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R M Strieter

Publications and source records attributed to R M Strieter.

At least 253 records · Page 14Linked to original sources
PubMed1994

In vitro production of interleukin-1 receptor antagonist in IgG-mediated red cell incompatibility.

BACKGROUND: Recently, proinflammatory cytokines including interleukin 1 (IL-1) have been implicated in the pathophysiology of immune-mediated hemolysis. Little is known, however, about the mechanisms by which inflammatory events in these reactions may be downregulated. IL-1 receptor antagonist (IL-1ra) inhibits the actions of IL-1 by competition for cellular receptors, and thus it may regulate the biologic actions of IL-1 during immune-mediated hemolysis. The production of IL-1ra by peripheral blood mononuclear cells (PBMNCs) in response to IgG-coated red cells in vitro was investigated. STUDY DESIGN AND METHODS: Fresh PBMNCs were obtained by density gradient separation of heparinized whole blood. PBMNCs were cultured in the presence of anti-D-coated, Rh-positive red cells or uncoated Rh-negative red cells under nonadherent conditions. IL-1ra concentrations in the culture media were measured by enzyme-linked immunosorbent assay. IL-1ra and IL-1 beta gene expression was assessed by Northern blot analysis of PBMNC mRNA. RESULTS: IL-1ra production was evident 4 hours after stimulation with IgG-coated red cells and increased progressively over 24 hours. Gene expression of IL-1ra was first detected at 2 hours, lagging behind that of IL-1 beta. IL-1ra gene expression was not inhibited by neutralizing polyclonal antibodies to IL-1. Immunocytochemical staining to determine the cellular source localized IL-1ra production to monocytes engaged in erythrophagocytosis. IL-1ra production was inhibited by dexamethasone (10(-7) M). CONCLUSION: These results suggest that IL-1ra production may partly account for the variable pathophysiologic events seen in IgG-mediated autoimmune hemolysis and hemolytic transfusion reactions. Steroid treatment may also downregulate anti-inflammatory cytokine production in immune hemolysis.

Anemia, Hemolytic, Autoimmune↗
PubMed1994

Lipoteichoic acid induces secretion of interleukin-8 from human blood monocytes: a cellular and molecular analysis.

Invasion by gram-positive and gram-negative bacterial organisms is characterized immunopathologically by the activation of mononuclear phagocytic cells, leading to the elaboration of macrophage-derived regulatory and chemotactic factors, and the resultant influx of inflammatory leukocytes. Little is known regarding the mechanisms by which gram-positive organisms initiate macrophage activation and subsequent inflammation. In this investigation, we postulated that lipoteichoic acid (LTA) purified from two different gram-positive bacterial species was an important signal for the expression of chemotactic cytokines from human peripheral blood monocytes (PBM). In initial experiments, we demonstrated that cell-associated interleukin-8 (IL-8) was expressed by mononuclear phagocytes present in inflamed areas of endocardium in cases of acute Staphylococcus aureus endocarditis. We next demonstrated that LTA purified from either Staphylococcus aureus or Streptococcus pyogenes induced the time- and dose-dependent expression of IL-8 mRNA and protein from human PBM. The expression of IL-8 mRNA from LTA- but not lipopolysaccharide (LPS)-treated PBM was superinduced by concomitant treatment with cycloheximide, indicating that the expression of IL-8 mRNA from LTA-treated PBM was negatively controlled by repressor proteins. Furthermore, mRNA stability studies indicated that IL-8 mRNA was less stable in the presence of LTA than in the presence of LPS. Our findings indicate that LTA can induce the secretion of the polymorphonuclear leukocyte chemotactic factor IL-8 and that LTA may be an important cellular mediator of inflammatory cell recruitment that characterizes immune responses to gram-positive bacterial infections.

Cycloheximide↗
PubMed1994

Expression and regulation of macrophage inflammatory protein-1 alpha by murine alveolar and peritoneal macrophages.

A number of disease states are characterized by the accumulation of inflammatory cells at the site of tissue injury. Mononuclear phagocytes (M phi) represent key cellular mediators of inflammation via the production of regulatory and chemokinetic cytokines. One such cytokine, macrophage inflammatory protein-1 alpha (MIP-1 alpha), has been shown to be one of the major inducible chemotaxins expressed from murine macrophage cell lines (RAW 264.7). We postulated that MIP-1 alpha is a major monocyte chemoattractant produced by resident M phi, and the magnitude of production of this chemotaxin may depend upon the specific population of M phi studied. To test this hypothesis, we isolated alveolar macrophages (AM phi) and peritoneal macrophages (PM phi) from CD-1 mice by bronchoalveolar and peritoneal lavage, respectively. Recombinant murine MIP-1 alpha accounted for significant neutrophil chemokinetic rather than chemotactic activity, as assessed by checkerboard analysis. LPS-stimulated AM phi-derived monocyte chemotactic activity (MCA) was significantly neutralized by specific rabbit anti-murine MIP-1 alpha serum. In contrast, PM phi-derived conditioned media failed to produce MCA attributable to MIP-1 alpha. The production of MIP-1 alpha was then characterized from both AM phi and PM phi. While unstimulated AM phi and PM phi failed to express MIP-1 alpha mRNA, both AM phi and PM phi challenged with lipopolysaccharide (LPS) expressed MIP-1 alpha mRNA in a time-dependent fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Interleukin-4-dependent pulmonary eosinophil infiltration in a murine model of asthma.

The establishment of animal models of asthma is critical to elucidate the mechanisms involved in the pathogenesis of the disease. In the present study, we have used a parasite antigen from Schistosoma mansoni eggs, which induces a TH2 response, to elicit a pulmonary inflammatory reaction that resolves after 3 to 4 days. Histologic examination of the lungs of soluble egg antigens (SEA) or saline vehicle-challenged mice demonstrated a large influx of cells in the antigen- but not vehicle-challenged mice, thus demonstrating an antigen-specific reaction. A characteristic influx of eosinophils could be detected as early as 8 h, with significant increases at 24 to 72 h after challenge. An assessment of the bronchial alveolar lavage (BAL) fluid demonstrated dominant neutrophil infiltration at 8 h, with a subsequent decrease to background by 48 h. In addition, peak monocyte infiltration occurred at 24 h, and peak eosinophil extravasation into the airway was shown at 48 h. The examination of leukocyte infiltrates in the interstitium in dispersed lung preparations again demonstrated early neutrophil and monocyte infiltration at 8 h after challenge, with increases in lymphocyte and eosinophil infiltrates at 24 h. Examination of interleukin-4 (IL-4) production in the BAL fluid demonstrated the presence of IL-4 early in the response, with levels peaking between 8 and 24 h after antigen challenge, with no detectable IL-4 in the saline vehicle-challenged mice. Mice treated with anti-IL-4 antibodies demonstrated a tenfold decrease in BAL eosinophil influx at 48 h after challenge and a reduction in total pulmonary leukocyte cellularity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Macrophage inflammatory protein-1 alpha. A novel chemotactic cytokine for macrophages in rheumatoid arthritis.

We have shown that human macrophages (m phi s) play an important role in the elaboration of chemotactic cytokines in rheumatoid arthritis (RA) (Koch, A. E., S. L. Kunkel, J. C. Burrows, H. L. Evanoff, G. K. Haines, R. M. Pope, and R. M. Strieter. 1991. J. Immunol. 147:2187; Koch, A. E., S. L. Kunkel, L. A. Harlow, B. Johnson, H. L. Evanoff, G. K. Haines, M. D. Burdick, R. M. Pope, and R. M. Strieter. 1992. J. Clin. Invest. 90:772; Koch, A. E., P. J. Polverini, S. L. Kunkel, L. A. Harlow, L. A. DiPietro, V. M. Elner, S. G. Elner, and R. M. Strieter. 1992. Science (Wash. DC). 258:1798). Recently, m phi inflammatory protein-1 (MIP-1 alpha), a cytokine with chemotactic activity for m phi s and neutrophils (PMNs), has been described. We have examined the production of MIP-1 alpha using sera, synovial fluid (SF), and synovial tissue (ST) from 63 arthritic patients. MIP-1 alpha was higher in RA SF (mean, 29 +/- 8 ng/ml [SE]) compared with other forms of arthritis (2.8 +/- 1.7), or osteoarthritis (0.7 +/- 0.4; P < 0.05). RA SF MIP-1 alpha was greater than that found in either RA or normal peripheral blood (PB) (P < 0.05). Anti-MIP-1 alpha neutralized 36 +/- 3% (mean +/- SE) of the chemotactic activity for m phi s, but not PMNs, found in RA SFs. RA SF and PB mononuclear cells produced antigenic MIP-1 alpha. Mononuclear cell MIP-1 alpha production was augmented with phytohemagglutinin or LPS. Isolated RA ST fibroblast production of antigenic MIP-1 alpha was augmented upon incubation of cells with LPS, and to a lesser extent with tumor necrosis factor-alpha. Isolated RA ST m phi s expressed constitutive MIP-1 alpha mRNA and antigenic MIP-1 alpha. Using ST immunohistochemistry, MIP-1 alpha+ cells from RA compared with normal were predominantly m phi s and lining cells (P < 0.05). These results suggest that MIP-1 alpha plays a role in the selective recruitment of m phi s in synovial inflammation associated with RA.

Arthritis, Rheumatoid↗
PubMed1994

Epithelial neutrophil activating peptide-78: a novel chemotactic cytokine for neutrophils in arthritis.

We and others have shown that cells obtained from inflamed joints of rheumatoid arthritis (RA) patients produce interleukin-8, a potent chemotactic cytokine for neutrophils (PMNs). However, IL-8 accounted for only 40% of the chemotactic activity for PMNs found in these synovial fluids. Currently, we have examined the production of the novel PMN chemotactic cytokine, epithelial neutrophil activating peptide-78 (ENA-78), using peripheral blood, synovial fluid, and synovial tissue from 70 arthritic patients. RA ENA-78 levels were greater in RA synovial fluid (239 +/- 63 ng/ml) compared with synovial fluid from other forms of arthritis (130 +/- 118 ng/ml) or osteoarthritis (2.6 +/- 1.8 ng/ml) (P < 0.05). RA peripheral blood ENA-78 levels (70 +/- 26 ng/ml) were greater than normal peripheral blood levels (0.12 +/- 0.04 ng/ml) (P < 0.05). Anti-ENA-78 antibodies neutralized 42 +/- 9% (mean +/- SE) of the chemotactic activity for PMNs found in RA synovial fluids. Isolated RA synovial tissue fibroblasts in vitro constitutively produced significant levels of ENA-78, and this production was further augmented when stimulated with tumor necrosis factor-alpha (TNF-alpha). In addition RA and osteoarthritis synovial tissue fibroblasts as well as RA synovial tissue macrophages were found to constitutively produce ENA-78. RA synovial fluid mononuclear cells spontaneously produced ENA-78, which was augmented in the presence of lipopolysaccharide. Immunohistochemical localization of ENA-78 from the synovial tissue of patients with arthritis or normal subjects showed that the predominant cellular source of this chemokine was synovial lining cells, followed by macrophages, endothelial cells, and fibroblasts. Synovial tissue macrophages and fibroblasts were more ENA-78 immunopositive in RA than in normal synovial tissue (P < 0.05). These results, which are the first demonstration of ENA-78 in a human disease state, suggest that ENA-78 may play an important role in the recruitment of PMNs in the milieu of the inflamed joint of RA patients.

Arthritis↗
PubMed1994

Chemokine gene expression and secretion by cytokine-activated human microvascular endothelial cells. Differential regulation of monocyte chemoattractant protein-1 and interleukin-8 in response to interferon-gamma.

The elicitation of leukocytes from the circulation to inflamed tissue depends on the activation of both the leukocyte and endothelial cell. In this study we determined the gene expression and secretion patterns for the chemokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) in cytokine- and lipopolysaccharide (LPS)-treated cultured human lung microvascular endothelial cells (HLE). HLE constitutively expressed low levels of MCP-1 and IL-8. Treatment of HLE with a variety of cytokines and LPS up-regulated both IL-8 mRNA expression and release of immunoreactive IL-8 with an order of potency tumor necrosis factor-alpha (TNF-alpha) >> IL-1 alpha > LPS, whereas interferon-gamma (IFN-gamma) had no effect on IL-8 mRNA or antigenic levels. However, IFN-gamma, in combination with high doses of IL-1 alpha, resulted in a synergistic increase in IL-8 generation. MCP-1 gene expression and secretion was induced in a dose-dependent manner after IL-1 alpha, TNF-alpha, IFN-gamma, and LPS activation of HLE. IL-1 alpha was the most potent inducer of MCP-1 generation and LPS was relatively ineffective. IFN-gamma, in combination with low doses of IL-1 alpha, resulted in a synergistic increase in MCP-1 generation by HLE. These results demonstrate that although IL-8 and MCP-1 generation by HLE occurs on cytokine treatment, the relative ability of a given cytokine to elicit IL-8 generation is not directly parallel to effects on MCP-1 generation. These data suggest that the regulation of IL-8 and MCP-1 expression exhibit significant differences in their mechanisms. Such differences in the expression of specific chemokines may explain the specific appearance of various leukocytes at sites of inflammation and injury. These data also directly demonstrate that the lung microvascular endothelium contribute to the cytokine network of the lung, with the ability to respond to locally generated cytokines and to produce potent mediators of the local inflammatory response.

Base Sequence↗
PubMed1994

Production of interleukin-10 by human bronchogenic carcinoma.

Interleukin-10 (IL-10) is a recently characterized cytokine with suppressive activity against various aspects of the cellular immune response. Our laboratory has previously demonstrated that another anti-inflammatory cytokine, IL-1 receptor antagonist (IRAP) is produced and secreted by human bronchogenic carcinomas. We speculated that tumor production of IRAP may mitigate host responses and confer increased tumor viability. In this study, we investigated the capacity of human bronchogenic tumors to produce IL-10 as another possible mechanism to attenuate host defenses. We found increased levels of antigenic IL-10 in tissue homogenates of human bronchogenic carcinomas compared with normal lung tissue (13.69 +/- 2.87 versus 5.84 +/- 0.84 ng/mg total protein). Immunohistochemical staining of tumors illustrate primary localization of antigenic IL-10 to individual tumor cells. Analysis of supernatants of several unstimulated human bronchogenic cell lines in vitro demonstrated the ability of tumor cells to constitutively produce IL-10. Functional studies of mononuclear cells, cultured in the presence of conditioned medium from a bronchogenic cell line, demonstrated their increased tumor necrosis factor and IL-6 production with the addition of neutralizing antibodies to IL-10. These findings demonstrate that human bronchogenic carcinomas elaborate functional IL-10, which may significantly impair immune effector cell function and enable the tumor to evade host defenses.

Carcinoma, Bronchogenic↗
PubMed1994

Production of monocyte chemoattractant protein-1 and macrophage inflammatory protein-1 alpha by inflammatory granuloma fibroblasts.

The formation of hepatic granulomas around persistently deposited Schistosoma mansoni eggs leads to parenchymal damage, ongoing fibrosis, and ultimate loss of liver function. In this study, the production of macrophage inflammatory protein-1 alpha (MIP-1) and monocyte chemoattractant protein-1 (MCP-1) by granuloma fibroblasts was examined to establish the potential contribution of intragranuloma fibroblasts to the maintenance of the chronic inflammation. Isolated fibroblasts from dispersed acute infection hepatic granulomas were grown in tissue culture for 3 to 4 weeks and used on the third or fourth passage. We initially surveyed fibroblasts for production of MIP-1 and MCP-1 by reverse transcription-polymerase chain reaction (RT-PCR) after stimulation with interleukin (IL)-1, tumor necrosis factor, interferon (IFN)-gamma, IL-4, or IL-10: cytokines found within the granuloma. These studies demonstrated constitutive expression of MCP-1 and differential up-regulation of MIP-1 on cytokine stimulation. Protein expression was then verified by immunohistochemical localization of MIP-1 and MCP-1 in paraformaldehyde-fixed fibroblasts and by direct quantitation of MIP-1 and MCP-1 in culture supernatants by specific ELISAs. These studies demonstrated constitutive expression of MCP-1 in unstimulated and cytokine-stimulated granuloma fibroblasts. In contrast, IL-1 (0.1 to 2.5 ng/ml), IFN-gamma (10 micrograms/ml), and IL-10 (2.5 to 10 ng/ml) were able to induce the significant production of MIP-1 by the granuloma fibroblasts. Interestingly, normal noninflammatory fibroblasts from uninfected mice showed no significant production of MIP-1 or MCP-1 in response to these cytokines. These results suggest that granuloma fibroblasts may be phenotypically altered compared with normal fibroblasts and have a significant role in leukocyte recruitment, granuloma growth, and maintenance of the egg-induced lesion.

Animals↗
PubMed1994

Acute lung injury: the role of cytokines in the elicitation of neutrophils.

Cytokine networks between immune and nonimmune cells of the alveolar-capillary membrane are necessary for cellular communication during pulmonary inflammation. The subsequent events of these cellular/humoral interactions are pivotal to the initiation and propagation of the inflammatory response leading to pulmonary injury. The studies cited in this paper underscore the interrelationship of early response cytokines, adhesion molecules, and the chemokine IL-8 that orchestrate the recruitment of neutrophils into the lung. The paradigm for neutrophil extravasation is likely operative in the microvasculature of the lung, and consists of four or more steps (Figure 3). First, acute lung injury results in the activation of microvascular endothelium in response to the local generation of TNF or IL-1, leading to expression of endothelial cell-derived E- and P-selectins and ICAM-1. The constitutive presence of neutrophil-derived L-selectin allows for the initial adhesive interaction of neutrophils with endothelial cell selectins leading to the "rolling" effect. Second, generation of IL-8 leads to the activation of neutrophils in the vascular compartment and expression of beta 2 integrins, while L-selectin is concomitantly shed. Third, the interaction of the neutrophil beta 2 integrin with its receptor/ligand, ICAM-1, results in the rapid arrest of neutrophils on the endothelium. Fourth, the subsequent events leading to neutrophil extravasation beyond the vascular compartment are dependent upon a combination of haplotaxis (migration in response to an insoluble gradient), the continued expression of beta 2 integrins on neutrophils and ICAM-1 on nonimmune cells, and the maintenance of a neutrophil specific (IL-8) chemotactic gradient. The participation of IL-8 and potentially other C-X-C chemokines in the inflammatory response appears to be critical for the orchestration of the directed migration of inflammatory leukocytes into the lung. After arriving in the lung, these activated leukocytes can respond to noxious stimuli or induce pulmonary injury through the release of reactive oxygen metabolites, proteolytic enzymes, and additional cytokines. Our current knowledge and future investigations regarding the mechanisms involved in neutrophil elicitation may allow us to employ clinical interventional strategies that will attenuate neutrophil-dependent acute lung injury, such as ARDS.

Cell Adhesion Molecules↗
PubMed1993

Recruitment of inflammatory cells to the pleural space. Chemotactic cytokines, IL-8, and monocyte chemotactic peptide-1 in human pleural fluids.

Pleural effusions secondary to various diseases are associated with the presence of different inflammatory cells. The role of selective chemotactic cytokines in the recruitment of phagocytes to the pleural space is unclear. IL-8 and monocyte chemotactic peptide-1 (MCP-1) are recently described cytokines that are chemotactic for neutrophils and monocytes, respectively. We prospectively studied 63 patients, using strictly defined criteria for their selection. IL-8 concentrations were elevated in both empyema fluid (9.15 +/- 0.89 ng/ml) and parapneumonic effusions (4.7 +/- 0.697 ng/ml) when compared with pleural effusions secondary to other diseases. IL-8 levels were higher in empyema fluid than in parapneumonic effusions (p = 0.01). There was a significant correlation between IL-8 levels and the total numbers of neutrophils in empyema fluids (r = 0.80). Chemotactic activity for neutrophils was elevated in empyema fluid and the addition of IL-8 neutralizing serum decreased bioactivity by 32.22%. Malignant pleural effusions had the highest levels of MCP-1 (12.0 +/- 3.7 ng/ml) when compared with others. Cytology-positive pleural fluids (n = 10) had a higher level of MCP-1 than cytology-negative effusions (p = < 0.05). Malignant pleural fluid MCP-1 levels correlated (r = 0.70) with the absolute number of monocytes in the pleural fluid. Neutralization of monocyte chemotactic activity of malignant pleural fluid by specific neutralizing serum caused a 70.3% inhibition of bioactivity. Immunohistochemical staining of malignant pleural fluid localized antigenic MCP-1 to malignant cells. We conclude that both IL-8 and MCP-1 play major but not exclusive roles in the recruitment of neutrophils and monocytes from the vascular compartment to the pleural space.

Chemokine CCL2↗
PubMed1993

Interleukin-1 receptor antagonist blocks chemokine production in the mixed lymphocyte reaction.

The mixed lymphocyte reaction (MLR) has previously been used to elucidate pathways of cytokine activation and T-lymphocyte proliferation and is regarded as a model that simulates responses in allograft rejection. Studies have indicated that interleukin-1 (IL-1), a potent inflammatory cytokine, may have an important activating role in the MLR response. The discovery of a naturally occurring IL-1 receptor antagonist protein (IRAP) has renewed interest in control of IL-1--dependent responses both in vitro and in vivo. MLR cultures were used to study the role of IL-1 and IRAP in the regulation of subsequent cytokines during a T-lymphocyte-mediated alloantigen response. The temporal expression of IL-1 and IRAP during 5-day one-way MLR assays suggested antagonistic production of the two cytokines. IL-1 was produced early in the response, peaking at 4 hours through day 2, subsequently declining to near-background levels on day 5 of culture. In contrast, production of IRAP was delayed until day 2, steadily increased on days 3 and 4, and peaked on day 5 of culture, which correlated with the declining levels of IL-1. The addition of graded doses of IRAP (25 to 1,000 ng/mL) to MLR cultures decreased IL-1 production but had no effect on T-lymphocyte proliferative response. In addition, IRAP had little effect on the production of either IL-2 or tumor necrosis factor. The addition of 25 ng/mL of IRAP to MLR assays showed significantly decreased levels of two potent chemotactic cytokines, IL-8 and macrophage inflammatory protein-1 alpha (MIP-1 alpha), at peak chemokine production on day 5 of culture. The levels of IL-8 and MIP-1 alpha could be restored by the addition of IL-1 to the IRAP-treated cultures. IL-8 and MIP-1 alpha represent the two different families of chemotactic cytokines, C-X-C (IL-8) and C-C (MIP-1 alpha), and potentially play important roles in the recruitment of leukocytes to a site of immune allogeneic response. These studies indicate that regulation of IL-1 by IRAP does not significantly reduce T-lymphocyte activation but can regulate the production of chemokines involved in leukocyte recruitment.

Cells, Cultured↗
PubMed1993

Macrophage inflammatory protein-1 alpha expression in interstitial lung disease.

Mononuclear phagocyte (M phi) recruitment and activation is a hallmark of a number of chronic inflammatory diseases of the lung, including sarcoidosis and idiopathic pulmonary fibrosis (IPF). We hypothesized that macrophage inflammatory protein-1 (MIP-1 alpha), a peptide with leukocyte activating and chemotactic properties, may play an important role in mediating many of the cellular changes that occur in sarcoidosis and IPF. In initial experiments, we demonstrated that human rMIP-1 alpha exerted chemotactic activities toward both polymorphonuclear leukocytes and monocytes, and these activities were inhibited by treatment with rabbit anti-human MIP-1 alpha antiserum. In support of the potential role of MIP-1 alpha in interstitial lung disease, we detected MIP-1 alpha in the bronchoalveolar lavage fluid of 22/23 patients with sarcoidosis (mean 443 +/- 76 pg/ml) and 9/9 patients with IPF (mean 427 +/- 81 pg/ml), whereas detectable MIP-1 alpha was found in only 1/7 healthy subjects (mean 64 +/- 64 pg/ml). In addition, we found a 2.5- and 1.8-fold increase in monocyte chemotactic activity in BALF obtained from patients with sarcoidosis and IPF respectively, as compared to healthy subjects, and this monocyte chemotactic activity, but not neutrophil chemotactic activity, was reduced by approximately 22% when bronchoalveolar lavage fluid from sarcoidosis and IPF patients were preincubated with rabbit antihuman MIP-1 alpha antibodies. To determine the cellular source(s) of MIP-1 alpha within the lung, we performed immunohistochemical analysis of bronchoalveolar lavage cell pellets, transbronchial biopsies, and open lung biopsies obtained from patients with IPF and sarcoidosis. Substantial expression of cell-associated MIP-1 alpha was detected in M phi, including both alveolar AM phi and interstitial M phi. In addition, interstitial fibroblasts within biopsies obtained from sarcoid and IPF patients also expressed immunoreactive MIP-1 alpha. Minimal to no detectable MIP-1 alpha was expressed in alveolar M phi from healthy subjects or interstitial cells in lung biopsy specimens obtained from patients undergoing thoracotomy for malignancy. Furthermore, pulmonary fibroblasts isolated from patients with IPF produced greater amounts of MIP-1 alpha after challenge with IL-1 beta than did similarly treated pulmonary fibroblasts recovered from patients without fibrotic lung disease. Our findings suggest that MIP-1 alpha is expressed in increased amounts within the airspace and interstitium of patients with sarcoidosis and IPF, and that this cytokine may be an important mediator of both M phi activation and recruitment that characterize these disease states.

Adult↗
PubMed1993

Regulation of neutrophil-derived IL-8: the role of prostaglandin E2, dexamethasone, and IL-4.

Historically, the neutrophil has been perceived as a terminally differentiated leukocyte with limited ability to produce de novo proteins. Furthermore, in the context of acute inflammation the activated neutrophil has been appreciated only for its ability to release various proteases, reactive oxygen, and arachidonic acid metabolites. Recently, the neutrophil has been shown to have the capacity to produce a number of cytokines that may be instrumental in orchestrating the progression of acute inflammation to a more chronic and specific immune response. These cytokines include IFN-alpha, M-CSF, G-CSF, TNF, IL-1, and IL-6. Our laboratory and others have shown that neutrophils produce IL-8 in response to LPS or a phagocytic challenge. Although these studies have shown the induction of IL-8 from polymorphonuclear neutrophils (PMN), relatively little is known regarding the regulation of PMN-derived IL-8. Because PMN and monocytes share the same stem cell, and monocyte-derived IL-8 is regulated by prostaglandin E2 (PGE2), glucocorticoids (dexamethasone; DEX) and the T-Lymphocyte-derived IL-4, we postulated that PMN-derived IL-8 production may be regulated in a similar manner. To test this hypothesis, PMN were isolated (> 99% pure) from peripheral blood and cultured in media with 5% FCS in the presence or absence of LPS (10 ng/ml; a concentration of LPS that induced the half-maximal production of PMN-derived IL-8) and in the presence or absence of DEX (10(-6) M to 10(-10) M), PGE2 (10(-6) M to 10(-10) M), or IL-4 (100 ng/ml to 100 pg/ml). PMN-derived IL-8 was measured using a specific sandwich ELISA. DEX and IL-4 in the presence of LPS were found to inhibit PMN-derived IL-8 in both a dose- and time-dependent fashion. DEX and IL-4 in concentrations of 10(-6) M and 10 ng/ml resulted in maximal inhibition of LPS-induced PMN-derived IL-8, respectively. Moreover, both DEX and IL-4 administration could be delayed 4 hr post-stimulation with LPS and result in significant suppression of PMN-derived IL-8. Interestingly, in contrast to the regulation of monocyte-derived IL-8 by PGE2, PGE2 treatment of PMN failed to inhibit the generation of LPS-induced IL-8. Northern blot analysis of steady-state IL-8 mRNA demonstrated that both DEX and IL-4 treatment of PMN resulted in a 40 and 52% reduction in LPS-stimulated PMN-derived IL-8 mRNA, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Base Sequence↗
PubMed1993

Characterization of the production of monocyte chemoattractant protein-1 and IL-8 in an allogeneic immune response.

Delayed-type hypersensitivity and allograft rejection are dependent upon the generation of Ag-specific T cell immune responses. The mixed lymphocyte reaction is a model of alloantigen-driven immunity and has provided significant insight into the mechanisms of T cell proliferation. Recently, soluble mediators, including TNF-alpha have been shown to be involved in the full expression of this response. In order to elucidate the potential mechanisms of cellular recruitment in the context of either delayed-type hypersensitivity or allograft rejection, we employed a mixed lymphocyte reaction to study the production of chemokines, monocyte chemoattractant protein-1 (MCP-1), and IL-8. Time-course experiments demonstrated that significant levels of MCP-1 and IL-8 were produced in allogeneic cultures as early as day 1, and that this relationship persisted over 6 days in culture. Northern blot analysis of chemokine mRNA confirmed the early induction of these genes in the allogeneic response. The levels of MCP-1 and IL-8 protein from mixed lymphocyte reaction supernatants as measured by specific ELISA were positively correlated with the proliferative response as measured by [3H]TdR uptake. Although significant MCP-1 and IL-8 were produced during a mixed lymphocyte reaction, these molecules did not participate in the proliferative response, as neutralizing antibodies to either MCP-1 or IL-8 had no effect on proliferation. In order to ascertain the mechanism for the induction of MCP-1 and IL-8 during the mixed lymphocyte reaction, experiments were performed in the presence of neutralizing anti-human TNF antibodies. Neutralization of TNF resulted in significant abrogation of MCP-1 and IL-8 production (75 +/- 5 and 87 +/- 2 percent, respectively). Cells isolated from the mixed lymphocyte reaction at day 6, demonstrated that MCP-1 and IL-8 Ag were localized to mononuclear phagocytes. These results demonstrate that potent chemokines, MCP-1 and IL-8, are produced during the evolution of a mixed lymphocyte reaction, and their induction is TNF-dependent.

Base Sequence↗
PubMed1993

Expression and regulation of human neutrophil-derived macrophage inflammatory protein 1 alpha.

Neutrophil (polymorphonuclear leukocyte [PMN]) sequestration is one of the histologic hallmarks of an acute inflammatory response. During the natural evolution of an inflammatory response, PMNs are often replaced by mononuclear cells. This shift in the elicitation of specific leukocyte populations usually occurs as the inflammatory lesion enters either the repair/resolution stage or progresses to a chronic inflammation. To elucidate a potential mechanism for the temporal change from predominantly PMN recruitment to the presence of monocytes, we postulated that PMNs could be a rich source of monocyte chemotactic factors. In our studies, we have identified a dose-dependent induction of monocyte chemotactic activity by PMNs treated with lipopolysaccharide (LPS; 1-100 ng/ml). Interestingly, this monocyte chemotactic activity was significantly attenuated in the presence of neutralizing anti-human macrophage inflammatory protein 1 alpha (MIP-1 alpha) antibodies. Moreover, immunolocalization studies demonstrated the expression of MIP-1 alpha by stimulated PMNs. These findings showed that a significant amount of PMN-derived monocyte chemotactic activity was attributable to MIP-1 alpha. Subsequent characterization of MIP-1 alpha steady-state mRNA and antigen expression demonstrated both a dose- and time-dependent production by LPS-treated PMNs. Granulocyte/macrophage colony-stimulating factor (GM-CSF), a potent PMN activator, failed to induce the expression of MIP-1 alpha over a wide range of concentrations. However, PMNs stimulated in the presence of both LPS and GM-CSF resulted in a synergistic expression pattern for MIP-1 alpha. PMNs stimulated in the presence of both GM-CSF and LPS demonstrated an enhanced and prolonged expression for both MIP-1 alpha mRNA and antigen, as compared with LPS alone. Messenger RNA stabilization analyses demonstrated that MIP-1 alpha mRNA isolated from PMNs stimulated in the presence of GM-CSF and LPS had a prolonged mRNA t1/2, as compared with LPS alone. These findings support the notion that PMNs are capable of producing MIP-1 alpha in the presence of LPS, and that GM-CSF can influence this production through prolongation of MIP-1 alpha mRNA t1/2. The production of PMN-derived MIP-1 alpha, in association with the expression of appropriate adhesion molecules at a site of inflammation, may be one of the central events that contributes to the temporal shift from predominantly PMNs to monocytes during the evolution of inflammation.

Base Sequence↗