Eotaxin Receptor Research Articles

Involvement of Galectin-9 in Lung Eosinophilia in Patients with Eosinophilic Pneumonia

Background: Although we first found galectin-9 (Gal-9) as an eosinophil chemoattractant, its role in eosinophilic inflammation is still obscure. The purpose of the present study is to clarify the role of Gal-9 in human eosinophilic pulmonary inflammation in comparison with eotaxin (CCL11). Methods: We measured the levels of Gal-9 and eotaxin in the bronchoalveolar lavage fluid (BALF) of patients with acute and chronic eosinophilic pneumonia (AEP and CEP). Furthermore, the biological activities (chemotaxis and apoptosis) of Gal-9 were compared with those of eotaxin using interleukin-5-primed or -unprimed eosinophils. Results: The levels of Gal-9 and eotaxin in the BALF from patients with AEP and those with CEP were higher than those found in the controls. Although there was little difference in Gal-9 level between patients with AEP and patients with CEP, the eotaxin level was significantly lower in patients with CEP. In patients with AEP, the eosinophil number correlated well with both the Gal-9 and eotaxin levels. However, in patients with CEP, the eosinophil number only correlated well with the Gal-9 level. Moreover, the Gal-9 level correlated with the eotaxin level in patients with AEP, but there was no significant correlation between those levels in patients with CEP. Anti-Gal-9 antibody treatment strongly reduces eosinophil chemotactic activity in the BALF of patients with AEP and in that of patients with CEP, whereas the anti-CCR3 (receptor for eotaxin) antibody strongly reduces this activity in the BALF of patients with AEP but not in that of patients with CEP. Furthermore, Gal-9 exhibited both chemotactic and proapoptotic activities for activated eosinophils, though eotaxin only exhibited chemotactic activity. Conclusions: The present results provide two possibilities: that Gal-9 is involved in pulmonary eosinophilia in patients with AEP and CEP, and that Gal-9 exhibits regulatory functions for activated eosinophils at the site of inflammation.

Eotaxin/CCL11 expression by infiltrating macrophages in rat heart transplants during ongoing acute rejection

Eotaxin/CCL11 chemokine is expressed in different organs, including the heart, but its precise cellular origin in the heart is unknown. Eotaxin is associated with Th2-like responses and exerts its chemotactic effect through the chemokine receptor-3 (CCR3), which is also expressed on mast cells (MC). The aim of our study was to find the cellular origin of eotaxin in the heart, and to assess whether expression is changing during ongoing acute heart transplant rejection, indicating a correlation with mast cell infiltration which we observed in a previous study. In a model of ongoing acute heart transplant rejection in the rat, we found eotaxin mRNA expression within infiltrating macrophages, but not in mast cells, by in situ-hybridization. A five-fold increase in eotaxin protein in rat heart transplants during ongoing acute rejection was measured on day 28 after transplantation, compared to native and isogeneic control hearts. Eotaxin concentrations in donor hearts on day 28 after transplantation were significantly higher compared to recipient hearts, corroborating an origin of eotaxin from cells within the heart, and not from the blood. The quantitative comparison of eotaxin mRNA expression between native hearts, isografts, and allografts, respectively, revealed no statistically significant difference after transplantation, probably due to an overall increase in the housekeeping gene's 18S rRNA during rejection. Quantitative RT-PCR showed an increase in mRNA expression of CCR3, the receptor for eotaxin, during ongoing acute rejection of rat heart allografts. Although a correlation between increasing eotaxin expression by macrophages and mast cell infiltration is suggestive, functional studies will elucidate the role of eotaxin in the process of ongoing acute heart transplant rejection.

Pinellia ternata,Citrus reticulata, and Their Combinational Prescription Inhibit Eosinophil Infiltration and Airway Hyperresponsiveness by Suppressing CCR3+ and Th2 Cytokines Production in the Ovalbumin-Induced Asthma Model

Background and Objective. This study was aimed to analyse the curative effects of Pinellia ternata, Citrus reticulata, and their combination on airway hyperresponsiveness (AHR) to inhaled methacholine, pulmonary eosinophilic infiltration, Th2 cytokine production, and IgE and histamine production in a murine model of asthma. Methods. For this purpose, BALB/c mice were systemically sensitized to ovalbumin (OVA) followed intratracheally, intraperitoneally, and by aerosol allergen challenges for 12 weeks. We examined the development of pulmonary eosinophilic accumulation, control of Th2 cytokine, immunoglobulin E (IgE), and histamine productions in a murine model of asthma. Results. Our data suggest that the therapeutic mechanism by which Pinellia ternata, Citrus reticulata, and their combinational prescription effectively treats asthma is based on reductions of eosinophil infiltration, eotaxin receptor (CCR3), histamine, OVA-specific IgE productions in serum, and Th2 cytokines (IL-5, IL-13) by marked reductions of IL-5 and IL-13 mRNA expression in lung tissue. Conclusions. These findings provide evidence that Pinellia ternata, Citrus reticulata, and their combination play a regulatory role in allergic inflammation and offer therapeutic approaches as novel CCR3 antagonists for treatment asthma. However, it is not clear whether pharmacological activities of prescription composed of two herbs are potentiated due to synergistic effect or additive effect.

Ontogeny of the eotaxins in human lung

The ontogeny of the C-C chemokines eotaxin-1, eotaxin-2, and eotaxin-3 has not been fully elucidated in human lung. We explored a possible role for eotaxin in developing lung by determining the ontogeny of eotaxin-1 (CCL11), eotaxin-2 (CCL24), eotaxin-3 (CCL26), and the eotaxin receptor, CCR3. We tested discarded surgical samples of developing human lung tissue using quantitative RT-PCR (QRT-PCR) and immunostaining for expression of CCL11, CCL24, CCL26, and CCR3. We assessed possible functionality of the eotaxin-CCR3 system by treating lung explant cultures with exogenous CCL11 and analyzing the cultures for evidence of changes in proliferation and activation of ERK1/2, a signaling pathway associated with CCR3. QRT-PCR analyses of 22 developing lung tissue samples with gestational ages 10-23 wk demonstrated that eotaxin-1 mRNA is most abundant in developing lung, whereas mRNAs for eotaxin-2 and eotaxin-3 are minimally detectable. CCL11 mRNA levels correlated with gestational age (P < 0.05), and immunoreactivity was localized predominantly to airway epithelial cells. QRT-PCR analysis detected CCR3 expression in 16 of 19 developing lung samples. Supporting functional capacity in the immature lung, CCL11 treatment of lung explant cultures resulted in significantly increased (P < 0.05) cell proliferation and activation of the ERK signaling pathway, which is downstream from CCR3, suggesting that proliferation was due to activation of CCR3 receptors by CCL11. We conclude that developing lung expresses the eotaxins and functional CCR3 receptor. CCL11 may promote airway epithelial proliferation in the developing lung.

Allergen-induced CD11b+ CD11cint CCR3+ macrophages in the lung promote eosinophilic airway inflammation in a mouse asthma model

Although the recruitment of macrophages to the lung is a central feature of airway inflammation, its function in ongoing T(h)2 cell-mediated eosinophilic airway inflammation remains controversial. Here, we have demonstrated that the allergen-induced CD11b(+) CD11c(int) macrophage expressing CC chemokine receptor 3 (CCR3) in the lung performs a crucial function in the induction of eosinophilic asthma in a murine model. In the lungs of normal mice, residential cells evidencing high granularity phenotypically evidenced CD11b(int) CD11c(+) or CD11b(+) CD11c(int) cells, appearing at a 2:1 ratio. After allergen challenge, however, this reverses dramatically, up to a ratio of one to six. Approximately 91% of increased CD11b(+) CD11c(int) cells evidenced the expression of the CCR3 eotaxin receptor, but not other chemokine receptors, such as CCR5 and CXCR4. Interestingly, the CD11b(+) CD11c(int) cells purified from the lungs of OVA (ovalbumin)-sensitized and challenged mice evidenced higher antigen-presenting activity than was observed in CD11b(int) CD11c(+) cells. In order to investigate the in vivo function of CD11b(+) CD11c(int) cells, the cells were isolated from the lungs of OVA-sensitized and challenged mice and then adoptively transferred prior to the allergen challenge of normal mice. In the CD11b(+) CD11c(int)-transferred mice airway hyperresponsiveness, eosinophilic inflammation in the lung and T(h)2 cytokine secretion in the bronchoalveolar lavage fluids were significantly enhanced as the result of OVA challenge, as compared with the mice that received OVA-primed CD90(+) T cells or CD11b(int) CD11c(+) cells. These findings show that CD11b(+) CD11c(int) macrophages expressing CCR3 as key pro-inflammatory cells are both necessary and sufficient for allergen-specific T cell stimulation during ongoing eosinophilic airway inflammation.

EMR1, the human homolog of F4/80, is an eosinophil‐specific receptor

The EGF-TM7 F4/80 is a defining marker of murine macrophage populations. Applying flow cytometric analysis using the newly generated mAb A10, and quantitative real-time PCR, we here report the surprising observation that the human ortholog of F4/80, EGF-like module containing mucin-like hormone receptor (EMR)1, is absent on mononuclear phagocytic cells including monocytes, macrophages, and myeloid dendritic cells. Unexpectedly, we found that EMR1 expression is restricted to eosinophilic granulocytes, where expression is overlapping with the eotaxin receptor CCR3 and the immunoglobulin-like lectin Siglec-8. Absence on other leukocytes, including basophils, implies that EMR1 is a highly specific marker for eosinophils in humans.

Glutathione Redox Regulates Airway Hyperresponsiveness and Airway Inflammation in Mice

Glutathione is the major intracellular redox buffer. We have shown that glutathione redox status, which is the balance between intracellular reduced (GSH) and oxidized (GSSG) glutathione, in antigen-presenting cells (APC) regulates the helper T cell type 1 (Th1)/Th2 balance due to the production of IL-12. Bronchial asthma is a typical Th2 disease. Th2 cells and Th2 cytokines are characteristic of asthma and trigger off an inflammation. Accordingly, we studied the effects of the intracellular glutathione redox status on airway hyperresponsiveness (AHR) and allergen-induced airway inflammation in a mouse model of asthma. We used gamma-Glutamylcysteinylethyl ester (gamma-GCE), which is a membrane-permeating GSH precursor, to elevate the intracellular GSH level and GSH/GSSG ratio of mice. In vitro, gamma-GCE pretreatment of human monocytic THP-1 cells elevated the GSH/GSSG ratio and enhanced IL-12(p70) production induced by LPS. In the mouse asthma model, intraperitoneal injection of gamma-GCE elevated the GSH/GSSG ratio of lung tissue and reduced AHR. gamma-GCE reduced levels of IL-4, IL-5, IL-10, and the chemokines eotaxin and RANTES (regulated on activation, normal T cell expressed and secreted) in bronchoalveolar lavage fluid, whereas it enhanced the production of IL-12 and IFN-gamma. Histologically, gamma-GCE suppressed eosinophils infiltration. Interestingly, we also found that gamma-GCE directly inhibited chemokine-induced eosinophil chemotaxis without affecting eotaxin receptor chemokine receptor 3 (CCR3) expressions. Taken together, these findings suggest that changing glutathione redox balance, increase in GSH level, and the GSH/GSSG ratio by gamma-GCE, ameliorate bronchial asthma by altering the Th1/Th2 imbalance through IL-12 production from APC and suppressing chemokine production and eosinophil migration itself.

Eosinophilic esophagitis: New insights into an emerging disease

Eosinophilic esophagitis: New insights into an emerging disease

Eotaxin-3 and a uniquely conserved gene-expression profile in eosinophilic esophagitis

Eosinophilic esophagitis (EE) is an emerging disorder with a poorly understood pathogenesis. In order to define disease mechanisms, we took an empirical approach analyzing esophageal tissue by a genome-wide microarray expression analysis. EE patients had a striking transcript signature involving 1% of the human genome that was remarkably conserved across sex, age, and allergic status and was distinct from that associated with non-EE chronic esophagitis. Notably, the gene encoding the eosinophil-specific chemoattractant eotaxin-3 (also known as CCL26) was the most highly induced gene in EE patients compared with its expression level in healthy individuals. Esophageal eotaxin-3 mRNA and protein levels strongly correlated with tissue eosinophilia and mastocytosis. Furthermore, a single-nucleotide polymorphism in the human eotaxin-3 gene was associated with disease susceptibility. Finally, mice deficient in the eotaxin receptor (also known as CCR3) were protected from experimental EE. These results implicate eotaxin-3 as a critical effector molecule for EE and provide insight into disease pathogenesis.

582. CNS Gene Delivery Targeting CCR3 Protects Brain Microglia from HIV-1

Top of pageAbstract Infection by human immunodeficiency virus (HIV-1) requires virus binding to human CD4 plus a coreceptor. CCR5 and CXCR4, are the primary coreceptors used by most HIV-1 isolates. The eotaxin receptor (CCR3) has also been implicated as a coreceptor for HIV infection, particularly in the microglial cells of the brain. This study focuses on the role of CCR3 in CNS HIV-1 infection and therefore as a target for manipulation gene transfer. Two approaches were applied to targeting CCR3. First an anti- CCR3 hybridoma, 5E8-G9-B4, was used to develop a single chain antibody (SFv) that contained the immunoglobulin variable heavy (VH) and variable light (VL) chain. Using overlapping RT-PCR techniques with hybridoma mRNAs, the two V region coding sequences, separated by a flexible hinge region, were cloned into a mammalian expression vector. We also tested a panel of interfering RNA's designed to target a sequence shared by mouse and human CCR3 transcripts. Both approaches were used to test the effectiveness of CCR3 downregulation and consequent protection from M-tropic strains of HIV-1. Cells were treated by adding soluble siRNAs and by transfecting with an expression construct carrying the SFv cDNA. Transfection efficiencies were measured using a marker gene. Of a panel of CCR3 siRNAs, R3-526, and SFv addition to cultures resulted in 60-80% decrease in CCR3 expression when tested in U87.CD4.CCR3 cells, primary human microglia derived from fetal brain and monocyte derived macrophages (MDM). CCR3 downregulation was measured using FACS and immunostaining. Both the SFv and siRNA also significantly decreased (>70%) productive HIV-1 infection, as measured by p24 HIV infection in microglia cells when tested using two different CCR3-tropic HIV-1 isolates: HIV-1ADA and a primary brain isolate. Strains of HIV-1 that utilize only CCR5 as a coreceptor were not inhibited. Because of their effectiveness in transducing microglial cells, rSV40 vectors carrying these moieties are being prepared. Studies involving transduction of these anti-CCR3 moieties, both to assess their effectiveness in downregulating CCR3 and protecting from CCR3- tropic strains of HIV-1, are in progress. Since CCR3 and CCR5 are expressed by microglial cells, therapies targeting both may be needed in treating CNS AIDS. Utilization of CCR3 by these HIV-1 isolates and their susceptibility to inhibition by anti-CCR3 siRNA and SFv in primary brain microglia/macrophages may both help clarify the role of CCR3 as a coreceptor in CNS establishing HIV-1 and provide useful therapeutic insights.

Neuronal eotaxin and the effects of ccr3 antagonist on airway hyperreactivity and M2 receptor dysfunction

Eosinophils cluster around airway nerves in patients with fatal asthma and in antigen-challenged animals. Activated eosinophils release major basic protein, which blocks inhibitory M2 muscarinic receptors (M2Rs) on nerves, increasing acetylcholine release and potentiating vagally mediated bronchoconstriction. We tested whether GW701897B, an antagonist of CCR3 (the receptor for eotaxin as well as a group of eosinophil active chemokines), affected vagal reactivity and M2R function in ovalbumin-challenged guinea pigs. Sensitized animals were treated with the CCR3 antagonist before inhaling ovalbumin. Antigen-challenged animals were hyperresponsive to vagal stimulation, but those that received the CCR3 antagonist were not. M2R function was lost in antigen-challenged animals, but not in those that received the CCR3 antagonist. Although the CCR3 antagonist did not decrease the number of eosinophils in lung tissues as assessed histologically, CCR3 antagonist prevented antigen-induced clustering of eosinophils along the nerves. Immunostaining revealed eotaxin in airway nerves and in cultured airway parasympathetic neurons from both guinea pigs and humans. Both IL-4 and IL-13 increased expression of eotaxin in cultured airway parasympathetic neurons as well as in human neuroblastoma cells. Thus, signaling via CCR3 mediates eosinophil recruitment to airway nerves and may be a prerequisite to blockade of inhibitory M2Rs by eosinophil major basic protein.

The Th2 response as monitored by CRTH2 or CCR3 expression is severely decreased during septic shock

The shift of T lymphocytes toward a Th2 profile during septic shock has been established on the basis of in vitro cytokine production. In the present study, the Th2 response was investigated at the level of cell surface marker expression (whole blood flow cytometry). In 58 patients with septic shock, we observed a reduced CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells) expression on Th2 lymphocytes and regulatory T cells in comparison with 39 healthy volunteers. Eosinophils, which constitutively express CRTH2 in healthy individuals, also exhibited low levels of CRTH2 in patients. In addition, eosinophil CCR3 expression (eotaxin receptor, type 2 chemokine) was strongly correlated with CRTH2, suggesting thus an extended modulation of Th2 related molecules. Importantly, the persistence over time of low levels of CRTH2 or CCR3 expression was found in nonsurvivors. We hypothesize that the restoration of CRTH2/CCR3 expression may be an indicator for optimal recovery after septic shock.

Éotaxine, chimiokine de premier plan de l'allergieEotaxin, a prominent chemokine in allergy

L’éotaxine joue un rôle de tout premier plan dans l’inflammation allergique. Cette CC chimiokine a été décrite initialement dans un modèle d’inflammation pulmonaire allergique chez le cochon d’Inde. Une chimiokine homologue a été décrite chez la souris et l’homme. La séquence de l’éotaxine est très proche de celle des MCPs. On sait maintenant que les polynucléaires éosinophiles humains expriment les récepteurs pour l’éotaxine (CCR3) qui sont également reconnus par MCP-3 et Rantes. Néanmoins, l’éotaxine se lie avec une plus grande affinité au CCR3 et ne semble pas interagir de façon efficace avec les autres récepteurs de chimiokines connus. La production bronchique accrue d’éotaxine chez l’asthmatique est maintenant bien démontrée. Les doubles marquages ont souligné que l’épithélium et l’endothélium bronchiques sont des sources importantes de cette cytokine in vivo. Les chimiokines se liant à CCR3 constituent actuellement une cible thérapeutique privilégiée par le biais d’antagonistes de CCR3. Eotaxin plays a prominent role in allergy. This CC chemokine was initially identified in a model of allergic pulmonary inflammation in guinea pigs. Subsequently, eotaxin was identified in mice and in humans. The sequence of this chemokine is similar to that of the MCPs. It is now known that, eosinophils express the eotaxin receptor CCR3 that can also bind other CC chemokines, including RANTES and MCP3. Nevertheless, eotaxin binds with greater affinity and seems to be more specific for CCR3 than it is for receptors of other chemokines. Increased eotaxin expression in the bronchi of asthmatics has now been clearly demonstrated. Double staining techniques have shown that, the main sources of eotaxin in vivo are endothelial and epithelial cells. Selective CCR3 antagonists now represents interesting targets for future therapies.

Éotaxine, chimiokine de premier plan de l’allergie

Eotaxin plays a prominent role in allergy. This CC chemokine was initially identified in a model of allergic pulmonary inflammation in guinea pigs. Subsequently, eotaxin was identified in mice and in humans. The sequence of this chemokine is similar to that of the MCPs. It is now known that, eosinophils express the eotaxin receptor CCR3 that can also bind other CC chemokines, including RANTES and MCP3. Nevertheless, eotaxin binds with greater affinity and seems to be more specific for CCR3 than it is for receptors of other chemokines. Increased eotaxin expression in the bronchi of asthmatics has now been clearly demonstrated. Double staining techniques have shown that, the main sources of eotaxin in vivo are endothelial and epithelial cells. Selective CCR3 antagonists now represents interesting targets for future therapies.

Allergen-induced fluctuation in CC chemokine receptor 3 expression on bone marrow CD34+ cells from asthmatic subjects: significance for mobilization of haemopoietic progenitor cells in allergic inflammation.

There is increasing evidence that primitive progenitors migrate from the bone marrow (BM) via the peripheral circulation to tissue sites where they undergo in situ differentiation to provide a continued source of effector cells, such as eosinophils, during an allergic inflammatory response. To study mechanisms of progenitor cell mobilization in allergic reactions, we investigated fluctuations in the expression of the eotaxin receptor, CC chemokine receptor 3 (CCR3), on CD34+ cells from stable asthmatics following allergen (i.e. antigen) challenge. BM aspirates were taken from seven early responder (ER) and 10 dual responder (DR) asthmatics who, following antigen challenge developed only an early bronchoconstrictor response and an early and late- bronchoconstrictor response, respectively. Expression of CCR3 was detected on primitive (CD34+ cells) and eosinophil-lineage committed progenitors (CD34+ interleukin-5 receptor alpha-subunit+ cells) by flow cytometry and confirmed by co-localization of CCR3 messenger RNA to CD34 immunopositive cells using in situ hybridization. When preantigen levels were compared to 24-hr postantigen levels, significant increases in BM CD34+ CCR3+ cells were detected in DR, who also developed a significant sputum and blood eosinophilia and increased methacholine airway responsiveness. In contrast, a significant attenuation of BM CD34+ CCR3+ cells was observed in ER. In a dose-dependent manner eotaxin, but not interleukin (IL)-5, stimulated CD34+ progenitor cell migration in vitro. This migrational response to eotaxin was abrogated by anti-CCR3 monoclonal antibody and primed by preincubation with IL-5. We propose that fluctuations in CCR3 expression on human BM CD34+ cells may facilitate chemokine-mediated progenitor cell mobilization to the peripheral circulation and the resultant development of pulmonary eosinophilia, a cardinal feature of asthma.

Characterization of Hodgkin's lymphoma-like undifferentiated carcinoma of the nasopharyngeal type as a particular UCNT subtype mimicking Hodgkin's lymphoma

Undifferentiated carcinoma of the nasopharyngeal type (UCNT) that histologically mimics Hodgkin's lymphoma (HL) ("Hodgkin's lymphoma-like UCNT"--HL-like UCNT) is known as a diagnostic pitfall. Using immunohistochemistry, Western blot and cDNA array technology, we wanted to document its phenotypical and molecular characteristics. We report herein 5 cases of UCNT that morphologically mimic HL and 3 classical UCNT cases. We compared the expression profiles of a thousand selected genes in HL-like UCNT and in classical UCNT cases. No difference in the profile of EBV infection was noted between the HL-like UCNT and control cases. Significant differences were detected in the expression of genes involved in the matrix modelling, angiogenesis, apoptosis and regulation of the Th-2 interleukins. The eosinophil chemoattractant eotaxin was expressed in the stroma of HL-like UCNT, but not in the control cases. The eotaxin receptor CCR3 was expressed in both stromal and carcinoma cell populations of HL-like UCNT, this pattern being similar to the one observed in HL. These results show that UCNT morphologically resembling HL share also some specific phenotypical and molecular features with HL, and might deserve to be isolated as a particular UCNT subtype.

Functional expression of the eotaxin receptor CCR3 in CD30+ cutaneous T-cell lymphoma

Little is known about mechanisms involved in skin-specific homing of cutaneous T-cell lymphoma (CTCL). Chemokine/chemokine receptor interactions have been implicated in the homing of lymphoma cells to various tissue sites. We investigated tissue samples and tumor cell suspensions of patients with CD30(+) CTCL (n = 8) and CD30(-) CTCL (mycosis fungoides, n = 6; Sézary syndrome, n = 6) for expression of the chemokine receptors CCR3, CCR4, and CCR8 and the CCR3 ligands eotaxin/CCL11, monocyte chemoattractant protein 3 (MCP-3)/CCL7, and RANTES (regulated on activation, normal T expressed and secreted)/CCL5. Of 8 CD30(+) CTCLs, 7 expressed CCR3, 4 CCR4, and none CCR8. CCR3 expression was not found in skin tissue samples from 12 CD30(-) CTCLs. Coexpression of CCR3 and CD30 was demonstrated by flow cytometry in tumor cell suspensions. Internalization experiments demonstrated functionality of CCR3 expressed by freshly isolated tumor cells. Actin polymerization as well as migration in response to eotaxin was demonstrated in a CD30(+) cutaneous lymphoma cell line. CCR3 ligand eotaxin/CCL11 was detected in lesional skin of CD30(+) CTCL by immunohistochemistry, preferentially in tumor cells. Eotaxin/CCL11 expression in tumor cells was confirmed by intracellular immunofluorescence. Analysis of cytokine expression pattern of CCR3-bearing infiltrating cells showed a predominance of interleukin-4 (IL-4) but not interferon-gamma (IFN-gamma) protein expression,1 consistent with a T-helper 2 (Th-2) profile. These results suggest that expression of CCR3 and its ligand eotaxin/CCL11 plays a role in the recruitment and retention of CD30(+) malignant T cells to the skin.

Role of the chemokine eotaxin in the pathogenesis of equine sweet itch

The chemokine eotaxin is involved in the recruitment of eosinophils and T helper 2 lymphocytes in human allergic diseases, and drugs that block its activity, including eotaxin receptor (CCR3) antagonists,...

Allergen-induced accumulation of airway dendritic cells is supported by an increase in CD31hiLy-6Cneg bone marrow precursors in a mouse model of asthma

Airway dendritic cells (DCs) are held responsible for inducing sensitization to inhaled antigen, leading to eosinophilic airway inflammation, typical of asthma. However, less information is available about the role of these cells in ongoing inflammation. In a mouse model of asthma, sensitization to ovalbumin (OVA) was induced by intratracheal injection of myeloid OVA-pulsed DCs. Upon OVA aerosol challenge and induction of eosinophilic airway inflammation in sensitized mice, there was a time-dependent and almost 100-fold increase in the number of MHCII(+) CD11b(+) CD11c(+) endogenous airway DCs as well as CD11b(+) blood DCs. The mechanism of this increase was studied. Adoptive transfer experiments demonstrated that accumulation of airway DCs was not due to reduced migration to the mediastinal lymph nodes. Rather, the massive increase in airway and lymph node DCs was supported by an almost 3-fold expansion of myeloid CD31(hi)Ly-6C(neg) hematopoietic precursor cells in the bone marrow (BM). There was no change in any of the other 5 populations revealed by CD31/Ly-6C staining. When these CD31(hi)Ly-6C(neg) BM precursors were sorted and grown in granulocyte macrophage-colony-stimulating factor, they differentiated into MHCII(+) CD11c(+) DCs. The same CD31(hi)Ly-6C(neg) precursors also expressed the eotaxin receptor CCR3 and differentiated into eosinophils when grown in interleukin 5. Serum levels of eotaxin were doubled in mice with inflammation. These findings in an animal model of asthma suggest that the BM increases its output of myeloid precursors to meet the enhanced demand for DCs and eosinophils in inflamed airways.

Expression of a functional eotaxin (CC chemokine ligand 11) receptor CCR3 by human dendritic cells.

Critical to the function of Ag-presenting dendritic cells (DCs) is their capacity to migrate to lymphoid organs and to sites of inflammation. A final stage of development, termed maturation, yields DCs that are strong stimulators of T cell-mediated immunity and is associated with a remodeling of the cell surface that includes a change in the levels of expression of many molecules, including chemokine receptors. We show in this study that CCR3, a chemokine receptor initially discovered on eosinophils, is also expressed by human DCs that differentiate from blood monocytes, DCs that emigrate from skin (epidermal and dermal DCs), and DCs derived from CD34+ hemopoietic precursors in bone marrow, umbilical cord blood, and cytokine-elicited peripheral blood leukapheresis. Unlike other chemokine receptors, such as CCR5 and CCR7, the expression of CCR3 is not dependent on the state of maturation. All DC subsets contain a large intracellular pool of CCR3. The surface expression of CCR3 is not modulated following uptake of particulate substances such as zymosan or latex beads. CCR3 mediates in vitro chemotactic responses to the known ligands, eotaxin and eotaxin-2, because the DC response to these chemokines is inhibited by CCR3-specific mAbs. We postulate that expression of CCR3 may underlie situations where both DCs and eosinophils accumulate in vivo, such as the lesions of patients with Langerhans cell granulomatosis.