bluuebunny/crossref_metadata_2025 huggingface dataset:
Retinoic acid up-regulates myeloid ICAM-3 expression and function in a cell-specific fashion—evidence for retinoid signaling pathways in the mast cell lineage
Authors: Babina Magda , Mammeri Kerstin , Henz Beate M
Published: September 2022

Investigation of mast cell responsiveness toward retinoic acid (RA) revealed selective promotion of ICAM-3 expression in the human mast cell line HMC-1. This process was dose- and time-dependent and detectable by flow cytometry, Western blot analysis, ELISA, and Northern blot analysis. ICAM-3 modulation was found to be cell-type dependent, detectable also for HL-60 cells and monocytes but not U-937 and only weakly for KU812 cells. Terminally differentiated skin mast cells also failed to up-modulate their ICAM-3, suggesting the requirement for some degree of immaturity for the process. RA-mediated effects on ICAM-1 expression, studied in parallel, were clearly distinct from those on ICAM-3. Investigation of retinoid receptor expression, known to mediate intracellular RA signaling, revealed presence of RARα, RARγ, RXRβ, and RXRγ transcripts in all cell lines studied, and HMC-1 cells were the only line lacking RXRα. RARβ, not expressed at baseline, was induced by RA in a fashion obviously correlating with ICAM-3 up-regulation. Increased ICAM-3 expression was of functional significance, such that processes stimulated or co-stimulated via ICAM-3 (homotypic aggregation, IL-8 secretion) were clearly enhanced upon RA pretreatment, suggesting that RA may contribute via hitherto unrecognized pathways to immune function and host defense.
Alternative versus classical macrophage activation during experimental African trypanosomosis
Authors: Namangala Boniface , De Baetselier Patrick , Noël Wim , Brys Lea , Beschin Alain
Published: September 2022

The type I/type II cytokine balance may influence the development of different subsets of suppressive macrophages, i.e., classically activated macrophages (caMφ, type I) versus alternatively activated macrophages (aaMφ, type II). Recently, we showed that although mice infected with phospholipase C-deficient (PLC−/−) Trypanosoma brucei brucei exhibit a clear shift from type I to the type II cytokine production, wild type (WT)-infected mice remain locked in a type I cytokine response. In the present study, phenotype and accessory cell function of macrophages elicited during WT and PLC−/−T. b. brucei infection were compared. Results indicate that caMφ develop in a type I cytokine environment in the early phase of WT and PLC−/− trypanosome infection, correlating with inhibition of T cell activation triggered by a mitogen, a superantigen, or an antigen. In the late stage of infection, only PLC−/−-infected mice resisting the infection develop type II cytokine-associated aaMφ correlating with impaired antigen- but not mitogen- or superantigen-induced T cell activation.
Inhibition of glucocorticoid-mediated, caspase-independent dendritic cell death by CD40 activation
Authors: Kim Kwang Dong , Choe Yong-Kyung , Choe In Seong , Lim Jong-Seok
Published: September 2022

Glucocorticoids (GC) are potent anti-inflammatory and immunosuppressive agents that act on a variety of immune cells, including T cells, monocytes/macrophages, osteoclasts, and dendritic cells (DC). However, the mechanism(s) by which GC exert anti-inflammatory effects is still largely unknown. It is already well known that GC treatment inhibits DC maturation and interleukin (IL)-12 production by DC. In this study, we investigated the apoptosis induction of DC by a synthetic GC, dexamethasone (Dex). The stimulation with Dex resulted in DC apoptosis in a dose- and time-dependent manner as it was measured by determining annexin V-positive cells and mitochondrial potential. In contrast, monocytes that are precursor cells of DC are resistant to Dex-mediated apoptosis. The Dex-induced apoptosis of DC was independent of caspase activation because it was not inhibited by the broad caspase inhibitor, Z-VAD-fmk. It is interesting that agonistic CD40 antibody completely inhibited Dex-induced cell death, whereas other inflammatory stimuli did not show the same effect, suggesting that CD40 signaling may selectively modulate GC-mediated DC apoptosis. Taken together, our findings revealed an important role of GC and CD40 signaling in the regulation of immune responses in which DC play a key role in the inflammatory process of various immunomediated diseases.
Lymphocytes induce monocyte chemoattractant protein-1 production by renal cells after Fcγ receptor cross-linking: role of IL-1β
Authors: Rovin Brad H , Lu Ling , Marsh Clay B
Published: September 2022

Leukocyte recruitment to the kidney in immune complex disease like systemic lupus erythematosus (SLE) is mediated in part by local expression of chemokines such as monocyte chemoattractant protein-1 (MCP-1). Recent studies from this laboratory demonstrated that cross-linking FcγR on lymphocytes causes release of a soluble factor that induces monocyte chemokine production. To explain the induction of renal chemokine expression in immune complex disease, we postulated that this lymphocyte factor stimulates renal parenchymal cell MCP-1 expression. To test this hypothesis, human peripheral blood lymphocytes were incubated on immobilized IgG, a model for immune complex FcγR cross-linking. Supernatants from these lymphocyte cultures significantly increased MCP-1 production by human mesangial, glomerular capillary endothelial, and proximal tubular epithelial cells. Mesangial cells incubated on immobilized IgG or with soluble, preformed immune complexes did not secrete MCP-1 above control levels. Lymphocyte supernatant-induced MCP-1 production appeared to be dependent on the presence of interleukin (IL)-1β in the supernatant. Removing IL-1β from the supernatants, antagonizing its activity, or preventing conversion to mature IL-1β abrogated renal cell MCP-1 expression by the lymphocyte supernatants. These data demonstrate that in response to cross-linking FcγR, lymphocytes induce renal cell MCP-1 expression by secreting IL-1β. Renal chemokine expression in immune complex disease may thus be triggered as lymphocytes traffic through the kidney and encounter deposited immune complexes.
Divergent effects of tumor necrosis factor α on apoptosis of human neutrophils
Authors: van den Berg J Merlijn , Weyer Sebastiaan , Weening Jan J , Roos Dirk , Kuijpers Taco W
Published: September 2022

Apoptosis of neutrophils is a key mechanism to control the intensity of the acute inflammatory response. Previously, the cytokine tumor necrosis factor α (TNF-α) was reported by some to have pro-apoptotic and by others to have anti-apoptotic effects on neutrophils. The aim of this study was to explain these contradictory results. We found that TNF-α at low concentrations strongly decreased apoptosis of neutrophils. However, at higher concentrations, TNF-α lost its protective effects, and also reversed the protective effects of interferon-γ (IFN-γ) and granulocyte-macrophage colony-stimulating factor (GM-CSF). This pro-apoptotic effect of TNF-α was blocked by anti-CD11b and was absent in neutrophils from patients with chronic granulomatous disease, which cannot produce toxic oxygen metabolites. Under these circumstances, we found that TNF-α retained its anti-apoptotic effects even at high concentrations. In conclusion, the protective effects against apoptosis of IFN-γ, GM-CSF, and TNF-α itself are overruled when the concentration of TNF-α is high enough to produce a respiratory burst. These dual, concentration-dependent effects of TNF-α provide an explanation for previous controversial reports and support a dominant role for TNF-α in neutrophil apoptosis.
Caspase-mediated cleavage of TRAF3 in FasL-stimulated Jurkat-T cells
Authors: Lee Zang Hee , Lee Shee Eun , Kwack KyuBum , Yeo Whanho , Lee Tae Ho , Bae Sun Sik , Suh Pann-Ghill , Kim Hong-Hee
Published: September 2022

The tumor necrosis factor receptor (TNFR)-associated factor (TRAF) proteins play a central role in the early steps of signal transduction by TNFR superfamily proteins, which induce various cellular responses, including apoptosis. Influences of TRAF proteins on the regulation of cell death and physical interactions between TRAFs and caspases have been reported. In this study, we demonstrate that TRAF3 is proteolyzed during cell death in a caspase-dependent manner. TRAF3 was found to be cleaved by incubation with caspase3 in vitro and by Fas- or CD3-triggering in Jurkat-T cells. The Fas- or CD3-induced cleavage of TRAF3 was blocked by caspase inhibitors and by introduction of alanine substitutions for D347 and D367 residues. Furthermore, the amino-terminal fragment of TRAF3 showed a different intracellular localization from the full-length TRAF3 with preferential distribution to particulate fractions and the nucleus. These findings suggest that TRAF3 may be regulated by caspases during apoptosis of T cells.
CD38 expression and functional activities are up-regulated by IFN-γ on human monocytes and monocytic cell lines
Authors: Musso Tiziana , Deaglio Silvia , Franco Luisa , Calosso Liliana , Badolato Raffaele , Garbarino Giovanni , Dianzani Umberto , Malavasi Fabio
Published: September 2022

Human CD38, a surface molecule expressed by immature and activated T and B lymphocytes, has been characterized as a molecule transducing activation and proliferation signals, and intervening in adhesion to endothelium via its ligand CD31. CD38 is also a complex ectoenzyme featuring ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase activities, leading to the synthesis and degradation of cADPR, a Ca+-mobilizing agent. We investigated the effects of monocyte-activating stimuli (IFN-γ, IL-2, LPS, TNF-α, and GM-CSF) on the expression and function of CD38, starting from the observation that human monocytes and the derived lines U937, THP-1, and Mono-Mac-6 bear the molecule on their surface. Our results indicate that IFN-γ is a strong up-modulator of CD38, and IL-2 increases its expression only modestly. LPS, TNF-α, and GM-CSF had no detectable effects. Treatment with IFN-γ produced a dose- and time-dependent up-regulation of CD38 in monocytes and monocytic lines, which was paralleled by increased ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase activities. Furthermore, CD38 ligation by specific MoAb reduced the IFN-γ-dependent enhancement of monocyte-dynamic adhesion to endothelial monolayers. These findings identify IFN-γ as a modulator of monocytic CD38 expression and indicate that CD38 plays a specific role in the activation and adhesion processes performed by monocytes.
Differential effects of 15-deoxy-Δ12,14-prostaglandin J2 and a peroxisome proliferator-activated receptor γ agonist on macrophage activation
Authors: Guyton Kelly , Bond Robert , Reilly Chris , Gilkeson Gary , Halushka Perry , Cook James
Published: September 2022

Prostaglandin J2 metabolite15-deoxy-Δ12,14-prostaglandin J2(15-PGJ2) appears to possess anti-inflammatory properties.Unlike other prostaglandins, it has no known plasma membrane receptor.Its effects have been thought to occur through activation of thenuclear peroxisome proliferator-activated receptor γ (PPARγ), but15-PGJ2 may exhibit effects independent of PPARγ. Wehypothesized that 15-PGJ2 modulates macrophage (Mφ)mediator production by acting on cell signaling proteins upstream ofPPARγ. The effects of 15-PGJ2 on bacterial endotoxinLPS-induced rat peritoneal Mφ mediator production were compared withthose of a specific PPARγ agonist, BRL 49653 (BRL), and to theeicosanoids prostaglandin D2 (PGD2) andcicaprost (CICA, a prostacyclin analogue). 15-PGJ2inhibited LPS-induced production of NO, TNF-α, and thromboxaneB2 (TxB2). Equimolar concentrations ofPGD2 and CICA significantly inhibited LPS-stimulatedTNF-α but not NO, and CICA increased TxB2 production. BRLinhibited LPS-induced NO, but augmented LPS-induced TNF-α andTxB2. 15-PGJ2 also inhibited degradation ofLPS-induced IκBα and phosphoactivation of ERK 1/2, but BRL had nosignificant effect on either protein. The cyclopentenone ring2-cyclopenten-1-one also inhibited LPS-induced ERK 1/2 activation;however, neither 15-PGJ2 nor the cyclopentenone inhibitedPMA-induced ERK 1/2 activation. Inhibition of LPS-stimulated mediatorproduction by 15-PGJ2 differed from inhibition byPGD2, CICA, and BRL. The ability of 15-PGJ2 toinhibit LPS-induced Mφ mediator production and cell signaling mayoccur in part through reactivity of its cyclopentenone ring.
Regulation ofl-selectin expression by a dominant negative Ikaros protein
Authors: Christopherson Indu , Piechoki Marie , Liu Guo , Ratner Stuart , Galy Anne
Published: September 2022

Ikaros family members play critical roles in hematopoietic development, yet molecules regulated by Ikaros proteins remain incompletely characterized. To determine the requirements for functional Ikaros proteins, we overexpressed Ik7, a dominant negative Ikaros protein, in human cell lines and hematopoietic progenitor cells. Ik7 is known to block the normal function of other Ikaros family members in human and mouse cells. Retroviral-mediated overexpression of Ik7 affected two distinct, migratory properties of the CEM T-cell line. Ik7 down-regulated l-selectin cell-surface expression, an effect not a result of increased shedding but of a decrease in l-selectin mRNA levels. Ik7 also reduced the spontaneous migration of CEM T cells in 3-D collagen gels. A reduction in l-selectin, cell-surface expression was also induced by Ik7 in CD34+ hematopoietic progenitor cells. In contrast, the Reh B cell line showed an up-regulation of l-selectin, cell-surface levels when expressing Ik7. For the first time, this study defines an effect of Ikaros proteins in the control of migration-related properties and shows that intact Ikaros proteins are important in a cell type-specific manner for the normal regulation of l-selectin expression.
Phenotypic and functional change of cytokine-activated neutrophils: inflammatory neutrophils are heterogeneous and enhance adaptive immune responses
Authors: Yamashiro Shigeo , Kamohara Hidenobu , Wang Ji-Ming , Yang De , Gong Wang-Hua , Yoshimura Teizo
Published: September 2022

Polymorphonuclear leukocytes (PMN) are the most abundant leukocytes, comprising about two-thirds of peripheral blood leukocytes, and play major roles in innate immunity. In addition, PMN play critical roles in the development of adaptive immunity. Recently, defensins and other peptides pre-stored in PMN granules were shown to attract monocytes, dendritic cells, and T cells, leading to the hypothesis that the release of PMN granular peptides may link innate and adaptive immunity. During the past several years, we have focused on an alternative hypothesis that activated PMN further differentiate and acquire new phenotypes and functions that enable them to link the two responses. To test our hypothesis, we have taken local and global approaches and have shown several key findings that support the hypothesis. The findings include the requirement for priming PMN by cytokines to induce the delayed expression of MCP-1/CCL2, a signal for mononuclear cells, and the expression of new cell-surface markers by such cytokine-activated PMN. In the present manuscript, we focus on the phenotypic and functional changes that occur during PMN activation with selected cytokines. The results of our study indicate that inflammatory PMN are heterogeneous and play roles in not only innate but also adaptive immunity in response to stimuli released in injured tissues.
Phosphatidylinositol 3-kinase inhibitors prevent mouse cytotoxic T-cell development in vitro
Authors: Phu Tommy , Haeryfar S M Mansour , Musgrave Bruce L , Hoskin David W
Published: September 2022

To become competent killer cells, CD8+ T cells requirestimulation through signal transduction pathways associated with the T-cell receptor, costimulatory molecules such as CD28, and cytokinereceptors such as the interleukin (IL)-2 receptor. We used wortmanninand LY294002, two inhibitors of phosphatidylinositol 3-kinase (PI3-K), to study the role of PI3-K in mouse cytotoxic T-lymphocyte (CTL)induction in response to mitogenic anti-CD3 antibody. Anti-CD3-inducedCD8+ T-cell proliferation and CTL development wereinhibited dose dependently by both PI3-K inhibitors. IL-2 synthesis byanti-CD3-activated CD8+ T cells was also diminished byPI3-K inhibition. PI3-K inhibition resulted in a modest decrease inanti-CD3-induced CD4+ T-cell proliferation but failed toaffect IL-2 expression by anti-CD3-activated CD4+ T cells. PI3-K inhibition during CTL induction resulted in decreased levels ofmRNAs coding for granzyme B, perforin, and Fas ligand. In addition, CTLinduced in the presence of PI3-K inhibitors failed to conjugatenormally with P815 target cells. Exogenous IL-2 did not reverse theeffects of PI3-K inhibition on CD8+ T-cell proliferationand CTL induction. These results support the conclusion that PI3-Kactivation is involved in T-cell receptor, CD28, and IL-2 receptorsignaling of CD8+ T cells. PI3-K is, therefore, animportant component of multiple signal transduction pathways involvedin CTL generation.
Mechanisms of neutrophil apoptosis in uremia and relevance of the Fas (APO-1, CD95)/Fas ligand system
Authors: Jaber Bertrand L , Perianayagam Mary C , Balakrishnan V S , King Andrew J , Pereira Brian J G
Published: September 2022

The regulation of neutrophil apoptosis in chronic renal failure (CRF) has not been clearly defined. The Fas/FasL system is an important apoptotic regulatory pathway in a wide variety of cells. Fas is a widely expressed cell surface protein that transduces an apoptotic signal after interaction with its natural ligand FasL. In contrast to the extensive tissue distribution of Fas, constitutive expression of FasL is relatively limited. We examined Fas and FasL expression by neutrophils in healthy subjects, patients with CRF, and patients on hemodialysis (HD) and peritoneal dialysis (PD). Fas expression was significantly higher among patients with CRF compared with control subjects, HD patients, and PD patients. FasL expression was significantly higher among patients with CRF compared with control subjects. At 24 h, neutrophil apoptosis was higher among patients with CRF compared with control subjects. Furthermore, high-neutrophil Fas expression was paralleled by a higher sensitivity to Fas-mediated apoptosis. There was a strong correlation between Fas-stimulated apoptosis and creatinine clearance as well as Fas expression. Finally, we found that uremic serum increased the expression of neutrophil-associated Fas and FasL proteins, when compared with normal serum. Further studies are under way to examine the regulation of this pathway in the uremic environment.
Signaling networks regulating β1 integrin-mediated adhesion of T lymphocytes to extracellular matrix
Authors: Woods Melody L , Shimizu Yoji
Published: September 2022

T-cell recognition of foreign antigen and migration to specificanatomic sites in vivo involves transient adhesive contacts betweenβ1 integrins expressed on T cells and cell surface proteins orextracellular-matrix components. Engagement of the CD3-T-cell receptor(CD3-TCR) complex initiates a complex signaling cascade involvingcoordinated regulation and recruitment of tyrosine and lipid kinases tospecific regions or microdomains in the plasma membrane. Althoughconsiderable attention has been focused on the signaling events bywhich the CD3-TCR complex regulates transcriptional events in thenucleus, CD3-TCR signaling also rapidly enhances integrin-mediatedadhesion without increasing surface expression of integrins. Recentstudies suggest that CD3-TCR signaling to β1 integrins involvescoordinated recruitment and activation of the Tec family tyrosinekinase Itk by src family tyrosine kinases and phosphatidylinositol3-kinase. These signaling events that regulate integrin-mediated T-celladhesion share both common and distinct features with the signalingpathways regulating interleukin-2 gene transcription.
Neutrophil recruitment, chemokine receptors, and resistance to mucosal infection
Authors: Godaly G , Bergsten G , Hang L , Fischer H , Frendéus B , Lundstedt A-C , Samuelsson M , Samuelsson P , Svanborg Catharina
Published: September 2022

Neutrophil migration to infected mucosal sites involves a series of complex interactions with molecules in the lamina propria and at the epithelial barrier. Much attention has focussed on the vascular compartment and endothelial cells, but less is known about the molecular determinants of neutrophil behavior in the periphery. We have studied urinary tract infections (UTIs) to determine the events that initiate neutrophil recruitment and interactions of the recruited neutrophils with the mucosal barrier. Bacteria activate a chemokine response in uroepithelial cells, and the chemokine repertoire depends on the bacterial virulence factors and on the specific signaling pathways that they activate. In addition, epithelial chemokine receptor expression is enhanced. Interleukin (IL)-8 and CXCR1 direct neutrophil migration across the epithelial barrier into the lumen. Indeed, mIL-8Rh knockout mice showed impaired transepithelial neutrophil migration, with tissue accumulation of neutrophils, and these mice developed renal scarring. They had a defective antibacterial defense and developed acute pyelonephritis with bacteremia. Low CXCR1 expression was also detected in children with acute pyelonephritis. These results demonstrate that chemokines and chemokine receptors are essential to orchestrate a functional antimicrobial defense of the urinary tract mucosa. Mutational inactivation of the IL-8R caused both acute disease and chronic tissue damage.
A chimeric MIP-1α/RANTES protein demonstrates the use of different regions of the RANTES protein to bind and activate its receptors
Authors: Blanpain Cédric , Buser Raphaële , Power Christine A , Edgerton Michael , Buchanan Catherine , Mack Matthias , Simmons Graham , Clapham Paul R , Parmentier Marc , Proudfoot Amanda E I
Published: September 2022

Human RANTES (CCL5) and MIP-1α (CCL3) bind and activate several CC chemokine receptors. RANTES is a high-affinity ligand for CCR1 and CCR5, and it binds CCR3 with moderate affinity and CCR4 with low affinity. MIP-1α has similar binding characteristics to RANTES except that it does not bind to CCR3. Here we have generated a chimera of human MIP-1α and RANTES, called MIP/RANTES, consisting of the eight amino terminal residues of MIP-1α preceding the CC motif, and the remainder of the sequence is RANTES. The chimera is able to induce chemotaxis of human monocytes. MIP/RANTES has >100-fold reduction in binding to CCR1 and does not bind to CCR3 but retains full, functional binding to CCR5. It has equivalent affinity for CCR5 to MIP-1α and RANTES, binding with an IC50 of 1.12 nM, and is able to mobilize calcium and induce endocytosis of CCR5 in PBMC in a manner equi-potent to RANTES. It also retains the ability to inhibit R5 using HIV-1 strains. Therefore, we conclude that the amino terminus of RANTES is not involved in CCR5 binding, but it is essential for CCR1 and CCR3.
Potentiation of interferon-γ-stimulated nitric oxide production by retinoic acid in RAW 264.7 cells
Authors: Austenaa Liv M I , Ross A Catharine
Published: September 2022

Nitric oxide (NO) production is essential for normal immunity. We have examined the capacity of retinoic acid (RA), a pleiotropic hormone necessary for normal immunity, to modulate NO production in RAW 264.7 cells. NO production induced by suboptimal concentrations of interferon-γ (IFN-γ) was significantly greater in cells cultured in low-retinoid medium and treated with all-trans-RA (10−10– 10−6 M, P <0.05), as well as with 9-cis-RA and several retinoids selective for the RA receptor subfamily of nuclear retinoid receptors. Similar results were obtained with lipopolysaccharide and monophosphoryl lipid A as stimuli. The RA-potentiated production of NO was positively correlated with inducible NO synthase (iNOS) protein (r =0.94, P <0.002), although the expression of iNOS mRNA was not altered. We hypothesize that modulation of the macrophage response to suboptimal immune stimuli by physiological concentrations of RA, as observed in these studies, may be important in establishing an optimal balance between T helper (Th) 1- and Th2-mediated immunity.
Mechanism of extracellular release of human neutrophil calprotectin complex
Authors: Voganatsi Alexandra , Panyutich Alexander , Miyasaki Kenneth T , Murthy Rekha K
Published: September 2022

Calprotectin is an abundant cytosolic protein complex of humanneutrophils with in vitro extracellular antimicrobial activity. Studiessuggest that calprotectin may be actively secreted from intact HL-60cells and that it can be translocated to polymorphonuclear neutrophil(PMN) cell membranes. To examine whether calprotectin is secretedextracellularly, we incubated soluble and particulate stimuli,including live and heat-inactivated Candida albicans, withwhole blood and measured calprotectin levels in the plasma. We comparedthe release of calprotectin to that of lactoferrin, a protein known tobe secreted by PMNs. Extracellular lactoferrin was detected afterincubation with any of the particulate stimuli. In contrast, asignificant increase in extracellular calprotectin was found only afterincubation with live C. albicans. Specifically, theincrease in extracellular calprotectin correlated directly with aproportional decrease in PMN viability. Our results indicate that humanPMN calprotectin is not secreted extracellularly except as a result ofcell disruption or death.
Effects of macrophage-CSF on pulmonary-macrophage repopulation after bone marrow transplantation
Authors: Bernier Tanja , Tschernig Thomas , Pabst Reinhard , Macke Olaf , Steinmueller Christiane , Emmendörffer Andreas
Published: September 2022

Pulmonary infections are important causes of morbidity and mortality in immunosuppressed patients after transplantation. After experimental irradiation and syngeneic bone marrow transplantation in mice, macrophages show reduced repopulation in the lung compared with that in other tissues. Macrophages are major microbicidal immune effector cells in host pulmonary defense. Therefore, we examined the role of locally applied cytokines for macrophage repopulation in the lung. An accelerated repopulation of macrophages in the lung was observed after intranasal application of macrophage-colony stimulating factor (M-CSF), but this effect was not enhanced by a combination of M-CSF with interleukin (IL)-3. Local proliferation contributed to this effect. Macrophages in the lung tissue of M-CSF-treated mice displayed greater secretion of IL-6, whereas M-CSF treatment did not enhance the gene expression of other macrophage-specific chemokines. The role of M-CSF treatment was determined in pulmonary murine cytomegalovirus infection using an irradiation/reconstitution model. The M-CSF treatment had no effect on virus load in the lung tissue. However, phosphate-buffered saline-treated mice seemed to develop stronger inflammation after viral infection than M-CSF-treated mice. We conclude that local M-CSF treatment modulates cellular inflammation in the lung during immunosuppression.
Reactive oxygen species mediate angiotensin II-induced leukocyte-endothelial cell interactionsin vivo
Authors: Alvarez Angeles , Sanz Maria-Jesus
Published: September 2022

Chronically elevated angiotensin II (Ang-II)-induced hypertension is partly mediated by superoxide production. In this study, we have investigated whether the leukocyte-endothelial cell interactions elicited by Ang-II involve reactive oxygen species (ROS) generation. Intravital microscopy within the rat mesenteric microvessels was used. Superfusion (60 min) with Ang-II (1 nM) induced significant increases in leukocyte rolling flux, adhesion, and emigration, which were inhibited by pretreatment with superoxide dismutase or catalase. Dihydrorhodamine-123 oxidation indicated that ROS are primarily produced by the vessel wall. Administration of dimethylthiourea, desferrioxamine, or N-acetylcisteine provoked significant reductions in Ang-II-induced leukocyte-endothelial cell interactions. In addition, a blockade of platelet-activating factor or leukotrienes also attenuated such responses significantly. The results presented indicate that in vivo Ang-II-induced leukocyte recruitment is dependent on the generation of intra- and extracellular ROS. Therefore, the use of anti-oxidants might constitute an alternative therapy for the control of the subendothelial leukocyte infiltration associated with hypertension and atherosclerosis.
Growth factor regulation of neutrophil-endothelial cell interactions
Authors: Zhang Hong , Issekutz Andrew C
Published: September 2022

The effects of the angiogenic factors basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) on human polymorphonuclear leukocyte (PMNL)-endothelial cell adhesion and transendothelial migration (TEM) were investigated. Stimulation of human umbilical vein endothelial cells by VEGF or bFGF for 18 h up-regulated intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 expression and significantly increased PMNL adhesion and TEM in response to complement fragment 5a (C5a) or interleukin (IL)-8. In contrast, continued exposure to bFGF (24 h–6 days) down-regulated basal and IL-1- or tumor necrosis factor (TNF)-induced intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin expression as well as PMNL adhesion and TEM. These effects could be reversed by introduction of high concentrations of TNF-α, C5a, or IL-8. None of these inhibitory effects was observed with VEGF. The acute effects of bFGF and VEGF may facilitate PMNL emigration during acute inflammation, but continued bFGF production may have anti-inflammatory actions during chronic inflammation, angiogenesis, and tumor defense by inhibition of endothelial activation for leukocyte recruitment.
Early effects of insulin-like growth factor-1 in activated human T lymphocytes
Authors: Brocardo Mariana G , Schillaci Roxana , Galeano Adriana , Radrizzani Martín , White Verónica , Guerrico Anatilde González , Santa-Coloma Tomás A , Roldán Alicia
Published: September 2022

This study evaluates the effects of insulin-like growth factor (IGF)-1 receptor (IGF-1R) down-regulation in stimulated T lymphocytes by investigating the expression of early activation proteins CD69, CD25, and interleukin (IL)-2. We found that IGF-1 does not modify CD69 expression but increases transcription and protein synthesis of CD25 and IL-2. The lowest level of IGF-1R detected after 15 min of activation suggested that the effects of IGF-1 occur at the initiation of cell activation. The activation of IGF-1R was confirmed by IGF-1R phosphorylation and increased phosphorylation of microtubule-associated protein kinase. We also detected the alternative IGF-1 transcripts Ea, with paracrine/autocrine regulation, and Eb, with endocrine regulation, in Jurkat cells and in quiescent T lymphocytes, and we detected IGF-1 protein in the culture medium after stimulation. These data suggest that the proliferative effects of IGF-1 on T lymphocytes include both autocrine/paracrine and endocrine processes.
Negative regulation of cytokine signaling
Authors: Greenhalgh Christopher J , Hilton Douglas J
Published: September 2022

Cytokines use complex signaling cascades to elicit their biological effects, many of which involve phosphorylation as a mechanism of activation. Rapid and efficient attenuation of cytokine signals is crucial to maintaining regulation of these processes and to preventing toxic side effects. Phosphatases have been shown to be involved in these regulatory processes, but more recent research has seen the discovery of two new families of negative regulators, the suppressor of cytokine signaling (SOCS) and protein inhibitors of signal transducer and activator of transcription (STAT) (PIAS) protein families. SOCS proteins are induced by and inhibit many cytokine-signaling systems in a classic negative-feedback loop, and the generation of transgenic and knockout models has greatly increased our understanding of their physiological functions. PIAS proteins interact with the transcriptional mediators of cytokine action, the STATs, to suppress their DNA-binding activity. These three classes of molecules form what is now emerging as an integrated system for deactivating cytokine signaling at a number of levels, from the receptor to the transcription factor.
Regulation of interleukin-8 gene expression after phagocytosis of zymosan by human monocytic cells
Authors: Friedland Jon S , Constantin Despina , Shaw Terry C , Stylianou Eleni
Published: September 2022

Monocyte phagocytosis of pathogens or inflammatory debris leads to chemokine secretion and heralds the influx of leukocytes to the site of injury. Persistent chemokine secretion can lead to tissue damage. However, the mechanisms by which phagocytosis regulates chemokine synthesis remain poorly understood. As a first step, we have studied regulation of interleukin (IL) 8 gene expression after interaction with zymosan or latex. IL-8 secretion was consistently one- or twofold higher after incubation with zymosan than with latex. Nuclear factor (NF) κB translocation to the nucleus was induced by zymosan but not latex, indicating that its translocation is dependent on the nature of the phagocytic stimulus. NFκB activation coincided with IκBα degradation but had no effect on processing of NFκB1/p105, the precursor of the NFκB protein p50. The NFκB inhibitor gliotoxin abrogated zymosan-induced IL-8 synthesis in peripheral blood monocytes, further demonstrating that the induction of IL-8 mRNA by zymosan is NFκB dependent. SB203580 inhibition of the p38 mitogen-activated protein kinase (MAPK) pathway significantly decreased zymosan-induced IL-8 mRNA accumulation. Inhibitors of protein kinases A and C or tyrosine kinases had no significant effect on zymosan-induced IL-8 synthesis. These data indicate that p38 MAPK and NFκB are critical in controlling zymosan-induced IL-8 secretion.
Morphine modulates lymph node-derived T lymphocyte function: role of caspase-3, -8, and nitric oxide
Authors: Wang Jinghua , Charboneau Richard , Balasubramanian Sudha , Barke Roderick A , Loh Horace H , Roy Sabita
Published: September 2022

The major objective of this paper is to characterize the mechanism by which morphine modulates lymphocyte function and if these effects are mediated through the μ-opioid receptor. We evaluated the in vitro effects of morphine on lymphocytes that were freshly isolated from lymph nodes from wild type (WT) and μ-opioid receptor knock-out (MORKO) mice. Results show that morphine inhibits Con A-induced lymph node T-cell proliferation and IL-2 and IFN-γ synthesis in a dose-dependent manner. This effect was abolished in lymph node cells isolated from MORKO mice. The inhibition of T-cell function with low-dose morphine was associated with an increase in caspase-3- and caspase-8-mediated apoptosis. The inhibition of T-cell function with high-dose morphine was associated with an increase in the inducible NO synthase mRNA expression. NG-nitro-L-arginine methyl ester (l-NAME) antagonized the apoptosis induced by high-dose morphine. Our results suggest that low-dose morphine, through the μ-opioid receptor, can induce lymph node lymphocyte apoptosis through the cleavage activity of caspase-3 and caspase-8. Morphine at high doses induces NO release. This effect of morphine is also mediated through the μ-opioid receptor present on the surface of macrophages.
Inhibition of antibody-dependent stimulation of lipoteichoic acid-treated human monocytes and macrophages by polyglycerolphosphate-reactive peptides
Authors: Gargir Ari , Ofek Itzhak , Hasty David , Meron-Sudai Shiri , Tsubery Hayim , Keisari Yona , Nissim Ahuva
Published: September 2022

By itself, lipoteichoic acid (LTA) obtained from S. pyogenes, S. aureus, or E. hirae poorly stimulated cytokine production by macrophages, whereas in the presence of anti-polyglycerol phosphate (PGP), the cells secreted significant amounts of IL-6. Two peptides constructed from the deduced sequence of the selected anti-PGP phage-antibody's complementary-determining region 3 of the variable heavy chain (VH-CDR3) reacted specifically with PGP. The monomeric form of the peptides markedly inhibited cytokine production by macrophages pretreated with LTA and anti-LTA. In contrast, the polyvalent form of biotinylated peptides complex with streptavidin-induced cytokine production by the LTA-treated macrophages. The data taken together support the concept that cross-linking of macrophage-bound LTA by anti-PGP is required for cytokine release by these cells. Importantly, these studies identified small, PGP-reactive peptides as potential tools in reducing this proinflammatory process.
CCL18/DC-CK-1/PARC up-regulation in hypersensitivity pneumonitis
Authors: Pardo Annie , Smith Kathleen M , Abrams John , Coffman Robert , Bustos Martha , McClanahan Terrill K , Grein Jeffrey , Murphy Erin E , Zlotnik Albert , Selman Moisés
Published: September 2022

Hypersensitivity pneumonitis (HP) is a lung inflammatory disorder characterized by accumulation of T lymphocytes. However, the mechanisms implicated in this process remain undefined. We examined the expression of dendritic cell (DC)-derived CC chemokine 1 (CK1)/CCL18, a chemokine putatively involved in naive T cell recruitment, in lungs from 10 patients with HP, 9 patients with idiopathic pulmonary fibrosis (IPF), and 20 healthy lungs. CCL18 was measured by real-time quantitative PCR and localized in lungs by in situ hybridization and immunohistochemistry. CCL18 expression was significantly increased in lungs affected by HP in comparison with lungs affected by IPF (2,085±393 vs. 1,023±110; P<0.05) and controls (2,085±393 vs. 467±94; P<0.01). Macrophages, DCs, and alveolar epithelial cells were the main sources of CCL18. There was a direct correlation between the levels of tissue CCL18 and the number of lymphocytes in the bronchoalveolar lavage fluids. High levels of CCL18 were detected in the subacute rather than the chronic phase of HP. These findings suggest a role for CCL18 in the pathogenesis of HP.
CD antigens 2001
Authors: Mason David , André Pascale , Bensussan Armand , Buckley Chris , Civin Curt , Clark Edward , de Haas Masja , Goyert Sanna , Hadam Martin , Hart Derek , Horejší Václav , Meuer Stefan , Morrissey James , Schwartz-Albiez Reinhard , Shaw Stephen , Simmons David , Uguccioni Mariagrazia , van der Schoot Ellen , Vivier Eric , Zola Heddy
Published: September 2022

This paper reviews the Seventh Human Leucocyte Differentiation Antigen (HLDA7) workshop. Due to the limitations of “blind” antibody screening, which had been evident at the previous meeting in 1996, participants at HLDA7 adopted a more selective approach to the choice of antibodies by identifying new CD specificities. This resulted in the addition of more than 80 new CD specificities. Plans for the eighth and subsequent workshops are also previewed.
Involvement of caspases and of mitochondria in Fas ligation-induced eosinophil apoptosis: modulation by interleukin-5 and interferon-γ
Authors: Létuvé Séverine , Druilhe Anne , Grandsaigne Martine , Aubier Michel , Pretolani Marina
Published: September 2022

In this study, we examined the relative importance of caspases and mitochondria in Fas-mediated eosinophil apoptosis. Stimulation of human peripheral blood eosinophils with an agonistic anti-human Fas monoclonal antibody, but not with control IgM, induced a time-dependent increase in their apoptosis, which was associated with a loss in mitochondrial transmembrane potential (ΔΨm) and with caspase-8 and caspase-3 activation. Interleukin (IL)-5 and interferon (IFN)-γ, two cytokines known to prolong eosinophil survival, inhibited Fas-mediated apoptosis and caspase activation but poorly affected the decrease in ΔΨm. Eosinophil incubation with bongkrekic acid, an inhibitor of the mitochondrial permeability transition pore (MPTP) opening, failed to modify Fas-mediated loss in ΔΨm, caspase activation, and apoptosis. In contrast, caspase inhibitors markedly reduced eosinophil apoptosis without significantly affecting ΔΨm dissipation. We conclude that caspase-8 and caspase-3 activation, but not MPTP opening, mediate Fas-induced eosinophil apoptosis and are the main targets for the protective effect of IL-5 and IFN-γ.
Intercellular cell adhesion molecule-1 regulates lymphocyte movement into intestinal microlymphatics of rat Peyer's patches
Authors: Hokari Ryota , Miura Soichiro , Nagata Hiroshi , Fujimori Hitoshi , Koseki Seiichiro , Kato Shingo , Kurose Iwao , Sekizuka Eiichi , Granger D Neil , Ishii Hiromasa
Published: September 2022

The objective of this study was to determine whether specific adhesion molecules modulate lymphocyte movement from Peyer's patches into intestinal microlymphatics. The fluorochrome acridine orange was injected via a micropipette into Peyer's patches to fill lymphatics. The flux of labeled lymphocytes into intestinal microlymphatics was monitored with intravital fluorescence microscopy. The lymphatic microvessels in the perifollicular area of Peyer's patches were filled with lymphocytes, most of which remained within the lymphatics. Some lymphocytes became detached and were drained into intestinal lymph. Administration of antibodies directed against ICAM-1 significantly increased lymphocyte flux into interfollicular lymphatics. The immunohistochemical study showed intense ICAM-1 expression on the lymphocytes densely packed in the lymphatics surrounding follicles in Peyer's patches. A large number of lymphocytes are normally sequestered in the lymphatic network of Peyer's patches. This sequestration of lymphocytes is largely mediated by ICAM-1-dependent cell-cell interactions.
Cytokines regulate membrane adenosine deaminase on human activated lymphocytes
Authors: Cordero Oscar J , Salgado Francisco J , Fernández-Alonso Carmen M , Herrera Carolina , Lluis Carmen , Franco Rafael , Nogueira Montserrat
Published: September 2022

CD26 is a lymphocyte marker that can anchor adenosine deaminase (ADA) on the T cell surface. We found that ADA is regulated by cytokines on the cell surface during T cell activation. By means of flow cytometry, immunofluorescence, and immunoblotting techniques, we found that interleukin (IL)-2 and IL-12 up-regulate ecto-ADA and CD26 expression. In clear contrast, IL-4 led to down-regulation of lymphocyte surface ADA without modifying the level of CD26. Moreover, neither circulating ADA transcription nor mRNA translation was regulated by cytokines. These results, along with absence of total-ADA modulation, the variable amount of ADA found in purified plasma membranes, and the different effect of Brefeldin A on the surface presence of ADA and CD26 indicated that cytokines regulate the translocation of ADA towards the cell surface through a mechanism not involving CD26. Ecto-ADA protected activated lymphocytes from the toxic effects of extracellular adenosine. Therefore, this cell surface ADA control might constitute part of the fine immunoregulatory mechanism of adenosine-mediated signaling through purinergic receptors in leukocytes.
Mechanisms underlying reduced responsiveness of neonatal neutrophils to distinct chemoattractants
Authors: Weinberger Barry , Laskin Debra L , Mariano Thomas M , Sunil Vasanthi R , DeCoste Christina J , Heck Diane E , Gardner Carol R , Laskin Jeffrey D
Published: September 2022

Potential mechanisms underlying impaired chemotactic responsiveness of neonatal neutrophils were investigated. Two distinct chemoattractants were compared: bacterially derivedN-formyl-methionyl-leucyl-phenylalanine (fMLP) and a unique chemotactic monoclonal antibody, designated DL1.2, which binds to a neutrophil antigen with an apparent molecular mass of 120 kDa. Chemotaxis of neutrophils toward fMLP, as well as DL1.2, was reduced in neonates when compared with adult cells. This did not appear to be a result of decreased fMLP receptor or DL1.2 antigen expression by neonatal neutrophils. fMLP, but not DL1.2, induced a rapid increase in intracellular calcium in adult and neonatal cells, which reached a maximum within 30 s. The calcium response of cells from neonates to fMLP was reduced when compared with adult cells, and an unresponsive subpopulation of neonatal neutrophils was identified. NF-κB nuclear binding activity induced by fMLP and DL1.2, as well as expression of the p65 NF-κB subunit and IκB-α, was also significantly reduced in neonatal cells, when compared with adult cells. In contrast, although fMLP, but not DL1.2, activated p42/44 and p38 mitogen-activated protein (MAP) kinases in neutrophils, no differences were observed between adults and neonates. Chemotaxis of adult and neonatal neutrophils toward fMLP and DL1.2 was also blocked to a similar extent by inhibitors of phosphatidylinositol 3-kinase, as well as an inhibitor of NF-κB. These findings indicate that reduced chemotactic responsiveness in neonatal neutrophils is a result of, at least in part, aberrations in chemoattractant-induced signaling. However, the biochemical pathways mediating this defect appear to be related to the specific chemoattractant.
Nutrients and their role in host resistance to infection
Authors: Field Catherine J , Johnson Ian R , Schley Patricia D
Published: September 2022

Almost all nutrients in the diet play a crucial role in maintaining an “optimal” immune response, such that deficient and excessive intakes can have negative consequences on immune status and susceptibility to a variety of pathogens. Iron and vitamin A deficiencies and protein-energy malnutrition are highly prevalent worldwide and are important to the public health in terms of immunocompetence. There are also nutrients (i.e., glutamine, arginine, fatty acids, vitamin E) that provide additional benefits to immunocompromised persons or patients who suffer from various infections. The remarkable advances in immunology of recent decades have provided insights into the mechanisms responsible for the effects of various nutrients in the diet on specific functions in immune cells. In this review, we will present evidence and proposed mechanisms for the importance of a small group of nutrients that have been demonstrated to affect host resistance to infection will be presented. An inadequate status of some of these nutrients occurs in many populations in the world (i.e., vitamin A, iron, and zinc) where infectious disease is a major health concern. We will also review nutrients that may specifically modulate host defense to infectious pathogens (long-chain polyunsaturated n-3 fatty acids, vitamin E, vitamin C, selenium, and nucleotides). A detailed review of the effect of long-chain polyunsaturated n-3 fatty acids on host defense is provided as an example of how the disciplines of nutrition and immunology have been combined to identify key mechanisms and propose nutrient-directed management of immune-related syndromes.
Neutrophil leukocyte motility requires directed water influx
Authors: Loitto Vesa-Matti , Forslund Tony , Sundqvist Tommy , Magnusson Karl-Eric , Gustafsson Mikael
Published: September 2022

The ability of neutrophils to sense and move to sites of infection is essential for our defense against pathogens. For motility, lamellipodium extension and stabilization are prerequisites, but how cells form such membrane protrusions is still obscure. Using contrast-enhanced video microscopy and Transwell® assays, we show that water-selective aquaporin channels regulate lamellipodium formation and neutrophil motility. Addition of anti-aquaporin-9 antibodies, HgCl2, or tetraethyl ammonium inhibited the function(s) of the channels and blocked motility-related shape changes. On human neutrophils, aquaporin-9 preferentially localized to the cell edges, where N-formyl peptide receptors also accumulated, as assessed with fluorescence microscopy. To directly visualize water fluxes at cell edges, cells were loaded with high dilution-sensitive, self-quenching concentrations of fluorophore. In these cells, motile regions always displayed increased fluorescence compared with perinuclear regions. Our observations provide the first experimental support for motility models where water fluxes play a pivotal role in cell-volume increases accompanying membrane extensions.