab5a:wt were cultured in serum-free conditions and showed GFP-rab5a:wt localized to endosomal vesicles with a mean diameter of 0.3 ± 0.1 μm. Endosome fusion, membrane ruffling, and pinosome formation were rarely detected in these cells. Coexpression of H-ras:G12V, a constitutively active H-ras mutant that activates rab5a, in cells resulted in marked enlargement of labeled endosomes (mean diameter 0.7 ± 0.2 μm) and large numbers of giant GFP-rab5a:wt-positive endosomes were present. Time-lapse recordings showed abundant fusion among giant labeled endosomes, and membrane ruffling and pinosome formation were commonly observed. Alterations in GFP-rab5a:wt endosome structure and activity in cells expressing H-ras:G12V were linked to rab5a activation because these changes were identical to those found in cells expressing GFP-rab5a:Q79L, a constitutively activated rab5a mutant. Furthermore, cells co-expressing H-ras:G12V and GFP-rab5a:S34N, an inactive rab5a mutant, exhibited no evidence of H-ras:G12V-induced endosome enlargement. To observe changes in endosome structure and activity that directly followed activation of GFP-rab5a:wt, we performed time-lapse recordings of cells cultured overnight in serum-free media after addition of EGF. EGF caused a rapid increase in endosome fusion and in membrane ruffling activity. Membrane ruffling was often associated with GFP-rab5a:wt-positive vesicle (pinosome) formation at the base of membrane ruffles. Endosome and pinosome fusion were common in EGF-stimulated cells. Phagocytosis is also regulated by GFP-rab5a:wt. J774 macrophages that expressed GFP-rab5a:wt showed transiently activation and recruitment of GFP-rab5a:wt to newly formed phagosomes that contained rhodamine-labeled Escherichia coli. These studies show that GFP-rab5a:wt activation results in dynamic alterations in the structure and activity of the early endosomal and early phagosomal elements.
Losartan, a selective inhibitor of subtype AT1 receptors for angiotensin II, inhibits neutrophil recruitment in the lung triggered by fMLP
Authors: Raiden Silvina , Pereyra Yanina , Nahmod Víctor , Alvarez Clarisa , Castello Liliana , Giordano Mirta , Geffner Jorge 
Published: September 2022

Abstract
We have shown that losartan, a selective inhibitor of AT1 receptors for angiotensin II (AII), inhibits the binding of [3H]fMLP to neutrophil receptors (FPR). Here, we analyze, in Wistar rats, the effect of losartan on neutrophil recruitment in the lung triggered by fMLP. We found that i.v. infusion of losartan (0.4–20.0 μg/kg/min) inhibits neutrophil recruitment induced by i.t. instillation of fMLP, without affecting the responses induced by other stimuli, such as aggregated human IgG (aIgG), precipitating immune complexes (IC), or zymosan. Histological evaluation of lungs as well as the analysis of lung hemorrhage indices showed that losartan prevents tissue injury partially in fMLP-challenged rats. We also analyzed the effect of losartan on lung-neutrophil recruitment triggered by i.t. instillation of Pseudomonas aeruginosa. Not only was there a marked decrease in neutrophil recruitment but also a significant increase in the survival of rats instillated with Pseudomonas aeruginosa, as a consequence of losartan treatment. Our results support the notion that losartan may be useful in the treatment of certain lung inflammatory disorders associated with bacterial infectious diseases.
Homotypic cluster formation of dendritic cells, a close correlate of their state of maturation. Defects in the biobreeding diabetes-prone rat
Authors: Delemarre Frans G A , Hoogeveen Patricia G , de Haan-Meulman Meeny , Simons Peter J , Drexhage Hemmo A 
Published: September 2022

AbstractAggregation of dendritic cells (DCs) in homotypic clusters has been described in vivo in lymph and skin, and here we report studies on homotypic clustering of rat splenic (s) DCs in vitro. Wistar rat sDCs readily formed homotypic clusters in culture, which increased in number and size over time (with a peak att = 3 h). Keeping the cells at higher densities or treatment with anti-CD43 induced more and larger homotypic clusters. After such enhanced clustering the DCs had increased their T cell stimulating capabilities in syngeneic mixed lymphocyte reaction, and had a higher expression of CD80 and CD86 (signs of maturation). Ag transfer from bovine serum albumin-fluorescein isothiocyanate-pulsed to unpulsed DCs was observed during clustering. Here we also show that sDCs of the biobreeding diabetes-prone (BB-DP) rat, a model of autoimmune diabetes/thyroiditis, formed fewer and smaller clusters than Wistar sDCs, and that DC-DC clustering resulted in only a modest maturation of the cells (as determined in syn MLR and by phenotyping). Anti-CD43 completely restored the clustering defect BB-DP DCs in vitro, yet T cell-stimulating capability was only restored to a limited extent. Ag transfer in BB-DP DC clusters was similar.
Protein kinase C θ is expressed in mast cells and is functionally involved in Fcɛ receptor I signaling
Authors: Liu Yin , Graham Caroline , Parravicini Valentino , Brown Martin J , Rivera Juan , Shaw Stephen 
Published: September 2022

AbstractWe investigated possible expression and function in mast cells ofprotein kinase C (PKC) θ, a member of the PKC family withdemonstrated function in a limited range of cell types. We found thatPKC θ is expressed in bone marrow-derived mast cells and in the RBL-2H3 mast cell line. PKC θ underwent translocation to the membranein response to Fcɛ receptor I (FcɛR I) activation. Receptoractivation induced phosphorylation of PKC θ. The tyrosinephosphorylation of PKC θ is delayed relative to PKC δ and coincidestemporally with PKC θ association with c-src family members Lyn andSrc. Studies of RBL-2H3 cells transduced with PKC θ constructsindicated a role for PKC θ in receptor-induced activation ofextracellular regulated kinases, interleukin-3 gene transcription, anddegranulation in response to antigen stimulation. These studies extendthe known functions of PKCθ to another important immune cell type andindicate the concurrent participation of multiple PKCs in the FcɛRI-mediated response of mast cells.
Different Toll-like receptor agonists induce distinct macrophage responses
Authors: Jones Bryan W , Means Terry K , Heldwein Kurt A , Keen Marc A , Hill Preston J , Belisle John T , Fenton Matthew J 
Published: September 2022

AbstractWe previously reported that gram-negative bacterial lipopolysaccharide (LPS) activates cells via Toll-like receptor (TLR) 4, whereas the mycobacterial cell wall glycolipid lipoarabinomannan (LAM) activates cells via TLR2. We also identified a secreted TLR2 agonist activity in short-term culture filtrates of Mycobacterium tuberculosis bacilli, termed soluble tuberculosis factor (STF). Here we show that STF contains mannosylated phosphatidylinositol (PIM) and that purified PIM possesses TLR2 agonist activity. Stimulation of RAW 264.7 macrophages by LPS, LAM, STF, and PIM rapidly activated nuclear factor (NF)-κB, activator protein-1 (AP-1), and mitogen-activated protein (MAP) kinases. These TLR agonists induced similar levels of NF-κB and AP-1 DNA-binding activity, as well as trans-activation function. Unexpectedly, these TLR agonists induced tumor necrosis factor α secretion, whereas only LPS was capable of inducing interleukin-1β and nitric oxide secretion. Thus, different TLR proteins are still capable of activating distinct cellular responses, in spite of their shared capacities to activate NF-κB, AP-1, and MAP kinases.
Role of extracellular signal-regulated protein kinase cascade in macrophage killing ofCandida albicans
Authors: Ibata-Ombetta Stella , Jouault Thierry , Trinel Pierre-André , Poulain Daniel 
Published: September 2022

AbstractThe pathogenic yeast Candida albicans and its derivedmolecules stimulate a wide range of macrophage secretory functions andmay adapt to escape being killed by this phagocyte. In this study,phagocytosis of C. albicans and of the nonpathogenic yeastSaccharomyces cerevisiae was shown to be associated withphosphorylation of the mitogen-activated protein kinase(MAPK)/extracellularly regulated kinase (ERK) pathway in the absence ofsignificant activation of either p38MAPK or stress-activated proteinkinase/c-Jun N-terminal kinase. However, although 80% of endocytosedC. albicans survived after 1 h, 80% of S.cerevisiae cells were killed. Considerable quantitativedifferences were observed between the two species in the sequentialphosphorylation of MAPK/ERK kinase (MEK), extracellularly regulatedkinase-1, and 90-kDa-ribosomal S6 kinases. A lower level of activationof the pathway by C. albicans was associated with aspecies-specific overexpression of the MEK phosphatase MAPK phosphatase(MKP)-1. Killing of both C. albicans and S.cerevisiae could be reduced using PD98059, which mimics MKP-1 andinhibits MEK phosphorylation, suggesting that specific MKP-1 activationby C. albicans could contribute to its ability to escapethe yeast lytic potential of macrophages.
Induction of interleukin-8 in human neutrophils after MHC class II cross-linking with superantigens
Authors: Lei Li , Altstaedt Julia , von der Ohe Maren , Proft Thomas , Gross Ulrike , Rink Lothar 
Published: September 2022

AbstractNeutrophils have been shown to express major histocompatibility complex class II (MHC II) after stimulation. However, reports concerning the functional effect of MCH II expression are still lacking. In our hands, granulocyte-monocyte colony-stimulating factor (GM-CSF) alone and in combination with interferon (IFN)-γ, but not IFN-γ or interleukin (IL)-3, induced a significant level of expression of human leukocyte antigen DR on neutrophils. The addition of staphylococcal enterotoxin E to neutrophils resulted in a significant increase in IL-8 production only after prestimulation with GM-CSF alone or in combination with IFN-γ but had no effect on neutrophils preincubated with IFN-γ alone or IL-3. Staphylococcal enterotoxin A, another bivalent superantigen, also stimulated production of IL-8 by preincubated polymorphonuclear neutrophils, whereas staphylococcal enterotoxin A mutants that are not able to cross-link MHC II molecules failed to induce IL-8 production. Taken together, our results clearly demonstrate that after induction of MHC II, neutrophils are able to respond to MHC II-specific stimulation. These findings support the ideas that the induced MHC II complex is completely functional and that neutrophils may be able to present antigens.
MC148 encoded by human molluscum contagiosum poxvirus is an antagonist for human but not murine CCR8
Authors: Lüttichau Hans R , Gerstoft Jan , Schwartz Thue W 
Published: September 2022

AbstractThe viral CC chemokines MC148, encoded by the poxvirus molluscum contagiosum, and viral macrophage inflammatory protein (vMIP)-I and vMIP-II, encoded by human herpesvirus 8, were probed on the murine CC receptor (CCR) 8 in parallel with human CCR8. In calcium mobilization assays, vMIP-I acted as a high-affinity agonist, whereas vMIP-II acted as a low-affinity antagonist on the murine CCR8 as well as the human CCR8. MC148 was found to bind and block responses through the human CCR8 with high affinity, but surprisingly MC148 was unable to bind and block responses through the murine CCR8. Because MC148 is the only high-affinity antagonist known to target and be selective for CCR8, MC148 is a valuable tool to decipher the role played by CCR8 in the immune system. This study shows that MC148 could not be used in murine inflammatory models; however, it will be interesting to see whether it can be used in other animal models to delineate the role played by CCR8.
FcγR-mediated phagocytosis by human macrophages involves Hck, Syk, and Pyk2 and is augmented by GM-CSF
Authors: Kedzierska Katherine , Vardaxis Nicholas J , Jaworowski Anthony , Crowe Suzanne M 
Published: September 2022

AbstractThe receptors for the constant region of immunoglobulin G (FcγR) arewidely expressed on cells of hemopoietic lineage and plays an importantrole in host defense. We investigated the signaling pathways duringFcγR-mediated phagocytosis in human monocyte-derived macrophages(MDMs) and examined the effect of granulocyte-macrophagecolony-stimulating factor (GM-CSF) on these events. FcγR-mediatedphagocytosis resulted in enhanced tyrosine phosphorylation of a widerange of cellular proteins and activation of tyrosine kinases Hck, Syk,and Pyk2, as well as the multidomain adapter protein paxillin.Stimulation of MDMs with GM-CSF augmented FcγR-mediated phagocytosisand increased the levels of tyrosine phosphorylation in phagocytosingMDM cultures, indicating tyrosine kinase-mediated activation. GM-CSFtreatment of MDMs without a phagocytic stimulus did not activate Syk,suggesting that GM-CSF may act either distally to Syk in theFcγR-mediated signaling cascade or on a parallel pathway activated bythe FcγR. This study shows that early signaling events duringFcγR-mediated phagocytosis in human MDMs involve activation of Syk,Hck, and paxillin. It also provides the first evidence for Pyk2activation during phagocytosis and a baseline for further studies onthe effect of GM-CSF on FcγR-mediated phagocytosis.
A defect in HIV-1 transgenic murine macrophages results in deficient nitric oxide production
Authors: Dickie Peter , Roberts Amanda , Lee Raymond 
Published: September 2022

AbstractHIV transgenic mice bearing multiple copies of a noninfectious(Δgag/pol) proviral DNA were tested for the systemicproduction of nitric oxide (NO). Serum levels of NO metabolites werereduced about 50% in HIV transgenic mice compared with nontransgenicsibling mice. This difference persisted when NO production was inducedwith peritoneal injections of bacterial endotoxin (LPS). Peritonealinflammatory macrophages, but not resident peritoneal macrophages, derived from HIV-1 transgenic mice and activated in vitro with LPS andIFN-γ (or tumor necrosis factor α and IFN-γ) also produced about50% less NO than did macrophages harvested from nontransgeniclittermates. Isogenic, transgenic mice bearing mutated nefor vpr genes had normal serum levels of NO metabolites andtheir macrophages produced normal levels of NO when stimulated. Anexplanation for the reduced NO response of HIV[Vpr+Nef+] macrophageswas not apparent from measured levels of iNOS expression, viral geneexpression, or arginase activity in activated macrophages. Inhibitionof nitric oxide synthase (NOS) isoforms with l-NAME oraminoguanidine blocked time-dependent increases in HIV gene expressionin activated macrophages cultured ex vivo. Inhibition withl-NAME occurred despite high levels of NO generated byiNOS, and exogenously supplied NO induced HIV gene expression onlyweakly, suggesting that cNOS had the greater influence on proviral geneinduction. This system is presented as a model of HIV-1 proviral geneexpression and dysfunction in macrophages.
Role of Src kinases and Syk in Fcγ receptor-mediated phagocytosis and phagosome-lysosome fusion
Authors: Majeed Meytham , Caveggion Elena , Lowell Clifford A , Berton Giorgio 
Published: September 2022

AbstractPhagocytosis is increased by Fcγ receptors (FcγRs), and studies with syk−/− macrophages demonstrated that Syk kinase is required for FcγR phagocytosis. Similar studies with macrophages lacking the Src family kinases Hck, Fgr, and Lyn showed that these kinases are not required for phagocytosis but that they enhance the rate of particle engulfment. In this report we show that both wild-type and hck−/−fgr−/− macrophages expressed Fyn, Src, and Yes and that these kinases were activated on ingestion of immunoglobulin G (IgG)-coated particles and redistributed, together with Syk, to actin-rich phagocytic cups and the phagosomal membrane. At doses blocking IgG-dependent phagocytosis, the tyrosine kinase inhibitors PP1 and piceatannol inhibited both Src family kinase and Syk activities, as well as their redistribution to actin-rich phagocytic cups. Hck, Fgr, and Lyn were dispensable for lysosome-phagosome fusion (PLF) induced by IgG-coated particles. However, PP1 or piceatannol hampered unopsonized yeast-induced PLF despite the fact that they did not block yeast internalization.