bluuebunny/crossref_metadata_2025 huggingface dataset:
Tropism for primary monocytes and for monocytoid cell lines are separate features of HIV-1 variants
Authors: Valentin Antonio , Nilsson Kenneth , åsjö Birgitta
Published: January 2018

We have analyzed the phenotype of five human monocytoid cell lines (U-937, THP-1, RC.2A, Mono Mac 6, and DD) and their capacity to support replication of HIV-1 strains with known tropism for T lymphocytes and mononuclear phagocytes. HIV-1Ba-L, a prototype monocytotropic HIV-1 strain, was unable to establish continuous replication in any of the cell lines used. In contrast, the lymphotropic strain IIIB could replicate in all CD4-positive cell lines. We conclude that the capacity of HIV-1 isolates to replicate in established human monocytoid malignant cells does not correlate with the tropism of the virus for primary mononuclear phagocytes. Since monocytoid cell lines do not distinguish HIV-1 variants tropic for mononuclear phagocytes, we suggest the use of primary cells for studies of HIV-1 tropism. J. Lcukoc. Biol. 56: 225–229; 1994.
Endotoxin stimulates the expression of glucose-6-phosphate dehydrogenase in Kupffer and hepatic endothelial cells
Authors: Spolarics Zoltán , Navarro Lan
Published: January 2018

The aim of the study was to elucidate the effect of lipopolysaccharide (LPS) administration in vivo (Escherichia coli endotoxin, 1 mg/kg body weight) on the expression and cellular activity of glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), the rate-limiting enzyme of the hexose monophosphate shunt in hepatic cells. Under basal conditions, Kupffer cells displayed higher activity of G6PDH than endothelial or parenchymal cells. In vivo LPS treatments for 7 and 22 h resulted in 40 and 60% increases, respectively, in the cellular activity of G6PDH in Kupffer cells. G6PDH activity was increased by 140 and 90% after 7- and 22-h LPS treatments in endothelial cells. G6PDH activity in parenchymal cells prepared from animals after 22 h of LPS treatment was decreased by approximately 60% compared with that in cells from saline-injected animals. Total cellular RNA or protein extracts from these cells were analyzed by Northern or Western blots. Under basal conditions, G6PDH mRNA levels relative to total cellular RNA were higher in Kupffer than in endothelial cells and were not detectable in parenchymal cells. LPS injection caused a time-dependent increase in G6PDH mRNA expression in Kupffer and endothelial cells. Western blot analysis of Kupffer cell extracts also showed that LPS treatments cause markedly elevated expression of protein in these cells. These results show that endotoxemia results in marked induction of G6PDH in Kupffer and hepatic endothelial cells but has no such effect in the parenchymal cells. These findings also suggest that the elevated cellular expression of G6PDH is an important regulatory event in the adaptive responses of hepatic nonparenchymal cells to infections. The elevated expression of G6PDH may be important for support of the upregulated NADPH-dependent pathways, such as superoxide anion and nitric oxide production, macromolecular synthesis, or the maintenance of cellular glutathione status. J. Leukoc. Biol. 56: 453–457; 1994.
Costimulatory receptors for the superantigen staphylococcal enterotoxin B on human vascular endothelial cells and T cells
Authors: Krakauer Teresa
Published: January 2018

Cell-surface molecules on human vascular endothelial cells (ECs) and T lymphocytes that mediate staphylococcal enterotoxin B (SEB)-induced T cell proliferation and cytokine production were investigated. Expression of HLA-DR and intercellular adhesion molecule 1 (ICAM-1) on EC was induced by interferon-7 (IFN-γ). IFN-γ-treated ECs bound SEB effectively and stimulated T cells to proliferate and secrete tumor necrosis factor α (TNF-α) and IFN-γ. SEB-induced T cell proliferation was inhibited by monoclonal antibodies to CD2, CD11a, CD28, ICAM-1, and endothelial leukocyte adhesion molecule (ELAM). These antibodies also blocked production of the proinflammatory mediators, TNF-α and IFN-γ, in SEB-stimulated T cell-EC cocultures. These results suggest that the surface molecules, CD11a:CD18/ICAM-1, CD2, CD28, and ELAM, are all important costimulatory receptors for T cell activation by superantigens with the EC as the antigen-presenting cell. Thus, like conventional antigens, multiple stimulatory signals from the interactions of these receptors are required for superantigen-induced immune responses with ECs and T cells. Reducing proinflammatory mediators such as TNF-α and IFN-γ by these antibodies in SEB-induced T cell responses may be a useful therapeutic strategy for circumventing SEB toxicity and pathogenesis. J. Leukoc. Biol. 56: 458–463; 1994.
Pulmonary surfactant lipids inhibit prostanoid production of guinea pig alveolar macrophages
Authors: Földes-Filep éva , Sirois Pierre , Filep János G
Published: January 2018

Changes in the amount and composition of pulmonary surfactant are important features of the adult respiratory distress syndrome. The goal of the present study was to investigate the effects of natural surfactant material and several of its lipid components on prostanoid production and superoxide generation by guinea pig alveolar macrophages. Natural surfactant (10–500 μg/ml) inhibited (up to 65%) prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) production elicited by platelet-activating factor (PAF, 10-6 M) and arachidonic acid (5 10-6 M) but not fMet-Leu-Phe (10-7 M). Dioleyl-phosphatidylglycerol (diOPG, 1–100 μg/ml) and dioleyl-phosphatidylcholine (diOPC, 1–100 μg/ml) prevented fMet-Leu-Phe- and PAF-stimulated prostanoid release in a concentration-dependent fashion with a maximal inhibition of 94%. DiOPC (100 μg/ml) also inhibited arachidonic acid induced PGE2 production by 67%. Phosphatidylcholine (100 μg/ml) and sphingomyelin (10–100 μg/ml) significantly attenuated TxB2 production elicited by arachidonic acid. Neither PAF- nor fMet-Leu-Phe-stimulated superoxide production was affected significantly by natural surfactant and its lipid components with the exception of phosphatidylcholine. At a concentration of 100 μg/ml, phosphatidylcholine decreased superoxide production by about 57% in response to PAF. These results show that diOPC and diOPG are capable of inhibiting prostanoid production of guinea pig alveolar macrophages in response to inflammatory stimuli and suggest that a decrease in the diOPG and diOPC content of surfactant would lead to enhanced intrapulmonary formation of prostanoids and consequently to the deterioration of pulmonary function in the adult respiratory distress syndrome. J. Leukoc. Biol. 56: 475–480; 1994.
Signaling pathways mediated by the mitogen-activated protein (MAP) kinase kinase/MAP kinase cascade
Authors: Matsuda Satoshi , Gotoh Yukiko , Nishida Eisuke
Published: January 2018

Mitogen-activated protein (MAP) kinase and its direct activator, MAP kinase kinase (MAPKK), comprise the MAPKK/MAP kinase cascade, which may play a pivotal role in a variety of intracellular signal transduction pathways from yeast to human. Vertebrate MAPKK, a dual-specificity kinase, is activated by serine phosphorylation catalyzed by upstream serine/threonine kinases, MAPKK kinases (MAPKK-Ks). MAPKK is, on the other hand, threonine phosphorylated by MAP kinase, although a physiological role of this MAP kinase–mediated phosphorylation of MAPKK is unknown. Biochemical fractionation of extracts from Xenopus mature oocytes revealed two major and one minor peaks for the MAPKK-K activity. One of the major peaks contained a proto-oncogene product c-Mos, while the other peaks did not. These observations, together with a recent finding that several MAPKK-Ks such as Raf-1 and MEKK may function within a cell, suggest a diversity of MAPKK-Ks. A variety of extracellular signals converge at the MAPKK/MAP kinase cascade through different MAPKK-Ks and elicit a wide spectrum of cellular responses. Therefore, mechanisms that control activation of the MAP kinase cascade temporally and spatially may be important for specification of cellular responses. J. Leukoc. Biol. 56: 548-553; 1994.
Differential effects of temperature on macrophages of ectothermic vertebrates
Authors: Pxytycz Barbara , Józkowicz Alicja
Published: January 2018

The role of macrophages in vertebrate defense reactions is especially important at low temperatures, which commonly affect representatives of ectothermic species. The aim of this work was to compare the effects of in vivo thermal acclimation and in vitro assay temperatures on peritoneal macrophages (PMs) from fish (carp and goldfish) and amphibians (salamanders and toads). The substratum adherence of PMs was undisturbed over the wide range of temperatures experienced by animals in nature. Dehydrogenases and endocytosis were sensitive to temperature fluctuations in a species-specific manner, more or less dependent on the previous thermal history of animals. The MTT reduction, inhibited by low assay temperatures, was slightly improved in PMs from cold-acclimated amphibians but not fishes. Endocytosis by the amphibian PMs, very efficient over the wide range of assay temperatures, was additionally improved by previous in vivo cold exposure. Contrasting effects of thermal acclimation were most evident in the case of endocytic properties of fish PMs; endocytosis by PMs from cold-acclimated fishes was extraordinarily efficient at a temperature just above zero, which almost completely inhibited cells from fishes adapted to warmth. J. Leukoc. Biol. 56: 729–731; 1994.
The role of IL-4, IL-10, and TNF-α in the immune suppression induced by ultraviolet radiation
Authors: Rivas Jorge M , Ullrich Stephen E
Published: January 2018

Cytokines produced by keratinocytes play an essential role in the induction of immune suppression following ultraviolet (UV) exposure. Using antibodies specific for either interleukin-10 (IL-10) or tumor necrosis factor α (TNF-α), we present evidence indicating that IL-10 suppresses delayed-type hypersensitivity (DTH) but not contact hypersensitivity (CHS), whereas TNF-α suppresses CHS but not DTH following UV exposure. UV exposure also activates antigen-specific suppressor T cells. To determine whether the antigen-specific CD4+ T cells that transfer suppression in this system mediate their suppressive effect by releasing IL-4 or IL-10, we transferred UV Ts into normal mice that were then injected with either anti-IL-4 or anti-IL-10 antibody. Both anti- IL-4 and anti-IL-10 blocked the ability of UV Ts cells to suppress DTH in the recipient animals. When UV Ts that suppress CHS were transferred into normal recipients, however, neither antibody was able to block the UV Ts activity. These findings suggest that UV Ts suppress DTH by secreting IL-4 and IL-10 and appear to act like Th2 cells. Because anti-IL-4 and anti-IL-10 did not block the activity of the UV Ts that regulate contact hypersensitivity, their effects appear to be mediated by a different mechanism. J. Leukoc. Biol. 56: 769–775; 1994.
Modification of leukocyte adhesion in spontaneously hypertensive rats by adrenal corticosteroids
Authors: Suzuki Hidekazu , Zweifach Benjamin W , Forrest Michael J , Schmid-Schönbein Geert W
Published: January 2018

Leukocyte adhesion is a key factor in the pathogenesis of organ injury following a variety of stimuli. In this study we have addressed the role of leukocyte adhesion in hypertensives as a risk factor for organ injury. In the spontaneously hypertensive rat (SHR), the number of circulating leukocytes and their level of activation are significantly increased compared with its normotensive control, the Wistar-Kyoto rat (WKY). We have demonstrated that elevated levels of glucocorticoid in SHR suppress P-selectin–mediated leukocyte-endothelial interaction in the microcirculation. It is possible that the disturbance in leukocyte-endothelial interactions may result in an elevated number of leukocytes in the circulation. The aim of the present study was to investigate the contribution of the adrenal glands to the disturbance in leukocyte behavior in SHR by subjecting the animals to bilateral adrenalectomy and investigating the effect of hydrocortisone. In addition, we have studied by immuno-histochemistry the expression of the endothelial adhesion molecule, P-selectin, in response to histamine in the mesenteric venules of normal and adrenalectomized SHR and WKY. The elevated blood pressure, above-normal leukocyte counts, and elevated number of activated neutrophils (nitroblue tetrazolium test) in SHR were blunted after adrenalectomy. The blunted histamine-induced leukocyte-endothelial interaction in the mesenteric venules of SHR was restored after adrenalectomy. Treatment with hydrocortisone significantly attenuated the elevated leukocyte adhesion in the adrenalectomized SHR as well as in WKY. The suppressed P-selectin expression in SHR mesentery was restored after adrenalectomy. In conclusion, the subnormal leukocyte-endothelial interaction in response to an inflammatory stimulation in SHR is abolished after adrenalectomy, suggesting a relationship between the altered leukocyte adhesiveness and the adrenal corticosteroids in hypertensives. J. Leukoc. Biol. 57: 20–26; 1995.
Characterization of eosinophil homotypic aggregation
Authors: Teixeira Mauro M , Williams Timothy J , Au Bo-Ting , Hellewell Paul G , Rossi Adriano G
Published: January 2018

Guinea pig peritoneal eosinophils stimulated by platelet-activating factor (PAF), leukotriene B4 (LTB4), and human recombinant C5a (C5a) undergo a rapid concentration-dependent and partially reversible homotypic aggregation as assessed by changes in light transmission. The phorbol ester phorbol myristate acetate similarly induces a concentration-dependent aggregation, which is, however, slower in onset, takes longer to reach maximal aggregation, and is irreversible. In addition, we confirmed, using light microscopy, that these agonist-induced changes in light transmission do indeed represent true homotypic aggregation. We further characterized the aggregation response and showed that there is homologous but little heterologous desensitization when PAF and LTB4 are used as stimuli. A requirement for both Ca2+ and Mg2+ for full manifestation of agonist-induced aggregation was observed. LTB4- and PAF-induced superoxide anion generation is enhanced by the diacylglycerol kinase inhibitor R59022, whereas aggregation induced by LTB4, but not PAF, is augmented. Lastly, we show that eosinophil aggregation is partially dependent on the adhesion glycoprotein CD18. In summary, therefore, we believe that eosinophil aggregation provides a useful and reliable measure of eosinophil activation. J. Leukoc. Biol. 57: 226–234; 1995.
Transforming growth factor β modulates C3 and factor B biosynthesis and complement receptor 3 expression in cultured human monocytes
Authors: Høgåsen Anne Kirsti Myrvang , Hestdal Kjetil , Høgåsen Kolbjørn , Abrahamsen Tore G
Published: January 2018

Complement biosynthesis in monocytes is stimulated by different pathogens and modulated by a variety of cytokines, but little is known about the possible effect of transforming growth factor β (TGF-β) on this monocyte function. We therefore studied the effect of TGF-βl and TGF-β2 on constitutive, lipopolysaccharide (LPS)- and Candida albicans-induced monocyte biosynthesis of complement components C3 and factor B. Under all three conditions, both forms of TGF-β (20 ng/ml) induced a two- to fourfold increase in C3 concentration in monocyte supernatants harvested after 2 or 5 days of cell culture, an effect that was abrogated by cycloheximide. In contrast, constitutive and pathogen-induced production of factor B was suppressed by TGF-β. The effects of TGF-β on complement production were neutralized by a monoclonal anti-TGF-β antibody. Moreover, TGF-β suppressed the pathogen-induced release of granulocyte-macrophage colony-stimulating factor and down-regulated the expression of complement receptor 3 (CD11b/CD18), while the expression of CD11a/CD18, a related β  2 integrin, was unaffected. These novel effects of TGF-β emphasize the immunomodulatory significance of this cytokine. J. Leukoc. Biol. 57: 287–296; 1995.
Activation of casein kinase II in ML-1 human myeloblastic leukemia cells requires IGF-1 and transferrin
Authors: Wang L G , Liu X M , Wikiel H , Bloch A
Published: January 2018

Casein kinase II (CK II), a key enzyme involved in the regulation of cell growth, has been variously reported to be activated by diverse mitogens, including insulin-like growth factor 1 (IGF-1) and epidermal growth factor (EGF). Activation of the enzyme is generally carried out in the presence of serum, and we examined the question whether serum components participate in the activation process. We demonstrated previously that ML-1 cells require IGF-1 plus transferrin (TF) for growth and transforming growth factor β or tumor necrosis factor α plus TF for differentiation. We now found that CK II is activated only when the cells are exposed to both IGF-1 and TF or when TF is replaced in this combination with relatively high levels of iron salts. Induction of differentiation with TGF-β and TF did not result in CK II activation. These results show that CK II activation in ML-1 cells requires the application of both components of the growth signal, IGF-1 and TF, demonstrating that the growth factor alone is incapable of enhancing the activity of the enzyme. J. Leukoc. Biol. 57: 332–334; 1995.
75- but not 55-kDa tumor necrosis factor receptor is active in the homotypic aggregation and proliferation of human lymphokine-activated T killer (T-LAK) cells in vitro
Authors: Abe Yasuhito , Yamauchi Kuniyoshi , Kimura Shigeru
Published: January 2018

Lymphotoxin (LT) and tumor necrosis factor (TNF) play important roles in the maturation and growth of human lymphokine-activated T killer (T-LAK) cells in vitro. The role of 55- and 75-kDa TNF receptor (TNF-R) in the aggregation and proliferation of T-LAK cells was investigated using agonistic anti-TNF-R rabbit polyclonal antibodies. Human peripheral blood T cells and T-LAK cells predominantly express 75-kDa TNF-R. The proliferation of T-LAK cells during the generation phase is supported by innate LT and TNF. In this phase, the proliferation was upregulated by anti–75- but not 55-kDa TNF-R antibody. Homotypic aggregation of T-LAK cells was induced by LT, TNF, and anti–75- but not by anti–55-kDa TNF-R antibody. The increase of homotypic aggregation was accompanied by up-regulation of intercellular adhesion molecule 1 but not lymphocyte function–associated antigen 1 expression on cells and by an elevation of membrane fluidity, both of which were up-regulated by anti–75- but not 55-kDa TNF-R antibody. Interestingly, LT and TNF suppressed the proliferation of mature T-LAK cells. Anti–75- but not 55-kDa TNF-R antibody suppressed the proliferation, mimicking LT and TNF. These findings indicated that 75- but not 55-kDa TNF-R is biologically active in the modulation of aggregation and proliferation of human T-LAK cells in vitro. J. Leukoc. Biol. 57: 462–468; 1995.
Synergism between interferon-γ and cytokines or lipopolysaccharide in the activation of the HIV-LTR in macrophages
Authors: Warfel Alwin H , Thorbecke G Jeanette , Belsito Donald V
Published: January 2018

Macrophages (mfs) obtained from transgenic mice carrying the HIV long terminal repeat-chloramphenicol acetyl transferase (LTR-CAT) sequence were used to study the influence of various biologic response modifiers (BRMs) on the activation of LTR-directed CAT expression. It was found that LPS or IL-6 alone induced moderate levels of CAT expression, whereas IFN-γ or TNF-α had no significant effect. Co-exposure of mφs to IFN-γ and either LPS, IL-6, or TNF-α led to significant synergistic increases in CAT levels. Levels were also synergistically augmented when mφs were exposed first to IFN-γ (priming), washed, and then exposed to either LPS, IL-6, or TNF-α. Although IL-6 was synergistic with subsequently added IFN-γ, the reverse sequence of addition was more effective. LPS and TNF-α were inactive when added before IFN-γ. Initial priming signals were rapid as exposure for 3 h to IFN-γ was sufficient to prepare the cells for subsequent activation by other BRMs. These results suggest that the duration of latency and progression of HIV infections may be greatly influenced by events such as intercurrent infections that cause IFN-γ production, thereby priming mfs to respond to other cytokines that have been reported to be constitutively elevated during the course of infection with HIV (e.g., IL-6 and/or TNF-α). J. Leukoc. Biol. 57: 469–476; 1995.
Identification of macrophage activation associated proteins by two-dimensional gel electrophoresis and microsequencing
Authors: Walsh B J , Gooley A A , Williams K L , Breit S N
Published: January 2018

To understand activation in monocytes and macrophages we have studied changes in protein synthesis using the human monocytoid U937 cell line and twodimensional polyacrylamide gel electrophoresis (2D PAGE) and protein sequencing. U937 cells that had been metabolically labeled during treatment with PMA, LPS, or IFN-γ showed appreciable increases or decreases in synthesis of 14 proteins when analyzed by 2D PAGE. Although some 20 proteins are reported to be affected by these agents in U937 cells, none of them correspond with the 14 proteins studied here. Of the 14 observed changes, four spots (p41/65, p35/65, p26/44, p20/53) were up-regulated by PMA only, one (p16/44) by LPS only, five spots (p29/47, p26/45, p26/48, p12/47, p10/45) by both LPS and PMA, and, finally, one (p29/45) by all three agents. Two spots (p20/59 and p20/61) were down-regulated by IFN-γ and one of these spots (p20/59) was up-regulated by LPS. Only one spot (p20/48) was up-regulated by IFN-γ. Eleven spots with matching mobilities (both Mr and pI) to those identified in U937 were observed on 2D PAGE gels from human culture derived macrophages. Ten spots from U937 were sequenced by Edman degradation. Two were could not identified from information contained in the available DNA and protein databases and thus represent novel proteins, whereas a further six of the proteins were N-terminally blocked. The remaining two (29/47 and 12/47, respectively) were identified from existing protein databases as translationally controlled tumor protein (TCTP) and cytokeratin. This is the first report of the presence of TCTP in hemopoietic cells and its modulation by PMA or LPS in any cell type. We believe that 2D PAGE and sequencing is a powerful approach for identifying key proteins in macrophage cellular activation. J. Leukoc. Biol. 57: 507–512; 1995.
Monoclonal antibody EG2 reactivity: the need for clarification
Authors: Rosenberg Helene F , Lee Tiffany H
Published: January 2018

Authors’ reply: We are puzzled by the reaction of Jahnsen and Brandtzaeg to our paper [1], In this work, we determined that the capacity of mAb EG2’s to react with both eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN) was directly dependent on the glycosylation state of these granule proteins. We showed that mAb EG1 detected all glycosylated forms of ECP, whereas the mAb EG2 detected only the least glycosylated (and deglycosylated) forms of both ECP and EDN. We attempted to reconcile these purely biochemical findings with the prevailing understanding of these antibodies—indeed, the only published data at the time this work went to press—which was that the mAb EG1 detected both resting and activated eosinophils, while EG2-reactivity was an indicator of eosinophil activation and secretion [2]. Our experiments were not designed to determine the validity of this claim; in fact, our conclusions included the possibility that the EG2-reactive forms of ECP and EDN existed within the resting eosinophil granule, in a location or conformation rendering them inaccessible to the antibody under standard fixation conditions (1).
NFATp, a cyclosporin-sensitive transcription factor implicated in cytokine gene induction
Authors: Rao Anjana
Published: January 2018

The transcription factor NFATp (nuclear factor of activated T cells, preexisting) is likely to regulate the cyclosporin-sensitive transcription of cytokine genes and other activation-associated genes during the immune response. NFATp is the first identified member of a new family of transcription factors, whose DNA binding do mains show a weak sequence similarity to those of the Rel (NF-xB) family of proteins. NFATp is expressed in several types of immune cells as a cytosolic protein that translo cates to the nucleus following activation. The nuclear translocation is regulated by calcium and calcineurin and inhibited by cyclosporin A and FK506. In the nucleus, NFATp cooperates with Fos-Jun dimers and possibly with other transcription factors at composite elements in the regulatory regions of cytokine genes. The potential roles of NFATp and a related family member, NFATc, in cytokine gene transcription are discussed. J. Leukoc. Biol. 57: 536–542; 1995.
Functional significance of two cytolytic pathways of cytotoxic T lymphocytes
Authors: Podack Eckhard R
Published: January 2018

Cytotoxic lymphocytes are equipped with several effector molecules mediating cytotoxicity. Two pathways have been molecularly defined and functionally characterized through the analysis of deficiency states. It is evident from these results that lysis by granule exocytosis serves primarily to eliminate exogenous and en dogenous hazards such as virally infected and trans formed cells. In contrast, lysis by induced suicide in the fas pathway is used to maintain homeostasis of rapidly expanding and contracting cell populations including T cells. J. Leukoc. Biol. 57: 548–552; 1995.
Extracellular matrix proteins and leukocyte function
Authors: Pakianathan Deepika R
Published: January 2018

Extracellular matrix (ECM) proteins profoundly affect physiological functioning at the cellular level. Cell growth and differentiation, as well as cell shape and migration via the cytoskeleton, are all affected by ECM proteins. Leukocyte interactions with matrices have recently become an exciting field of research because a number of different leukocyte functions are significantly affected by their binding to ECM proteins. This may be especially important in inflammatory responses where leukocytes are primed for inflammatory mediator and cytokine production by binding to ECM proteins during extravasation. Because activated leukocytes produce potentially damaging substances, the progress of an inflammatory response can be profoundly affected by the ECM proteins encountered by leukocytes during their migration from within the peripheral circulation to sites of inflammation. This review summarizes recent publications describing components of the ECM that influence leukocyte function, the receptors involved in leukocyte binding to ECM proteins, and focuses on the effects of ECM proteins on the production of inflammatory mediators and cytokines by human peripheral blood leukocytes. J. Leukoc. Biol. 57: 699–702; 1995.
Induction of macrophage suppressor activity by fibrosarcoma-derived transforming growth factor-β1: contrasting effects on resting and activated macrophages
Authors: Alieva David G , Walker Thomas M , Elgert Klaus D
Published: January 2018

Tumor-derived transforming growth factor-β1 (TGF-β1) suppresses several immune responses. Because tumor growth induces macrophage (mφ) suppressor activity, we determined whether murine fibrosarcoma-derived TGF-β1 contributed to mφ-mediated suppression of autoantigen- and alloantigen-stimulated T cell proliferation. The murine fibrosarcoma Meth-KDE cell line constitutively produced TGF-β1. Meth-KDE tumor-bearing host (TBH) syngeneic splenic mφs suppressed autoantigen- and alloantigen-stimulated normal host (NH) CD4+ T cell proliferation. Pretreatment with Meth-KDE supernatants induced NH mφs to suppress T cell proliferation as much as TBH mφs. Anti-TGF-β1 antibody treatment reversed Meth-KDE-induced NH mφ-mediated suppression. Recombinant TGF-β1-induced mφ-mediated suppression was not blocked during inhibition of prostaglandin E2 (PGE2), nitric oxide (NO), or TGF-β1 production. However, Meth-KDE-induced mφ-mediated suppression was partly reduced when PGE2 production was inhibited. Pretreatment with tumor cell-derived TGF-β1, but not recombinant TGF-β1, increased activated mφ PGE2 production. These results show that additional tumor-derived molecules aid in TGF-β1-enhanced PGE2 production. Also, TGF-β1 alone up-regulates mφ synthesis of suppressor molecules that are different from PGE2, NO, and TGF-β1. Although TGF-β1 has direct suppressor activity on lymphocytes, these results show that release of tumor cell TGF-β1 also induces mφ suppressor activity. J. Leukoc. Biol. 57: 919–928; 1995.
Interferon-α and interferon-γ down-regulate the production of interleukin-8 and ENA-78 in human monocytes
Authors: Schnyder-Candrian Silvia , Strieter Robert M , Kunkel Steven L , Walz Alfred
Published: January 2018

The two chemotactic cytokines interleukin-8 (IL-8) and epithelial neutrophil activating protein 78 (ENA-78) were recently shown to be potent chemoattractants and activators of neutrophil function and to be present in certain inflammatory diseases. We have studied the effects of recombinant and natural interferon-α (IFN-α) and of recombinant interferon gamma (rIFN-γ) on the production of EL-8 and ENA-78 in lipopolysaccharide- and interleukin-1–stimulated human monocytes. Both types of interferons showed a strong, concentration-dependent inhibition of neutrophil-stimulating bioactivity. Similarly, the secretion of IL-8 and ENA-78 was also inhibited by up to 73%. Northern blot experiments demonstrated that IFN-α decreases the steady-state levels of IL-8 and ENA-78 mRNA in monocytes, suggesting that IFN-α as well as IFN-γ may control the expression of neutrophil chemotactic cytokines at the mRNA level. J. Leukoc. Biol. 57: 929–935; 1995.
Preparation of specific antibodies against murine IL-1ra and the establishment of IL-1ra as an endogenous regulator of bacteria-induced fulminant hepatitis in mice
Authors: Fujioka Nakaba , Mukaida Naofumi , Harada Akihisa , Akiyama Mariko , Kasahara Tadashi , Kuno Kouji , Ooi Akishi , Mai Masayoshi , Matsushima Kouji
Published: January 2018

Blocking monoclonal antibodies (mAbs) specific to mouse interleukin-1 receptor antagonist (IL-1ra) were prepared by immunizing Armenian hamsters with recombinant mouse IL-1ra. A sensitive and specific ELISA against mouse IL-1ra was also established. In Propionibacterium αcnes-induced liver injury, P. acnes induced transient increase of serum tumor necrosis factor-α levels but not those of IL-1ra, IL-1, and IL-6. However, subsequent lipopolysaccharide (LPS) challenge induced the increase of serum levels of all these cytokines and the peak serum IL-1ra level was more than 20 times as high as serum IL-1 levels. Immunohistochemical analysis demonstrated that IL-1ra was predominantly produced by hepatocytes during the course of the priming phase by P. acnes and eliciting phase by LPS challenge. Furthermore, the administration of a mAb to mouse IL-1ra exacerbates the liver injury induced by P. acnes and sublethal dose of LPS, suggesting a protective role of endogenous IL-1ra in this liver injury model. J. Leukoc. Biol. 58: 90–98; 1995.
IL-10 up-regulates human monocyte phagocytosis in the presence of IL-4 and IFN-γ
Authors: Capsoni Franco , Minonzio Francesca , Ongari Anna Maria , Carbonelli Vincenzo , Galli Andrea , Zanussi Carlo
Published: January 2018

Interleukin-10 (IL-10), a cytokine produced by type 2 belper T (Th2) cells, inhibits the microbicidal effector function of interferon-γ (EFN-γ)-activated macrophages. However, recent observations indicate that IL-10, like IFN-γ, increases FcγRI expression and FcγR-mediated cytotoxic activity on human monocytes, suggesting that this cytokine cannot be classified purely as a monocyte deactivator. The present study found that incubation for 40 h of human monocytes or monocyte-derived macrophages in the presence of EL-10 caused a significant enhancement of their capacity to ingest particles coated with immunoglobulin G (FcγR-mediated ingestion) or with C3b/C3bi fragments of the complement system (GR1/CR3-mediated ingestion). The number of phagocytosing cells (% phagocytosis) and the number of ingested particles per cell (phagocytic index) were both significantly higher after 40-h incubation of monocytes with IL-10 concentrations ≥1 U/ml. This up-regulating activity on phagocytosis was completely reversed by anti-EL-10 monoclonal antibody (mAb). As previously reported, ILIO stimulated FcγRI expression on monocytes but did not induce the expression of FcγRII, FcγRIII, CR1, and CR3. IFN-γ, like EL-10, up-regulated only FcγRI expression but significantly reduced both FcγR- and CR-mediated ingestion. IL-10 almost completely reversed the IFN-γ-induced inhibition of both FcγR- and CR-mediated phagocytosis, without concomitant changes in membrane expression of phagocytic receptors. Exposure of monocytes to IL-4 reduced the membrane expression of all three FcγRs and also inhibited FcγR-mediated ingestion. On the other hand, IL-4 up-regulated both CR3 expression and CR-mediated ingestion on cultured monocytes. IL-10 not only neutralized the down-regulatory effect of IL-4 on FcγR expression but also completely reversed the IL-4-induced suppression of FcγR-mediated phagocytosis. Exposure of monocytes to a combination of IL-10 and IL-4 resulted in a synergistic effect on CR-mediated ingestion, even though no additive effects were observed on CR membrane expression. Finally, culture of monocytes in medium containing anti-EL-10 mAb significantly reduced their capacity to ingest IgG- or C3b/C3bi-coated particles, suggesting a role for endogenously produced IL-10 in the modulation of phagocytosis by human monocytes. These results demonstrate that IL-10 is a potent up-regulator of the phagocytic activity of human mononuclear phagocytes and indicate that this function may be in sensitive balance with the relative concentrations of EL-10, IL-4, and IFN-γ.
Function of the urokinase receptor (CD87) in neutrophil Chemotaxis
Authors: Gyetko Margaret R , Sitrin Robert G , Fuller Jennifer A , Todd Robert F , Petty Howard , Standiford Theodore J
Published: January 2018

During recruitment, leukocytes respond to chemotaxins and traverse matrix barriers. Urokinase-type plasminogen activator (uPA), bound to its receptor (uPAR; CD87) facilitates plasmin formation, which promotes matrix proteolysis. Polymorphonuclear leukocytes (PMNs) are critical to the inflammatory response and express both uPA and CD87. To determine whether uPA and CD87 are required for PMN Chemotaxis, PMNs were pretreated with an anti-CD87 monoclonal antibody (mAb), a neutralizing anti-uPA mAb, or uPA. PMN Chemotaxis was profoundly suppressed by the anti-CD87 mAb but was unaffected by anti-uPA mAb or uPA. The role CD87 plays in Chemotaxis may be related to its ability to associate with CR3. CD87/CR3 coupling can be disrupted by specific saccharides. The same saccharides that disrupt CD87/CR3 coupling (NADC, D-mannose, and mannoside) inhibit PMN Chemotaxis. We conclude that CD87 plays a crucial role in PMN Chemotaxis in vitro that is independent of uPA enzyme activity but may be related to the ability of CD87 to interact with CR3.
The role of tumor necrosis factor, interferon-γ, Transforming growth factor-β, and nitric oxide in the expression of immunosuppressive functions of splenic macrophages induced by Mycobacterium avium complex infection
Authors: Tomioka Haruaki , Sato Katsumasa , Maw Win Win , Saito Hajime
Published: January 2018

In order to verify the participation of some cytokines in the expression of the suppressor activity of splenic macrophages (Mφs) induced by Mycobacterium avium complex (MAC) infection, we studied whether anticytokine antibodies were capable of blocking their suppressor activity against concanavalin A (Con A)–induced mitogenesis of splenocytes (SPCs). When either anti-tumor necrosis factor (TNF), anti-Transforming growth factor-β (TGF-β), or anti-interferon-γ (IFN-γ) antibody was added to culture medium, suppressor activity was markedly reduced, in the order of anti-TNF, anti-IFN-γ, and anti-TGF-β antibodies. By contrast, neither anti-interleukin-6 (IL-6) nor anti-IL-10 antibody exerted such a blocking effect. Therefore, TNF, IFN-γ, and TGF-β seem to be related to the full display of the suppressor function of MAC-induced Mφs. However, TNF-α and IFN-γ but not TGF-β were substantially lacking in inhibitory action against SPC mitogenesis, when added exogenously. Hence, it is unlikely that TNF-α and IFN-γ directly modulated the proliferative response of T cells. On the other hand, both TNF-α and IFN-γ potentiated the effector function of the suppressor Mφs. Because their suppressor activity was severely reduced by NG-monomethyl-L-arginine and aminognanidine, nitric oxide (NO) synthase inhibitors, an NO-dependent mechanism is important for the expression of the immunosuppressive function of MAC-induced Mφs. Moreover, because these Mφs seem to produce a substantial amount of TNF-α in membrane-bound form, cell-to-cell contact might be needed for efficient expression of their suppressor action on target T cells.
A synthetic peptide containing a predominant protein kinase C site within p47phox inhibits the NADPH oxidase in intact neutrophils
Authors: Labadia Mark E , Zu You-Li , Huang Chi-Kuang
Published: January 2018

In vivo loading of a synthetic peptide (peptide 4) corresponding to residues 314–331 (RSRKRLSQDAYRRNSVRF) consistently diminished the oxidative burst in response to either phorbol 12-myristate 13-acetate (PMA) or formylmethionyl-leucyl-phenylalanine and cytochalasin B (fMLP/CB) compared to other synthetic peptides derived from the p47phox sequence. The effects of peptide 4 were concentration dependent with respect to both PMA and fMLP/CB. In contrast, peptide 4 enhanced the oxidative burst in response to fMLP alone. Peptide 4 inhibited the PMA and fMLP-mediated phosphorylation of endogenous neutrophil cytosolic proteins including p47phox. The PMA-induced translocation of p47phox to the plasma membrane was diminished in neutrophils loaded with peptide 4. These data represent the first report of a synthetic peptide derived from p47phox that inhibits the NADPH oxidase in intact neutrophils and inhibits the protein kinase C–mediated phosphorylation of endogenous p47phox.
Lipopolysaccharide regulates cysteine-rich intestinal protein, a zinc-finger protein, in immune cells and plasma
Authors: Hallquist Nora A , Khoo Christina , Cousins Robert J
Published: January 2018

Cysteine-rich intestinal protein (CRIP), a double zinc-finger LIM protein, is expressed in great abundance in the intestine. We have found comparable levels of CRIP mRNA in peritoneal macrophages, peripheral blood mononuclear cells (PBMC), and lesser amounts in thymus and spleen. Because CRIP expression was high in immune cells, rats were challenged with lipopolysaccharide (LPS) to determine whether expression was altered during the acute-phase immune response. Immunocytochemistry showed that, in adherent mononuclear cells, CRIP protein was localized in the cytoplasm. CRIP mRNA levels increased over time after LPS injection in peritoneal macrophages, PBMC, spleen, and intestine. No changes in CRIP mRNA level were seen in either liver or thymus. In PBMC, the level of CRIP mRNA decreased before increasing later in the acute-phase immune response. CRIP protein was found in the plasma. Shortly after LPS administration plasma CRIP decreased, suggesting that CRIP was either passively diffused out of capillaries or was actively shunted into tissues to execute its function. Increased CRIP expression seen in response to IPS suggests that CRIP may play a role in immune cell activation or differentiation or in processes associated with cellular repair.
Gadolinium induces macrophage apoptosis
Authors: Mizgerd Joseph P , Molina Ramon M , Stearns Rebecca C , Brain Joseph D , Warner Angeline E
Published: January 2018

Gadolinium (Gd) suppresses reticuloendothelial functions in vivo by unknown mechanisms. In vitro exposure of rat alveolar macrophages to GdCl3·6H2O caused cell death, as measured by trypan blue permeability, in both dose- and time-dependent fashions. Even a 10-min exposure to Gd caused significant cell death by 24 h. The morphology of Gd-treated cells, pyknosis and karyorrhexis prior to loss of membrane integrity, suggested apoptosis. Upon flow cytometric examination, Gd-treated propidium iodide-excluding cells demonstrated light scatter changes characteristic of apoptotic cells (decreased forward and increased right angle scatter). Gel electrophoresis of DNA from Gd-treated macrophages clearly showed the ladder pattern unique to apoptotic cells. Electron-dense structures containing Gd were observed via electron spectroscopic imaging within phagosomes and also within nuclei (associated with condensed chromatin). Gadolinium, endocytosed by macrophages and distributed to nuclei, causes apoptosis of macrophages in vitro.
In vitro characterization of rat bone marrow-derived dendritic cells and their precursors
Authors: Chen-Woan M , Delaney C P , Foumier V , Wakizaka Y , Murase N , Fung J , Starzl T E , Demetris A J
Published: January 2018

Although the rat is commonly used for basic immunology and transplantation research, phenotypic and functional characterization of rat dendritic cells (DCs) lags behind similar studies in the human and mouse. Therefore, these features were examined using DCs propagated from cultures of rat bone marrow maintained in a medium supplemented with granulocyte-monocyte colony-stimulating factor. Analysis of cytospin preparations of cultured cells showed that DCs arise from OX7+ myelomonocytic precursors. Typical mature rat DCs were morphologically similar to their mouse and human counterparts and expressed major histocompatibility complex (MHC) class II (common part determinant of Ia), OX62 (integrin molecule), OX7 (CD90), ICAM-1 (CD54), and CTLA4 counterreceptor, but were negative for OX8 (CD8), OX19 (CD5), W3/25 (CD4), and ED2, a rat macrophage marker. Functional analysis of OX62+ sorted DCs showed that they could effectively present the soluble antigen ovalbumin to naive T cells in vitro. A combination of anti-MHC class II monoclonal antibody and CTLA4-immunoglobulin inhibited allostimulatory ability more effectively than either reagent alone. Implications for studying the role of DCs in immune responses in the rat are discussed.
The role of CD11/CD18 integrins in the reverse passive Arthus reaction in rat dermal tissue
Authors: Rote William E , Dempsey Erin , Maki Steve , Vlasuk George P , Moyle Matthew
Published: January 2018

The GD11/CD18 leukocyte integrins are necessary for tissue localization of neutrophils, an early requisite event in inflammation. We have analyzed the contribution of CD11a/CD18 and CD11b/CD18 to local neutrophil accumulation and tissue injury in the reverse passive Arthus reaction in the rat dermis. Experimental groups comprised animals that an intravenous infusion of (1) recombinant neutrophil inhibitory factor (NIF), a hookworm-derived antagonist of CD11b/CD18; (2) monoclonal antibody to CD11a/CD18 (TA-3); (3) a combination of these agents; (4) a monoclonal antibody to CD18 (WT.3); or (5) saline. Administration of recombinant NIF or anti-CD11a/CD18 monoclonal antibody alone produced a slight reduction in neutrophil accumulation but did not affect edema formation. In contrast, a combination of these antagonists yielded a significant reduction in neutrophil accumulation and a modest reduction in edema, equivalent to levels observed with either anti-CD18 antibodies or animals that were rendered neutropenic. These results indicate that neutrophil infiltration in rat dermal tissue in the reverse passive Arthus reaction is dependent predominantly on the leukocyte integrins CD11a/CD18 and CD11b/CD18 and that either of these integrins is sufficient for neutrophil trafficking in this inflammatory setting.
Role of the type I interferons in allograft rejection
Authors: Tovey Michael G , Benizri Eric , Gugenheim Jean , Bemard Ghislaine , Eid Pierre , Blanchard Brigitte , Hofman Paul
Published: January 2018

Type I interferons are potent immuno-modulatory cytokines that enhance expression of the major histocompatibility complex (MHC) class I antigens, T-cell cytotoxicity, and natural killer (NK) cell activity, all of which are implicated in graft rejection. A monoclonal antibody (mAb) directed against the extracellular domain of the human interferon α (IFN-α) receptor (IFN-αR), which inhibits both the binding and biological activity of all the type I IFNs tested, exerted a dose-dependent inhibition of the mixed lymphocyte reaction and induced permanent survival of skin allografts in MHC-divergent Cynomologus monkeys treated with a subeffective dose of cyclosporin A. Marked differences were observed in the composition of T lymphocyte sub-populations in anti-IFN-αR mAb-treated animals relative to the various control groups. Skin biopsies from animals treated with anti-IFN-R Mab + cyclosporin A revealed very low levels of MHC class I and class II antigen expression and the absence of histological signs of rejection, whereas skin biopsies from control animals exhibited high levels of MHC antigen expression and the histological signs of acute rejection, including a pronounced lymphocytic infiltrate, edema, and necrosis. No monkey antibodies (IgG) to the mouse anti-human IFN-αR mAb were detected in the serum of any of the animals treated with the anti-IFN-αR mAb either alone or together with cyclosporin A. Treatment of lethally irradiated Cynomologus monkeys with the anti-IFN-αR mAb together with a subeffective dose of cyclosporin A was also found to markedly enhance the survival of animals grafted with allogeneic bone marrow cells from donors differing in both MHC class I and class II antigens. These results show that selective and lasting immunosuppression can be obtained by the short-term administration of an IFN-α antagonist together with a subeffective dose of cyclosporin A, and may have important implications for the therapy of human allograft rejection.
Transcriptional and post-transcriptional regulation of GM-CSF-induced IL-1β gene expression in PMN
Authors: Fernandez Marilyn C , Walters John , Marucha Phillip
Published: January 2018

Polymorphonuclear leukocytes (PMN) play an important role in inflammation, immune responses, and tissue repair by secreting interleukin-1β (IL-1β). We investigated the regulation of IL-1β gene expression in human PMN treated with granulocyte-macrophage colony-stimulating factor (GM-CSF). GM-CSF induced IL-1β mRNA accumulation at 0.1 ng/ml and maximal induction was observed at 1 ng/ml. IL-1β mRNA levels reached a maximum within 1–2 h after stimulation with GM-CSF and returned to baseline levels by 4–6 h. The time course of IL-1β mRNA induction by GM-CSF was more protracted than previously reported for PMN stimulated with tumor necrosis factor-α (TNF-α, 10 ng/ml). Nuclear run-on analysis indicated that GM-CSF, like TNF, increases IL-1β transcription. Kinetic studies with the RNA synthesis inhibitor, actinomycin D, showed that GM-CSF induces stable IL-1β mRNA. Cycloheximide enhanced the IL-1β mRNA accumulation by GM-CSF at the level of mRNA stabilization, but blocked IL-1β mRNA expression by TNF. Thus, GM-CSF increases IL-1β message accumulation in PMN at both the transcriptional and post-transcriptional levels by mechanisms that are different from TNF induction of IL-1β gene expression.