Neutrophils produce biologically active macrophage inflammatory protein-3alpha (MIP-3alpha)/CCL20 and MIP-3beta/CCL19.

Macrophage inflammatory protein-3alpha (MIP-3alpha)/CCL20 and MIP-3beta/CCL19 are members of the CC chemokine subfamily which exert their effects through specific receptors, CCR6 and CCR7, respectively. Previously, we have reported that human neutrophils have the capacity to produce a number of chemokines, including IL-8/CXCL8, GROalpha/CXCL1, IP-10/CXCL10, and MIG/CXCL9. Herein, we show that neutrophils also have the ability to express and release MIP-3alpha/CCL20 and MIP-3beta/CCL19 when cultured with either LPS or TNF-alpha. We also report that MIP-3alpha/CCL20 and MIP-3beta/CCL19 production by LPS-stimulated neutrophils is negatively modulated by IL-10. Remarkably, we found that supernatants harvested from stimulated neutrophils not only induced chemotaxis of both immature and mature dendritic cells (DC), but also triggered rapid integrin-dependent adhesion of CCR6- and CCR7-expressing lymphocytes to purified VCAM-1 and ICAM-1, respectively. Importantly, both chemotaxis and rapid integrin-dependent adhesion were dramatically suppressed by anti-MIP-3alpha/CCL20 and anti-MIP-3beta/CCL19 neutralizing antibodies, indicating that MIP-3alpha/CCL20 and MIP-3beta/CCL19 present in the supernatants were both biologically active. As these chemokines are primarily chemotactic for DC and specific lymphocyte subsets, the ability of neutrophils to produce MIP-3alpha/CCL20 and MIP-3beta/CCL19 might be significant in orchestrating the recruitment of these cell types to the inflamed sites and therefore in contributing to the regulation of the immune response.     

Lipopolysaccharide from an Escherichia coli htrB msbB mutant induces high levels of MIP-1 alpha and MIP-1 beta secretion without inducing TNF-alpha and IL-1 beta

OBJECTIVE: To identify a lipopolysaccharide (LPS) that retains the capacity to induce beta-chemokine secretion without the concomitant activation of pyrogenic cytokines. METHODS: LPS was extracted from strain MLK986 (mLPS), an htrB1::Tn10, msbB::ocam mutant of Escherichia coli that is defective for lipid A synthesis, and from wild-type parent E coli strains, W3110 (wtLPS). The capacity of these LPS preparations to induce tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and macrophage inflammatory proteins 1 alpha (MIP-1 alpha) and MIP-1 beta was assessed using a human peripheral blood mononuclear cell (PBMC) activation assay. RESULTS: Stimulation of PBMCs with mLPS did not induce measurable levels of pyrogenic cytokines TNF-alpha and IL-1 beta, whereas wtLPS induced high levels of these cytokines. Furthermore, mLPS antagonized the induction of TNF-alpha secretion by wtLPS. Nonetheless, mLPS retained a discrete agonist activity that induced MIP-1 alpha and MIP-1 beta secretion by PBMCs. This latter agonist activity appears to be unique to mLPS, since two previously documented LPS antagonists, Rhodobacter sphaeroides diphosphoryl lipid A and synthetic lipid IVA, did not induce MIP-1 alpha and MIP-1 beta secretion. Furthermore, synthetic lipid IVA was an antagonist of MIP-1 alpha and MIP-1 beta induction by mLPS. CONCLUSION: These results show that mLPS exhibits a novel bipartite activity, being an effective antagonist of TNF-alpha induction by wtLPS, while paradoxically being an agonist of MIP-1 alpha and MIP-1 beta secretion.     

CXC chemokines Gro(alpha)/IL-8 and IP-10/MIG in Helicobacter pylori gastritis

Infection with Helicobacter pylori causes chronic active gastritis, which is characterized by neutrophils infiltrating the gastric epithelial layer and the underlying lamina propria as well as by T, B lymphocytes and macrophages accumulating in the lamina propria. In this study, the chemokine profile responsible for the recruitment of these inflammatory cells is investigated. Using both RNA/RNA in situ hybridization and immunohistochemistry, the expression of the neutrophil and/or lymphocyte-attractant CXC chemokines growth-related oncogene alpha (Gro(alpha)), IL-8, interferon-gamma (IFN-gamma)-inducible protein-10 (IP-10), monokine induced by IFN-gamma (MIG) and the CC chemokines macrophage inflammatory protein-1alpha (MIP-1alpha), -1beta, regulated on activation normal T cell expressed and secreted (RANTES) and monocyte chemoattractant protein-1 (MCP-1) is studied and microanatomically localized in the gastric mucosa. Macrophages in the lamina propria at sites with neutrophil infiltration and gastric epithelium infiltrated by neutrophils highly expressed the neutrophil-attractant chemokines Gro(alpha) and IL-8. Additionally, Gro(alpha) and IL-8 were expressed by neutrophils themselves localized within gastric epithelium, in the foveolar lumen and in the cellular debris overlying mucosal erosion. IP-10 and to a lower extent MIG, both selectively chemotactic for inflammatory T cells, were expressed by endothelial cells of gastric mucosal vessels and by mononuclear cells at sites with T cell infiltration. Expression of all other CC chemokines tested was significantly lower. These in vivo data indicate that a set of predominantly CXC chemokines modulates the inflammation in H. pylori gastritis. Gro(alpha) and IL-8 may play an important role in neutrophil trafficking from the mucosal vessel into the gastric epithelium, whereas IP-10 and MIG contribute to the recruitment of inflammatory T cells into the mucosa.     

MIP-3alpha, MIP-3beta and fractalkine induce the locomotion and the mobilization of intracellular calcium, and activate the heterotrimeric G proteins in human natural killer cells.

We demonstrate here that the CC chemokines macrophage inflammatory protein-3alpha (MIP-3alpha), macrophage inflammatory protein-3beta (MIP-3beta) and the CX3C chemokine fractalkine induce the chemotaxis of interleukin-2 (IL-2)-activated natural killer (IANK) cells. In addition, these chemokines enhance the binding of [gamma-35S]guanine triphosphate ([gamma-35S]GTP) to IANK cell membranes, suggesting that receptors for these chemokines are G protein-coupled. Our results show that MIP-3alpha receptors are coupled to Go, Gq and Gz, MIP-3beta receptors are coupled to Gi, Gq and Gs, whereas fractalkine receptors are coupled to Gi, and Gz. All three chemokines induced a robust calcium response flux in IANK cells. Cross-desensitization experiments show that MIP-3alpha, MIP-3beta or fractalkine use receptors not shared by each other or by the CC chemokine regulated on activation, normal, T-cell expressed, and secreted (RANTES), the CXC chemokines stromal-derived factor-1alpha (SDF-1alpha) and interferon-inducible protein-10 (IP-10), or the C chemokine lymphotactin.     

Altered intracellular expression of the chemokines MIP-1alpha,MIP-1beta and IL-8 by peripheral blood CD4+ and CD8+ T cells in mild allergic asthma

BACKGROUND: The ability of chemokines to regulate Th1 and Th2 responses suggests a role in the pathogenesis of atopic disorders such as allergic asthma where Th2 response dominance has been observed. Although the impact of allergic asthma on local chemokine production in the lung has been the subject of investigation, little is know about the influence of disease progression on peripheral chemokine production. We now report use of whole blood culture and flow cytometry to assess the influence of mild allergic asthma on peripheral T-cell chemokine expression. METHODS: Study participants included patients with mild allergic asthma (n = 7) and nonasthmatic controls (n = 7). Following in vitro stimulation of peripheral venous blood with phorbol 12-myristate acetate (PMA) and ionomycin, flow cytometry was used to estimate the percentage of CD4+ and CD8+ T cells producing a number of chemokines, including macrophage inflammatory proteins MIP-1alpha and MIP-1beta, RANTES (regulated on activation, T-cell expressed and secreted), monocytic chemotactic protein-1 (MCP)-1, and interleukin (IL)-8, or the cytokines interferon (IFN)-gamma and IL-4. Serum levels of MIP-1alpha, MIP-1beta, RANTES, MCP-1, IL-8, IFN-gamma and IL-4 were also assessed by quantitative ELISA. RESULTS: Intracellular expression of MIP-1beta by CD4+ and CD8+ T cells from allergic asthmatics was significantly reduced in comparison to that observed for nonasthmatics (median = 2.29% (1.75-3.50) vs 4.57% (3.38-6.64), P = 0.05; 14.20% (13.18-17.88) vs 44.10% (30.38-48.70), P = 0.01). Similarly, intracellular expression of MIP-1alpha by CD8+ T cells from allergic asthmatics was also significantly lower (3.67% (1.17-5.42) vs 17.10% (4.97-20.43), P = 0.05). Conversely, IL-8 expression by both CD4+ and CD8+ T cells from allergic asthmatics demonstrated significant enhancement (9.93% (7.77-11.28) vs 4.14% (3.61-7.11), P = 0.05; 8.40% (6.97-10.04) vs 4.98% (3.37-6.08), P = 0.05). Examination of intracellular IFN-gamma and IL-4 revealed no significant difference in the expression of either cytokine by CD4+ T-cells from allergic asthmatics and nonasthmatics. In contrast, expression of IFN-gamma was significantly reduced in CD8+ T-cells from allergic asthmatics (24.60% (21.08-32.50) vs 48.40% (41.50-55.28), P = 0.01). CONCLUSIONS: The occurrence in mild allergic asthma of peripheral T-cell chemokine expression suggestive of a diminished Th1 response, coinciding with marginal change in cytokine profiles indicative of a Th2 response bias, confirms the importance of chemokine involvement in the etiology of allergic asthma. The ability to use whole blood culture to estimate chemokine expression in T cell subsets may ultimately provide a practical means to evaluate disease status and to monitor early intervention therapies which target chemokines.     

IFN-gamma potentiates the release of TNF-alpha and MIP-1alpha by alveolar macrophages during allergic reactions

Viral infections play an important role in the exacerbation of asthma. The production of interferons (IFNs) is well known to limit viral spread, but IFN-gamma can also prime alveolar macrophages to release more inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and macrophage inflammatory protein-1alpha (MIP-1alpha). Given the importance of these cytokines, we have investigated the effect of IFN-gamma on their release by alveolar macrophages during stimulation by immunoglobulin (Ig)E/anti-IgE. Alveolar macrophages from normal or Nippostrongylus brasiliensis-infected rats, the latter having increased numbers of low-affinity receptors for IgE (Fcepsilon RII) on their alveolar macrophages, were treated with IgE for 2 h and stimulated with anti-IgE for 18 h. The increase of TNF-alpha release (153 +/- 48 pg/10(6) cells) by IgE/anti-IgE occurred only with alveolar macrophages from infected rats. The messenger RNA level for TNF-alpha in rat alveolar macrophages was also increased by stimulation with IgE/anti-IgE. Treatment with IFN-gamma prior to stimulation with IgE/anti-IgE showed a time- and concentration-dependent increase of TNF-alpha release. Interestingly, IgE/anti-IgE treatment did not stimulate the release of MIP-1alpha (15 +/- 5 pg/10(6) cells), but IFN-gamma treatment alone and with IgE /anti-IgE significantly increased and potentiated MIP-1alpha release (98 +/- 40 pg/10(6) cells) by alveolar macrophages, respectively. These results suggest that IFN-gamma produced at times such as during viral infections primes alveolar macrophages for enhanced release of inflammatory mediators during allergic reactions, thereby contributing to the inflammatory process.     

MIP-1alpha expression in tissues from patients with hemophagocytic syndrome

Hemophagocytic syndrome (HPS) is a clinicopathologic syndrome that can be precipitated by a variety of causes and is characterized by a systemic activation of macrophages, which are induced to undergo phagocytosis. Chemokines play an important role in the inflammatory cell recruitment into tissues. We examined the expression of chemokines and cytokines in tissues exhibiting histologic evidence of HPS in a variety of settings: peripheral T-cell lymphoma, three patients; nasal T/NK cell lymphoma, one patient; subcutaneous panniculitis-like T-cell lymphoma, one patient; and chronic EBV infection, one patient. Compared with control tissues, we found elevated macrophage inflammatory protein-1alpha (MIP-1alpha) and interferon-gamma (IFN-gamma) expression, but not macrophage-derived chemotactic factor (MDC) or TNF-alpha, in tissues of patients with HPS irrespective of the cause or setting. MIP-1alpha can promote macrophage chemotaxis and IFN-gamma promotes macrophage activation. Elevated expression of IP-10 and monokine induced by IFN-gamma (Mig) was also detected in tissues exhibiting features of HPS, providing an explanation for the occurrence of chemoattraction of T-cells and NK cells. Immunohistochemical analysis of tissues with evidence of phagocytic activity in that site showed MIP-1alpha characteristically localized to endothelial cells of blood vessels and splenic sinuses, lymphocytes, and macrophages. These results provide evidence for MIP-1alpha chemokine expression in tissues from patients with HPS and suggest that MIP-1alpha may play an important role in the pathogenesis of the hemophagocytic syndrome.     

GM-CSF, IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, ICAM-1 and VCAM-1 gene expression and cytokine production in human duodenal fibroblasts stimulated with lipopolysaccharide, IL-1 alpha and TNF-alpha.

The role of mucosal fibroblasts in intestinal inflammatory reactions is not known. In this study, we demonstrate that fibroblasts grown from histologically normal human duodenal biopsy tissues expressed mRNA genes for granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) when stimulated with lipopolysaccharide (LPS) or IL-1 alpha. The increased mRNA expression of GM-CSF, IL-1 alpha, IL-1 beta, IL-6 and IL-8 in response to IL-1 alpha and LPS stimulation was time- and dose-dependent. In contrast, IL-10 was weakly expressed when fibroblasts were stimulated with LPS, IL-1 alpha or tumour necrosis factor-alpha (TNF-alpha), but the expression was enhanced in the presence of cycloheximide combined with optimal concentrations of LPS, IL-1 alpha or TNF-alpha, IL-1 alpha was a more potent stimulator than LPS for GM-CSF, IL-6, IL-8 and IL-10 expression, but not for IL-1 alpha and IL-1 beta. Increased GM-CSF, IL-6 and IL-8 gene expression was associated with the production of cytokine proteins in culture supernatant, but IL-1 alpha and IL-1 beta remained undetectable. Dexamethasone suppressed both gene expression and protein production of GM-CSF, IL-6 and IL-8 when fibroblasts were exposed to IL-1 alpha. TNF-alpha stimulated the release of GM-CSF, IL-6 and IL-8 and, combined with IL-1 alpha, cytokine production was enhanced synergistically. Finally, both LPS and IL-1 alpha up-regulated ICAM-1 and VCAM-1 gene expression. These findings implicate duodenal fibroblasts in the initiation and/or regulation of intestinal inflammation.     

Expression patterns of cytokines and chemokines genes in human hepatoma cells

Various cytokines and chemokines play a role in carcinogenesis. However, no study has previously been undertaken to investigate comprehensively the expressions of cytokines and chemokines in hepatoma cells. In this study, we determined which cytokines and chemokines are expressed in hepatoma cells. Recently, it was reported that the expressions of several chemokines could be increased by Fas stimulus in many normal and cancer cells. Therefore, we also investigated whether chemokines expression is regulated by Fas ligation. To address this issue, we performed RNase protection assays upon 13 cytokines and 8 chemokines genes in 10 human hepatoma cell lines, comprising 8 hepatitis B virus (HBV)-associated hepatoma cell lines. Transforming growth factor-beta2 (TGF-beta2) was found to be expressed in 8 HBV-associated hepatoma cell lines, and to be potently expressed in 5 cell lines; however, the mRNA expressions of interleukin-10 (IL-10), IL-12, interferon-gamma(IFN-gamma) and tumor necrosis factor-alpha(TNF-alpha) were not detected in any cell lines examined. Among the chemokines investigated in this study, IL-8 was expressed by 8 HBV- associated hepatoma cell lines, and monocyte chemoattractant protein-1 (MCP-1) by 7 HBV-associated hepatoma cell lines. However, the mRNA expressions of macrophage inflammatory protein-1alpha(MIP-1alpha), MIP-1beta, interferon-inducible protein-10 (IP-10), RANTES, lymphotactin and I-309 were either very weak or undetectable. Fas ligation did not increase chemokines expression in hepatoma cells. Conclusively, TGF-beta2, IL-8 and MCP-1 were overexpressed in HBV-associated hepatoma cells, and the expressions of chemokines were not increased by Fas ligation in human hepatoma cells.     

Selective induction of the monocyte-attracting chemokines MCP-1 and IP-10 in vesicular stomatitis virus-infected human monocytes.

It is characteristic of viral infections that monocytes/macrophages and lymphocytes infiltrate infected tissue, and neutrophils are absent. CC and non-ELR CXC chemokines predominantly attract mononuclear leukocytes, whereas the ELR motif-expressing CXC chemokines primarily act on neutrophils. To investigate the general role of chemokines in viral diseases, we determined their release and expression patterns after infection of human monocytes with vesicular stomatitis virus (VSV). Human monocytes were productively infected by VSV. Surprisingly, VSV did not induce the release of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6. In contrast, we found a strong induction of the CC chemokine monocyte chemotactic protein-1 (MCP-1) and the non-ELR CXC chemokine interferon-gamma (IFN-gamma) inducible protein-10 (IP-10) by VSV on the gene and protein level. The expression and release of the neutrophil chemoattractants IL-8 and growth-related oncogene-alpha (GRO-alpha) remained unaffected after VSV infection. Our results indicate that the typical monocyte and lymphocyte-dominated leukocyte infiltration of virus-infected tissue is based on a selective induction of mononuclear leukocyte-attracting chemokines.     

Cryptococcus neoformans induces macrophage inflammatory protein 1alpha (MIP-1alpha) and MIP-1beta in human microglia: role of specific antibody and soluble capsular polysaccharide

We characterized the expression of the beta-chemokines macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, and RANTES by primary human microglia after exposure to Cryptococcus neoformans. In the absence of specific antibody, C. neoformans failed to elicit a chemokine response, while in the presence of specific antibody, microglia produced MIP-1alpha and MIP-1beta in amounts comparable to those induced by lipopolysaccharide. RANTES was also induced but at much lower levels. In addition to MIP-1alpha and MIP-1beta mRNA, we observed a robust induction of monocyte chemoattractant protein 1 and interleukin-8 mRNA following incubation of microglia with opsonized C. neoformans. In contrast, cryptococcal polysaccharide did not induce a chemokine response even when specific antibody was present and inhibited the MIP-1alpha induction associated with antibody-mediated phagocytosis of C. neoformans. The role of the Fc receptor in the observed chemokine induction was explored in several experiments. Treatment of microglia with cytochalasin D inhibited internalization of C. neoformans but did not affect MIP-1alpha induction. In contrast, treatment with herbimycin A, a tyrosine kinase inhibitor, inhibited MIP-1alpha induction. Microglia stimulated with immobilized murine immunoglobulin also produced MIP-1alpha and RANTES (MIP-1alpha > RANTES). Our results show that microglia produce several chemokines when stimulated by C. neoformans in the presence of specific antibody and that this process is likely to be mediated by Fc receptor activation. This response can be down-regulated by cryptococcal capsular polysaccharide. These findings suggest a mechanism by which C. neoformans infections fail to induce strong inflammatory responses in patients with cryptococcal meningoencephalitis and have important implications for antibody therapy.     

Multiplex analysis of cytokines in the blood of cynomolgus macaques naturally infected with Ebola virus (Reston serotype)

Ebola virus (EBO) causes the most severe form of viral hemorrhagic fever in humans and nonhuman primates with up to 90% of infections culminating in death. The requirement of maximum containment laboratories for Ebola virus research has limited opportunities to study the pathogenesis of EBO infections. While tissue damage does occur, often it would appear not to be sufficient to explain death, indicating that soluble mediators play an important role in disease progression. In previous studies, fatal human infections with the Zaire subtype of Ebola (EBO-Z) were associated with an increase in the levels of inflammatory cytokines. In this investigation, a new multiplex assay was developed and used to measure circulating levels of cytokines and chemokines in cynomolgus macaques infected with the Reston subtype of EBO (EBO-R). Increased levels of IL-6, TNF-alpha, IFN-gamma, IL-2, IL-4, IL-8, IL-10, and GM-CSF were detected in infected animals, and the increase in circulating cytokines correlated with an increase in circulating viral antigen. Blood samples from animals showing high levels of cytokines were also tested for the chemokines: MCP-1, IL-1beta, MIP-1alpha, MIP-1beta, IP-10, and RANTES. High levels of MCP-1 and MIP-1beta, and RANTES were found in infected primates and, while levels were more variable, IL-1beta was detected only in infected animals.     

Production of macrophage inflammatory protein 3alpha (MIP-3alpha) (CCL20) and MIP-3beta (CCL19) by human peripheral blood neutrophils in response to microbial pathogens

Effects of bacterial pathogens on the production of macrophage inflammatory protein 3alpha (MIP-3alpha) and MIP-3beta from human peripheral blood neutrophils were investigated. Neutrophils produced both chemokines by coincubation with either gram-positive or gram-negative bacteria. Neutrophils may initiate antigen-specific immune responses through the release of these chemokines that are capable of promoting selective recruitment of dendritic cells and T-cell subsets.     

Neutrophil depletion exacerbates experimental Chagas' disease in BALB/c, but protects C57BL/6 mice through modulating the Th1/Th2 dichotomy in different directions

To elucidate the roles of neutrophils in experimental Chagas' disease, we depleted the peripheral neutrophils in BALB/c and C57BL/6 mice with a monoclonal antibody 1 day before Trypanosoma cruzi infection. Neutrophil depletion in BALB/ c mice resulted in exacerbation of the disease and decreased expression of mRNA for Th1 cytokines, including IL-2 and IFN-gamma, IL-12p40 and TNF-alpha in their spleens after the infection, while a Th2 cytokine, IL-10, increased especially 1 day after infection. Neutrophils from infected BALB / c mice expressed mRNA for IL-12p40, IFN-gamma, TNF-alpha and Th1 chemoattractive chemokines, monokine induced by IFN-gamma (MIG) and macrophage inflammatory protein-1alpha (MIP-1alpha ). In contrast, in C57BL/6 mice neutrophil depletion induced resistance to the disease and enhanced the expression of the above Th1 cytokines, although IL-10 mRNA in neutrophil-depleted C57BL/6 mice was also higher than in control mice. Neutrophils from C57BL/6 mice did not express IL-12p40, IFN-gamma and MIG but expressed TNF-alpha, MIP-1alpha and IL-10. Therefore, neutrophils may play opposite roles in these two strains of mice with respect to protection versus exacerbation of T. cruzi infection, possibly through modulating the Th1/Th2 dichotomy in different directions.     

Topical steroid treatment of allergic rhinitis decreases nasal fluid TH2 cytokines, eosinophils, eosinophil cationic protein, and IgE but has no significant effect on IFN-gamma, IL-1beta, TNF-alpha, or neutrophils

BACKGROUND: Topical treatment with glucocorticoids (GCs) is known to decrease eosinophils but not neutrophils in patients with allergic rhinitis. OBJECTIVE: We sought to examine whether the differential effects of GC treatment on eosinophils and neutrophils are mirrored by differential effects on T(H)1/T(H)2 cytokines and the neutrophil-associated cytokines IL-1beta and TNF-alpha. METHODS: Differential counts of eosinophils and neutrophils in nasal fluids from 60 children with seasonal allergic rhinitis treated with a topical GC were examined after staining with May-Grünwald-Giemsa stain. Nasal fluid levels of IFN-gamma, IL-4, IL-6, IL-10, IL-1beta, and TNF-alpha were examined with ELISA, and IgE and eosinophil cationic protein (ECP) levels were examined with RIA. RESULTS: After GC treatment, there was a statistically significant decrease of the T(H)2 cytokines IL-4, IL-6, and IL-10, as well as ECP and IgE. By contrast, there were no significant changes of the levels of IFN-gamma, IL-1beta, TNF-alpha, or neutrophils. In the GC-treated patients IL-1beta and TNF-alpha levels correlated with neutrophils and ECP, and IL-1beta correlated with eosinophils. Furthermore, ECP correlated with both eosinophils and neutrophils. Neither IL-1beta nor TNF-alpha correlated with IgE. Patients with high neutrophil counts after GC treatment were found to have significantly higher eosinophil counts and ECP than patients with low counts. CONCLUSIONS: The beneficial effects of topical treatment with GC in patients with allergic rhinitis could be attributed to downregulation of T(H)2 cytokines, with an ensuing decrease of eosinophils, ECP, and IgE. It is possible that neutrophils could counteract the beneficial effects of GCs by releasing the proinflammatory cytokines IL-1beta and TNF-alpha.     

Polymorphonuclear leucocytes selectively produce anti-inflammatory interleukin-1 receptor antagonist and chemokines, but fail to produce pro-inflammatory mediators

The role of neutrophils in the immune response has long been regarded as mainly phagocytic, but recent publications have indicated the production of several cytokines by polymorphonuclear leucocytes (PMN). The results of the individual reports, however, vary considerably. In this study, we established a cytokine profile of pure human neutrophils and demonstrated that minor contamination of peripheral blood mononuclear cells (PBMCs) in PMN preparations can lead to false-positive results. In our hands, peripheral blood PMN fail to produce the pro-inflammatory cytokines interleukin (IL)-1beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha). Instead, they secrete large amounts of the chemokine IL-8 and the anti-inflammatory IL-1 receptor antagonist (IL-1ra). Additionally, PMN preparations of a high purity show production of the chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and growth-related oncogene-alpha (GRO-alpha), as well as macrophage colony-stimulating factor (M-CSF). The neutrophil therefore represents a novelty by producing the antagonist of IL-1beta (i.e. IL-1ra) in the absence of IL-1beta itself. To support our results, we differentiated stem cells from human cord blood into PMN and monocytes, respectively. These in vitro-differentiated PMN showed the same cytokine profile as peripheral blood PMN lacking IL-1beta, while differentiated monocytes produced the expected IL-1beta in addition to IL-1ra. The clear anti-inflammatory nature of their cytokine profile enables PMN to antagonize pro-inflammatory signals in experimental conditions. It is therefore possible that PMN play a key role in immune regulation by counteracting a dysregulation of the inflammatory process. Clinical studies, in which administration of recombinant G-CSF had a favourable effect on the outcome of severe infections and even sepsis without worsening inflammation, could thus be explained by our results.     

Differential induction of the toll-like receptor 4-MyD88-dependent and -independent signaling pathways by endotoxins

The biological response to endotoxin mediated through the Toll-like receptor 4 (TLR4)-MD-2 receptor complex is directly related to lipid A structure or configuration. Endotoxin structure may also influence activation of the MyD88-dependent and -independent signaling pathways of TLR4. To address this possibility, human macrophage-like cell lines (THP-1, U937, and MM6) or murine macrophage RAW 264.7 cells were stimulated with picomolar concentrations of highly purified endotoxins. Harvested supernatants from previously stimulated cells were also used to stimulate RAW 264.7 or 23ScCr (TLR4-deficient) macrophages (i.e., indirect induction). Neisseria meningitidis lipooligosaccharide (LOS) was a potent direct inducer of the MyD88-dependent pathway molecules tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 3alpha (MIP-3alpha), and the MyD88-independent molecules beta interferon (IFN-beta), nitric oxide, and IFN-gamma-inducible protein 10 (IP-10). Escherichia coli 55:B5 and Vibrio cholerae lipopolysaccharides (LPSs) at the same pmole/ml lipid A concentrations induced comparable levels of TNF-alpha, IL-1beta, and MIP-3alpha, but significantly less IFN-beta, nitric oxide, and IP-10. In contrast, LPS from Salmonella enterica serovars Minnesota and Typhimurium induced amounts of IFN-beta, nitric oxide, and IP-10 similar to meningococcal LOS but much less TNF-alpha and MIP-3alpha in time course and dose-response experiments. No MyD88-dependent or -independent response to endotoxin was seen in TLR4-deficient cell lines (C3H/HeJ and 23ScCr) and response was restored in TLR4-MD-2-transfected human embryonic kidney 293 cells. Blocking the MyD88-dependent pathway by DNMyD88 resulted in significant reduction of TNF-alpha release but did not influence nitric oxide release. IFN-beta polyclonal antibody and IFN-alpha/beta receptor 1 antibody significantly reduced nitric oxide release. N. meningitidis endotoxin was a potent agonist of both the MyD88-dependent and -independent signaling pathways of the TLR4 receptor complex of human macrophages. E. coli 55:B5 and Vibrio cholerae LPS, at the same picomolar lipid A concentrations, selectively induced the MyD88-dependent pathway, while Salmonella LPS activated the MyD88-independent pathway.     

Th2- and to a lesser extent Th1-type cytokines upregulate the production of both CXC (IL-8 and gro-alpha) and CC (RANTES,eotaxin, eotaxin-2, MCP-3 and MCP-4) chemokines in human airway epithelial cells

BACKGROUND: Both CXC and CC chemokines play an important role in leukocyte recruitment. However, a systematic examination of their production by human airway epithelial cells (HAECs) has not been carried out. The objective of this study was to investigate whether Th1- and Th2-type cytokines regulate chemokine production in HAECs. METHODS: HAECs were grown from both nasal and bronchial tissue and subsequently stimulated with either Th1- or Th2-type cytokines. RESULTS: Constitutive mRNA expression for gro-alpha, IL-8 and RANTES was seen in both human nasal and human bronchial epithelial cells. IL-4 was the strongest stimulus for both gene expression and protein production of the chemokines RANTES, IL-8 and gro-alpha, while both IL-13 and IFN-gamma were weaker inducers of these chemokines, with the exception of gro-alpha (IL-13 was a strong stimulus for gro-alpha production). TNF-alpha synergized with IL-4, and to a lesser extent with IFN-gamma and IL-13, to release RANTES, IL-8 and gro-alpha. IL-4 and to a lesser extent IL-13 and IFN-gamma stimulated the production of MCP-3 and -4, eotaxin and eotaxin-2 immunoreactivities. However, no induction of the mRNAs encoding these chemokines was observed, suggesting that they may be released from a preformed pool within the HAECs. CONCLUSION: These findings suggest that when released into the airways, Th2- and to a lesser extent Th1-type cytokines may stimulate recruitment of eosinophils and neutrophils through the release of CC (RANTES, MCP-3 and -4, eotaxin and eotaxin-2) and CXC chemokines (gro-alpha and IL-8).