Monokine-induced Neutrophil Chemotactic Factor Gene Expression in Human Fibroblasts

Differential effects of protein kinase C inhibitors on chemokine production in human synovial fibroblasts

1. Rheumatoid arthritis is associated with the accumulation and activation of selected populations of inflammatory cells within the arthritic joint. One putative signal for this process is the production, by resident cells, of a group of inflammatory mediators known as the chemokines. 2. The chemokines interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1) and RANTES (regulated on activation normal T-cell expressed and presumably secreted) are target-cell specific chemoattractants produced by synovial fibroblasts in response to stimulation with interleukin-1 alpha (IL-1 alpha) or tumour necrosis factor alpha (TNF alpha). The signalling pathways involved in their production are not well defined. We therefore used four different protein kinase C inhibitors to investigate the role of this kinase in the regulation of chemokine mRNA and protein expression in human cultured synovial fibroblasts. 3. The non-selective PKC inhibitor, staurosporine (1-300 nM) significantly increased the production of IL-1 alpha-induced IL-8 mRNA and protein. A specific PKC inhibitor, chelerythrine chloride (0.1-3 microM), also caused a small concentration-dependent increase in IL-8 mRNA and protein production. In contrast, 3-[1-[3-(amidinothio)propyl]-3-indoly]-4-(1-methyl-3-indolyl )- 1H-pyrrole-2,5-dione methanesulphonate (Ro 31-8220) and 2[1-(3-dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3- yl)-maleimide (GF 109203X), two selective PKC inhibitors of the substituted bisindolylmaleimide family had a concentration-dependent biphasic effect on IL-1 alpha or TNF alpha-induced chemokine expression. At low concentrations they caused a stimulation in chemokine production, which was especially evident at the mRNA level. At higher concentrations both inhibited IL-1 alpha or TNF alpha-induced chemokine mRNA and protein production. Ro 31-8220 was 10 fold more potent than GF 109203X, with an IC50 of 1.6 +/- 0.08 microM (mean +/- s.e.mean, n = 4) for IL-1 alpha induced IL-8 production. Ro 31-8220 also inhibited the expression of IL-1 alpha or TNF alpha-induced MCP-1 and RANTES mRNA with a similar potency. 4. The stimulatory effect of staurosporine is discussed in relation to the known poor selectivity of this inhibitor for PKC. It is proposed that activation of an isoform of PKC, possibly PKC epsilon or zeta, which is inhibited by higher concentrations of the bisinodolylmaleimides, plays a role in the regulation of chemokine expression induced by IL-1 alpha or TNF alpha in synovial cells. 5. The inhibition of chemokine production by bisindolylmaleimide compounds heralds a novel approach for future anti-inflammatory therapies.

Design and evaluation of small peptides mapping the exposed surface of IL-8

In an effort to determine which regions of IL-8 are involved in interactions with its receptors, eight peptides were designed to correspond to distinct exposed regions of the IL-8 monomer, using the proton NMR-derived structure of the dimer as a basis. The peptides were evaluated singularly, and as equimolar mixtures of two to six peptides, in an IL-8 receptor binding assay and found to have no binding interaction with either alpha or beta IL-8 receptor as single peptides or mixtures of two peptides. In contrast, one of these peptides having the sequence AVLPRSAKEL, which corresponds to the N-terminal 10 amino acid residues of the 77 amino acid form of IL-8, exhibited potent chemotactic activity in human neutrophils. These results indicate that there is no contiguous ligand that can be designed based on the NMR and X-ray determined structure of IL-8 and that there may be multiple receptors responsible for neutrophil activation and chemotaxis.

The immunology of thyroid cancer

This article reviews the immunologic aspects of thyroid cancer, including thyroid-specific effector elements on thyroid cancer, and discusses the potential antigens, unique molecular markers, and transcription factors that could serve as targets for immunotherapy. The potential role of this type of treatment for thyroid cancer is examined also.

Interleukin 10 (IL-10) regulation of tumour necrosis factor alpha (TNF-alpha) from human alveolar macrophages and peripheral blood monocytes

BACKGROUND

Regulation of the inflammatory response within the human lung is essential to prevent this important part of the normal host defence response becoming a pathological process. Tumour necrosis factor alpha (TNF-alpha) is a cytokine involved in the pathogenesis of shock and in granuloma formation, tissue necrosis, and fibrosis in many organ systems including the lung. Interleukin 10 (IL-10) has been proposed as having an inhibitory effect on the production of several inflammatory cytokines including TNF-alpha.

METHODS

The effect of IL-10 administration on TNF-alpha production was explored in human alveolar macrophages and peripheral blood monocytes from matched individuals. The effects of IL-10 on TNF-alpha protein production were determined by sandwich enzyme linked immunosorbant assay (ELISA), whereas the TNF-alpha mRNA response was established by Northeren blotting using a TNF-alpha specific oligonucleotide probe. The protein synthesis inhibitors actinomycin D and cyclohexamide were utilised to monitor IL-10 effects on mRNA degradation and de novo protein synthesis, respectively.

RESULTS

The lipopolysaccharide-mediated TNF-alpha production in alveolar macrophages was reduced from 3.508 (0.629) to 2.035 (0.385) ng/ml by 100 U/ml IL-10. Lipopolysaccharide-induced TNF-alpha production in peripheral blood monocytes was reduced from 2.035 (0.284) to 0.698 (0.167) ng/ml. TNF-alpha gene expression was also inhibited in both alveolar macrophages and peripheral blood monocytes; lipopolysaccharide-induced TNF-alpha mRNA was reduced by 47.8 (15.2)% and 83.1 (4.2)%, respectively, by IL-10. The IL-10 mediated suppression of TNF-alpha mRNA was unaffected by addition of cyclohexamide, suggesting that de novo protein synthesis was not required for TNF-alpha inhibition. mRNA stability experiments indicated no acceleration in lipopolysaccharide-induced TNF-alpha mRNA degradation in response to IL-10.

CONCLUSIONS

These findings suggest that IL-10 is a potent inhibitor of TNF-alpha expression and release from alveolar macrophages and peripheral blood monocytes, and thus it may have an important role in the cytokine network of the pulmonary immune response.

Increased interleukin 8 expression in the colon mucosa of patients with inflammatory bowel disease

To test whether there is a difference in the expression of interleukin 8 (IL8) between Crohn's disease and ulcerative colitis and to determine the main site of its synthesis this study analysed IL8 in mucosal biopsy specimens of patients with Crohn's disease and ulcerative colitis by enzyme linked immunosorbent assay (ELISA) and by in situ hybridisation. IL8 was measured by ELISA in 38 normal control patients, eight inflammatory control patients, 55 Crohn's disease biopsy specimens (26 patients), and 67 ulcerative colitis biopsy specimens (35 patients). IL8 mRNA was determined in samples by in situ hybridisation using a specific IL8 RNA probe. IL8 protein was significantly increased in macroscopically inflamed specimens of Crohn's disease (median 118 pg/specimen, p < 0.0001), ulcerative colitis (median 140 pg/specimen, p < 0.001), and inflammatory controls (median 30 pg/specimen, p = 0.010) compared with normal controls (median 4 pg/specimen). IL8 was also increased in uninflamed specimens of Crohn's disease (median 46 pg/specimen, p < 0.001) but not of ulcerative colitis patients (median 9 pg/specimen, p = 0.3). IL8 protein in the mucosa correlated significantly with macroscopic inflammation in Crohn's disease (r = 0.47, p < 0.001) and in ulcerative colitis (r = 0.60, p < 0.001). IL8 mRNA was detected by in situ hybridisation in 31 of 55 biopsy specimens (56%) of Crohn's disease patients, in 38 of 67 specimens of ulcerative colitis patients (57%), in five of eight inflammatory controls (63%) and in five of 38 normal controls (13%). Mucosal IL8 mRNA expression correlated with mucosal IL8 protein (r = 0.46, p < 0.001). IL8 mRNA was only detected in inflammatory cells of the interstitium but not in mucosal epithelial cells. IL8 is produced mainly in the lamina propria of the colon in inflammatory bowel disease and correlates with mucosal inflammation.

Interleukin-8 inhibits non-small cell lung cancer proliferation: a possible role for regulation of tumor growth by autocrine and paracrine pathways

Interleukin-8 (IL-8) is an 8 kD chemokine and angiogenic factor produced by alveolar macrophages, endothelial cells, monocytes, fibroblasts, T lymphocytes, and epithelial cells in response to a variety of stimuli, including LPS, TNF-alpha, IL-1, IL-7, and hypoxia. Pulmonary tumors produce a variety of growth factors and cytokines that may act in both autocrine and paracrine fashion. A549, a well-characterized human lung adenocarcinoma line, was cloned for different levels of IL-8 production by limiting dilution. Clone 3B4 produced 361 +/- 73 pg/ml, and clone 2B2 produced 7818 +/- 614 pg/ml of IL-8 (p = 0.003). Clone 3B4 proliferated at 1.7 times the rate of 2B2. Anti-IL-8 reversed the decrement in proliferation of clone 2B2 by 50%, but recombinant IL-8 decreased the proliferation of 3B4 by 40-55% compared with control. In addition to A549, three other non-small cell lung cancer (NSCLC) lines showed significantly decreased proliferation in response to exogenous recombinant IL-8 (5-30 ng/ml; p < 0.05). These findings suggest that in addition to its chemotactic and angiogenic activities, IL-8 may inhibit lung tumor proliferation by both autocrine and paracrine pathways.

Interleukin-1-induced IL-8 and IL-6 gene expression and production in human mesangial cells is differentially regulated by cAMP

We have previously proposed that activated mesangial cells (MC) have a direct role in the initiation and propagation of inflammatory events within the glomerulus via the generation of the mesangioproliferative cytokine IL-6 and the chemokines IL-8 and MCP-1. The objective of this study was to investigate the role of cAMP in the regulation of IL-6 and IL-8 gene expression and peptide production in IL-1 stimulated human MC. Agents known to elevate cAMP, including dibutyryl cAMP (db-cAMP), forskolin or isobutyl-methylxanthine (IBMX) were alone unable to induce IL-6 or IL-8 expression or production above media control levels, indicating activation of the cAMP pathway could not mimic IL-1 signaling events. In the presence of IL-1, all three agents produced a marked potentiation of IL-6 mRNA expression and dose-dependent increase in IL-6 peptide production (twofold), but had little or no effect on IL-8 mRNA expression or peptide generation. In marked contrast cholera toxin (CT) caused a dose-dependent potentiation of both IL-1-induced IL-6 (approximately fourfold) and IL-8 peptide (approximately twofold) generation. The control agent, the purified binding subunit of cholera toxin (CT-B) which is devoid of ADP-ribosylating activity also enhanced IL-6 and IL-8 (approximately twofold) peptide generation indicating cAMP-independent mechanisms may be involved in the CT up-regulation of these cytokines. Treatment of MC with the cycloxygenase inhibitor indomethacin resulted in partial inhibition (37%) of IL-6 production but had no effect on IL-8 generation. Thus our data show that cAMP can potentiate IL-1 induced IL-6 production, while having no effect on IL-8 induction, and PGE2 may operate via a positive feedback loop to up-regulate IL-1 induced IL-6. Taken together, our results demonstrate that cAMP differentially regulates IL-6 and IL-8 production in IL-1-stimulated human MC.

Expression and biology of neutrophil and endothelial cell-derived chemokines

The elicitation of polymorphonuclear leukocytes or neutrophils to an area of tissue injury is one of the most fundamental of all cell responses during the initiation of host defense. Historically, the neutrophil has been identified as an important phagocytic cell with a limited capacity to synthesize de-novo proteins. However, recent investigations have now shown that stimulated neutrophils can express a variety of cytokines, such as tumor necrosis factor, interleukin-1, interferon-alpha and interleukin-8. The ability of neutrophils and endothelial cells to produce interleukin-8 is extremely important, as this chemokine can contribute to the continued maintenance of cell infiltrates into the developing inflammatory lesion.

The functional role of the ELR motif in CXC chemokine-mediated angiogenesis

In this study, we demonstrate that the CXC family of chemokines displays disparate angiogenic activity depending upon the presence or absence of the ELR motif. CXC chemokines containing the ELR motif (ELR-CXC chemokines) were found to be potent angiogenic factors, inducing both in vitro endothelial chemotaxis and in vivo corneal neovascularization. In contrast, the CXC chemokines lacking the ELR motif, platelet factor 4, interferon gamma-inducible protein 10, and monokine induced by gamma-interferon, not only failed to induce significant in vitro endothelial cell chemotaxis or in vivo corneal neovascularization but were found to be potent angiostatic factors in the presence of either ELR-CXC chemokines or the unrelated angiogenic factor, basic fibroblast growth factor. Additionally, mutant interleukin-8 proteins lacking the ELR motif demonstrated potent angiostatic effects in the presence of either ELR-CXC chemokines or basic fibroblast growth factor. In contrast, a mutant of monokine induced by gamma-interferon containing the ELR motif was found to induce in vivo angiogenic activity. These findings suggest a functional role of the ELR motif in determining the angiogenic or angiostatic potential of CXC chemokines, supporting the hypothesis that the net biological balance between angiogenic and angiostatic CXC chemokines may play an important role in regulating overall angiogenesis.

Synthesis of proinflammatory cytokines by human gingival fibroblasts in response to lipopolysaccharides and interleukin-1 beta

We have examined the ability of gingival fibroblasts (GF) to participate in inflammatory response and function as accessory immune cells. The accessory immune function of GF cells was evaluated by their ability to elaborate proinflammatory cytokines following stimulation with lipopolysaccharides and interleukin-1 beta (IL-1 beta). Using three separate clonally derived and characterized human gingival fibroblast (GF) cell lines, we demonstrate that LPS from Actinobacillus actinomycetemcomitans (Aa) and Escherichia coli (Ec) induce mRNA and synthesis of proinflammatory cytokines, IL-1 beta, IL-6 and IL-8. IL-1 beta activation of GF cells showed that IL-1 beta non only induces the expression of IL-6, IL-8 and TNF-alpha, but also acts in an autocrine manner of GF cells and induces IL-1 beta expression. Furthermore, the continuous presence of IL-1 beta in GF cell cultures did not down regulate the response of GF cells to IL-1 beta. Pretreatment of GF cells with IL-1 beta resulted in the enhanced synthesis of TNF-alpha in response to additional IL-1 beta. These findings indicate that GF cells, in addition to providing structural support, may also function as accessory immune cells and play an important role in the initial inflammatory reaction as well as in the amplification of immune response.

Cytokines in proliferative diabetic retinopathy and proliferative vitreoretinopathy

We determined whether interleukin-8, monocyte chemotactic protein-1, and macrophage-colony stimulating factor are present in the vitreous of patients with proliferative diabetic retinopathy (PDR) or proliferative vitreoretinopathy (PVR). The levels of these cytokines were measured by specific enzyme-linked immunoassays in vitreous from 30 patients with PDR, 13 patients with PVR, and 26 control individuals, including 10 cadaver eyes and 16 patients with idiopathic macular holes, idiopathic macular puckers, vitreous hemorrhages, or uncomplicated retinal detachments. Detectable levels of interleukin-8 were found in 90% of vitreous samples of patients with PDR, 85% with PVR, and 58% of control samples. IL-8 was significantly increased in PDR (mean +/- SEM; 25.0 +/- 5.3 ng/ml; p = 0.01), but not in PVR (11.9 +/- 3.9 ng/ml; p = 0.50) compared to control human vitreous (8.5 +/- 2.5 2.5 ng/ml). MCP-1 was detected in 90% of vitreous samples of patients with PDR, 92% with PVR, and 81% of control samples. MCP-1 was significantly increased in PDR (6.2 +/- 0.9 ng/ml, p = 0.001) and PVR (7.7 +/- 2.5 ng/ml, p = 0.001) over the levels in control vitreous (1.2 +/- 0.2 ng/ml). M-CSF was detected in 94% of vitreous samples of patients with PDR, 88% with PVR, and 92% from control vitreous. M-CSF was significantly elevated in PDR (32.3 +/- 8.3 ng/ml, p = 0.03), but not in PVR (23.6 +/- 12.8 ng/ml, p = 0.4) compared to control (10.7 +/- 3.5 ng/ml). Our results suggest that IL-8, MCP-1, and M-CSF participate in the pathogenesis of PDR and PVR.

Cytokine-induced neutrophil chemoattractant production by primary rat alveolar type II cells

This study was designed to determine the production of the chemokine cytokine-induced neutrophil chemoattractant (CINC) by primary rat alveolar type II (ATII) cells upon stimulation with exogenous and endogenous proinflammatory factors. Cultures of primary rat ATII cells were exposed to lipopolysaccharide (LPS), interleukin-1 beta (IL-1 beta) or tumor necrosis factor-alpha (TNF alpha) over a 16 hour period and the production of CINC both apically and basolaterally was measured by ELISA. Compared to unstimulated (UNS) cultures, LPS, IL-1 beta and TNF alpha were found to significantly increase the level of CINC detected in culture by two, four and sixteen hours post stimulation, respectively. ATII cells also demonstrated a polar secretion of CINC. The accumulation of CINC basolaterally was significantly more than apically; 133%, 45%, 117% and 123% for UNS, IL-1 beta, LPS and TNF alpha respectively. We demonstrated that primary rat ATII cells may participate in the chemokine network during inflammation by the production of CINC upon stimulation with endogenous and exogenous factors.

Cytokine production in pouchitis is similar to that in ulcerative colitis

PURPOSE

Controversy exists as to whether pouchitis represents a reactivation of the immunologic mechanisms that lead to ulcerative colitis (UC). The aims of this study were to determine local levels of the cytokines: interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF alpha) in the mucosa of patients with "asymptomatic" ileoanal pouch (n = 25), pouchitis (n = 9), active UC (n = 20), normal ileum (n = 15), proctitis (n = 10), and normal colon (n = 15).

METHODS

Lamina propria mononuclear cells were isolated from mucosal biopsies by enzymatic dispersion and cultured for 48 hours. Proinflammatory cytokine levels were measured in the supernatants by enzyme-linked immunosorbent assay.

RESULTS

IL-1 beta, IL-6, IL-8, and TNF alpha secretions were significantly greater in pouchitis and active UC than in the noninflamed ileoanal pouch and normal controls (P < 0.001). There was significant correlation (r = 0.63, P < 0.05) between levels of cytokines expressed in pouchitis and active UC.

CONCLUSIONS

Increased cytokine expression occurs in both active UC and pouchitis and to a lesser extent in the long-standing ileoanal pouch.

An anti-interleukin 8 monoclonal antibody that interferes with the binding of interleukin 8 to cellular receptors and the activation of human blood neutrophils

Interleukin 8 (IL-8) is a proinflammatory cytokine produced by a wide variety of cells. Interleukin 8 acts as a neutrophil activator and chemotactic factor. In the current studies, we examined the properties of a monoclonal antibody against human IL-8. The estimated affinity of the antibody was 1.74 x 10(7) liters/mol. The antibody interfered with the binding of radiolabeled recombinant human IL-8 (rhIL-8) to human blood neutrophils (IC50 = 3 x 10(-7) M, at an IL-8 concentration of 2.4 nM). Neutrophil degranulation elicited by 5 x 10(-6)-4 x 10(-8) M rhIL-8 was blocked by the antibody at three-fold molar excess. However, a higher concentration of anti-IL-8 antibody was needed to suppress the chemotactic activity of rhIL-8. The inhibition of neutrophil chemotaxis triggered by 2 x 10(-7)-2 x 10(-9) M rhIL-8 required 6 x 10(-5) M antibody. Similarly, a 300-fold molar excess of anti-IL-8 antibody [10(-5) M] was necessary to abrogate the increase in cytosolic free calcium in neutrophils stimulated with 4 x 10(-8) M rhIL-8. In addition, epitope analysis using synthetic peptides corresponding to different regions of the IL-8 molecule showed that peptide consisting of residues 44-72 (corresponding to the C-terminal of the IL-8 molecule) competed with the antibody for binding to rhIL-8. Because IL-8 is an important inflammatory mediator in several human diseases, anti-IL-8 antibodies may have pharmacological potential.

Regulation of interleukin-8 production in a human colon epithelial cell line (HT-29)

BACKGROUND/AIMS

Interleukin (IL) 8 is a major neutrophil-activating cytokine synthesized by intestinal epithelial cell lines. The aim of this study was to improve the understanding of the regulation of IL-8 synthesis by investigating the roles of protein kinase C (PKC), protein kinase A (PKA), and protein tyrosine kinase (PTK) in the induction of IL-8.

METHODS

HT-29 cells were stimulated with IL-1 beta or tumor necrosis factor alpha (TNF-alpha) together with activators or inhibitors of PKC and PKA or with inhibitors of PTK. The presence of IL-8 protein was detected by enzyme-linked immunosorbent assay and that of IL-8 messenger RNA by Northern blotting and in situ hybridization.

RESULTS

TNF-alpha and IL-1 beta dose-dependently induced IL-8 production in HT-29 cells. Activation of PKC by phorbol myristate acetate also stimulated IL-8 production; however, the effects of IL-1 beta or TNF-alpha did not require PKC, as shown by the PKC inhibitor staurosporin or PKC depletion. Stimulation of PKA by forskolin or inhibition by H89 or H7 had no influence on the synthesis of IL-8. However, induction of IL-8 by IL-1 beta or TNF-alpha was reduced by the PTK inhibitors herbimycin (by 79% or 89%, respectively) and genistein (by > 95%).

CONCLUSIONS

The synthesis of IL-8 is stimulated in HT-29 cells by IL-1 beta or TNF-alpha. This stimulation is independent from PKC or PKA but depends on protein tyrosine phosphorylation.

Venous thrombosis-associated inflammation and attenuation with neutralizing antibodies to cytokines and adhesion molecules

Thrombosis and inflammation are closely related. However, the response of the vein wall to venous thrombosis has been poorly documented. This study examines the hypothesis that venous thrombosis is associated with an inflammatory response in the vein wall. In a rat model of inferior vena caval thrombosis, vein wall was temporally examined for inflammation by assessment of histopathology, leukocyte morphometrics, and cytokine levels. Animals were killed 1 hour and 1, 3, and 6 days after thrombus induction. Our findings demonstrated an early (day 1) neutrophil infiltration into the vein wall followed by a later (days 3 and 6) monocyte/macrophage and lymphocyte response. Cytokines were elevated only under conditions of venous thrombosis. Levels of epithelial neutrophil activating protein-78 (ENA-78), tumor necrosis factor-alpha (TNF), interleukin-6, and JE/monocyte chemoattractant protein-1 (JE/MCP-1) increased over the 6-day period, while macrophage inflammatory protein-1 alpha (MIP-1 alpha) peaked at day 3 after thrombus induction. Additionally, rats were passively immunized with neutralizing antibodies to TNF, ENA-78, MIP-1 alpha, JE/MCP-1, intercellular adhesion molecule-1 (ICAM-1), and CD18 compared with control antibodies. The most effective antibody early after thrombus induction for attenuating vein wall neutrophil extravasation was anti-TNF (P < .01). The monocyte/macrophage extravasation was inhibited most by anti-ICAM-1 followed by anti-TNF (P < .01). These findings demonstrate that venous thrombosis is associated with significant vein wall inflammation that is partially inhibited by neutralizing antibodies to cytokines and adhesion molecules.

Chemokines and their role in human disease

The recruitment of leukocyte populations to an area of inflammation is one of the most fundamental processes of immune reactivity, yet a number of the mechanisms which are important to this process are not clearly understood. Investigations directed at understanding the mechanisms of leukocyte elicitation have centered around classical chemotactic factors such as C5a and fMLP, however, these known agents have demonstrated little specificity for recruiting particular leukocyte populations. Recent advances in this field have been made with the discovery of a novel supergene family of chemotactic cytokines or chemokines. These cytokines are important as they possess a high degree of specificity for the recruitment of specific subpopulations of leukocytes.

Bronchoalveolar lavage neutrophilia in asthmatic and healthy volunteers after controlled exposure to ozone and filtered purified air

STUDY OBJECTIVE

To characterize the pulmonary response of asthmatic and healthy nonsmoking adult men to 0.20 ppm ozone by controlled chamber exposure.

DESIGN

A prospective, crossover study of five atopic asthmatic and five normal subjects randomly exposed to ozone and filtered purified air (FPA) for 6 h, consisting of 30-min alternating periods of rest and moderate exercise. The two exposures were separated by at least 30 days.

SETTING

A controlled exposure in a stainless steel chamber.

PATIENTS

Five atopic asthmatic and five normal subjects between 18 and 45 years of age. Treatment with medications was withheld from asthmatics prior to the exposures. All subjects were nonsmokers.

INTERVENTIONS

Symptoms were assessed throughout the exposures. Pulmonary function was measured at baseline, hourly throughout an exposure, and after an exposure. Bronchoalveolar lavage (BAL) was performed 18 h after the completion of an exposure. The BAL fluid (BALF) was analyzed for cell count and differential; the cell-free supernatant was analyzed for albumin, tumor necrosis factor (TNF), interleukin 1 (IL-1), interleukin 6 (IL-6), and interleukin 8 (IL-8).

RESULTS

There were statistically significant increases in IL-8 levels, as well as percent polymorphonuclear neutrophils (PMNs) and PMNs per milliliter of lavage in asthmatics exposed to ozone as compared with the same asthmatics exposed to FPA and the same normal subjects exposed to ozone and FPA. Interleukin 6 was also significantly increased in asthmatics exposed to ozone. The BALF albumin, TNF, and IL-1 levels were not significantly different among the four groups. There were no differences between asthmatics and healthy controls exposed to ozone or FPA in baseline to postexposure FEV1, FVC, FEV1/FVC, and sRaw.

CONCLUSIONS

We conclude that asthmatics exposed to ozone develop a significant BALF neutrophilia and increased levels of the cytokines, IL-8 and IL-6. These BALF findings occur even though the level of ozone exposure was not significant enough to reduce pulmonary function.

Mononuclear cells in exudative malignant pleural effusions. Characterization of pleural phagocytic cells

The aims of this study were to develop a methodology for the isolation of highly enriched mononuclear phagocyte populations from exudative malignant pleural effusions (EMPE) and to characterize the phenotype and functional properties of these cells. Pleural effusion mononuclear cells (PEMC) were isolated by Ficoll centrifugation of EMPE and transudative pleural effusions and allowed to adhere to plastic for 1 h to obtain a pleural effusion mononuclear adherent cell (PEMAC) fraction. Only 66.0 +/- 4.2 percent of PEMAC ingested latex particles, indicating that a significant proportion of PEMAC were not phagocytic cells. Latex-positive PEMAC had the morphologic appearance of macrophages and stained positive (97.3 +/- 4.3 percent) with the anti-CD68 monoclonal antibody (MoAb), specific for macrophages. Conversely, latex-negative PEMAC (34.0 +/- 4.1 percent of PEMAC) did not react with the anti-CD68 MoAb and stained with anti-CD3 (34.7 +/- 10.7 percent) and anticytokeratin (50.5 +/- 16.4 percent) MoAbs, indicating that T cells and mesothelial cells were present in the PEMAC fraction. To improve the purification of pleural macrophages, PEMAC were cultured for an additional 18 h and the cells that remained adherent after this period constituted the firmly adherent mononuclear cell (FAMC) fraction. Nearly 90 percent of FAMC ingested latex particles and were CD68-positive. Virtually all FAMC were CD3-negative and cytokeratin-negative. Similar percentages of FAMC from EMPE and transudative effusions expressed the monocyte-lineage markers CD11b and CD14, suggesting that the proportion of monocyte-like mononuclear phagocytes in the pleural space is not increased during local tumor-associated inflammatory responses. The FAMC from EMPE (1) expressed HLA-DR antigens, (2) released interleukin 1 (IL-1) beta and tumor necrosis factor (TNF) alpha, and (3) stimulated allogeneic T-lymphocyte proliferation. The results of this study suggest that pleural mononuclear phagocytes may be involved in tumor-associated inflammatory reactions in the pleural compartment by stimulating the proliferation of other inflammatory cells and by releasing inflammatory cytokines.

Molecular cloning and expression of canine interleukin 8 cDNA

Molecular cloning of canine interleukin-8 (IL-8) was performed to establish a basis for its investigation in the canine immune system. From a cDNA pool constructed from LPS-stimulated popliteal lymph node cells, canine IL-8 cDNA covering the whole coding region was amplified by polymerase chain reaction. The nucleotide sequence of a canine IL-8 clone, designated pcIL-8#38, was highly similar to those of human, rabbit and porcine IL-8, and comprised 353 bp with an open reading frame that encoded 101 amino acids. Analysis of the deduced amino acid sequence of insert DNA in pcIL-8#38 showed 76.5, 80.2, and 87.0% similarities with human, rabbit and porcine IL-8 proteins, respectively. Insert DNA of pcIL-8#38 was transferred to a mammalian expression vector, pcDL-SR alpha 296, and transfected into Cos7 cells. The supernatant of the transfectant had neutrophil chemotactic activity when it was examined by the neutrophil migration assay, suggesting that our cloned cDNA was biologically active. The cloned canine IL-8 cDNA will be useful for canine inflammatory disease and comparative immunology research.

Interleukin-8 induces cervical ripening in rabbits

OBJECTIVE

The purpose of this study was to determine whether cervical ripening can be induced in rabbits by interleukin-8.

STUDY DESIGN

Nonpregnant and pregnant rabbits were treated for 5 days with vaginal suppositories containing 100 ng of interleukin-8. Collagen and glycosaminoglycan concentration in the cervices were assessed histologically by picrosirius red and alcian blue, and the mean optical density was calculated. The mean neutrophil count in five random fields was calculated from each biopsy specimen.

RESULTS

Interleukin-8 induced softening and dilatation of the rabbit cervices. Water content was significantly increased (p < 0.0001 and p < 0.001, respectively). Cervical collagen concentration was found to be significantly decreased (p < 0.0004 and p < 0.0001, respectively). Glycosaminoglycan concentration was significantly increased in nonpregnant and pregnant cervices (p < 0.0009 and p < 0.1, respectively). The mean number of neutrophils was significantly increased (p < 0.0005 and p < 0.006, respectively).

CONCLUSION

Interleukin-8 can induce cervical ripening in nonpregnant and pregnant rabbits.

Correlation of serum interleukin-8 and cell surface lysosome-associated membrane protein expression with clinical disease activity in systemic lupus erythematosus

Cell surface expression of lysosome-associated membrane proteins (LAMPs) correlates with serum interleukin-8 (IL-8) levels, shorter disease duration, greater functional impairment from disease-related symptoms and soluble IL-2 receptor levels (sIL-2R) in patients with scleroderma. In this study of 46 patients with systemic lupus erythematosus (SLE), the relationship of serum IL-8 and cell surface LAMP to two clinical measures of disease activity, the SLEDAI and SLAM scales, was evaluated. IL-8 levels were determined on serum samples by the immunometric sandwich enzyme immunoassay technique. Cell surface LAMP expression was determined by flow cytometric quantitation of peripheral blood mononuclear cells with monoclonal antibodies directed against two of the major LAMP proteins, lamp1 and lamp2. The clinical disease activity scales correlated significantly with each other, with C3 levels, serum IL-8, C4, dsDNA and sIL-2R. Lamp1 and lamp2 expression correlated with the SLAM but not the SLEDAI scale. Serum IL-8 levels were elevated in 49 of 51 samples tested (44 of 46 patients) and had a stronger correlation with disease activity than C4, dsDNA and sIL-2R levels. Significantly higher levels of IL-8 were seen in patients with evidence of renal involvement. Serum IL-8 and cell surface LAMP expression may be useful indicators of disease activity in patients with SLE. The possible role of IL-8 in the pathogenesis of SLE requires further investigation.

Interleukin 8 in serum in granulocytopenic patients with infections

Serum levels of interleukin 8 (IL-8) were examined in eight patients with acute myeloid leukaemia during 16 courses of chemotherapy. The patients experienced 14 episodes of fever which occurred in periods with granulocyte counts < 0.5 x 10(9)/l. Febrile episodes were classified as bacteriologically defined infection (n = 6), clinically defined infection (n = 2), and unexplained fever (n = 6). IL-8 was detected in 18/25 (72%), 2/3 (67%) and 3/7 (43%) of the serum samples in the respective groups. In contrast, IL-8 was detected in 22/90 (24%) of the samples taken when no fever was present (P < 0.00003 versus bacteriologically defined infection). The median concentration of IL-8 in samples taken during febrile episodes was 194 ng/ml (range 0-6358 ng/ml) and 0 (range 0-5392 ng/ml) on days without fever (not significant). In three patients with infections caused by, respectively, Streptococcus sanguis, Acinetobacter calcoanitratus and Candida albicans, IL-8 rose to a peak levels and declined during recovery. We conclude that IL-I is released systemically during infections with gram-positive and gram-negative bacteria and Candida albicans in patients with acute myeloid leukaemia and peripheral granulocytopenia due to chemotherapy. However, IL-8 can also be detected when no sign of infection is present.

Elevated cytokine levels in synovial fluid of rheumatoid arthritis correlates with the presence of cytomegalovirus genome

Synovial fluid aspirated from 34 patients with symptomatic rheumatoid arthritis (RA) was evaluated for the presence of human cytomegalovirus (CMV) genomic material using polymerase chain reaction (PCR), and for levels of interleukin 8 (IL-8) and IL-6 using enzyme-linked immunoadsorbence assay. IL-8 and IL-6 levels were significantly higher in CMV DNA-positive RA patients than CMV DNA-negative RA patients and at least 10-fold higher than in both corresponding control groups of patients with osteoarthritis (OA). These findings suggest an association between elevated IL-8 and IL-6 levels and the presence of the CMV genome in RA patients.

A synthetic peptide which specifically inhibits heat-treated interleukin-8 binding and chemotaxis for neutrophils

Interleukin-8 (IL-8) is a peptide which is secreted by stimulated human monocytes and which is chemotactic for human neutrophils. We synthesized three overlapping peptides spanning the amino-terminal region of the IL-8 sequence. None of the peptides retained the chemotactic activity of the native molecule. One of the peptides, IL-8(3-25), inhibited the neutrophil chemotactic activity of recombinant IL-8 (rIL-8) which had been preheated to 40 degrees C but did not reduce neutrophil chemokinesis, or the chemotactic activity of unheated rIL-8, FMLP, C5a or LTB4. Interleukin-8 exhibited similar binding kinetics and chemotaxis for neutrophils regardless of whether it had been pretreated at 40 degrees C. In addition, IL-8(3-25) was also able to decrease the binding of preheated IL-8 to neutrophils. IL-8(3-25), which can self-associate, binds directly to receptors on the neutrophil. The data suggest that heat-treated, but not untreated, IL-8 causes the IL-8(3-25) multimers to disaggregate, allowing the monomeric peptide to directly bind to the IL-8 receptor and thus inhibiting IL-8/receptor binding.

Interleukin-8: an important neutrophil chemotaxin in some cases of exudative pleural effusions

It was hypothesized that IL-8, a neutrophil chemotaxin, contributes to the influx of neutrophils into the pleural cavity of patients with pleural effusions. Pleural fluids were collected from 57 patients including 13 with effusions due to congestive heart failure, 28 with pleural involvement by carcinoma, 5 with empyema, 4 with parapneumonic effusions complicating bacterial pneumonia, 3 with hemothorax, 3 with tuberculosis, and 1 with rheumatoid arthritis. All exudate groups had significantly higher IL-8 concentrations than the CHF group (p < .001). In 18 of the exudate fluids, the concentrations of IL-8 was equal to or in excess of the optimal concentration of IL-8 which causes neutrophil chemotaxis in vitro. Between 20 and 90% of the chemotactic activity in the fluids was removed by absorbing the IL-8 with an IL-8 affinity column. These data showed that IL-8 is a major chemotaxin in the fluid. The percentage of neutrophils in the fluids was not correlated with the IL-8 concentration. Although TNF alpha, a potent stimulator of IL-8 production, is present in some pleural effusions, no correlation was found between the concentrations of IL-8 and TNF alpha in the fluids. The data suggest that IL-8 contributes to the neutrophil influx into the pleural space of patients with pleural exudates in conjunction with other chemoattractants. It is unlikely that TNF alpha is the sole stimulus for the IL-8 production in pleural disease states.

Synergistic effect of interleukin-1 beta and tumor necrosis factor alpha on interleukin-8 gene expression in synovial fibroblasts. Evidence that interleukin-8 is the major neutrophil-activating chemokine released in response to monokine activation

OBJECTIVE

To investigate both the involvement of chemokines in general and the relative importance of specific chemokines in rheumatoid arthritis (RA), we characterized the effect of the monokines tumor necrosis factor alpha (TNF alpha) and interleukin-1 beta (IL-1 beta) on the synthesis of neutrophil-activating factors by synovial fibroblasts isolated from the joints of patients with RA.

METHODS

Neutrophil-stimulating activity was assessed by determining intracellular calcium mobilization. IL-8 synthesis and secretion was assessed by specific enzyme-linked immunosorbent assay, and IL-8 messenger RNA (mRNA) levels were determined by Northern blot.

RESULTS

Treatment of synovial fibroblasts with IL-1 beta and TNF alpha resulted in the production of an activity which induced intracellular calcium mobilization in peripheral blood neutrophils. The 2 monokines combined had a synergistic effect on the release of the neutrophil-stimulating activity. The effect of the 2 monokines required gene transcription and translation, and closely mimicked the pattern of IL-8 secretion induced in these cells by the monokines. We confirmed that the majority of the neutrophil-stimulating activity was IL-8 by 3 different approaches: cross-desensitization experiments with IL-8, melanoma growth-stimulatory activity, and neutrophil-activating peptide 2, stimulation of calcium mobilization in cells transfected with the IL-8 receptor complementary DNA, and inhibition of the activity following pretreatment of the supernatants with an anti-IL-8 antibody. TNF alpha and IL-1 beta induced a time- and dose-dependent release of immunoreactive IL-8. A synergistic effect of TNF alpha and IL-1 beta was also observed for both IL-8 production and accumulation of IL-8 mRNA.

CONCLUSION

These results indicate that the monokines TNF alpha and IL-1 beta synergistically activate IL-8 expression and protein secretion by synovial fibroblasts, and that under these conditions, IL-8 appears to be the major neutrophil-activating factor released.

Neutrophil mucosal involvement is accompanied by enhanced local production of interleukin-8 in ulcerative colitis

The concentration of myeloperoxidase, a neutrophil granule constituent, was measured in the perfusion fluid from sigmoid and rectal segments in patients with ulcerative colitis. The concentrations of myeloperoxidase were increased severalfold in the patients with ulcerative colitis compared with healthy controls pointing to an enhanced neutrophil activity. The release of myeloperoxidase correlated to an enhanced local release of the neutrophil activating peptide interleukin-8 (IL-8). Increased values of tumour necrosis factor (TNF-alpha) were also found during intestinal perfusion of the patients and correlated with those of IL-8. The results obtained are compatible with the hypothesis that local mucosal recruitment/activation of neutrophils in ulcerative colitis is mediated by an enhanced IL-8 synthesis. TNF-alpha may be one relevant factor as a stimulus to IL-8 synthesis.

Oestrogen effects on osteoblasts and osteoclasts

Although it has been recognized for many years that oestrogen is a key component in the maintenance of normal bone balance, the mechanisms by which oestrogen exerts its influence have remained unresolved. Recent identification of oestrogen receptors in both bone-forming osteoblasts and bone-resorbing osteoclasts has opened up exciting new areas of research on the direct effects of oestrogen on both osteoblasts and osteoclasts. This review presents an updated model for the molecular mechanisms involved in oestrogen action, the mechanism of anti-oestrogen action, and outlines recent advances in knowledge of oestrogen effects on osteoblasts, osteoclasts, and the coupling of bone resorption and bone formation.

Interferon-gamma regulation of human renal cortical epithelial cell-derived monocyte chemotactic peptide-1

The chemoattractant signal(s) that results in the transmigration of monocytes/macrophage into the tubulointerstitium during acute inflammation is not known. Monocyte chemotactic peptide-1 (MCP-1), a recently described chemotactic cytokine, may function as both a potent monocyte chemotaxin and activator in renal inflammation. We have studied the proinflammatory conditions in which cultured human renal cortical epithelial cells (RCEC) of tubular origin may be stimulated to produce MCP-1. RCEC were stimulated in a dose-time dependent manner with: IL-1 beta (0.01 to 1.0 ng/ml), TNF (0.1 to 10 ng/ml), LPS (0.1 to 10 micrograms/ml) or INF-gamma (10-1000 U/ml). Conditioned media from RCEC stimulated with either IL-1 beta or INF-gamma produced a monocyte chemoattractant activity which was significantly suppressed with neutralizing antibody to MCP-1. Stimulation of RCEC with either IL-1 beta or INF-gamma resulted in a significant (4- to 5-fold) increase in steady state levels of MCP-1 mRNA. MCP-1 antigenic peptide in RCEC conditioned media was significantly increased over control (2- to 2.5-fold) after stimulation with either IL-1 beta or IFN-gamma. In contrast, production of interleukin-8 (IL-8), a neutrophil chemotactic cytokine, was not stimulated by IFN-gamma in RCEC. Thus, the chemokine signaling repertoire of renal tubule cells may be selectively controlled by IFN-gamma.

Isolation and amino acid sequence of a chemotactic protein, LECT/interleukin 8, from a human myeloid leukemia cell line, ML-1

We looked for chemotaxin/interleukin 8 (CT/IL-8) activity in the culture fluids of 97 human leukemia cell lines and found it in two of the T cell lines, six of the myeloid cell lines, and one of the normal B-cell lines. It was particularly strong in the culture fluids of two cell lines. These cell lines secreted a chemotactic protein into the culture fluids under certain conditions of stimulation with phorbol-12-myristate 13-acetate (PMA), lipopolysaccharide, or hemagglutinin-P. A myeloid leukemia cell line, ML-1, secreted an inducible chemotaxin when stimulated with PMA (1 ng/ml) for 24 h. We purified the chemotaxin from ML-1 cell culture fluid using an improved procedure: concentration with DEAE-Sepharose CL-6B and CM-Sepharose CL-6B, CM-Sepharose column chromatography, and reverse-phase 5TMS-300 column on HPLC with the retention time coinciding with that of LUCT/IL-8 [Suzuki et al., 1989, J. Exp. Med. 169, 1895]. The yield was 200 micrograms protein from 6 liters of the culture fluid. The N terminus of CT/IL-8 was AVLPR-SAKELRXQXIKTYSK- - -, the same as that of LUCT/IL-8, which is constitutively secreted from lung giant cell carcinoma LU65C cells. The optimal concentration in the chemotactic activity of CT/IL-8, equivalent to that of bacterial chemotactic peptide fMet-Leu-Phe (10 nM), was found to be 5 nM. The results show that this chemotaxin is identical to LUCT/IL-8.

Effect of protein kinase inhibitors on IL-8/NAP-1 release from human umbilical vein endothelial cells

Several protein kinase inhibitors (PKIs) were investigated for their effects on IL-1 beta, TNF alpha and PMA-induced IL-8 production from human umbilical vein endothelial cells (HUVEC). IL-1 beta (ED50 0.07 ng/ml), TNF alpha (ED50 100 ng/ml) and PMA (ED50 20 ng/ml) induced IL-8 production that could be detected as early as 2 h following stimulation. Staurosporine, a potent but non-specific inhibitor of protein kinases, inhibited PMA-induced (IC50 2 nM) but not IL-1 beta or TNF alpha (IC50 > 200 nM) induced IL-8 production. Neither the cAMP-dependent PKI, KT5720, nor the tyrosine PKIs, genistein, tyrphostin (1-100 microM) or lavendustin A (0.0001-1 microM), inhibited IL-8 production elicited by IL-1 beta. However, the macrolide protein kinase inhibitor geldanamycin (IC50 = 30 nM), but not the closely related analog herbimycin A (5-500 nM), inhibited IL-8 production by 60%. Northern blot analysis of IL-8 mRNA revealed that staurosporine suppressed mRNA increase following stimulation by PMA but not by IL-1. It is proposed that a novel protein kinase susceptible to geldanamycin inhibition may be involved in IL-1-mediated signal transduction.

Regulation of neutrophil interleukin 8 gene expression and protein secretion by LPS, TNF-alpha, and IL-1 beta

Neutrophils are possibly involved in the pathogenesis of various lung diseases through the release of numerous mediators. In the present study, we studied the regulation of IL-8 gene induction and protein secretion in human blood neutrophils. Northern blot analysis revealed that LPS increased IL-8 mRNA levels in neutrophils, with a maximal fivefold increase by 2 h. IL-8 mRNa levels returned to baseline values within 12 h. In contrast, LPS-stimulated monocytes demonstrated a sustained increase of IL-8 mRNA levels for more than 24 h. TNF-alpha, IL-1 beta, and phorbol myristate acetate also increased IL-8 mRNA levels in neutrophils. Immunohistochemical analysis confirmed that IL-8 was localized within stimulated neutrophils. IL-8 secretion by neutrophils and monocytes was quantified using a specific ELISA for IL-8. Resting neutrophils secreted minimal IL-8 activity. However when cells were stimulated with LPS, TNF-alpha, or IL-1B, neutrophils secreted IL-8. IL-8 secretion was most marked during the first 2 h after stimulation and decreased thereafter. In contrast, monocytes maintained a high rate of IL-8 secretion over 12 h. Although a single monocyte secreted 70-fold more IL-8 than did a single neutrophil after 4 h of incubation, the high abundance of neutrophils in peripheral blood made the neutrophil-secreted IL-8 more significant. During the first 2 h, neutrophils secreted approximately 40% of the IL-8 released by monocytes in the same volume of blood. This ratio decreased to 9% after 12 h. Neutrophil-secreted IL-8 may play an autocrine or paracrine role during the initial stage of inflammation.

Cytokine-induced expression of mRNAs for chemotactic factors in human synovial cells and fibroblasts

In response to interleukin 1 or tumor necrosis factor, human synovial cells and fibroblasts expressed several genes encoding known chemotactic factors or related proteins. Transcripts for interleukin 8 (IL-8), gro/MGSA, pAT 464, IP-10, pAT 744 and Monocyte Chemotactic and Activating Factor (MCAF) accumulated rapidly in IL-1 and TNF-treated cells. The inhibition of protein synthesis led to the superinduction of IL-8 and gro/MGSA mRNAs in IL-1, but not in TNF-treated cells. Thus, IL-1 and TNF are likely to regulate the expression of these mRNAs by different mechanisms. Important cell-specific differences in mRNA accumulation characterized the expression of chemotactic factor genes. Moreover, only a subset of the same genes was activated in quiescent cells stimulated by serum. Therefore, genes encoding closely related proteins each had a distinct pattern of expression. continuous stimulation of fibroblasts and synovial cells with IL-1 resulted in high and prolonged expression of IL-8 and gro/MGSA mRNAs. These results extend the list of chemotactic factor genes expressed by mesenchymal cells in vitro and suggest a pivotal role for these cells in processes such as chronic inflammation.

Interleukin-8 is a major neutrophil chemotactic factor derived from cultured human gingival fibroblasts stimulated with interleukin-1 beta or tumor necrosis factor alpha

Inflammatory mediators produced by cells in the gingiva have been implicated in the initiation and progression of periodontal disease, a common infectious disease. In this study, we examined the biological activity of neutrophil chemotactic factors and the kinetics of expression of interleukin-8 (IL-8) mRNA derived from normal gingival fibroblasts in response to inflammatory mediators in an in vitro model. Gingival fibroblasts stimulated by either recombinant human interleukin-1 beta or recombinant human tumor necrosis factor alpha produced neutrophil chemotactic factors after 4 h, whereas expression of cell-derived IL-8 mRNA was detected within 1 h after stimulation. Furthermore, in a neutralization assay, rabbit anti-recombinant human IL-8 antiserum inhibited neutrophil chemotactic activity to basal levels. These results provide evidence that gingival fibroblasts synthesize potent chemotactic factors such as IL-8 in the presence of the inflammatory mediators interleukin-1 beta and tumor necrosis factor alpha. The activity of these factors may contribute to neutrophil-mediated processes in the pathogenesis of periodontal disease.

A highly sensitive enzyme-linked immunosorbent assay for the measurement of interleukin-8 in biological fluids

Interleukin-8 (IL-8) is a chemotactic and activating cytokine for neutrophils, which plays an important role in acute inflammatory responses. We aimed to develop a sensitive enzyme-linked immunosorbent assay (ELISA) for IL-8 and established 18 clones of anti-IL-8 monoclonal antibodies (mAbs). These mAbs were evaluated in terms of their antigen-binding affinities, and five clones were selected and used for the comparative study of various combinations of antibodies in sandwich ELISA. Affinity purified rabbit polyclonal antibody was also used in this study. One antibody pair, which showed relatively high sensitivity and which was not severely interfered with blood components, was selected and the assay conditions were optimized by choosing the appropriate buffer for sample dilution and by directly labeling the second antibody with enzyme. The finalized ELISA, using polyclonal antibody as first (coated) antibody and horseradish peroxidase-labeled mAb (clone EL139) Fab' fragment as second antibody, could detect as low as 2.5 pg/ml (0.125 pg/well) of IL-8 by in total 2 h incubation, without being affected by body fluid components. The ELISA was specific to IL-8, showing no cross-reactivity with other cytokines or various IL-8 family proteins which share some amino acid sequence homology with IL-8. As an example of its application to clinical specimens, plasma samples from patients with septic shock were measured. The results showed that sepsis patients contain significantly higher levels of plasma IL-8 compared to normal controls. When analyzed by gel-filtration chromatography, IL-8 in sepsis plasma was eluted in a molecular weight (M(r) region corresponding to the monomer form. The ELISA established here is expected to be effectively used for further investigations on the relationship between IL-8 and various diseases.

The role of CD18 in IL-8 induced dermal and synovial inflammation

1. The intradermal administration of endothelial IL-8 (IL-8(1-77) or monocyte derived IL-8 (IL-8(1-72) to rabbits produced a concentration-dependent increase in plasma extravasation and an accumulation of polymorphonuclear leukocytes (PMNs) when measured over a 3 h time period. When plasma extravasation and PMN accumulation were measured over a 30 min time period no significant increases in PMN accumulation or plasma extravasation were observed in response to IL-8 alone. However, under these conditions, the addition of prostaglandin E2 (100 pmol) produced a significant potentiation of IL-8-induced plasma extravasation. There was no significant difference between the biological activities of IL-8(1-77) and IL-8(1-72). 2. Plasma extravasation and PMN accumulation induced by IL-8 were inhibited in rabbits pretreated with the monoclonal antibody designated IB4 (1 mg kg-1, i.v.) directed against the common beta chain (CD18) of the leukocyte integrins. 3. The intra-articular administration to rabbits of IL-8(1-77) (1 nmol) resulted 24 h later in the appearance of a mixed population of leukocytes (PMNs and mononuclear cells) in synovial lavage fluid. Biochemical analyses revealed the presence of an increased level of sulphated proteoglycans (sPG) and of the metalloproteinase stromelysin. Pretreatment of rabbits with IB4 (3 mg kg-1, i.v.) inhibited the accumulation of PMNs but had no effect on the mononuclear infiltrate nor on the levels of sPG or stromelysin. 4. The intradermal or intra-articular injection of E. coli-derived endotoxin induced similar inflammatory changes to those observed with IL-8.The possibility that the biological activities of IL-8 were attributable to minor contamination with endotoxin is unlikely for two reasons. Firstly, biological effects of endotoxin were observed at levels greater than that contained in the IL-8 preparation. Secondly,reduction of the endotoxin content of the IL-8 preparation by a factor of 10 did not produce a concomitant reduction in the observed biological activity of the IL-8.

Lipopolysaccharides of Bacteroides intermedius (Prevotella intermedia) and Bacteroides (Porphyromonas) gingivalis induce interleukin-8 gene expression in human gingival fibroblast cultures

Lipopolysaccharides (LPS) prepared from Bacteroides intermedius (Prevotella intermedia) and Bacteroides (Porphyromonas) gingivalis by hot phenol-water extraction induced interleukin-8 (IL-8) mRNA in normal human gingival fibroblast cultures, as demonstrated by Northern (RNA) blot analysis. IL-8 mRNA levels began to increase after a 2-h exposure, reached a maximum after 12 h, and then dropped to the unstimulated level at 48 h. IL-8 mRNA levels were also enhanced in a dose-dependent manner. By contrast, LPS specimens from various Salmonella species with S and R chemotypes and bacterial [corrected] and synthetic lipid A preparations did not increase IL-8 mRNA levels in fibroblasts. Although recombinant human IL-1 alpha induced IL-8 mRNA expression in fibroblast cultures, an antiserum to recombinant human IL-1 alpha did not decrease the IL-8 mRNA accumulation induced by B. intermedius LPS. Fibroblasts primed with natural human gamma interferon (IFN-gamma) expressed higher IL-8 mRNA levels upon stimulation with B. intermedius LPS, but not with Salmonella LPS, compared with nontreated cells. Natural human IFN-beta exhibited a similar priming effect on the fibroblasts, and antiserum to IFN-beta added to the cultures together with B. intermedius LPS decreased the IL-8 mRNA levels. Therefore, endogenous IFN-beta enhanced IL-8 mRNA production in response to B. intermedius LPS in fibroblasts.

Amnion cell biosynthesis of interleukin-8: regulation by inflammatory cytokines

The cellular constituents of the placenta are important participants in the recruitment and trafficking of inflammatory cells within the placenta. In infection-induced labor, gestational tissues synthesize and release a variety of inflammatory cytokines whose effects include increased prostaglandin biosynthesis and the initiation of uterine contractions. Interleukin-8 (IL-8), a potent neutrophil chemoattractant, has been recently described as being elevated in the amniotic fluid of mothers with chorioamnionitis. We investigated the biosynthesis of IL-8 by human amnion cells and its regulation by other inflammatory cytokines. Cultured amnion cells obtained from normal term placentae were found to produce IL-8 in response to pathophysiologic concentrations of interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha). Treatment of amnion cells stimulated by IL-1 beta with cycloheximide resulted in increased IL-8 production, while incubation of IL-1 beta treated amnion cells with actinomycin D resulted in a concentration-dependent decrease in detectable amounts of IL-8. Northern blot analysis of cultured amnion cells stimulated with IL-1 beta demonstrated a rapid increase in IL-8 mRNA which peaked at 2-4 hr. These in vitro results suggest inflammation of gestational tissues in vivo may result in locally produced IL-8 and, in association with other inflammatory mediators, may be important in the pathophysiology of infection-induced labor.

Human dermal fibroblast interleukin-1 receptor antagonist (IL-1ra) and interleukin-1 beta (IL-1 beta) mRNA and protein are co-stimulated by phorbol ester: implication for a homeostatic mechanism

Although the major functions of fibroblasts are to produce extracellular matrix and to maintain a structural framework for organ systems, recent studies have demonstrated that fibroblasts are active participants in inflammatory processes by synthesizing various inflammatory mediators. In this report, we provide evidence that fibroblasts may contribute to the regulation of inflammation by the synthesis of both the intracellular form and the secretory form of interleukin-1 receptor antagonists in conjunction with interleukin-1 beta production. Indirect immunofluorescence microscopy localized interleukin-1 receptor antagonist and interleukin-1 beta proteins primarily in the fibroblast cytoplasm. Polymerase chain reaction amplification of reverse-transcribed mRNA with primers specific for the intracellular form of interleukin-1 receptor antagonist detected cDNA fragments present in both unstimulated and phorbol ester-stimulated fibroblasts, identical in molecular size to that in unstimulated keratinocytes. Amplification with primers specific for the secretory form of interleukin-1 receptor antagonist, however, detected cDNA fragments in phorbol ester-stimulated fibroblasts and phytohemagglutinin-stimulated peripheral mononuclear cells, but not in unstimulated fibroblasts or keratinocytes. The amplified fibroblast cDNA sequences for both intracellular and secretory interleukin-1 receptor antagonists were confirmed by digestion with three restriction endonucleases. By ethidium bromide visualization of amplified cDNA derived from serially diluted total cellular RNA and by Southern blot hybridization analysis of amplified cDNA, we have demonstrated that fibroblast interleukin-1 receptor antagonist mRNA and interleukin-1 beta mRNA were co-stimulated by phorbol ester. Similarly, ELISA demonstrated that fibroblast cytoplasmic interleukin-1 receptor antagonist protein and interleukin-1 beta protein were co-stimulated by phorbol ester. Our data suggests that the intracellular form of interleukin-1 receptor antagonist may be important in maintaining physiologic homeostasis in fibroblasts during interleukin-1 beta induction and release.

Expression of interleukin-8 by lipopolysaccharide-stimulated bone marrow-derived mononuclear cells

Interleukin-8 (IL-8) is a potent neutrophil chemoattractant, produced by a variety of immune and nonimmune cells in response to exogenous and host-derived inflammatory stimuli. We demonstrate here that a suspension of normal bone marrow mononuclear cells, consisting principally of myeloid precursors, produces IL-8 in response to stimulation with lipopolysaccharide (LPS). IL-8-specific mRNA is rapidly induced, being detected first 30 min after stimulation. IL-8 is detected by enzyme-linked immunosorbent assay within 2 h of stimulation, with steady a increase in its level through 72 h. Further studies demonstrated that LPS could serve as a primary stimulus for the expression of IL-8, since LPS challenge in the presence of cycloheximide resulted in superinduction of bone marrow mononuclear cell-derived IL-8 mRNA. These investigations suggest that the stimulatory effect of LPS is independent of other cytokines such as IL-1 beta. When compared with LPS, IL-1 beta proved to be a weak signal for the expression of IL-8 by bone marrow mononuclear cells. In a dose-response study, the maximum stimulatory concentration of IL-1 beta (300 pg/ml) resulted in the production of 500 pg of IL-8 per 10(6) cells, whereas 1 microgram of LPS resulted in the production of 5.5 ng/10(6) cells. Although IL-1 beta was not a particularly potent stimulus for IL-8 production by bone marrow mononuclear cells, peripheral blood mononuclear cells were highly susceptible to IL-1 beta challenge. In addition, the potential dependence of LPS-induced marrow-derived IL-8 production on the intermediate synthesis of IL-1 beta was further investigated. Results of studies assessing kinetics, addition of cycloheximide, and blocking with IL-1 beta neutralizing antibody were all consistent with the ability of LPS to directly induce bone marrow-derived IL-8 independently of IL-1 beta. These investigations demonstrate that bone marrow may be a significant source of IL-8 and may play a significant role in acute infectious, inflammatory responses.

IL-1 receptor antagonist inhibits monocyte chemotactic peptide 1 generation by human mesangial cells

The elicitation of neutrophils and monocytes from the circulation into the inflamed glomerulus is a key process in the pathogenesis of proliferative glomerulonephritis. The aim of this study was to determine the factors which regulate the expression and synthesis of the monocyte specific chemotaxin, monocyte chemotactic peptide 1 (MCP-1). Mesangial cells in culture did not constitutively express MCP-1, but could be induced to express both MCP-1 mRNA and antigenic MCP-1 by either stimulation with IL-1 alpha or TNF alpha, which are also stimuli for interleukin 8 (IL-8/NAP-1) expression and release. Pre-treatment of mesangial cells with the IL-1 receptor antagonist (IL-1ra) induced dose-dependent inhibition of both the expression of MCP-1 and IL-8 mRNA as well as the release of both chemotactic peptides in response to IL-1 alpha, while the receptor antagonist had no significant effect on TNF alpha induced MCP-1 and IL-8 generation. This study demonstrates that the IL-1 receptor antagonist was four times more effective at inhibiting the IL-1 induced expression and release of IL-8 compared to that of MCP-1. These results suggest that mesangial cell-derived MCP-1 may play an important role in the recruitment of monocytes in glomerular inflammation and that an IL-1 receptor antagonist may have therapeutic potential for the treatment of glomerulonephritis.