Progenitor egress from the bone marrow after allergen challenge: role of stromal cell-derived factor 1alpha and eotaxin

BACKGROUND

CCR3 expression on CD34+ cells mediates migration to eotaxin in vitro. CXCR4 and stromal cell-derived factor (SDF)-1alpha are important for stem cell homing to hemopoietic compartments.

OBJECTIVE

To study chemokine-mediated progenitor cell traffic in allergic inflammation.

METHODS

Bone marrow (BM) aspirates were obtained at baseline from normal subjects; atopic subjects without asthma; and subjects with asthma before, 5 hours after, and 24 hours after allergen inhalation (dual and early responders). Changes in chemokine receptor expression and migration were assessed.

RESULTS

Expression of CXCR4, but not CCR3, on BM CD34+ cells was greater in normal subjects compared with atopic subjects with asthma. Likewise, SDF-1alpha, but not eotaxin, stimulated a greater migrational response by BM CD34+ cells from normal subjects compared with subjects with asthma. For all subjects, a positive correlation was found between intensity of CXCR4 expression and magnitude of CD34+ cell response to SDF-1alpha. Allergen inhalation attenuated both intensity of CXCR4 expression and SDF-1alpha levels in marrow from dual compared with early responders 24 hours postallergen. In contrast, the intensity of CCR3 expression on BM CD34+ cells increased in dual compared with early responders at 24 hours postallergen. In addition, an increase in migrational responsiveness of BM CD34+ cells to eotaxin and a decrease to SDF-1alpha 24 hours postallergen was found in dual responder subjects with asthma.

CONCLUSION

After allergen inhalation in subjects with asthma, a downregulation in CXCR4 intensity on BM CD34+ cells and a reduction in BM SDF-1alpha levels may reduce progenitor retention to marrow stroma promoting peripheral egress, possibly mediated by the CCR3/eotaxin axis.

Increased lymphocyte trafficking to colonic microvessels is dependent on MAdCAM-1 and C-C chemokine mLARC/CCL20 in DSS-induced mice colitis

Although enhanced lymphocyte trafficking is associated with colitis formation, little information about its regulation is available. The aim of this study was to examine how the murine liver and activation-regulated chemokine (mLARC/CCL20) contributes to lymphocyte recruitment in concert with vascular adhesion molecules in murine chronic experimental colitis. T and B lymphocytes isolated from the spleen were fluorescence-labelled and administered to recipient mice. Lymphocyte adhesion to microvessels of the colonic mucosa and submucosa was observed with an intravital microscope. To induce colitis, the mice received two cycles of treatment with 2% dextran sodium sulphate (DSS). In some of the experiments antibodies against the adhesion molecules or anti-mLARC/CCL20 were administered, or CC chemokine receptor 6 (CCR6) of the lymphocytes was desensitized with excess amounts of mLARC/CCL20. Significant increases in T and B cell adhesion to the microvessels of the DSS-treated mucosa and submucosa were observed. In chronic colitis, the accumulation of lymphocytes was significantly inhibited by anti-mucosal addressin cell adhesion molecule (MAdCAM)-1 mAb, but not by anti-vascular cell adhesion molecule-1. In DSS-treated colonic tissue, the expression of mLARC/CCL20 was significantly increased, the blocking of mLARC/CCL20 by monoclonal antibody or the desensitization of CCR6 with mLARC/CCL20 significantly attenuated the DSS-induced T and B cell accumulation. However, the combination of blocking CCR6 with MAdCAM-1 did not further inhibit these accumulations. These results suggest that in chronic DSS-induced colitis, both MAdCAM-1 and mLARC/CCL20 may play important roles in T and B lymphocyte adhesion in the inflamed colon under flow conditions.

Characterization of CCL20 secretion by human epithelial vaginal cells: involvement in Langerhans cell precursor attraction

Mucosa represents the main site of pathogen/cell interactions. The two main types of cells forming the epithelial structure [epithelial cells and Langerhans cells (LC)] coordinate the first defense responses to avoid infection. To evaluate the involvement of epithelial cells in the early steps leading to a specific adaptive immune response, we have studied the interactions between vaginal epithelial and LC through the establishment of a human vaginal epithelial mucosa. We demonstrate that normal human vaginal epithelial cells constitutively secrete the chemokine macrophage inflammatory protein 3alpha/CC chemokine ligand 20 (CCL20), known to recruit LC precursors (LCps) selectively via its cognate CC chemokine receptor 6 (CCR6). This secretion is up-regulated by the proinflammatory cytokine interleukin-1beta through the nuclear factor-kappaB pathway. Similar results were obtained with the human vaginal epithelial cell line SiHa, which displays numerous homologies with normal vaginal cells. The chemotactic activity of the secreted CCL20 was demonstrated by its ability to attract LCp CCR6+. Moreover, the use of neutralizing polyclonal antibodies directed against the CCL20 molecule abolished this migration completely, suggesting that CCL20 is the main attracting factor for LCps, which is produced by the vaginal cells. These data indicate that vaginal epithelial cells play an important role in the immunological defense by attracting immune cells to the site of epithelial/pathogen contact.

MIP-1alpha[CCL3] acting on the CCR1 receptor mediates neutrophil migration in immune inflammation via sequential release of TNF-alpha and LTB4

In the present study, we investigated the involvement of macrophage-inflammatory protein-1alpha (MIP-1alpha)[CC chemokine ligand 3 (CCL3)], MIP-1beta[CCL4], regulated on activation, normal T expressed and secreted (RANTES)[CCL5], and CC chemokine receptors (CCRs) on neutrophil migration in murine immune inflammation. Previously, we showed that ovalbumin (OVA)-triggered neutrophil migration in immunized mice depends on the sequential release of tumor necrosis factor alpha (TNF-alpha) and leukotriene B(4)(LTB(4)). Herein, we show increased mRNA expression for MIP-1alpha[CCL3], MIP-1beta[CCL4], RANTES[CCL5], and CCR1 in peritoneal cells harvested from OVA-challenged, immunized mice, as well as MIP-1alpha[CCL3] and RANTES[CCL5] but not MIP-1beta[CCL4] proteins in the peritoneal exudates. OVA-induced neutrophil migration response was muted in immunized MIP-1alpha[CCL3](-/-) mice, but it was not inhibited by treatment with antibodies against RANTES[CCL5] or MIP-1beta[CCL4]. MIP-1alpha[CCL3] mediated neutrophil migration in immunized mice through induction of TNF-alpha and LTB(4) synthesis, as these mediators were detected in the exudates harvested from OVA-challenged immunized wild-type but not MIP-1alpha[CCL3](-/-) mice; administration of MIP-1alpha[CCL3] induced a dose-dependent neutrophil migration, which was inhibited by treatment with an anti-TNF-alpha antibody in TNF receptor 1 (p55(-/-))-deficient mice or by MK 886 (a 5-lipoxygenase inhibitor); and MIP-1alpha[CCL3] failed to induce LTB(4) production in p55(-/-) mice. MIP-1alpha[CCL3] used CCR1 to promote neutrophil recruitment, as OVA or MIP-1alpha[CCL3] failed to induce neutrophil migration in CCR1(-/-) mice, in contrast to CCR5(-/-) mice. In summary, we have demonstrated that neutrophil migration observed in this model of immune inflammation is mediated by MIP-1alpha[CCL3], which via CCR1, induces the sequential release of TNF-alpha and LTB(4). Therefore, whether a similar pathway mediates neutrophil migration in human immune-inflammatory diseases, the development of specific CCR1 antagonists might have a therapeutic potential.

The chemokine receptor D6 limits the inflammatory response in vivo

How the inflammatory response is initiated has been well defined but relatively little is known about how such responses are resolved. Here we show that the D6 chemokine receptor is involved in the post-inflammatory clearance of beta-chemokines from cutaneous sites. After induction of inflammation by phorbol esters, wild-type mice showed a transient inflammatory response. However, in D6-deficient mice, an excess concentration of residual chemokines caused a notable inflammatory pathology with similarities to human psoriasis. These results suggest that D6 is involved in the resolution of the cutaneous inflammatory response.

Salmonella enterica Serovar Typhimurium infection of dendritic cells leads to functionally increased expression of the macrophage-derived chemokine

Gene expression in murine dendritic cells (DCs) infected with green fluorescent protein-expressing Salmonella enterica serovar Typhimurium BRD509 was studied by mRNA differential display. Infected DCs were sorted from uninfected cells by flow cytometry. The mRNA expression patterns of infected and uninfected cells revealed a number of differentially expressed transcripts, which included the macrophage-derived chemokine (MDC). Up-regulation of MDC transcription in infected DCs was confirmed by Northern blotting, and the kinetics of MDC expression was examined by real-time reverse transcription-PCR, with which 31- and 150-fold increases were detected at 2 and 6 h postinfection, respectively. The increased release by DCs of MDC into culture media was detected by an enzyme-linked immunosorbent assay. The biological activity of MDC was investigated in in vitro and in vivo assays. In vitro, supernatants from S. enterica serovar Typhimurium-infected DCs were chemoattractive to T cells, and neutralization of MDC in these supernatants inhibited T-cell migration. Passive transfer of anti-MDC antibody to mice infected with BRD509 revealed that neither growth of the bacterium nor resistance of the mice to reinfection was affected and that in vivo inhibition of MDC did not affect T-cell responses, as measured by the gamma interferon ELISPOT method 3 days after challenge infection.

Involvement of CC chemokine ligand 18 (CCL18) in normal and pathological processes

CC chemokine ligand 18 (CCL18) was originally discovered as pulmonary and activation-regulated chemokine (PARC), dendritic cell (DC)-chemokine 1 (DC-CK1), alternative macrophage activation-associated CC chemokine-1 (AMAC-1), and macrophage inflammatory protein-4 (MIP-4). CCL18 primarily targets lymphocytes and immature DC, although its agonistic receptor remains unknown so far. CCL18 is mainly expressed by a broad range of monocytes/macrophages and DC. A more profound understanding of the various activation programs and functional phenotypes of these producer cells might give a better insight in the proinflammatory versus anti-inflammatory role of this CC chemokine. It is interesting that CCL18 is constitutively present at high levels in human plasma and likely contributes to the physiological homing of lymphocytes and DC and to the generation of primary immune responses. Furthermore, enhanced CCL18 production has been demonstrated in several diseases, including various malignancies and inflammatory joint, lung, and skin diseases. The lack of a rodent counterpart for human CCL18 sets all hope on primate animal models to further elucidate the importance of CCL18 in vivo. This review will address these different aspects in more detail.

CCL22-induced responses are powerfully enhanced by synergy inducing chemokines via CCR4: evidence for the involvement of first ?-strand of chemokine

In an attempt to clarify how cells integrate the signals provided by multiple chemokines expressed during inflammation, we have uncovered a novel mechanism regulating leukocyte trafficking. Our data indicate that the concomitant exposure to CCR4 agonists and CXCL10/IP-10 strongly enhances the chemotactic response of human T lymphocytes. This enhancement is synergistic rather than additive and occurs via CCR4 since it persists after CXCR3 blockade. Besides chemotaxis, other cellular responses are enhanced upon stimulation of CCR4-transfected cells with CCL22/MDC plus CXCL10. Several other chemokines in addition to CXCL10 were able to increase CCL22-mediated chemotaxis. The first beta-strand of the chemokine structure is highly and specifically implicated in this phenomenon, as established using synergy-inducing and non-synergy-inducing chimeric chemokines. As shown in situ for skin from atopic and allergic contact dermatitis patients, this organ becomes the ideal environment in which skin-homing CCR4(+) T lymphocytes can accumulate under the stimulus offered by CCR4 agonists, together with the synergistic chemokines that are concomitantly expressed. Overall, our results indicate that chemokine-induced synergism strengthens leukocyte recruitment towards tissues co-expressing several chemokines.

Oncostatin M causes eotaxin-1 release from airway smooth muscle: Synergy with IL-4 and IL-13

BACKGROUND

Eotaxin is implicated in asthmatic eosinophilia. Oncostatin M (OSM) causes eotaxin release from fibroblasts.

OBJECTIVE

We sought to examine the effects and mechanism of action of OSM and other IL-6 family cytokines on eotaxin release from human airway smooth muscle cells.

METHODS

Eotaxin 1 release was measured by means of ELISA. Western blotting was used to examine mitogen-activated protein kinase and signal transducer and activator of transcription 3 (STAT-3) phosphorylation. Eotaxin promoter activity was analyzed in cells transfected with wild-type STAT-3, a mutant form of STAT-3 that cannot be phosphorylated, and a constitutively active form of STAT-3. The mRNA and protein expression of IL-4R alpha, the signaling receptor for IL-4 and IL-13, was evaluated by means of real-time PCR and flow cytometry, respectively.

RESULTS

OSM increased eotaxin 1 release and augmented IL-4- or IL-13-induced eotaxin release, whereas other IL-6 family cytokines did not. OSM caused a greater increase in STAT-3 phosphorylation and STAT-3-mediated gene transcription than other IL-6 family cytokines. OSM increased eotaxin promoter activity and augmented IL-13- and IL-4-induced increases in promoter activity. The constitutively active form of STAT-3 increased eotaxin promoter activity, whereas the mutant form of STAT-3 that cannot be phosphorylated significantly reduced eotaxin promoter activity induced by OSM or IL-4 plus OSM. OSM increased IL-4R alpha mRNA and protein levels.

CONCLUSIONS

OSM induces eotaxin 1 expression in human airway smooth muscle cells by a mechanism involving STAT-3. OSM synergizes with IL-13 and IL-4 to increase eotaxin 1 expression, possibly as a result of effects on IL-4R alpha expression.

Eotaxin-1-regulated eosinophils have a critical role in innate immunity against experimental Brugia malayi infection

Using two models of filarial infection in which Brugia malayi microfilariae (Mf) are contained in distinct anatomical compartments, in blood or tissue sites, we have demonstrated a critical role for eotaxin-1 in parasite clearance. In the first model, implantation of adult B. malayi into the peritoneal cavity of eotaxin-1(-/-) mice resulted in increased Mf survival associated with a dramatic reduction in peritoneal cavity eosinophilic infiltration. In the second model Mf were injected intravenously into eotaxin-1(-/-) mice; Mf clearance from the blood was more rapid than in wild-type mice and was associated with a pronounced blood eosinophilia, resulting from the inability of eosinophils to migrate to tissue sites in the absence of eotaxin-1. (Eotaxin-1 + IL-5)(-/-) mice had extended Mf survival in the blood and significantly reduced blood eosinophil levels. Interestingly, rapid clearance of a secondary Mf infection following immunization was unaltered in either eotaxin-1(-/-) mice or (eotaxin-1 + IL-5)(-/-) mice. Eosinophil peroxidase levels were high during primary, but not secondary infection, suggesting that eosinophil degranulation is important during primary Mf clearance. Thus, our data show that the presence of eosinophils is critical for innate clearance of B. malayi Mf infection, whereas rapid clearance of secondary infections is independent of both eotaxin-1 and IL-5.

Novel monoclonal antibodies detect elevated levels of the chemokine CCL18/DC-CK1 in serum and body fluids in pathological conditions

CC chemokine ligand 18/dendritic cell-chemokine 1 (CCL18/DC-CK1) is a CC chemokine, preferentially expressed by DC, which acts as a chemoattractant for naive T cells and mantle zone B cells. Applying a newly developed CCL18/DC-CK1 sandwich enzyme-linked immunosorbent assay, we demonstrate that DC secrete high amounts of CCL18/DC-CK1 and that this expression can be increased by interleukin-10. High levels of CCL18/DC-CK1 were also detected in human serum (average of 88 ng/ml). Moreover, elevated CCL18/DC-CK1 levels were detected in synovial fluid from rheumatoid arthritis patients and in drain fluid (average of 254 ng/ml and 122 ng/ml, respectively). Immunoprecipitation experiment using anti-CCL18/DC-CK1 monoclonal antibodies revealed a protein of 6-7 kDa in serum and drain fluid that was indistinguishable from recombinant CCL18/DC-CK1 on Western blot and in re-aggregation assays. The concentration of CCL18/DC-CK1 found in human serum is in the same order of magnitude as was previously reported to completely inhibit CCL11/eotaxin-induced CC chemokine receptor 3 (CCR3) activation and consequent migration of eosinophils. CCL18/DC-CK1 may therefore function as an agonist (for naive T and B cells) and as an antagonist for CCR3-expressing leukocytes such as eosinophils.

CD28 and secretory immunoglobulin A-dependent activation of eosinophils: inhibition of mediator release by the anti-allergic drug, suplatast tosilate

BACKGROUND

Eosinophils are major effector cells in allergic diseases. After their recruitment to sites of inflammation, they contribute to the pathophysiology of the disease by releasing granule proteins and cytokines. Suplatast tosilate (IPD-1151T), a new anti-allergic agent, has shown beneficial effect in the treatment of asthma, associated with reduced bronchoalveolar lavage eosinophil infiltration and eosinophilic cationic protein (ECP) release in serum and sputum.

OBJECTIVE

We investigated whether suplatast tosilate could exert direct effects on human eosinophil activation.

METHODS

Eosinophils from hypereosinophilic patients or normal donors were purified by Percoll gradient and the magnetic cell separation system. Chemotaxis was studied using the Boyden chamber technique using three chemoattractants, formyl-methionine-leucine-phenylalanine (fMLP), IL-5 and eotaxin. Oxidative metabolism was determined by a luminol-dependent chemiluminescence assay after activation with eotaxin or secretory IgA (sIgA). The release of ECP and eosinophil derived neurotoxin (EDN) was measured by radioimmunoassay and cytokine production was determined by ELISA following activation with sIgA or anti-CD28.

RESULTS

The chemotactic response to fMLP, IL-5 and eotaxin was significantly inhibited by IPD-1151T. Suplatast tosilate was partially inhibiting the release of reactive oxygen species (ROS) induced by eotaxin and sIgA. Activation by sIgA and CD28 ligation resulted in the release of ECP and EDN, which was inhibited by IPD-1151T. Upon activation by anti-CD28, only IL-13 production was inhibited by IPD-1151T, whereas release of IL-2 and IFN-gamma was not affected. IL-10 release induced by sIgA was also inhibited by IPD-1151T. Additionally, the pro-inflammatory cytokine IL-6, which was secreted following anti-CD28 and sIgA stimulation, was strongly inhibited by IPD-1151T.

CONCLUSION

Through inhibition of chemotaxis, IPD-1151T might limit the number of eosinophils at the inflammation site. Furthermore, it could reduce the pathological potential of eosinophils by inhibiting the release of ROS and cationic proteins, main inflammatory mediators produced by eosinophils. Moreover, the inhibition of immunoregulatory cytokines released by eosinophils could locally modify the immune response.

A DNA vaccine targeting survivin combines apoptosis with suppression of angiogenesis in lung tumor eradication

A novel strategy achieved the eradication of lung tumor metastases by joint suppression of angiogenesis in the tumor neovasculature and induction of tumor cell apoptosis. This was accomplished by CTLs induced by a DNA vaccine encoding secretory chemokine CCL21 and the inhibitor of apoptosis protein survivin, overexpressed by both proliferating endothelial cells in the tumor vasculature and tumor cells. Oral delivery of this DNA vaccine by doubly attenuated Salmonella typhimurium (dam(-) and AroA(-)) to such secondary lymphoid organs as Peyer's patches in the small intestine, elicited marked activation of antigen-presenting dendritic cells, and an effective CD8(+)T cell immune response against the survivin self-antigen. This resulted in eradication or suppression of pulmonary metastases of non-small cell lung carcinoma in both prophylactic and therapeutic settings in C57BL/6J mice. Moreover, the suppression of angiogenesis induced by the vaccine did not impair wound healing or fertility of treated mice. It is anticipated that such novel DNA vaccines will aid in the rational design of future strategies for the prevention and treatment of cancer.

Identification of a cooperative mechanism involving interleukin-13 and eotaxin-2 in experimental allergic lung inflammation

Pulmonary eosinophilia, a hallmark pathologic feature of allergic lung disease, is regulated by interleukin-13 (IL-13) as well as the eotaxin chemokines, but the specific role of these cytokines and their cooperative interaction are only partially understood. First, we elucidated the essential role of IL-13 in the induction of the eotaxins by comparing IL-13 gene-targeted mice with wild type control mice by using an ovalbumin-induced model of allergic airway inflammation. Notably, ovalbumin-induced expressions of eotaxin-1 and eotaxin-2 mRNA in the lungs were almost completely dependent upon IL-13. Second, in order to address the specific role of eotaxin-2 in IL-13-induced pulmonary eosinophilia, we generated eotaxin-2 gene-deficient mice by homologous recombination. Notably, in contrast to observations made in eotaxin-1-deficient mice, eotaxin-2-deficient mice had normal base-line eosinophil levels in the hematopoietic tissues and gastrointestinal tract. However, following intratracheal IL-13 administration, eotaxin-2-deficient mice showed a profound reduction in airway eosinophilia compared with wild type mice. Most interestingly, the level of peribronchial lung tissue eosinophils in IL-13-treated eotaxin-2-deficient mice was indistinguishable from wild type mice. Furthermore, IL-13 lung transgenic mice genetically engineered to be deficient in eotaxin-2 had a marked reduction of luminal eosinophils. Mechanistic analysis identified IL13-induced eotaxin-2 expression by macrophages in a distinct lung compartment (luminal inflammatory cells) compared with eotaxin-1, which was expressed solely in the tissue. Taken together, these results demonstrate a cooperative mechanism between IL-13 and eotaxin-2. In particular, IL-13 mediates allergen-induced eotaxin-2 expression, and eotaxin-2 mediates IL-13-induced airway eosinophilia.

Chronic immune activation associated with chronic helminthic and human immunodeficiency virus infections: role of hyporesponsiveness and anergy

Chronic immune activation is one of the hallmarks of human immunodeficiency virus (HIV) infection. It is present also, with very similar characteristics, in very large human populations infested with helminthic infections. We have tried to review the studies addressing the changes in the immune profiles and responses of hosts infected with either one of these two chronic infections. Not surprisingly, several of the immune derangements and impairments seen in HIV infection, and considered by many to be the "specific" effects of HIV, can be found in helminth-infected but HIV-noninfected individuals and can thus be accounted for by the chronic immune activation itself. A less appreciated element in chronic immune activation is the immune suppression and anergy which it may generate. Both HIV and helminth infections represent this aspect in a very wide and illustrative way. Different degrees of anergy and immune hyporesponsiveness are present in these infections and probably have far-reaching effects on the ability of the host to cope with these and other infections. Furthermore, they may have important practical implications, especially with regard to protective vaccinations against AIDS, for populations chronically infected with helminths and therefore widely anergic. The current knowledge of the mechanisms responsible for the generation of anergy by chronic immune activation is thoroughly reviewed.

Alterations in eotaxin, monocyte chemoattractant protein-4, interleukin-5, and interleukin-13 after systemic steroid treatment for nasal polyps

OBJECTIVE

To determine alterations in Th2 chemokines eotaxin and monocyte chemoattractant protein-4 (MCP-4), and cytokines interleukin-5 (IL-5) and interleukin-13 (IL-13), in nasal polyps (NP) after steroid treatment.

STUDY DESIGN

Cytokine/chemokine levels were measured in NP before and after steroid therapy and compared to control sinus mucosa.

RESULTS

Twenty-one patients (control = 7, NP = 14) were enrolled. Eotaxin and MCP-4 were significantly higher than control tissue (P = 0.004 and 0.003). All four mediators decreased after steroid treatment (P < 0.03). IL-5 and IL-13 in untreated polyps were not significantly different from controls. Patients showed clinical improvement according to SNOT-20 scores (average presteroid score 19, poststeroid score 13) and endoscopic grading (1.75 each side presteroid, 1.13 poststeroid).

CONCLUSIONS

Steroids significantly decreased all cytokine/chemokine levels, but the impact on Th2 chemokines was of a much greater magnitude.

SIGNIFICANCE

Novel approaches to block inflammatory mediators, particularly Th2 chemokines, may lead to better control of nasal polyposis in the future.

Production of a monoclonal antibody to canine thymus and activation-regulated chemokine (TARC) and detection of TARC in lesional skin from dogs with atopic dermatitis

A monoclonal antibody to canine thymus and activation-regulated chemokine (TARC/CCL17) was developed to examine the association of TARC with the immunopathogenesis of canine atopic dermatitis (AD). Recombinant canine TARC was prepared using an E. coli expression system. Results of transwell chemotaxis assay demonstrated that the recombinant canine TARC showed chemotactic activity for canine lymphoid cells expressing CC chemokine receptor 4 (CCR4). Mice were then immunized with the recombinant canine TARC to obtain monoclonal antibodies. Among the monoclonal antibodies thereby obtained, one monoclonal antibody (CTA-1) was found to react with both recombinant and authentic canine TARC in ELISA and flowcytometric assays, respectively. Immunohistochemical analysis using the monoclonal antibody CTA-1 demonstrated that keratinocytes were major TARC producing cells in lesional skin of dogs with AD.

Role of CC chemokines and their receptors in multiple aspects of mast cell biology: comparative protein profiling of FcepsilonRI- and/or CCR1-engaged mast cells using protein chip technology

Apart from the FcepsilonRI-mediated mechanism, mast cells are activated by chemokines. Evidence has accumulated indicating that there is cross-talk between the FcepsilonRI-mediated signalling pathway and CC chemokine receptor (CCR)-mediated signalling pathways in mast cells. We have found that costimulation with IgE/antigen and CC chemokine ligand 3 (CCL3) enhances degranulation but inhibits chemotaxis of rat basophilic leukaemia (RBL)-2H3 cells expressing human CCR1 (RBL-CCR1 cells). We hypothesize that this signalling cross-talk in mast cells may play important roles in the orchestration and focusing of the allergic response. In this study, we have sought information about global protein networks either enhanced or inhibited following cross-talk between the FcepsilonRI-mediated and CCR-mediated signalling pathways in mast cells. We believe this information may be useful for providing an understanding of mast cell function and in the establishment of new anti-inflammatory drugs for allergic diseases. Proteomics is a promising tool for studying protein profiles within biological samples and facilitates an understanding of the complex responses of an organism to a stimulus. Here, we show comparative data of protein profiles derived from FcepsilonRI-engaged and/or CCR1-engaged RBL-CCR1 cells using protein chip array technology, a proteomic technology. We also discuss our view of the role of CC chemokines and CCRs in regulating multiple aspects of mast cell biology.

Changes in thymus- and activation-regulated chemokine (TARC) associated with allergen immunotherapy in patients with perennial allergic rhinitis

BACKGROUND

Thymus- and activation-regulated chemokine (TARC), which is a CC chemokine receptor (CCR) 4 ligand with ability to recruit Th2 cells to inflammatory sites, is pathogenetically important in allergic rhinitis. Specific immunotherapy (IT), among the most effective therapies for allergic rhinitis, has incompletely understood mechanisms of action. TARC might be involved in some benefits of IT.

METHODS

TARC in sera was assayed, obtained from 50 patients with house dust mite allergic rhinitis before and 1 year after beginning IT. Their ages ranged from 6 to 34 years (mean, 10), 30 were male and 20 were female.

RESULTS

In patients whose nasal obstruction responded to IT, TARC decreased significantly with IT, while when response was defined in terms of sneezing or rhinorrhea, TARC did not change significantly.

CONCLUSION

TARC might be an important target of IT in reducing obstructive allergic rhinitis.

TGF-beta differentially regulates TH2 cytokine-induced eotaxin and eotaxin-3 release by human airway smooth muscle cells

BACKGROUND

Human airway smooth muscle cells (HASMs) are involved in the pathogenesis of asthma. By producing chemokines, HASMs play a role in the inflammatory processes observed in this disease. Eotaxin, eotaxin-2, and eotaxin-3 are important chemoattractants for eosinophils, and these chemokines are expressed during different phases of the allergic reaction. TH2 cytokines and TGF-beta can be found in increased levels in patients with asthma, and these cytokines may be involved in the regulation of chemokine expression.

OBJECTIVE

The aim of this study was to determine the effect of TH2 cytokines and TGF-beta on the regulation of expression of eotaxin, eotaxin-2, and eotaxin-3 by HASMs.

METHODS

HASMs were incubated for 24 hours with IL-4, IL-13, TGF-beta1, or combinations of these cytokines. Protein and mRNA levels of eotaxin and eotaxin-3 were evaluated by sandwich ELISA and reverse transcriptase-PCR.

RESULTS

IL-4 and IL-13 induced mRNA and protein for both eotaxin and eotaxin-3. Eotaxin-2 mRNA and protein were not detected in HASMs. TGF-beta alone did not induce expression of the eotaxins. However, in combination with IL-4 or IL-13, TGF-beta enhanced eotaxin production and inhibited TH2 cytokine-induced eotaxin-3 production.

CONCLUSION

TGF-beta differentially regulates TH2 cytokine-induced eotaxin and eotaxin-3 release.

Nasal mucosal immunoexpression of the mast cell chemoattractants TGF-beta, eotaxin, and stem cell factor and their receptors in allergic rhinitis

BACKGROUND

Allergic rhinitis is characterized by the epithelial accumulation of cells, particularly mast cells and eosinophils. There is little information relating to the chemotaxins responsible for mast cell epithelial accumulation in this disease.

OBJECTIVE

Expression of the mast cell chemoattractants TGF-beta, eotaxin, and stem cell factor and their receptors was investigated in tissue sections from biopsy specimens obtained from patients with naturally occurring allergic rhinitis.

METHODS

Specific immunohistochemical staining was performed on thin sections of inferior turbinate biopsy specimens from patients with perennial and seasonal allergic rhinitis and, for comparison, from nonatopic and, where relevant, atopic healthy volunteers without rhinitis. Sequential staining of adjacent 2-microm sections was undertaken to colocalize TGF-beta receptors to mast cells.

RESULTS

Evidence was found of significantly increased epithelial immunoreactivity for TGF-beta1, TGF-beta2, TGF-beta3, TGF-beta receptor I, TGF-beta receptor II, and TGF-beta receptor III in patients with perennial and seasonal allergic rhinitis compared with that seen in healthy control subjects. TGF-beta receptors I and II were found to colocalize to mast cells. Eotaxin epithelial immunoreactivity was significantly increased in the perennial group, although there were no corresponding disease-related differences found in relation to CCR-3 immunoreactivity at this site. There was no increase in stem cell factor immunoreactivity within the epithelium in naturally occurring disease. Significant correlations were found between epithelial immunoreactivity for TGF-beta1, TGF-beta2, TGF-beta receptor I, TGF-beta receptor II, and the number of epithelial mast cells.

CONCLUSION

These findings of enhanced epithelial TGF-beta immunoreactivity in patients with rhinitis, the correlation with intraepithelial mast cell numbers, and the colocalization of TGF-beta receptors to mast cells suggest that the epithelial expression of TGF-beta might represent an important biologic process involved in either the recruitment or retention of mast cells within the epithelium in naturally occurring allergic rhinitis.

Determination of thymus and activation-regulated chemokine (TARC)-contents in scales of atopic dermatitis

BACKGROUND

Thymus and activation-regulated chemokine (TARC) is a cytokine which selectively controls the migration of type 2-helper T lymphocytes into inflammatory lesions, and the serum level is strongly associated with disease severity of atopic dermatitis (AD).

OBJECTIVE

To examine the role of TARC in the pathogenesis of AD, we determined TARC-contents in the scales obtained from lesional skin of the patients with AD.

RESULTS

High amount of TARC was detected in the scales of lesional skin obtained from the patients with AD, and the amount was well correlated with the serum IgE levels but not with the blood eosinophil counts. The TARC-content in the lesional scales was not correlated with a-431C/T polymorphism of TARC promotor gene, suggesting other regulating mechanisms in TARC production in the lesion.

CONCLUSION

High amount of TARC is produced in the kesion of AD, and analysis of cytokine content in lesional scales may provide some tools to clarify the pathogenesis of AD.

Disparate ability of murine CD8alpha- and CD8alpha+ dendritic cell subsets to traverse endothelium is not determined by differential CD11b expression

Upon Ag uptake and response to maturation stimuli, dendritic cells (DC) are directed through lymphatic or blood vessel endothelium to T cell areas of secondary lymphoid tissues by the constitutively expressed CC chemokines CCL19 and CCL21. We have shown that mature (m) murine CD8alpha+ DC exhibit poorer migratory ability to these chemokines than classic CD8alpha- DC by quantifying their in vitro chemotaxis through unmodified Transwell filters. We hypothesized that lower surface expression (compared to CD8alpha- mDC) of the adhesion molecule CD11b on CD8alpha+ DC might limit their ability to adhere to filter pores in vitro and/or endothelium in vitro/in vivo. To test the role of this and/or other adhesion molecules (CD11a, CD31, CD54 and CD62L) in regulating murine DC subset migration, we used specific mAbs to block their function and quantified their migration through resting or tumour necrosis factor (TNF)-alpha-activated endothelial cell (EC) layered-Transwell filters. Both CD8alpha+ and CD8alpha- subsets migrated through resting EC (albeit less than in the absence of EC) in response to CCL19 and CCL21, and migration through TNF-alpha-activated EC was enhanced. In contrast to reports concerning human DC, transendothelial migration of the murine DC subsets was not dependent on CD11b, CD31, or CD62L expression by these cells. CD54 and CD11a, however, were at least partly involved in DC/EC interactions. This is the first report to examine adhesion molecules involved in transendothelial migration of murine DC subsets.

Entamoeba histolytica cysteine protease 2 (EhCP2) modulates leucocyte migration by proteolytic cleavage of chemokines

Human amoebiasis is a disease produced by infection with the protozoan Entamoeba histolytica currently affecting many millions of people worldwide. Amoebic colitis is the most common clinical manifestation. Host protective immunity involves participation of both humoral and cellular responses. However, the mechanisms involved in immune evasion are not clear and remain under investigation. One of these mechanisms could be associated with the ability of parasite proteases to modulate or interfere with the inflammation process, which is initiated by expression of pro-inflammatory cytokines such as chemokines. To further clarify the potential role of cysteine proteases in modulating chemokine-mediated functions, we have analysed the ability of Entamoeba histolytica cysteine protease 2 (EhCP2) to have an effect on the chemotaxis of leucocytes by chemokine cleavage. We find that EhCP2 is capable of cleaving chemokines CCL2, CCL13 and CXCL8, and the resulting proteolysis products modulate the chemotaxis of leucocytes when compared to that induced by intact chemokine. Thus, the extracellular activity of the cysteine proteases affects chemokine-mediated responses and could be considered as part of the mechanisms used by Entamoeba histolytica to circumvent the host immune responses.