bluuebunny/crossref_metadata_2025 huggingface dataset:
Priming of human monocyte superoxide production and arachidonic acid metabolism by adherence to collagen- and basement membrane–coated surfaces
Authors: Gudewicz Paul W , Frewin Mary Beth , Heinel Lynn A , Minnear Fred L
Published: January 2018

Monocytes (mφs) come into intimate contact with basement membranes and extracellular matrix proteins as they extravasate from the blood to the interstitium or to sites of tissue injury. We examined the in vitro effects of mφ adherence to an endothelial cell-derived basement membrane or to purified extracellular matrix proteins on phorbol myristate acetate (PMA)-stimulated superoxide production and prostanoid secretion. Elutriation-purified human peripheral blood mφs were adhered to tissue culture wells that were precoated with the following purified proteins: bovine serum albumin (BSA), collagen type I (COL I), collagen type IV (COL IV), fibronectin (FN), or laminin (LM). To model the provisional matrix at sites of tissue injury, mφs were also adhered to wells coated with either denatured collagen type I or gelatin (GEL) or coated with basement membrane (BM) derived from endothelial cell monolayers. The mφs were adhered to the protein-coated surfaces for 1 h at 37° in serum-free medium and washed to remove nonadherent cells, and the number of adherent mφs was measured. Monolayers of mφs were also incubated for an additional 18 h, at which time both adherence and cell spreading were measured. PMA-stimulated superoxide production by adherent mφs was determined after 1 and 18 h of adherence to the protein-coated surfaces. PMA-stimulated release of two prostanoids, prostaglandin E2 (PGE2) and thromboxane B2 (TxB2), was measured after 18 h of mφ adherence to the surfaces. Following 18 h of adherence, PMA-stimulated superoxide anion secretion and secretion of PGE2 and TxB2 were augmented or primed by mφs adherent to COL I, GEL, or BM. In contrast, no such priming effects were observed by mφs adherent to COL IV, FN, or LM. The results suggest that adherence to basement membranes, collagen type I-containing surfaces in the interstitium, or denatured collagen at sites of tissue injury primes mφ respiratory burst and arachidonate metabolism to inflammatory agonists. Induction of priming events by substrate-specific adherence may be an important factor regulating host defense functions of mφs in the extracellular matrix. J. Leukoc. Biol. 55: 423–429; 1994.
Slow calcium waves imaged in myeloid cells derived from neonatal cord blood
Authors: Roberts G M , Davies E V , Hallett M B
Published: January 2018

Myeloid cells were derived from neonatal cord blood by culture with granulocyte-macrophage colony-stimulating factor for approximately 8 days. The resultant cell population contained large adherent cells (diameter ≥90 μm), expressing formylated peptide receptors that were functionally coupled to cytosolic free Ca2+ signaling. Imaging of the cytosolic free Ca2+ changes in these cells revealed initial focal release of Ca2+ from a site from within the cell, with elevated Ca2+ also near the cell edge. Increased cytosolic free Ca2+ moved as a slow oscillating wave across the cell (velocity 1 μm/s). As similar events may occur in mature neutrophils and monocytes but be difficult to resolve because of the small size of these cells, it was concluded that neonatal myeloid cells may provide a useful model system for the investigation of Ca2+ signaling in myeloid cells. J. Lcukoc. Biol. 55: 461–466; 1994.
HIV-1 envelope protein gp120 affects phenotype and function of monocytes in vitro
Authors: Dürrbaum-Landmann Iris , Kaltenhäuser Erika , Flad Hans-Dieter , Ernst Martin
Published: January 2018

We investigated the effect of human immunodeficiency virus type 1 (HIV-1) recombinant gp120 (rec.gp120) on phenotype and function of cultured monocytes. Rec.gp120 significantly reduced the accessory function of monocytes to stimulate autologous lymphocytes with anti-CD3, the Fc receptor–mediated chemiluminescence of monocytes, and the expression of CD4 and Fc receptor I/II, while the expression of the monocyte marker GD14 and major histocompatibility complex class I and II was not influenced. According to these phenotypic results, preincubation of monocytes with rec.gp120 depressed anti-CD3 antibody-induced T cell stimulation and Fc receptor-mediated phagocytosis as determined by chemiluminescence. Interferon-γ release of lymphocytes induced by purified protein derivative of tuberculin was enhanced by gp120. These effects of isolated gp120 on monocyte immune functions in vitro might contribute to the understanding of the pathophysiology of HIV-1 infection in viva J. Leukoc. Biol. 55: 545–551; 1994.
Serotonin-stimulated aortic endothelial cells secrete a novel T lymphocyte chemotactic and growth factor
Authors: Katz Marcia F , Farber Harrison W , Dodds-Stitt Zoe , Cruikshank William W , Bear Dennis J
Published: January 2018

Atherosclerotic lesions contain multiple cell types including smooth muscle cells, macrophages, and T lymphocytes. The development of an extralymphatic T lymphocyte focus of inflammation in this condition requires chemoattractant-induced cell migration and growth factor-induced cell activation. In a previous study, we described a novel 13–15-kDa T lymphocyte-specific chemotactic cytokine, endothelial cell–derived lymphocyte chemoattractant activity (ED-LCA), secreted by serotonin-stimulated bovine aortic endothelial cells that is distinct from previously identified endothelial cell–derived interleukins (IL) 1, 6, and 8. Because of the association between T lymphocyte chemotactic and growth factor activity, in the current study we investigated the effect of ED-LCA on T cell growth. We assessed its capacity to induce markers of the passage of T cells from the resting (G0) state into the G1 phase of the cell cycle, such as receptors for IL-2 (IL-2R) and transferrin (TFR) and class II major histocompatibility complex antigens (HLA-DR). Incubation of G0 freshly isolated human T lymphocytes for 48 h with chromatographically resolved, partially purified ED-LCA resulted in a threefold increase in expression of the p55 subunit of IL-2R, a threefold increase in TFR, and a twofold increase in HLA-DR. Passage into the G1 phase of the cell cycle was confirmed by cell cycle analysis employing acridine orange. Evaluation of CD4+ and CD8+ T cell subsets by double-antibody labeling demonstrated that the p55 subunit of IL-2R was induced in both T cell subsets. Although incubation of human T cells with ED-LCA alone did not induce proliferation, addition of exogenous IL-2 to T cells pulsed with ED-LCA for 24 h caused a proliferative response with a stimulation index of 3. By up-regulating functional cell surface receptors for IL-2, ED-LCA is a competence growth factor for T lymphocytes and primes them to respond to IL-2. By virtue of its effect on T cells, as a chemotactic and competence factor, this endothelial cell-derived mitoattractant could participate with other T cell growth factors like IL-2 in the recruitment and amplification of the extralymphatic T cell component of atherosclerosis. J. Leukoc, Biol. 55: 567–573; 1994.
Erythrocytes increase leukotriene C4 release from human eosinophils: characterization and examination of possible mechanisms
Authors: Raible Donald G
Published: January 2018

There has been considerable interest in the role of eosinophils in the pathogenesis of asthma and allergic diseases. While examining the conditions necessary for the release of leukotriene C4 (LTC4) from human eosinophils activated by immunoglobulin G-Sepharose (IgG-Seph), we observed that red blood cells (RBCs) potentiated eosinophil LTC4 release. The time course of IgG-Seph-stimulated LTC4 release was prolonged in the presence of RBCs. After 45 min of incubation, eosinophils without RBCs released 0.95 ± 0.11 ng/106 cells, and those with RBCs released 3.69 ± 0.67 ng/106 cells. Control experiments indicated that the effect was not due to platelet contamination of the RBCs and could not be reproduced with RBC supernatants or RBC membrane ghosts. An interesting characteristic of this interaction was that the eosinophils and RBCs had to be in close contact for the enhancement to occur. We also observed that at low calcium concentrations (0.6 mM), the eosinophils had to be primed with fMLP for the RBC effect to occur, but priming was not required at higher calcium concentrations. Several possible mechanisms that would explain the RBC effect on eosinophil LTC4 release were examined: (1) RBCs block the metabolism of LTC4; (2) RBCs protect the eosinophils from oxidative damage; (3) RBCs provide a substrate (or enzyme) that allows increased eosinophil LTC4 production. These mechanisms failed to explain our observation that erythrocytes enhance eosinophil LTC4 release, however, suggesting that alternative mechanisms are responsible for this effect J. Leukoc. Biol. 56: 65–73; 1994.
1α,25-Dihydroxyvitamin D3 promotes monocytopoiesis and suppresses granulocytopoiesis in cultures of normal human myeloid blast cells
Authors: Barton Aisling E , Bunce Christopher M , Stockley Robert A , Harrison Paul , Brown Geoffrey
Published: January 2018

Primitive myeloid blast cells (2-10 106) were purified from 18–22-week fetal liver–derived mononuclear cell preparations by negative selection followed by counterflow cell elutriation. The cells, when maintained in liquid culture in the presence of 100 U/ml interleukin-3 (IL-3) for the first 5 days and 10 U/ml IL-3 and 30 ng/ml granulocyte colony-stimulating factor thereafter, underwent considerable proliferation resulting in an ~ 30-fold increase in cell number by day 14. Analyses of cell morphology and of the numbers of cells that expressed the neutrophil-associated antigen CD15, the monocyte-associated antigen 61D3, and enzymes α-naphthyl acetate esterase (ANAE), human leukocyte elastase, and cathepsin G revealed that proliferation of the cells was associated with their concomitant differentiation toward neutrophils and monocytes. The cultures generated predominantly neutrophils; by day 14, wells seeded with 2 105 cells produced ~ 5 106 neutrophils as opposed to only ~ 3.5 105 cells with a monocytoid morphology. This predominance of granulocytopoiesis over monocytopoiesis was confirmed by the numbers of cells that had acquired expression of the CD15 antigen and ANAE, which were approximately 2 106 and 1 105, respectively. By contrast, parallel cultures containing 100 nM 1α,25-dihydroxyvitamin D3 (VitD3) generated more monocytes than neutrophils. At day 14, VitD3-treated cultures contained ~2 106 cells with morphologies consistent with their differentiation toward monocytes and ~ 1 106 ANAE-positive cells, compared with ~ 9.5 105 cells having morphologies of granulocyte-series cells and ~ 4.5 104 CD15-positive cells. In both control and VitD3-treated cultures, the enzymes cathepsin G and human leukocyte elastase were expressed almost exclusively by cells that were differentiating toward neutrophils. These data reveal that VitD3 promotes monocytopoiesis and suppresses granulocytopoiesis of primitive blast cells. J. Leukoc. Biol. 56: 124–132; 1994.
13-HODE inhibits the intracellular calcium increase of activated human polymorphonuclear cells
Authors: van de Velde Marco J , Engels Ferdi , Henricks Paul A J , Nijkamp Frans P
Published: January 2018

We studied the effect of the linoleic acid metabolite 13-hydroxyoctadecadienoic acid (13-HODE) on the increase of the intracellular calcium concentration, [Ca2+]i, induced by platelet-activating factor (PAF), leukotriene B4 (LTB4), and formyl-Met-Leu-Phe (fMLP) in human polymorphonuclear leukocytes (PMNs). 13-HODE by itself did not change the [Ca2+]i of PMNs. However, when PMNs were preincubated with 13-HODE and subsequently stimulated with PAF, LTB4, or fMLP, an inhibition of the increase of the [Ca2+]i was observed. The PAF-induced calcium response was concentration-dependently inhibited between 0.1 and 5 μM 13-HODE. These results suggest that 13-HODE can affect the increase of the [Ca2+]i and hence can modulate activation of PMNs. J. Leukoc. Biol. 56: 200–202; 1994.
Gene therapy: current status and future prospects
Authors: Kerr William G , Mulé James J
Published: January 2018

The ability to successfully introduce foreign genes into eukaryotic cells has made possible a new approach to the treatment of human disease. Gene therapy is now being brought to bear on genetic, malignant, and infectious diseases. In this review, we summarize the status of the field through an analysis of clinical protocols involving transfer of marker or therapeutic gene(s) into various somatic cell targets. Many of these trials will begin to examine whether or not patients with diseases that are unresponsive to conventional therapeutic interventions (e.g., pharmaceutical, surgical) will show benefit solely from somatic cell-based gene therapies. In other trials, the gene therapies are meant to complement or bolster the effect of conventional treatments. Although the field of gene therapy is now entering the clinical arena, we will also attempt to summarize certain shortcomings and technical hurdles that will need to be overcome for its eventual widespread use. J. Leukoc. Biol. 56: 210–214; 1994.
The neuropathogenesis of HIV-1 infection
Authors: Gendelman Howard E , Lipton Stuart A , Tardieu Marc , Bukrinsky Michael I , Nottet Hans S L M
Published: January 2018

HIV infection in brain revolves around productive viral replication in cells of mononuclear phagocyte lineage, including brain macrophages, microglia, and multinucleated giant cells [1–4]. Together, they are the instigators for cellular and viral neurotoxic activities [5–10]. Several published reports show that viral and/or cellular products produced from HIV-1-infected macrophages injure neurons and induce glial proliferation during advancing central nervous system (CNS) infection [11–18]. These findings are supported by the apparent discrepancy between the distribution and numbers of virus-infected cells and concomitant brain tissue pathology [5, 19]. Whether these soluble factors are indirectly responsible for neuronal damage remains undefined. The identification and regulation of neurotoxins produced from HIV-infected macrophages are central to uncovering how HIV mediates CNS disease. The authors who contributed to this work represent laboratories with overlapping areas of expertise. Broad-based complementary hypotheses regarding HIV neuropathogenesis are now provided. J. Leukoc. Biol. 56: 389–398; 1994.
Cytokine networks in solid human tumors: regulation of angiogenesis
Authors: Leek R D , Harris A L , Lewis C E
Published: January 2018

The isolation, purification, and molecular cloning of an increasing number of cytokines and their receptors have allowed major advances in our understanding of the relevance of these proteins to the pathobiology and treatment of such human diseases as neoplasia. Cytokines produced by the multiple cell types present within the microenvironment of solid tumors form a complex, dynamic network, in which they have overlapping properties, induce other cytokines and alter the expression of soluble and cell surface-bound cytokine receptors. A broad number of such intratumoral cytokines have multiple effects on tumor progression. These include direct and indirect effects both on tumor cell growth and metastatic behaviors and on such cells in the stromal compartment as fibroblasts, infiltrating immune cells, and endothelial cells in the microvasculature. Here, we review the sites of production and multifaceted role of several key cytokines in the stimulation of a new blood supply within growing neoplasms. The clinical implications and new therapeutic targets suggested by this rapidly emerging picture of the cellular and molecular mechanisms subserving tumor angiogenesis are also discussed. J. Leukoc. Biol. 56: 423–435; 1994.
Coengagement of CD2 with LFA-1 or VLA-4 by bispecific ligand fusion proteins primes T cells to respond more effectively to T cell receptor-dependent signals
Authors: Dietsch Mary T , Chan Po-Ying , Kanner Steven B , Gilliland Lisa K , Ledbetter Jeffrey A , Linsley Peter S , Aruffo Alejandro
Published: January 2018

To examine the effects of ligand engagement and accessory molecule juxtaposition on T cell receptor (TCR) signaling, we prepared LFA-3/ICAM-1 Rg and LFA-3/VCAM-1 Rg bispecific immunoglobulin fusion proteins (Rg, recombinant globulin). These novel fusion proteins allowed us to examine the effects of ligand driven co-engagement of T cell proteins CD2 and LFA-1 or CD2 and VLA-4 on TCR-dependent mobilization of intracellular Ca2+. We observed that preincubation of resting T cells with LFA-3/ICAM-1 Rg or LFA-3/VCAM-1 Rg fusion proteins resulted in significantly enhanced mobilization of intracellular Ca2+ following TCR-accessory molecule cross-linking relative to T cells preincubated with each of the monospecific Rgs alone or with combinations of the monospecific Rg fusion proteins. In addition, such coengagement stimulated TCR-dependent activation and tyrosine phosphorylation of phospholipase Cγ1 (PLCγ1). These results suggest that when T cells interact with antigen presenting cells the engagement of multiple cell adhesion molecules such as CD2, LFA-1, and VLA-4 primes the T cell to respond more effectively to signals delivered through the TCR. J. Leukoc. Biol. 56: 444–452; 1994.
Production of nitric oxide and peroxynitrite in the lung during acute endotoxemia
Authors: Wizemann Theresa M , Gardner Carol R , Laskin Jeffrey D , Quinones Susan , Durham Steven K , Goller Nancy L , Ohnishi S Tsuyoshi , Laskin Debra L
Published: January 2018

Nitric oxide is a short-lived cytotoxic mediator that has been implicated in the pathogenesis of endotoxin-induced tissue injury and septic shock. In the present studies we determined whether this mediator is produced in the lung during acute endotoxemia. We found that intravenous injection of rats with bacterially derived lipopolysaccharide (LPS), a condition that induces acute endotoxemia, caused a time-dependent increase in inducible nitric oxide synthase (iNOS) mRNA expression in the lung, which reached a maximum after 24 h. This was correlated with nitric oxide production in the lung as measured by electron paramagnetic spin trapping, which was detectable within 6 h. Alveolar macrophages (AMs) and interstitial macrophages (IMs) isolated from rats 6–12 h after induction of acute endotoxemia were also found to exhibit increased nitric oxide production in response to in vitro stimulation with interferon-γ (IFN-γ) and LPS measured by nitrite accumulation in the culture medium. The effects of acute endotoxemia on nitric oxide production by these cells were, however, transient and returned to control levels by 24 h in AMs and 36 h in IMs. Interestingly, although nitrite accumulation in the culture medium of IMs isolated 48 h after induction of acute endotoxemia and stimulated with low concentrations of IFN-γ and LPS was reduced, when compared with cells from control animals, these cells, as well as AMs, continued to express high levels of iNOS protein and mRNA. This was correlated with increased peroxynitrite production by the cells. Peroxynitrite has been shown to act as a nitrating agent and can generate nitrotyrosine residues in proteins. Using a specific antibody and immunohistochemistry, we found evidence of nitrotyrosine residues in sections of lungs 48 h after treatment of rats with endotoxin. These data suggest that nitric oxide produced by IMs and AMs can react with superoxide anion to form peroxynitrite. Taken together, the present studies demonstrate that AMs and IMs are activated following acute endotoxemia to produce reactive nitrogen intermediates and that both cell types contribute to inflammatory responses in the lung. J. Leukoc. Biol. 56: 759–768; 1994.
Identification of a proline-arginine-rich antibacterial peptide from neutrophils that is analogous to PR-39, an antibacterial peptide from the small intestine
Authors: Shi Jishu , Ross Christopher R , Chengappa M M , Blecha Frank
Published: January 2018

Neutrophil nonoxidative defense mechanisms include several low molecular weight antimicrobial peptides. We have isolated a proline-arginine-rich antibacterial peptide from porcine neutrophils. This cationic, low molecular weight peptide has a very high degree of identity (97%) to a bactericidal peptide, PR-39, that has been found in the porcine small intestine. Isolation of the same antimicrobial peptide from both neutrophils and cells of the small intestine in the same species is unique and suggests an important role for this protein in innate immune defenses. J. Leukoc. Biol. 56: 807–811; 1994.
Neuropeptide-mediated regulation of hapten-specific IgE responses in mice I. Substance P-mediated isotype-specific suppression of BPO-specific IgE antibody-forming cell responses induced in vivo and in vitro
Authors: Carucci John A , Auci Dominick L , Herrick Christina A , Durkin Helen G
Published: January 2018

The ability of substance P (SP) to regulate peak benzyl-penicilloyl (BPO)-specific IgE antibody-forming cell (AFC) responses in vivo and the ability of SP and other neuropeptides to regulate BPO-specific memory IgE AFC responses induced in vitro was determined. SP injected subcutaneously into BPO-keyhole limpet hemocyanin (BPO-KLH)-sensitized mice at the time of peak IgE responses suppressed these responses within 48 h (>90%). The suppression obtained was IgE isotype-specific, dose-dependent, and transient. When spleen cells from immunized mice were cultured for 5 days with BPO-KLH, peak memory IgE AFC responses were induced in vitro. Inclusion of either SP or vasoactive intestinal peptide (VIP), but not neurotensin, serotonin, somatostatin, or gastrin, in cultures suppressed these responses in isotype-specific, dose-dependent fashion (70%). SP-, but not VIP-mediated suppression of IgE responses was abrogated by inclusion of anti-IFNγ in culture. J. Leukoc. Biol. 57: 110–115; 1995.
Inhalation exposure to isobutyl nitrite inhibits macrophage tumoricidal activity and modulates inducible nitric oxide
Authors: Soderberg Lee S F , Barnett John B
Published: January 2018

Abuse of nitrite inhalants is common among male homosexuals and a history of abuse has been correlated with seropositivity to HIV and with the incidence of Kaposi’s sarcoma among AIDS patients. The present study shows that inhalation exposure of mice to 900 ppm isobutyl nitrite for 45 min/day for 14 days compromised macrophage tumoricidal activity by up to 40% and it remained compromised for at least 7 days after terminating exposures. The inhalation exposures did not affect tumor cell binding but did inhibit inducible nitric oxide (NO•). The NO• synthase inhibitor NG-methyl-l-arginine totally inhibited both NO• production and cytotoxicity, suggesting that reductions in NO• due to inhalant exposure may be responsible for the reduced cytotoxic activity. Exposure to the inhalant increased constitutive production of tumor necrosis factor-α (TNF-α). TNF-α has been reported to stimulate the replication of HIV and the proliferation of Kaposi’s sarcoma cells in vitro. J. Leukoc. Biol. 57: 135–140; 1995.
LPS inhibits the intracellular growth of Legionella pneumophila in thioglycolate elicited murine peritoneal macrophages by iron-dependent, tryptophan-independent, oxygen-independent, and arginine-independent mechanisms
Authors: Gebran Samir J , Yamamoto Yoshimasa , Newton Catherine , Tomioka Mitsugu , Widen Ray , Klein Thomas W , Friedman Herman
Published: January 2018

Thioglycolate-elicited murine macrophages from genetically susceptible A/J mice activated with lipopolysaccharide (LPS) and infected with Legionella pneumophila in vitro evince marked inhibition of intracellular growth of this bacterium. The mechanism of inhibition by LPS-activated macrophages in terms of replication of this intracellular pathogen is unclear. LPS activation of murine macrophages induced a downshift in transferrin receptor (TfR) expression and reduction in cellular iron content, and this was correlated with augmented intracellular growth of Legionella in the cells. When LPS-stimulated macrophages were first saturated with iron, partial reversion of L. pneumophila growth restriction was observed. However, an excess of exogenous L-tryptophan (Trp) did not reverse this growth inhibition, nor did supplementation of the macrophage culture medium with both iron and Trp. The antilegionella activity of the macrophages induced by LPS activation was independent of reactive oxygen intermediates (ROI), since the scavengers catalase, superoxide dismutase, mannitol, and thiourea had no effect on growth restriction. Likewise, notwithstanding the ability of LPS-activated macrophages to synthesize reactive nitrogen intermediates (RNI), which was inhibited by l-arginine analogs (NG-monomethyl-l-arginine and l-aminoguanidine), as well as by incubation in arginine-free medium, their ability to inhibit the intracellular replication of L. pneumophila was not affected. Thus, we conclude that LPS-activated macrophages inhibit the intracellular growth of L. pneumophila partially by iron-dependent, Trp-independent, and ROI- and RNI-independent mechanisms. We also suggest that additional unknown mechanisms are involved, since complete reversion was not obtained. J. Leukoc. Biol. 57: 80–87; 1995.
Chemoattractant receptor-specific differences in G protein activation rates regulate effector enzyme and functional responses
Authors: Jacobs Alfred A , Huber John L , Ward Richard A , Klein Jon B , McLeish Kenneth R
Published: January 2018

The hypothesis that disparate neutrophil functional responses to various chemoattractants are regulated by receptor-specific rates of G protein activation was examined in HL-60 granulocytes. The initial rates of G protein activation and the affinity of receptor-stimulated G proteins for GTPγS in HL-60 membranes stimulated by fMet-Leu-Phe, C5a, and leukotriene B4 (LTB4) differed significantly among the chemoattractants, with a rank order of fMet-Leu-Phe > C5a > LTB4. Equilibrium GTPγS binding showed that all three chemoattractants activated a common pool of G proteins. Stimulation of phospholipasc D activation, measured as phosphatidylethanol generation, and superoxide release in intact cells also occurred with a rank order of fMet-Leu-Phe > C5a > LTB+. On the other hand, the rank order of reccptor affinities for ligand and of the EC50 of chemoattractant stimulation of GTPγS binding was C5a > LTB4 > fMet-Leu-Phe. C5a and LTB4 receptor densities were similar but were less than formyl peptide receptor density. Graded pertussis toxin treatment proportionally reduced superoxide release and phospholipase D activation to all three chemoattractants. The results suggest that receptor-specific differences in G pro tein affinity for guanine nucleotides lead to different rates of guanine nucleotide exchange and, thereby, contribute to disparate effector enzyme and functional responses. J. Leukoc. Biol 57: 679–686; 1995.
A role for C-C chemokines in fibrotic lung disease
Authors: Smith Robert E , Stricter Robert M , Zhang Kai , Phan Sem H , Standiford Theodore J , Lukacs Nicholas W , Kunkel Steven L
Published: January 2018

Pulmonary fibrosis is the end point of a chronic inflammatory process characterized by leukocyte recruitment and activation, fibroblast proliferation, and increased extracellular matrix production. Previous studies of models of pulmonary fibrosis have investigated the role of cytokines in the evolution of the fibrotic response. The involvement of tumor necrosis factor and interleukin-1 in bleomycin-induced lung injury, a model of idiopathic pulmonary fibrosis, has been well established, suggesting that cytokines mediate the initiation and maintenance of chronic inflammatory lesions. However, the aforementioned cytokines alone cannot account for the recruitment and activation of specific leukocyte populations found in the bleomycin model. Recently, a family of novel proinflammatory cytokines (chemokines) was cloned and characterized, yielding many putative mediators of leukocyte functions. Macrophage inflammatory protein-1α (MIP-1α) and monocyte chemoattractant protein-1 (MCP-1) belong to the C-C chemotactic cytokine family, a group of low-molecular-weight peptides. These molecules modulate chemotaxis, proliferation, and cytokine expression in leukocyte subsets. Our group has investigated the roles of MCP-1 and MIP-1α in the bleomycin model. Both MCP-1 and MIP-1α are expressed in a time-dependent manner after bleomycin challenge, and passive immunization of these animals with either anti-MIP-1α or anti-MCP-1 antibodies attenuated leukocyte accumulation. In addition, we have identified specific cell types expressing MCP-1 or MIP-1α by in situ hybridization and immunohistochemical localization, respectively. Furthermore, our results indicate that MIP-1α expression is mediated by alveolar macrophage-derived tumor necrosis factor, identifying an important cytokine pathway in the initiation of pulmonary fibrosis. Finally, anti-MIP-1α therapy attenuated fibrosis, providing direct evidence for its involvement in fibrotic pathology. Our work has clearly established that the C-C chemokines MCP-1 and MIP-1α are expressed and contribute to the initiation and maintenance of the bleomycin-induced pulmonary lesion. J. Leukoc. Biol. 57: 782–787; 1995.
Macrophage colony stimulatory factor–activated bone marrow macrophages suppress lymphocytic responses through phagocytosis: a tentative in vitro model of Rosai-Dorfman disease
Authors: Jadus Martin R , Sekhon Sant , Barton Beverly E , Wepsic H Terry
Published: January 2018

NBXFO hybridoma cells produced macrophage colony-stimulating factor (M-CSF), which stimulated the growth of murine bone marrow–derived macrophages with potent suppressor activity. These macrophages suppressed lymphocyte responses to mitogens and antigens in a dose-dependent manner. Using a transwell chamber, we demonstrated that macrophages needed physical contact with the lymphocytes to suppress lymphocyte proliferation on day 1 in the concanavalin A mitogen reaction. In addition, no soluble suppressor factor was detected at that time. The number of lymphocytes disappeared with time when they were cocultured with the macrophages. Electron microscopy revealed that the macrophages phagocytosized the lymphocytes after 7 1/2 h. Dextran sulfate, heparan, and fucoidan prevented the macrophages from suppressing the lymphocytes. This phenomenon resembles the human disease sinus histiocytosis, also called Rosai-Dorfman disease, in which macrophages (histiocytes) phagocytosize autologous lymphocytes; occasionally, this disease is associated with immunological abnormalities. Thus we believe that macrophage-activating cytokines, such as M-CSF, may stimulate macrophages to phagocytose lymphocytes in vivo. J. Leukoc. Biol. 57: 936–942; 1995.
Cellular and molecular mechanisms of IFN-γ production induced by IL-2 and IL-12 in a human NK cell line
Authors: Ye Jianping , Ortaido John R , Conlon Kevin , Winkler-Pickett Robin , Young Howard A
Published: January 2018

Interferon-γ (IFN-γ) is an important immunoregulatory protein produced predominantly by T cells and large granular lymphocytes (LGL) in response to different extracellular signals. In particular, two interleukins (ELs), IL-2 and IL-12, have been shown to be potent inducers of IFN-γ gene expression in both T cells and LGL. Although it has been reported that there are some T cell lines that produce IFN-γ in response to IL-2 and IL-12 stimulation, there has as yet been no report of a natural killer (NK) cell line that responds in a similar manner. In this report we present evidence that the cell line NK3.3 derived from human NK cells, responds to both IL-2 and IL-12, as measured by increases in IFN-γ and granulocyte-macrophage colony-stimulating factor (GM-CSF) cytoplasmic mRNA and protein expression. In addition, when used together EL-2 and IL-12 synergized in the induction of IFN-γ and GM-CSF and this synergy was attributed to an increased accumulation and stability of the IFN-γ and GM-CSF mRNAs. To investigate the signaling pathways involved in the gene induction, five inhibitors, cyclosporin A (CsA), transforming growth factor-β, cydoheximide, genistein, and staurosporine A, were used in analyzing the effects of IL-2 and IL-12 on NK3.3 cells. The results suggest that activation of protein kinase C, but not new protein synthesis, is required for IL-2 induction of IFN-γ and GM-CSF cytoplasmic mRNA. In contrast, IL-12 induction of IFN-γ cytoplasmic mRNA appears to only partially depend on activation of protein kinase C. Furthermore, both transforming growth factor-β and genistein, a tyrosine kinase inhibitor, could suppress IL-2 and IL-12 signaling but CsA was generally inactive. It also was observed that suppression of cytokine gene expression by these agents was independent of the inhibition of proliferation. In addition, IL-2 but not IL-12 induced nudear factors NF-κB and API, and regulation of the nudear levels of these two DNA binding protein complexes is correlated with IFN-γ and GM-CSF gene expression. These data indicate that IL-2 and IL-12 may have distinct signaling pathways leading to the induction of IFN-γ and GM-CSF gene expression, and that the NK3.3 cell line may serve as a novel model for dissecting the biochemical and molecular events involved in these pathways. J. Leukoc. Biol. 58: 225–233; 1995.
On the expression of nitric oxide synthase by human macrophages. Why no NO?
Authors: Albina Jorge E
Published: January 2018

The production of nitric oxide (NO) and its role in the anti-tumor and anti-microbial effects of rodent macrophages appears well established. In contrast, the circumstances required for its release from human monocytes/macrophages and its potential role in human pathology remain controversial. Evidence to be discussed suggests that NO is a redundant, autotoxic, immunosuppressive, and inefficient mediator of macrophage function. For these reasons, the expression of nitric oxide synthase as a rapid-response, high-output effector pathway may have been evolved out of the human monocyte/macrophage response repertoire or severely restricted in its expression. Hypothetical roles for a modest and circumscribed production of NO by human macrophages are proposed.
Not only Th2 cells but also Th1 and Th0 cells express CD30 after activation
Authors: Bengtsson Åsa , Johansson Catharina , Linder Maria Tengvall , Halldén Gunilla , van der Ploeg Ingeborg , Scheynius Annika
Published: January 2018

To investigate whether the CD30 molecule, expressed only by a minority of T and B cells, defines a subtype of T helper cells, Pityrosporum orbiculare-specific CD4+ T cell clones were assessed for CD30 protein and gene expression. The clones were defined as Th1, Th0, and Th2 according to their cytokine mRNA profile detected by reverse transcription PCR (RT-PCR). The kinetics of CD30 expression after OKT3 (anti-CD3) stimulation was analyzed by flow cytometry, immunocytochemistry, and RT-PCR. OKT3 activation induced a high expression of CD30 in cells of both Th1 and Th0 as well as Th2 type after 1-3 days. A difference between the clones was noted in that the Th2 clones remained highly positive in CD30 expression, whereas expression in the other clones started to decline from day 3. These data indicate that CD30 is expressed in activated CD4+ T cells of all three subtypes, and that the expression is sustained in Th2 cells.
Activation of inducible nitric oxide synthase gene in murine macrophages requires protein phosphatases 1 and 2A activities
Authors: Dong Zhongyun , Yang Xiulan , Xie Keping , Juang Shin-Hun , Llansa Norma , Fidler Isaiah J
Published: January 2018

The purpose of these studies was to identify phosphatase activities required for the production of nitric oxide in murine macrophages exposed to lipopolysaccharide (LPS), synthetic lipopeptide (LPP), and mouse interferon-gamma (IFN-γ). The in vitro treatment of macrophages with IFN-γ and LPS or IFN-γ and LPP resulted in production of NO, which was inhibited by addition of the specific phosphatase 1 and 2A (PP1/2A) inhibitors okadaic acid (OA), calyculin A, and cantharidin (but not the nonactive analogues okadaic acid tetraacetate and 1,4-dimethylendothall). OA suppressed the accumulation of steady-state inducible NO synthase (iNOS) mRNA and iNOS protein (without alteration of their stability). The cytosol and nuclei of control macrophages contained large amounts of PP1/2A activities that were inhibited by OA in a dose-dependent manner. Taken together, these data indicate that PP1/2A activities are involved in the regulation of iNOS gene expression in murine macrophages.
Selectivity and antagonism of chemokine receptors
Authors: Wells Timothy N C , Power Christine A , Lusti-Narasimhan Manjula , Hoogewerf Arlene J , Cooke Robert M , Chung Chun-wa , Peitsch Manuel C , Proudfoot Amanda E I
Published: January 2018

The chemokine superfamily can be sub-divided into two groups based on their amino terminal cysteine spacing. The CXC chemokines are primarily involved in neutrophil-mediated inflammation and, so far, two human receptors have been cloned. The CC chemokines tend to be involved in chronic inflammation, and recently we have cloned a fourth leukocyte receptor for this group of ligands. Understanding what makes one receptor bind its range of agonists is important if we are to develop potent selective antagonists. We have started to investigate the molecular basis of this receptor selectivity by looking at why CC chemokines do not bind to the CXC receptors in several ways. First, we looked at the role of the three-dimensional structure of the ligand, and have solved the three-dimensional structure of RANTES using nuclear magnetic resonance spectroscopy. The structure is similar to that already determined for the CC chemokine macrophage inflammatory protein-1β, and it has a completely different dimer interface to that of the CXC chemokine interleukin-8 (IL-8). However, the monomer structures of all the chemokines are very similar, and at physiological concentrations the proteins are likely to be monomeric. Second, by examining all the known CC and CXC chemokines, we have found a region that differs between the two subfamilies. Mutations of one of the residues in this region, Leu-25 in IL-8, to tyrosine (which is conserved at this position in CC chemokines) enables the mutant IL-8 to bind CC-chemokine receptor-1 (CC-CKR-1) and introduces monocyte chemoattractant activity. Using other mutations in this region, we can show a direct interaction with the N-terminus of CC-CKR-1. Third, we have found that modification of the amino terminus of RANTES by addition of one amino acid makes it into an antagonist with nanomolar potency. Taken together, this data suggests a two-site model for receptor activation and for selectivity between CC and CXC chemokines, with an initial receptor contact provided by the main body of the chemokine, and activation provided by the amino terminal region.
Dissection of the pathologies induced by transmembrane and wild-type tumor necrosis factor in transgenic mice
Authors: Probert Lesley , Akassoglou Katerina , Alexopoulou Lena , Douni Eleni , Haralambous Sylva , Hill Sally , Kassiotis George , Kontoyiannis Dimitris , Pasparakis Manolis , Plows David , Kollias George
Published: January 2018

With increasing awareness that seemingly diverse immune-mediated diseases involve similar pathogenetic mechanisms, and the identification of a growing number of key effector molecules, it is becoming possible to design and generate effective transgenic models for such diseases. Tumor necrosis factor (TNF) plays a prominent role in immune and host defense responses and there is strong evidence that abnormal TNF production contributes to disease initiation and progression in rheumatoid arthritis, systemic inflammatory response syndrome, diabetes, multiple sclerosis, and many other immune-mediated disorders. The generation of TNF transgenic mice, in which TNF production is deregulated, has provided us with direct evidence that, in vivo, this cytokine can indeed trigger the development of such complex disease phenotypes. Transgenic mice that have been engineered to overexpress human or murine TNF molecules in peripheral joints, T cells, or neurons of the central nervous system represent important animal models for human rheumatoid arthritis, systemic inflammation, and multiple sclerosis, respectively. In addition to establishing a central role for TNF in such diseases, these animal models have already proved valuable for identifying additional important disease-effector molecules, and for gaining an insight into the complex in vivo mechanisms that are involved in disease pathogenesis. For example, in the case of arthritis, TNF has been found to transmit its pathogenic effects entirely through interleukin-1, which may therefore represent an additional important target for therapeutic intervention in the human disease. In summary, TNF transgenic models of human disease are expected to serve as important in vivo tools for defining details of disease pathogenesis, potential targets for therapeutic intervention, and for evaluating the possible involvement of additional genetic and environmental factors on the disease state.
Integrin-mediated epithelial-T cell interaction enhances nitric oxide production and increased intracellular inhibition of Chlamydia
Authors: Igietseme Joseph U , Uriri Ijindah M , Hawkins Ray , Rank Roger G
Published: January 2018

T cell-mediated immunity against Chlamydia in mice is mediated at least in part by T cell-derived interferon-γ (IFN-γ) induction of the nitric oxide synthase (iNOS) system in infected epithelial cells. Although IFN-γ alone could stimulate nitric oxide (NO) production from epithelial cells and inhibit the intracellular growth of Chlamydia, the effectiveness was less than when infected epithelial cells were co-cultured with IFN-γ-producing T cell clones. In co-cultures containing T cells and infected epithelial cells, additional NO produced by activated T cells could augment chlamydial killing; however, T cell-derived NO was insufficient to account for the total NO present in the co-culture and therefore could not explain the dramatic increase in chlamydial inhibition under those conditions. To determine whether direct cell-to-cell interaction involving adhesion molecules was involved in increased NO induction, the ability of neutralizing monoclonal antibodies directed against intercellular adhesion molecule type 1 (ICAM-1) and leukocyte function antigen-1 (LFA-1) to suppress NO production and lower intracellular chlamydial inhibition was investigated. It was found that monoclonal antibodies against ICAM-1/LFA-1 could significantly reduce the capacity of a protective CD4+ type 1 (Th1) clone (clone 2.14-0) to inhibit the intracellular growth of the C. trachomatis agent of mouse pneumonitis (MoPn). The suppression of the anti-chlamydial action of the clone by antibodies correlated with ~50% decrease in NO production. Also, paraformaldehyde-fixed clone 2.14-0 could enhance NO induction and chlamydial inhibition mediated by IFN-γ, and this effect could be reversed by anti-ICAM-1/LFA-1 antibodies. The results indicated that epithelial-T cell interaction via adhesion molecules enhances NO production and increased chlamydial inhibition by IFN-γ-secreting T cells.
PLA2 promotes fusion between PMN-specific granules and complex liposomes
Authors: Blackwood R Alexander , Transue Amy T , Harsh Donna M , Brower Ruth C , Zacharek Sima J , Smolen James E , Hessler Ronald J
Published: January 2018

Neutrophil stimulation results in the activation of a variety of phospholipases, including phospholipase A2 (PLA2), which releases arachidonic acid from the 2 position of membrane phospholipids, leaving a lysophospholipid. Because arachidonic acid is known to be a potent fusogen in vitro, we examined the effect of metabolism by PLA2 on the fusion of complex liposomes (liposomes prepared with a phospholipid composition similar to that found in neutrophil plasma membrane). We observed that PLA2 augmented the fusion of complex liposomes with each other as well as with specific granules isolated from human neutrophils, lowering the Ca2+ requirement for fusion by three orders of magnitude. Furthermore, although lysophospholipids inhibited fusion, the incorporation of arachidonic acid into liposome membranes overcame the inhibitory effects of the lysophospholipids. Thus with PLA2 and annexins we were able to obtain fusion of complex liposomes at concentations of Ca2+ that are close to physiological. Our data suggest that the activation of PLA2 and the generation of arachidonic acid may be the major fusion-promoting event mediating neutrophil degranulation.
A CD66a-specific, activation-dependent epitope detected by recombinant human single chain fragments (scFvs) on CHO transfectants and activated granulocytes
Authors: Jantscheff Peter , Nagel Gerhard , Thompson John , Kleist Sabine V , Embleton M J , Price Michael R , Grunert Fritz
Published: January 2018

Antibodies to CD66 recognize at least five members (CD66a–e) of the carcinoembryonic antigen (CEA) family. Recombinant human single-chain Fv fragments (scFvs) that bind specifically to CD66a (biliary glycoprotein) were obtained from a naive human scFv library. The scFvs bound to the N-domain of CD66a on Chinese hamster ovary (CHO) transfectants but did not bind to freshly isolated peripheral granulocytes or to dimethylsulfoxide-treated HL-60 cells. In contrast, scFvs bound well to granulocytes that were short-term activated with N-formyl-Met-Leu-Phe or phorbol 12-myristate 13-acetate and to human HL-60 cells that were treated with all-trans-retinoic acid to induce granulocytic differentiation. Quantification of antigenic sites showed that the activation-dependent CD66a epitopes were expressed on nearly all of the CD66a molecules on CHO-biliary glycoprotein transfectants, but they were detected only on a portion of the molecules on activated polymorphonuclear neutrophils and differentiated HL-60 cells. Binding of CD66a scFvs to their neoepitopes on prestimulated PMNs induced respiratory burst, suggesting that CD66a is capable of delivering transmembrane signals in these cells.
Oxidized LDL potentiates LPS-induced transcription of the chemokine KC gene
Authors: Hamilton Thomas A , Major Jennifer A
Published: January 2018

Oxidized low-density lipoprotein (LDL) has been shown to modulate the expression of multiple gene products associated with inflammation in several different cell types including mononuclear phagocytes. The reported effects vary dramatically, however, depending upon cell type, stimulus, and degree of LDL oxidation. In the present report, oxidized LDL has been found to markedly potentiate expression of the KC chemokine gene in lipopolysaccharide (LPS)-stimulated macrophages. Pretreatment of elicited mouse peritoneal macrophages with oxidized LDL but not native LDL produced a significant enhancement of LPS-induced KC mRNA expression, whereas levels of IP-10 mRNA, another CXC chemokine, were altered in opposite fashion. The alteration in KC mRNA expression was dependent upon the dose, exposure time, and extent of LDL oxidation. Oxidized LDL selectively prolonged the expression of KC mRNA. Surprisingly this was not a consequence of altered mRNA stability, but rather of prolonged transcription. These effects on KC gene transcription were in marked contrast to previous reports demonstrating inhibitory effects of oxidized LDL on LPS-induced macrophage chemokine expression. Thus extensively oxidized LDL acts on the transcriptional control process in macrophages in both positive and negative fashion on separate members of the same gene family.