bluuebunny/crossref_metadata_2025 huggingface dataset:
Macrophage priming by interferon gamma: a selective process with potentially harmful effects
Authors: Williams John G , Jurkovich Gregory J , Hahnel Greg B , Maier Ronald V
Published: January 2018

The tissue-fixed macrophage is a key cellular element in the initiation and regulation of inflammation. Understanding the regulation of macrophage activation may provide valuable clues to the mechanisms involved in both beneficial and deleterious effects of inflammation. The lymphokine interferon-γ (IFN-γ) is capable of producing paradoxical immunoinflammatory effects. In the immunocompromised host it up-regulates a variety of immune functions and improves survival, but it is also capable of producing harmful effects by sensitizing immunocompetent animals to subclinical doses of endotoxin. These paradoxical effects suggest that the state of activation or priming of the host immune system is a key determinant of its response to endotoxemia. Because tumor necrosis factor (TNF) and procoagulant activity (PCA) elaboration by the tissue-fixed macrophage play a central role in the host response to endotoxin, we asked whether the paradoxical effects of IFN-γ may be caused by priming of the macrophage for TNF and/or PCA production. In vitro, IFN-γ produces a marked augmentation in TNF but does not alter PCA elaboration in response to endotoxin, demonstrating the selectivity of IFN-γ priming of the macrophage. In vivo, IFN-γ pre- treatment followed by an established subclinical endotoxin exposure enhances toxicity while simultaneously increasing peak serum TNF levels. Exogenous priming by IFN-γ alters the activation state of the macrophage and modifies the host response to endotoxin. Because this response is also dependent on the host's underlying immune state, IFN-γ treatment in the immunocompetent host has the potential to produce deleterious effects by eliciting an exaggerated TNF response during endotoxemia.
Killing of Legionella pneumophila by nitric oxide in γ-interferon-activated macrophages
Authors: Summersgill James T , Powell Lori A , Buster Brad L , Miller Richard D , Ramirez Julio A
Published: January 2018

The role of nitric oxide (NO) radicals in killing the intracellular bacterial pathogen Legionella pneumophila (Lp) was examined in infected macrophages. Murine (RAW 264.7) and human (HL-60) cell monolayers were treated with 100 U/mlγ-interferon (IFN) and cocultured with Lp in the presence and absence of NGMMA, a specific inhibitor of NO production. Viable Lp in IFN-treated RAW 264.7 cells decreased from 3.8 to 0.7 ± 0.12 log CFU/ml after 24 h incubation, whereas in IFN + NGMMA-treated RAW 264.7 cells, viable Lp persisted at 2.2 ± 0.2 log CFU/ml after 24 h. This increased survival corresponded with an inhibition of NO production (5.65 ± 2.99 μM with NGMMA vs. 58.6 ± 5.36 μM without NGMMA). Viable Lp were susceptible to killing, in a dose-dependent fashion, by 0, 2.5, and 5.0 mM sodium nitroprusside, a source of NO radicals. IFN-treated RAW 264.7 cells also had significantly decreased levels of intracellular iron (below assay limit) when compared to IFN + NGMMA-treated cells (72.0 ± 0.78 % of control). Normally permissive HL-60 cells treated with IFN were bacteriostatic rather than bactericidal, and NO production was not detected above background. Thus, NO radicals play a critical role in the bactericidal activity against Lp by IFN-treated RAW 264.7 cells, but the absence of NO production limits IFN-treated HL-60 cells to bac- teriostasis.
Differentiation of dendritic cell populations in macrophage colony-stimulating factor-deficient mice homozygous for the osteopetrosis (op) mutation
Authors: Takahashi Kiyoshi , Naito Makoto , Shultz Leonard D , Hayashi Shin-ichi , Nishikawa Shin-ichi
Published: January 2018

In op/op mice, immunohistochemical and electron microscopic techniques were used to examine the effects of the OP mutation on dendritic cell populations in lymphoid tissues and skin. In the thymic medulla, T cell zone of lymph nodes, and splenic white pulp of op/op mice, numbers of NLDC-145-positive dendritic cells were not decreased. Compared to the normal litter- mates, numbers of BM8-positive macrophages were reduced in various tissues of the mutant mice, including the lymphoid tissues. These dendritic cells of op/op mice expressed la antigens but not F4/80 and BM8 antigens. Ultrastructurally, the dendritic cells developed a tubulo- vesicular system typical of interdigitating cells, but they were abnormal in that interdigitation of their cytoplasmic processes was not prominent. In the epidermis of the op/op mice, dendritic cells expressed NLDC-145, F4/80, la antigens, and adenosine diphosphatase or adenosine triphosphatase activity, and numbers of NLDC-145-, la-, or ADPase-positive dendritic cells were reduced slightly, but these reductions were not significant statistically. Bir- beck granules were detected in most of them electron microscopically. These results indicate that nonlymphoid dendritic cells develop in the lymphoid tissues and skin of op/op mouse, suggesting that they are differentiated from granulocyte-macrophage colony-forming cells or earlier hematopoietic cell precursors. J. Leukoc. Biol. 53: 19–28; 1993.
Platelet-activating factor–induced calcium mobilization and oxidative metabolism in hepatic macrophages and endothelial cells
Authors: Gardner Carol R , Laskin Jeffrey D , Laskin Debra L
Published: January 2018

Fluorescence image analysis of the calcium sensitive dye Indo-1 was used to characterize platelet-activating factor (PAF)-induced calcium mobilization in hepatic macrophages and endothelial cells. PAF, but not lyso-PAF, an inactive analog, induced a rapid and transient increase in intracellular levels of calcium that appeared to depend on the presence of extracellular calcium. In both macrophages and endothelial cells, these effects were dose dependent, reaching maximal levels with 10 nM PAF. However, the kinetics of the calcium response to PAF in macrophages and endothelial cells was distinct. The endothelial cells responded more rapidly to PAF than the macrophages (within 1 min vs. 2-3 min, respectively) and displayed longer recovery periods (4 min vs. >10 min, respectively). In contrast, the magnitude of the response to PAF was greater in the macrophages. In both cell types, triazolam and alprazolam, two PAF antagonists, and the calcium channel blocker verapamil inhibited PAF-induced calcium mobilization. PAF also stimulated superoxide anion production alone and in combination with the macrophage activator 12-0- tetradecanoyl-phorbol-13-acetate (TPA) in both cell types. Macrophages produced more of this reactive oxygen intermediate in response to PAF and TPA than endothelial cells. Interestingly, in the absence of extracellular calcium or when verapamil was added to the cultures, superoxide anion production by the macrophages, but not the endothelial cells, was significantly reduced. These results demonstrate that, although hepatic macrophages and endothelial cells mobilize calcium in response to PAF, the characteristics of the response in each cell type are different. These differences may underlie, at least in part, distinct functional responses of the cells to PAF. J. Leukoc. Biol. 53: 190–196; 1993.
Characterization of neutrophil activation by repeated injection of endotoxin in rabbits. Role of neutrophils in the generalized Shwartzman reaction
Authors: Toh Hiroto , Miyata Tadanori , Torisu Motomichi
Published: January 2018

The relationship between activated neutrophils and end-organ injury in endotoxemia was studied. The function of peripheral blood neutrophils (PMNs) in rabbits with the generalized Shwartzman reaction (GSR) was compared to that of PMNs rabbits receiving a single injection of endotoxin. The following results were obtained: (1) PMNs from rabbits with the GSR demonstrated enhanced adherence to endothelial cells and increased mitochondrial ATP production; (2) the GSR did not enhance chemotaxis and oxygen radical production of PMNs; (3) a single injection of endotoxin did not cause necrosis of visceral organs; (4) in vitro detachment of endothelial cells by PMNs was increased in rabbits with the GSR; (5) in vivo administration of monoclonal antibody (mAb) against CD1lb/CD 18 (Mac-1) suppressed the increase in PMN adherence; and (6) hemorrhagic necrosis did not occur when mAb to Mac-1 was injected. Thus, enhanced adherence of PMNs to endothelial cells appears to play a key role in endotoxin-induced end-organ injuries in this animal model. J. Leukoc. Biol. 53: 256–263; 1993.
Expansion of the liver-associated macrophage system in systemic lupus erythematosus-prone NZB/W mice
Authors: Emmendörffer Andreas , Müller Meike , Wedekind Dirk , Hartung Klaus , Lohmann-Matthes Marie-Luise
Published: January 2018

Systemic lupus erythematosus is characterized by profound changes of the immune system. We report on alterations of the macrophage system in the murine NZB/W model of this disease. A greatly increased number of mature macrophages was isolated from the liver of NZB/W mice as compared to BALB/c mice and several other inbred strains used as healthy controls. In addition, the macrophage precursor compartment in the liver of NZB/W mice was expanded severalfold as measured by proliferation of light-fraction nonadherent nonparen-chymal cells (NPCs) in response to colony-stimulating factors. Functional properties of the macrophages isolated from various anatomic sites of the lupus-prone mice were tested. Production of monokines by macrophages from liver, spleen, and peritoneal cavity, calculated on a per cell basis, was in the same range as in several healthy control strains tested. Yet the overall production of these immunregulatory molecules by the increased liver macrophage system, the body’s largest compartment of macrophages, is likely to result in increased levels of circulating monokines in the plasma of lupus-prone NZB/W mice. Indeed, significantly elevated levels of interleuldn-6, in-terleukin-1, and colony-stimulating activity could be demonstrated in the plasma of these mice both spontaneously and after stimulation with lipopolysaccharide. A possible contribution of the expansion of the macrophage system to the development of the disease is discussed. J. Leukoc. Biol. 53: 294–300; 1993.
Location of the domains of ICAM-1 by immunolabeling and single-molecule electron microscopy
Authors: Kirchhausen Tomas , Staunton Donald E , Springert Timothy A
Published: January 2018

Intercellular adhesion molecule 1 (ICAM-1), a member of the immunoglobulin gene superfamily, is a cell surface glycoprotein with an extracellular domain comprising five immunoglobulin-like domains. Soluble ICAM-1, a recombinant protein truncated at the transmembrane domain, has a rod-like shape, 19 nm long overall, with a characteristic bend 7.6 nm from one end of the molecule. Because the link between domain D2 and domain D3 is proline rich, it has been proposed that the short arm contains domains D1 and D2 and the long arm contains domains D3-D5. We used single-molecule electron microscopy of soluble ICAM-1 decorated with monoclonal antibodies specific for domains D1 and D4 to show that the bend instead lies between domains D3 and D4. Therefore, the short arm lies closer to the plasma membrane, whereas the long arm, containing all the known ligand binding sites on ICAM-1, is positioned toward the target cell surface. J. Leukoc. Biol. 53: 342–346; 1993.
Characterization of a human monocyte antigen, B148.4, regulated during cell differentiation and activation
Authors: Anegón Ignacio , Blottier Hervé , Cuturi Maria Cristina , Lenne Wonne , Trinchieri Giorgio , Faust Jeffrey , Perussia Bice
Published: January 2018

We analyzed the phenotypic changes associated with monocyte activation and differentiation using a newly developed monoclonal antibody (B148.4). Among peripheral blood leukocytes, the antigen recognized by this antibody is expressed on monocytes and granulocytes at high and low density, respectively. Antigen expression is lost during in vitro differentiation of monocytes and is absent on tissue macrophages, indicating that expression of this antigen is related to monocyte differentiation. Only la, 25-dihydroxyvitamin D3 and phorbol diesters, of several inducers tested, up-regulate B48.4 antigen expression on cells (monocytes and certain myeloid cell lines) that constitutively bear the antigen, without, however, allowing its maintenance during monocytic differentiation or inducing it on negative cells. By im- munoprecipitation from B148.4* U937 cells, the antigen is a complex of a major 116-kd and two minor 38- and 46-kd molecules. Analysis of eight different tissues reveals that the antigen is shared with endothelial cells. Biochemical characteristics, cellular distribution, and expression pattern on monocytes, myeloid cell lines, and AML cells upon culture with different stimuli indicate that B148.4 is a novel monocyte differentiation antigen. J. Leukoc. Biol. 53: 390–398; 1993.
Diminished transcription of interleukin-8 by monocytes from preterm neonates
Authors: Schibler Kurt R , Trautman Michael S , Liechty Kenneth W , White William L , Rothstein Gerald , Christensen Robert D
Published: January 2018

Developmental delays, which impair antibacterial host defense, are present in the neutrophil system of human preterm neonates. We hypothesized that diminished production of interleukin-8 (IL-8), a neutrophil chemotactic peptide, might in part be responsible for these defects. To test this, monocytes from the blood of preterm neonates, term neonates, and adults were isolated immunologically by “negative panning” and subsequently stimulated with interleukin-1α (IL-lα), tumor necrosis factor a (TNF-α), or lipopolysaccharide (LPS), after which IL-8 levels in the supernatants were measured by ELISA. Total cellular RNA was extracted and IL-8 mRNA was assessed by Northern blotting and by competitive polymerase chain reaction (PCR) analyses. After stimulation with IL-lα, IL-8 accumulation was lowest in supernatants of monocytes from preterm neonates, intermediate in supernatants of monocytes from term neonates and greatest from monocytes of adults. Similarly, when stimulated with TNF-α or LPS, monocytes from preterm neonates produced less IL-8 than cells from term neonates and adults. These differences in IL-8 concentrations paralleled differences in IL-8 mRNA expression. J. Leukoc. Biol. 53: 399–403; 1993.
Human neutrophil adhesion to bovine aortic endothelium. Evidence for endothelial lipoxygenase activity
Authors: Damtew Belai , Goldsmith George , Tserng Koy-Yi , Spagnuolo Philip J
Published: January 2018

We examined the effect of phorbol myristate acetate on cultured bovine aortic endothelial cells to determine the role of endothelial cells in neutrophil-endothelial cell adhesive interactions. Confluent endothelial cells were preincubated with phorbol myristate acetate and other inflammatory signals including JV-formylmethionyl- leucyl-phenylalanine (f-Met-Leu-Phe), the ionophore A23187, and thrombin; washed extensively; and incubated with 51Cr-labeled neutrophils. Preincubation of endothelium with A23187, phorbol ester, or thrombin increased adherence of neutrophils by 3.1-, 5.7-, and 3.7-fold over baseline. In contrast, f-Met-Leu-Phe preincubation failed to increase adhesion over baseline. Supernatants from endothelium preincubated with phorbol failed to augment adherence of untreated endothelial cells. Preincubation of endothelium with lipoxygenase inhibitors nordihydroguaiaretic acid (50μM), 5,8,11,14-eicosatetraenoic acid (50 μM), and BW755C (50 μM) inhibited the effect of phorbol preincubation of endothelium significantly by 55, 27, and 22%, respectively. In contrast, inhibitors of cyclooxygenase and thromboxane synthase or thromboxane receptor antagonists had no effect on phorbol-induced adhesion. Specific desensitization of neutrophil adhesion to phorbol-treated endothelium could be demonstrated by prior exposure of neutrophils to low concentrations of leukotriene B4 (3.8 × 10−10 M). Endothelium preincubated with phorbol but not f-Met-Leu-Phe or thrombin produced several fatty acid peaks at 280 nm, one of which comigrated with authentic leukotriene B4 (LTB4). This peak, isolated and purified, increased endothelial cell adherence in a temporal fashion in the same way as LTB4 and was demonstrated to be LTB4 by ultraviolet spectroscopy, high- performance liquid chromatography, and mass spectroscopy. These data demonstrate that endothelial cell-derived lipoxygenase metabolites, in particular LTB4, are involved, in part, in the acute regulation of neutrophil adhesion to endothelium induced by inflammatory signals such as phorbol ester. J. Leukoc. Biol. 53: 619–629; 1993.
Failure to establish long-term marrow cultures from immunodeficient mice (MAIDS): effect of zidovudine in vitro
Authors: Tse Kam-Fai , Hughes Nedda K , Gallicchio Vincent S
Published: January 2018

We report here the results of studies examining the ability of zidovudine (AZT) to influence the establishment and maintenance of long-term marrow cultures (LTMG) using marrow from murine immunodeficient mice (MAIDS). Normal C57BL6 mice were infected with LP-BM5 (MuLV) immunodeficiency virus (10μg total protein) intraperitoneally. Five weeks after viral infection, mice were sacrificed and marrow was harvested from normal non-virus-infected and virus-infected animals. LTMC were established in the presence or absence of dose escalation of AZT, that is, 10−6, 5 × 10−7, and 10−7 M in vitro. Compared with controls prepared from normal bone marrow, LTMC using MAIDS-infected marrow failed to establish and subsequently release supernatant-derived mononuclear cells. The addition of AZT was ineffective in either establishing LTMC or consistently producing mononuclear cells. Measurements of erythroid (BFU-E), myeloid (CFU-GM), and megakaryocyte (CFU-Meg) precursors were all depressed and none were observed after 5 weeks of culture. Treatment with AZT failed to reverse this depression of stem cell progenitors. Microscopic examination of cultures at 10 weeks demonstrated a failure of MAIDS-LTMC to establish an adequate stromal layer compared to LTMC prepared form non-virus-infected controls. This data indicate that LP-BM5 MuLV infection alters the establishment of a normal functioning hematopoietic microenvironment or stroma. Acknowledging that important differences between MAIDS and human AIDS exist, the implications of these findings concerning the establishment of the immunodeficiency disease state in human immunodeficiency virus infection is discussed. J. Leukoc. Biol. 53: 658–665; 1993.
Enhancement in vitro of the low interferon-γ production of leukocytes from human newborn infants
Authors: McKenzie Steven E , Kline Jane , Douglas Steven D , Polin Richard A
Published: January 2018

Interferon-γ (IFN-γ), a lymphokine produced by lymphocytes with the help of monocytes, is essential for host resistance to intracellular pathogens. Leukocytes from normal term newborn infants cannot produce IFN-γ in vitro in response to stimulation by antigen or mitogens in vitro or in vivo. We investigated the production of IFN-γ in vitro using endotoxin from Salmonella typhimurium as a stimulus. In contrast to those from adults, mononuclear cells derived from the cord blood of newborn infants did not produce IFN-γ in response to this endotoxin. We investigated the contribution of the functional immaturity of cord blood monocytes to this relative inability to produce IFN-γ. Aging of the monocytes for 2 weeks in vitro or treatment of freshly isolated cord blood monocytes with conditioned medium (from cultures of mononuclear cells from healthy adults) greatly enhanced IFN-γ production stimulated by endotoxin. Furthermore, recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony- stimulating factor (M-CSF), or IFN-γ was able to substitute in part for the conditioned medium from adult cells. Thus correction of the functional immaturity of monocytes derived from newborn infants can result in enhanced production of IFN-γ in vitro. J. Leukoc. Biol. 53: 691–696; 1993.
Uniform detection of HIV-1 in alveolar macrophages of pediatric but not adult AIDS patients
Authors: Pearce Tillman E , Nowakowski Maja , Eden Edward , Huang Zheng-Bo , Steiner Phillip , Shahabuddin Muhammad , Potash Mary Jane , Volsky David J
Published: January 2018

Manifestations of pulmonary disease in pediatric AIDS patients differ from those in adults. To evaluate whether differences in the frequency of alveolar macrophage (AM) infection with human immunodeficiency virus type 1 (HIV-1) could account for these clinical distinctions, we undertook a comparative analysis of HIV-1 DNA in AMs from pediatric and adult AIDS patients by enzymatic amplification. A higher frequency of viral DNA detection in pediatric cases (100%) compared with adults (67%) was observed. The sensitivity of detection was 1 viral DNA copy per 4000 AMs; matched peripheral blood mononuclear cells from six of seven pediatric and eight of nine adult patients tested HIV-1 DNA positive. Adult but not pediatric patients exhibited a marked alveolar lymphocytosis, 32% mean lymphocyte count compared with 7.0%, respectively. These results suggest that the burden of HIV-1 in the lungs of pediatric AIDS patients is greater than that in adults. J. Leukoc. Biol. 53: 722–726; 1993.
Characterization of a 64-kd protein phosphorylated during chemotactic activation with IL-8 and fMLP of human polymorphonuclear leukocytes. I. Phosphorylation of a 64-kd protein and other proteins
Authors: Shibata Michio , Ohoka Tadakazu , Mizuno Satoshi , Suzuki Kazuo
Published: January 2018

Interleukin-8 (IL-8) such as LUCT (lung giant cell carcinoma-derived chemotactic protein), NAP (neutrophil activating protein) and MDNCF (monocyte- derived neutrophil chemotactic factor), and formylmethionyl- leucyl-phenylalanine (fMLP) are well-known chemoattractants for human polymorphonuclear leukocytes (PMNs) and are able to stimulate phosphorylation of 64-kd protein (p64) in these leukocytes. To elucidate the molecular mechanism of PMN activation with chemoattractants, we investigated the phosphorylation process of p64 in an intact cell. 32P-Labeled PMNs were stimulated with LUCT/IL-8, fMLP, leukotriene B4, or C5a, and phosphorylated proteins were analyzed by two-dimensional electrophoresis and autoradiography. A marked phosphorylation of p64 was observed after stimulation. A new spot of phosphorylated p64 (pp64) could be detected on the gel stained with Coomassie Brilliant Blue, indicating that the isoelectric point (pI) of p64 shifted from 5.3 to a more acidic pI by the phosphorylation forming pp64. The spot of pp64 was shown to be dephosphorylated to p64 by treatment with calf intestine alkaline phosphatase. Other proteins having molecular masses 82, 66, 58, 55 and 50 kd were also phosphorylated. The fMLP- stimulated phosphorylation was time-dependent and saturated within 5 min. Maximum stimulation was achieved with 10 nM fMLP. Phosphoamino acid analysis revealed phosphorylation of serine residues in pp64. Staurosporine (100 nM) and W-7 (100 μΜ) significantly inhibited the phosphorylation of p64, but H-7 slightly inhibited it. H-8 and herbimycin A did not effect phosphorylation. Phorbol myristate acetate was found to stimulate significantly. Protein kinase C did not stimulate the phosphorylation. These data suggest that protein kinase C and calmodulin-like protein are indirectly involved in the phosphorylation of p64 during chemoattractant-activation of PMN.
Retinoic acid inhibits interleukin-1-induced cytokine synthesis in human monocytes
Authors: Gross Volker , Villiger Peter M , Zhang Baoping , Lotz Martin
Published: January 2018

Retinoids are pluripotent morphogens whose effects on gene expression are mediated through specific intracellular receptors. They have certain anti-inflammatory effects in vivo, the basis of which is not clearly understood. To characterize mechanisms involved with potential anti-inflammatory actions of retinoids, we studied the effects of retinoic acid (RA) on cytokine production in human peripheral blood monocytes. RA differentially modulated the expression of interleukin-1β (IL-10), IL-6, and IL-8 mRNAs depending on the inducing stimulus. While phorbol myristate acetate-induced IL-lβ and IL-8 mRNA expression was increased by RA (IL-6 could not be induced by this pathway in monocytes), IL-lβ-induced expression of IL-1β and IL-8 was markedly reduced and IL-6 gene expression was almost completely suppressed. Lipopolysaccharide (LPS)-induced cytokine synthesis was only slightly reduced and this required a longer preincubation (> 72 h) of monocytes with RA. IL-l-induced de novo synthesis of IL-6 protein and secretion of biologically active IL-6 were also inhibited by RA. The inhibition pattern of RA was different from that of dexamethasone, which inhibited both IL-1 and LPS effects. In summary, our data show that RA regulates monocyte cytokine expression selectively in response to the particular stimuli. Inhibition of IL-lβ-induced cytokine expression provides a mechanism that can explain some of the anti-inflammatory effects of RA.
Immune changes in test animals during spaceflight
Authors: Lesnyak A T , Sonnenfeld G , Rykova M P , Meshkov D O , Mastro A , Konstantinova I
Published: January 2018

Over the past two decades, it has become apparent that changes in immune parameters occur in cosmonauts and astronauts after spaceflight. Therefore, interest has been generated in the use of animal surrogates to better understand the nature and extent of these changes, the mechanism of these changes, and to allow the possible development of countermeasures. Among the changes noted in animals after spaceflight are alterations in lymphocytic blastogenesis, cytokine function, natural killer cell activity, and colony-stimulating factors. The nature and significance of spaceflight-induced changes in immune responses will be the focus of this review.
Autocrine amplification of PAF-acether formation in immunologically activated murine macrophages
Authors: Ninio Ewa , Maiza Hassina , Bidault Jocelyne
Published: January 2018

When murine macrophages activated in vivo with bacille Calmette-Guérin were triggered with either acetyl-CoA or propionyl-CoA to form PAF-acether (PAF), similar amounts of platelet-aggregating product were recovered. Liquid chromatographic purification and reversed-phase analysis showed that the composition of PAF molecular species formed in the presence of acetyl- CoA was an equimolar mixture of PAF bearing Cl 6:0 alkyl chain (57% ± 7, mean ± SD, n = 3) and PAF Cl8:1. The PAF-like material obtained from the propionyl-CoA- supplemented macrophages was a mixture of the propi- onyl analogue of PAF (66% ± 11, n = 3) and native PAF. The rate of lyso-PAF:acetyl-CoA acetyltransferase (EC 2.3.1.67) reaction in a macrophage lysate was similar for either substrate in the presence of an equimolar mixture of propionyl-CoA and acetyl-CoA. We conclude that the exogenously added propionyl-CoA is transferred to lyso- PAF acceptor to form propionyl-PAF by the PAF-forming acetyltransferase. Propionyl-PAF triggers the formation of native PAF probably from the endogenous acetyl-CoA pool. Two specific PAF antagonists, BN 52021 (60 μΜ) and WEB 2086 (3 μΜ), did not influence the rate of PAF synthesis in the presence of either acetyl-CoA or pro- pionyl-CoA and did not prevent native PAF formation when propionyl-CoA was added alone, suggesting that the classical PAF receptors are not involved. This is the first description of a possible mechanism of autocrine amplification of PAF biosynthesis in macrophages.
Modulation of the cytoskeleton and intracellular calcium in leukocytes exhibiting a cancer-associated chemotaxis defect
Authors: Janeczek A H , van Alten P J , Reyes H M , Walter R J
Published: January 2018

Monocyte chemotaxis is severely depressed in patients with advanced tumors, but the cellular basis for this chemotactic defect is not known. Because the ac- tomyosin cytoskeleton is thought to play a primary role in chemotaxis, we have employed flow cytometry to examine several aspects of the contractile machinery including myosin II, myosin light chain kinase (MLCK), actin, and cytoplasmic calcium in unstimulated and in formylpeptide- stimulated neutrophils and monocytes. Serum-pretreated polymorphonuclear leukocytes (PMNs) and monocytes from healthy blood donors or PMNs and monocytes isolated from tumor patients were studied. Leukocytes pretreated with serum from cancer patients exhibited decreased baseline myosin staining and a vastly different response to formylpeptide stimulation compared with leukocytes pretreated with normal human serum. In contrast, similar amounts of MLCK were observed in neutrophils and monocytes preincubated with normal or cancer serum with or without stimulation with formylpeptide. The fluorescent calcium indicator fluo-3 showed that resting and fMLP-stimulated levels of intracellular calcium were not significantly different in control and cancer serum-pretreated human leukocytes or in leukocytes isolated from tumor patients. Similarly, resting and fMLP-stimulated levels of F-actin in cancer patients’ leukocytes as assessed by NBD-phallacidin staining did not differ significantly from those of normal leukocytes. Because the actomyosin cytoskeleton is intricately involved in leukocyte chemotaxis, alterations in the cytoskeleton may dramatically affect cell motility. The cytoskeletal alterations and changes in the response of leukocytes pretreated with cancer patients’ serum to formylpeptide stimulation as described here may result in decreased chemotaxis by these cells.
Lipopolysaccharide structure-function relationship in activation versus reprogramming of mouse peritoneal macrophages
Authors: Zhang Xiaoke , Morrison David C
Published: January 2018

Lipopolysaccharide (LPS) is one of the most potent stimuli for macrophages. The activities of LPS have been attributed to the lipid A region of the molecule. We have previously shown that pretreatment of macrophages with very low doses of LPS can selectively “reprogram” these cells to respond differentially to subsequent activation, as assessed by tumor necrosis factor-α and nitric oxide (NO) production. Here we demonstrate that the relative capacity of various LPS preparations for induction of down-regulation of subsequent LPS-activated NO production correlates well with their relative potency for initiation of NO formation. Although LPS-dependent activation can be regulated by a pertussis toxin (PT)-sen- sitive factor, the LPS pretreatment-induced reprogramming is shown here to be refractory to regulation by PT. These results suggest that, although the structural components of LPS dictating the relative activities of the molecule for activation versus reprogramming are similar, there may exist different pathways in initiation of LPS-induced activation versus reprogramming.
Soluble FCγ receptors
Authors: Fridman Wolf H , Teillaud Jean-Luc , Bouchard Caroline , Teillaud Christophe , Astier Anne , Tartour Eric , Galon Jerome , Mathiot Claire , Sautes Catherine
Published: January 2018

Soluble FCγ receptors have been identified in biological fluids of mice and humans. They are produced either by alternative splicing of the exon encoding the transmembrane region of the receptor (FcγRII) or by proteolytic cleavage at the cell membrane (FCγRII and FC7RIII). They inhibit B cell proliferation and immunoglobulin production. Their concentrations in plasma seem to be modified during the development of certain diseases, as for instance in multiple myeloma, where plasma concentrations oi soluble FCγKIll are correlated with the stage of the disease.
Chemokines and serpentines: the molecular biology of chemokine receptors
Authors: Kelvin David J , Michiel Dennis F , Johnston James A , Lloyd Andrew R , Sprenger Hans , Oppenheim Joost J , Wang Ji-Ming
Published: January 2018

Chemokines are pro-inflammatory molecules with a diverse array of biological and biochemical functions. These molecules induce the migration of a number of leukocyte subsets including monocytes, neutrophils, and T-cells. The recent cloning of the IL-8, GRO, and MIP-lα chemokine receptors revealed that these glycoproteins belong to the serpentine family of seven transmembrane G-protein-coupled receptors. Other members of this family include die chemotactic receptors for fMLP and C5a, indicating that a common pathway for eliciting the directional migration of leukocytes is probably transduced via G proteins. Ligand binding to chemokine receptors is complex, featured by multiple chemokines binding to a single receptor and multiple receptors binding a specific ligand. Future directions in this field appear to be focused on the cloning of novel receptors and the identification of ligands for orphaned receptors.
Transendothelial migration of neonatal and adult bovine neutrophils in vitro
Authors: Bochsler Philip N , Neilsen Nancy R , Slauson David O
Published: January 2018

We have compared and quantitated transen-dothelial migration of neonatal neutrophils (N-PMNs) and adult bovine peripheral-blood PMNs (A-PMNs) in vitro using monolayers of endothelium and a two-chamber apparatus. Bovine aortic endothelial cells were cultured to confluence on polycarbonate filters perforated with 3.0-μm-diameter pores. 51Cr-labeled PMNs were added to the upper chamber, with or without an anti-CD18 antibody (monoclonal antibody 60.3). Chemotactic stimuli in the lower chambers included recombinant human interleukin-8 (rhIL-8; 75 ng/ml), rhC5a (10-7 M), and zymosan-activated bovine serum (ZAS; 10%). At 60 min incubation with rhIL-8, greater numbers (P < .01) of N-PMNs (24.70 ± 5.95%) than of A-PMNs (15.77 ± 3.66%) had migrated across the endothelial barrier, and a similar difference was present at 90 min. Migration rates of N-PMNs and A-PMNs were similar (P > .05) at all time points when using rhC5a and ZAS as stimuli. Anti-CD18 monoclonal antibody significantly decreased migration (P < .01) of both N-PMNs and A-PMNs to low levels when IL-8 and ZAS were used as stimuli. Because leukocyte integrin expression on PMNs affects transendothelial migration, we also compared surface expression of CD18, CD11a, and CD11c on PMNs from the two age groups. We found no significant quantitative differences in integrin expression between PMNs from the two age groups, regardless of whether the PMNs were incubated with buffer alone or with chemotaxins (rhIL-8, rhC5a, ZAS). J. Leukoc. Biol. 55: 43–49; 1994.
Determination of leukotriene effects on human neutrophil chemotaxis in vitro by differential assessment of cell motility and polarity
Authors: Krauss A H -P , Nieves A L , Spada C S , Woodward D F
Published: January 2018

The effects of leukotriene (LT) B4 and D4 on the motility of human peripheral blood neutrophils were investigated employing a novel analytical method. Using the under-agarose technique, migration distance and vectorial orientation of neutrophils in response to selected LT concentrations were determined with the aid of digital image processing. Neutrophil polarization induced by a chemotactic gradient was very apparent even at fields taken adjacent to the cell seeding well where little directional cell motility had occurred. Thus, cell polarization appeared to be the earliest response to chemoattractive LTs. Cell motility occurred in a dose-dependent manner to LTB4 according to determination of the leading edge. LTD4 produced similar effects on neutrophil polarization and motility, but these occurred only at very high concentrations. These data support the view that vectorial orientation is a prerequisite for directional migration of cells and it is also feasible that these are separately regulated events. Furthermore, our studies confirm that LTB4 and, to a much lesser extent, LTD4 are chemotactic for human peripheral blood neutrophils. J. Leukoc. Biol. 55: 201–208; 1994.
Mechanism of suppression of nitric oxide synthase expression by interleukin-4 in primary mouse macrophages
Authors: Bogdan Christian , Vodovotz Yoram , Paik John , Xie Qiao-wen , Nathan Carl
Published: January 2018

Nitric oxide (NO) contributes to the anti-tumor, antimicrobial, and immunosuppressive activity of macrophages. An inducible form of NO synthase (iNOS) is responsible for high output generation of nitric oxide by macrophages after stimulation with cytokines and/or lipopolysaccharide (LPS). In the present study, we demonstrate that interleukin 4 (IL-4) suppressed production of NO by primary mouse peritoneal macrophages exposed to IFN-γ with or without LPS, even while synergizing with IFN-γ to increase the secretion of TNF-α. Suppression of NO production was paralleled by decreases in iNOS enzyme activity and iNOS antigen. IL-4 did not inhibit induction of iNOS mRNA 4–6 h after exposure to IFN-γ, but strongly reduced iNOS mRNA at later times of stimulation (24–72 h), without increasing its turnover. The conditions for maximal suppression of iNOS expression by IL-4 and the mechanisms of suppression differed from those determined in parallel for transforming growth-factor-β as described elsewhere. These results illustrate the diversity of phenotypes of macrophages deactivated by different cytokines, and demonstrate that IL-4 has the potential to reduce one component of the anti-tumor, antimicrobial, and immunosuppressive activities of macrophages. J. Leukoc. Biol. 55: 227–233; 1994.
Human monocyte chemotaxis to complement-derived chemotaxins is enhanced by Gc-globulin
Authors: Piquette C A , Robinson-Hill R , Webster R O
Published: January 2018

Gc-globulin has been found in bronchoalveolar lavage fluid in patients with chronic obstructive pulmonary disease (COPD) and adult respiratory distress syndrome (ARDS) and has been shown to enhance neutrophil chemotaxis to C5-derived peptides in vitro. We proposed that Gc-globulin may enhance the inflammatory response in lungs by influencing monocyte chemotaxis to C5-derived peptides as it does with neutrophils. Monocyte chemotaxis was measured in blind well chambers by a leading-front technique. Purified human Gc-globulin had no intrinsic chemotactic activity for monocytes at concentrations ranging from 1 fM to 1 μM. However, Gc-globulin, at concentrations as low as 10 pM, increased monocyte chemotaxis over 10-fold in a concentration-dependent fashion when added to non-chemotactic doses of C5a (0.1 nM) and C5a des Arg (0.5 nM). The chemotaxis-enhancing effect of Gc-globulin was specific for C5-derived peptides, as Gc-globulin did not enhance monocyte chemotaxis to other chemoattractants such as leukotriene B4 or formyl-Met-Leu-Phe. The enhancement of monocyte chemotaxis to C5-derived peptides by Gc-globulin was not a nonspecific effect of anionic proteins, as other serum proteins of similar size and charge did not enhance monocyte chemotaxis to C5a des Arg. These results indicate that Gc-globulin enhances the monocyte response to C5-derived peptides and, together with previous work, indicates that its presence in the airways of patients with COPD and ARDS may up-regulate the monocyte inflammatory response in the lungs. J. Leukoc. Biol. 55: 349–354; 1994.
Metastatic competence of BW5147 T-lymphoma cell lines is correlated with in vitro invasiveness, motility and F-actin content
Authors: Verschueren Hendrik , Van der Taelen Imme , Dewit Joëlle , De Braekeleer Jos , De Baetselier Patrick
Published: January 2018

The aim of our study was to investigate whether the level of actin polymerization plays a role in the motile and tissue infiltrating behavior of malignant lymphoma cells. For a panel of cell lines derived from the murine BW5147 T-cell lymphoma, we had previously shown a correlation between experimental metastasis formation and in vitro monolayer invasion. We have analyzed the motility and the F-actin content of six non-metastatic, noninvasive (meta-inv-) and five metastatic, invasive (meta+inv+) variants of BW5147. Fourier analysis of cell contours was used to quantify shape changes of cells. All meta+inv+ lines rapidly protruded and retracted pseudopodia, whereas only one of the six meta-inv- lines showed this type of motility. Flow cytometry of cells stained with fluorescein-labeled phalloidin showed that the motile meta+inv+ cell lines have a higher F-actin content than their nonmotile meta-inv- counterparts. The results indicate that in lymphoma cells a high level of actin polymerization is a prerequisite for the formation of pseudopodia, which in turn are necessary for infiltration of the cells into tissues, and eventually for efficient metastasis formation. A corollary of this conclusion is that regulation of actin polymerization is a possible target for intervention aimed at moderating the spread of malignant lymphoma. J. Leukoc. Biol. 55: 552–556; 1994.
Induction of mycobacterial proteins during phagocytosis and heat shock: a time interval analysis
Authors: Alavi Mohammad R , Affronti Lewis F
Published: January 2018

Mycobacterium tuberculosis survives macrophage bactericidal activities by mechanisms that may include induction of stress proteins. We sought to determine whether the synthesis of any mycobacterial proteins is increased during phagocytosis and whether any of these proteins are also up-regulated during heat shock. Protein synthesis by M. tuberculosis H37Ra during phagocytosis by the mouse macrophage cell line IC-21, and during heat shock at 45 and 48 °, was monitored at various time intervals using 35S-labeled methionine/cysteine and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Our data suggest the existence of certain common elements in the stress response of mycobacteria to the three stress stimuli. This apparent similarity was best characterized by the up-regulation of a 25-kDa protein after exposure to each of the stress conditions. Furthermore, this 25-kDa protein and a 37-kDa protein that was also synthesized during phagocytosis appeared to be extracellular because they were preferentially solubilized when infected macrophages were lysed with 0.5% NP-40. J. Leukoc. Biol. 55: 633–641; 1994.
Interferon-γ inhibits tumor antigen presentation by epidermal antigen-presenting cells
Authors: Grabbe Stephan , Bruvers Sandra , Beissert Stefan , Granstein Richard D
Published: January 2018

Murine I-A+ epidermal antigen-presenting cells (APGs) have been shown to be capable of presenting soluble tumor fragments (TFs), as a source of tumor-associated antigens (TAAs), for primary and secondary tumor immune responses. In this study we investigated whether incubation of epidermal APCs in interferon-7 (IFN-γ) modulates their ability to present TAA and whether the effects of IFN-γ on the presentation of tumor antigen correspond to its effects on alloantigen presentation in both primed and unprimed systems. Our results show that three weekly subcutaneous injections of naive mice with GM-CSF-cultured but not with fresh TAA-pulsed epidermal APCs induce protective tumor immunity in naive mice and that the immunostimulatory effect of GM-CSF in this system is abrogated by coculture of epidermal cells in IFN–γ. Furthermore, epidermal APCs are able to present TAA to primed, tumor-immune mice, as assessed by the elicitation of tumor-specific delayed-type hypersensitivity after injection of TAA-pulsed epidermal APCs. IFN–γ was found to inhibit tumor antigen presentation by freshly prepared epidermal APCs in this system. The effects of IFN–γ on the presentation of tumor antigen correlated well with its effects on the primary and secondary mixed epidermal cell-lymphocyte reaction, indicating that IFN–γ differentially modulates the function of epidermal APCs with regard to induction versus elicitation of immunity. J. Lcukoc. Biol. 55: 695–701; 1994.
Blockade of liver macrophages by gadolinium chloride reduces lethality in endotoxemic rats—analysis of mechanisms of lethality in endotoxemia
Authors: Iimuro Yuji , Yamamoto Masayuki , Kohno Hiroshi , Itakura Jun , Fujii Hideki , Matsumoto Yoshiro
Published: January 2018

We investigated the effects of gadolinium chloride (GdCl3 · 6H2O), which blocks phagocytosis by liver macrophages, on the mortality, blood tumor necrosis factor (TNF) levels, and hepatotoxicity in a lethal endotoxic shock rat model system [10 mg/kg body weight lipopolysaccharide (LPS) intravenously]. With administration of GdCl3, twice at 0.5 or 5 mg/kg, the survival rate 24 h after LPS injection was 56% and 100%, respectively, whereas the level of TNF in blood was not affected. Microscopic investigation of the liver revealed that the focal necrosis of hepatocytes under endotoxemia was completely protected by the administration of GdCl3 at 5 mg/kg. We then investigated the effects of GdCl3 on superoxide (O2) production by isolated liver macrophages in vitro. The O2- production by liver macrophages isolated from control rats was suppressed by GdCl3 in a dose-dependent manner. GdCl3 also had a cytotoxic effect on these macrophages. The enhanced O2- production by liver macrophages isolated from sublethal endotoxemic (1 mg/kg) rats was suppressed by pretreatment with GdCl3 (5 mg/kg). It was suggested that lethality in endotoxemia cannot be explained only by the degree of increase in blood TNF levels and that the mechanism by which GdCl3 reduces mortality and hepatotoxicity in endotoxemia possibly includes suppression of superoxide production by liver macrophages. J. Leukoc. Biol. 55: 723–728; 1994.
Macrophage precursor cells produce perforin and perform Yac-1 lytic activity in response to stimulation with interleukin-2
Authors: Li Hao , Pohler Uwe , Strehlow Inga , Hertig Sylvie , Baccarini Manuela , Emmendörffer Andreas , Tschopp Jürg , Lohmann-Matthes Marie-Luise
Published: January 2018

Macrophage precursor cells, derived from mouse bone marrow culture with granulocyte-macrophage colony-stimulating factor or colony-stimulating factor 1 (CSF-1) as growth factor and interleukin-2 (IL-2) as stimulating factor, were activated by IL-2 to exert strong cytolytic activity against Yac-1 cells. In response to IL-2 stimulation these bone marrow macrophage precursor cells produced perforin as lytic molecules. The purity of the precursor cells for the study was proved as homogeneous positivity for Mac-1, NK-1.1 and negativity for Lyt 1 and 2. The cells express CSF-1 receptors on their surface, are able to proliferate and differentiate into typical macrophages when stimulated with CSF-1, and are therefore members of the macrophage lineage. Perforin transcripts were identified by Northern blot analysis of IL-2–treated macrophage precursor cells, and the presence of perforin protein in the cytoplasmic granules was demonstrated by immunhistochemical staining using a monoclonal antiperforin antibody. In addition, the biological activity of the perforin contained in the macrophage precursor’s granules could be documented as calcium-dependent lytic activity using Yac-1 and sheep red blood cells as targets. The results presented in this paper imply the existence of a bipotent precursor cell, which can mature into a typical macrophage if CSF-1 or phorbol 12-myristate 13-acetate is supplied as differentiation stimulating factor but develops into an NK/LAK cell when early activation with IL-2 is provided. J. Leukoc. Biol. 56: 117–123; 1994.
Analysis of human cytomegalovirus-infected peripheral blood mononuclear cells from infants with liver dysfunction by flow cytometry and the polymerase chain reaction
Authors: Numazaki Kei , Asanuma Hideomi , Nagata Nobuo , Chiba Shunzo
Published: January 2018

Perinatal human cytomegalovirus (HCMV) infection often involves the hepatobiliary tract, but infected individuals usually remain asymptomatic. We investigated the role of CD8+ lymphocytes in 13 infants with liver dysfunction associated with perinatal HCMV infection. In three patients more than 40% of CD8+ cells were positive for HCMV immediate early antigen (IEA) and late antigen (LA) by flow cytometry after selection of T lymphocytes subpopulations. In the other 10 infants, 20% to 30% of CD8+ cells were positive for HCMV IE A and LA. HCMV IE DNA was detected in CD8+ cells from one infant, in CD4+ cells from one infant, and in both CD4+ and CD8+ cells from three infants. HCMV infection of CD8+ cells may play an important role in the process of perinatal primary infection. J. Leukoc. Biol. 56: 187–191; 1994.