A cytokine-to-chemokine axis between T lymphocytes and keratinocytes can favor Th1 cell accumulation in chronic inflammatory skin diseases

The recruitment of T cells into the skin is regulated by chemokines released by resident cells. In this study, we found that normal human keratinocytes activated with Th1-derived supernatant (sup) expressed early (6-12 h) IP-10/CXCL10, MCP-1/CCL2, IL-8/CXCL8, and I-309/CCL1 mRNAs and with slower kinetics (24-96 h), RANTES/CCL5 and MDC/CCL22 mRNAs. Upon stimulation with the Th1 sup, keratinocytes secreted high levels of RANTES, IP-10, MCP-1, and IL-8 and moderate levels of I-309 and MDC. Although much less efficiently, Th2 sup could also induce keratinocyte expression of IL-8, IP-10, RANTES, and MCP-1 but not of I-309 and MDC. TARC/CCL17 was not significantly induced by any stimuli. Sup from keratinocytes activated with Th1-derived cytokines elicited a strong migratory response of Th1 cells and a limited migration of Th2 cells, whereas sup from Th2-activated keratinocytes promoted a moderate migration of Th1 and Th2 lymphocytes. Thus, keratinocytes appear considerably more sensitive to Th1- than to Th2-derived lymphokines in terms of chemokine release and can support the preferential accumulation of Th1 lymphocytes in the skin.     

Inhibition by IL-12 and IFN-alpha of I-309 and macrophage-derived chemokine production upon TCR triggering of human Th1 cells

Th1 and Th2 cells, which produce distinct sets of cytokines, differentially express several chemokine receptors that may regulate their tissue-specific localization. Although the expression pattern and regulation of chemokines are likely to play a critical role in many immunopathological processes, they remain largely unknown. Here, we investigated the requirements for Th1 and Th2 cells to produce the Th2 cell-attracting chemokines thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC) and I-309. TCR triggering of Th1 and Th2 cells leads to production of MDC and I-309 (CCR4 and CCR8 ligands, respectively), whereas TARC (CCR4 ligand) is selectively produced by Th2 cells. Secretion of these chemokines appears to be independent of endogenous production of IL-4 and IFN-gamma. IL-12 and IFN-alpha, cytokines that promote the differentiation of human Th1 cells, selectively inhibit secretion and mRNA expression of MDC and I-309 by Th1 cells. Suppression of I-309 secretion results in a decreased chemotactic effect on L1.2 cells transfected with human CCR8, indicating that IL-12 and IFN-alpha may inhibit the recruitment of CCR8-expressing cells such as Th2 cells. The inhibition of Th2 cell-attracting chemokines MDC and I-309 illustrates a novel mechanism by which IL-12 and IFN-alpha could promote and maintain an ongoing Th1 response.     

Increased levels of a TH2-type CC chemokine thymus and activation-regulated chemokine (TARC) in serum and induced sputum of asthmatics

BACKGROUND: Cytokines liberated by TH2 cells play crucial roles in the pathogenesis of bronchial asthma. Recent studies have demonstrated that CC chemokine receptor (CCR)4 is preferentially expressed by TH2 cells. These facts suggest possible involvement of two CCR4-specific ligands i.e., thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC), in the pathogenesis of bronchial asthma via recruitment of TH2 cells to inflammatory sites. We investigated the levels of TARC and MDC in the serum and induced sputum of asthmatics. METHODS: The levels of TARC in the serum (46 asthmatics and 26 healthy subjects) and induced sputum (30 asthmatics and 6 healthy subjects) were measured using a highly sensitive ELISA system. The levels of eotaxin and MDC were also measured by ELISA. RESULTS: TARC, but not MDC, was significantly increased in asthmatic sera (P<0.001). Although MDC was undetectable in the sputum of most cases by our assay system, sputum TARC was significantly increased (P=0.027). CONCLUSIONS: The elevated TARC levels in asthmatics might be involved in the pathophysiology of asthma.     

Potential role of the chemokine receptors CXCR3, CCR4, and the integrin alphaEbeta7 in the pathogenesis of psoriasis vulgaris

Various adhesion molecules have been implicated in T lymphocyte binding to dermal vascular endothelium in psoriasis vulgaris, but the chemotactic signals that promote subsequent homing into the adjacent dermis and overlying epidermis are poorly defined. We studied chemokine receptor (CCR1-CCR5, CXCR1-CXCR3), chemokine (interferon-gamma inducible protein 10 [IP-10]), monokine induced by interferon-gamma (MIG), thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC), and adhesion molecule (cutaneous lymphocyte antigen [CLA], E-selectin, lymphocyte function-associated antigen-1 [LFA-1], intercellular adhesion molecule-1 [ICAM-1], very late antigen 4 [VLA-4], vascular cell adhesion molecule-1 [VCAM-1], alphaEbeta7, and E-cadherin) expression in psoriasis by immunohistology, flow cytometry, and molecular techniques. CXCR3 and CCR4 were expressed by dermal CD3+ lymphocytes, and their chemokine ligands, IP-10, MIG, TARC, and MDC, were up-regulated in psoriatic lesions. Keratinocytes stimulated with tumor necrosis factor-alpha and interferon-gamma up-regulated expression of IP-10, MIG, and MDC mRNA, whereas dermal endothelial cells, similarly stimulated, up-regulated expression of IP-10, MDC, and TARC mRNA, suggesting that these cell types were sources of the chemokines detected in biopsies. There was enhanced expression of E-selectin, CLA, LFA-1, ICAM-1, VLA-4, VCAM-1, and alphaEbeta7 in psoriatic lesions versus nonlesional skin. Finally, intra-epidermal CLA+ and alphaEbeta7+ T lymphocytes selectively expressed the chemokine receptor CXCR3. Collectively, these data suggest that CXCR3 and CCR4 may be involved in T lymphocyte trafficking to the psoriatic dermis and that CXCR3 is selectively involved in subsequent T cell homing to the overlying epidermis.     

The assignment of chemokine-chemokine receptor pairs: TARC and MIP-1 beta are not ligands for human CC-chemokine receptor 8.

Identification of chemokine receptors and their associated ligands is crucial to the understanding of most immune reactions. Three human chemokines [I-309, thymus and activation-regulated chemokine (TARC) and macrophage inflammatory protein-1beta (MIP-1beta)] have been reported to be ligands for CC-chemokine receptor 8 (CCR8). In this report, we present evidence that TARC and MIP-1beta did not bind to or induce chemotaxis through CCR8 on a stable transfected cell line (1D-21) and did not bind to CCR8 on in vitro differentiated human CD4(+) Th(2) cell cultures. Also, I-309-dependent calcium mobilization in 1D-21 cells and in Th(2) cells was desensitized by I-309 but not by MIP-1beta or TARC. These results provide strong evidence that, at physiologically relevant concentrations, I-309 is the only known human ligand for CCR8. These data also provide a framework for suggesting minimum requirements for the assignment of chemokine receptor-ligand pairs.     

Chemokine-induced cutaneous inflammatory cell infiltration in a model of Hu-PBMC-SCID mice grafted with human skin

Recently, certain chemokines and chemokine receptors have been preferentially associated with the selective recruitment in vitro of type 1 T cells, such as IP-10 and its receptor CXCR3, or type 2 T cells such as monocyte-derived chemokine (MDC) and eotaxin and their receptors CCR4 and CCR3. Very few models have provided confirmation of these findings in vivo. Taking advantage of the humanized SCID mouse model grafted with autologous human skin, the ability of the chemokines IP-10, MDC, eotaxin, and RANTES to stimulate cell recruitment was investigated. Intradermal IP-10 injection resulted in an influx of CD4+ T lymphocytes but also surprisingly in the recruitment of dendritic cells. MDC recruited mainly CD8+ T lymphocytes, and had little effect on eosinophils. As predicted, eotaxin was a potent inducer of eosinophil and basophil migration, also recruiting CD4+ T cells. RANTES, a ubiquitous chemokine associated with both type 1 and type 2 profiles, was able to recruit all cell types. CXCR3-positive cells were preferentially recruited by IP-10, whereas CCR3- and CCR4-positive cells were predominantly found after injection of eotaxin and MDC. Thus, in a human environment in vivo, some chemokines have the ability to recruit cells expressing chemokine receptors preferentially expressed on type 1 or type 2 cells. Further investigations revealed that MDC and eotaxin induced the recruitment of type 2, but not type 1, cytokine-producing cells. RANTES, on the other hand, induced the migration of both type 1 and type 2 cytokine-secreting cells, whereas IP-10 did not induce the recruitment of either subtype. These studies provide detailed information on the properties of MDC, eotaxin, IP-10, and RANTES as chemotactic molecules in skin in vivo. The use of the humanized SCID mouse model grafted with human skin is validated as a useful model for the evaluation of chemokine function in the inflammatory reaction, and suggests that therapeutic targeting of certain chemokines might be of interest in diseases associated preferentially with a type 1 or type 2 profile.     

Pulmonary chemokines and their receptors differentiate children with asthma and chronic cough

BACKGROUND: Cough is a frequent symptom in children, but the differentiation of asthmatic cough from cough of other origins can be difficult. Chemokines recruit T lymphocytes to inflamed tissues, and the corresponding chemokine receptors are differentially expressed on T H 1 and T H 2 cells. OBJECTIVE: We sought to determine whether levels of T H 1/T H 2-related chemokines and their receptors differ in bronchoalveolar lavage fluid (BALF) from 12 children with allergic asthma, 15 nonatopic children with chronic cough, and 10 children without airway disease. METHODS: The T H 1-related (IFN-gamma-inducible protein of 10 kd [IP-10], IFN-gamma-inducible T cell alpha chemoattractant [ITAC], monokine induced by IFN-gamma [Mig], and IFN-gamma) and T H 2-related (thymus- and activation-regulated chemokine [TARC], macrophage-derived chemokine [MDC], IL-5, and IL-4) chemokines and cytokines were quantified in BALF by ELISA and a particle-based multiplex array. Percentages of pulmonary lymphocytes expressing CXCR3 + and CCR5 + (T H 1) and CCR4 + and CCR3 + (T H 2) chemokine receptors were determined in BALF by flow cytometry. RESULTS: Pulmonary CCR4 + CD4 + cells and levels of TARC and MDC were significantly increased in asthmatic children versus children with chronic cough or without airway disease. In asthmatic children CCR4 + CD4 + cells correlated positively with levels of TARC, MDC, and serum IgE levels and negatively with FEV 1 . In contrast, CXCR3 + CD8 + cells and levels of ITAC were significantly increased in children with non-atopic chronic cough compared with the other groups. In children with chronic cough, CXCR3 + CD8 + cells correlated with levels of ITAC and IFN-gamma. CONCLUSION: Pulmonary CCR4 + CD4 + and CXCR3 + CD8 + cells and their ligands TARC, MDC, and ITAC clearly differentiate asthmatic children from nonatopic children with chronic cough. The analysis of these markers could facilitate the diagnostic discrimination of asthma versus other reasons for chronic cough in children.     

Characterization of chemokines and chemokine receptors in two murine models of inflammatory bowel disease: IL-10-/- mice and Rag-2-/- mice reconstituted with CD4+CD45RBhigh T cells

We used quantitative PCR to investigate the expression of chemokines and chemokine receptors in two Th1-mediated murine models of inflammatory bowel disease (IBD). First, mRNA levels encoding the chemokines MIG, RANTES, lymphotactin, MIP-3alpha, TCA-3, TARC, MIP-3beta, LIX, MCP-1 and MIP-1beta and the receptors CCR4, CCR6 and CCR2 were significantly increased in chronically inflamed colons of IL-10-/- mice when compared with wildtype mice. Interestingly, reversal of colitis in IL-10-/- mice by anti-IL-12 mAb was accompanied by the inhibition in the expression of LIX, lymphotactin, MCP-1, MIG, MIP-3alpha, MIP-3beta, TCA-3, CCR2 and CCR4, whereas the increased mRNA levels of MIP-1beta, RANTES, TARC and CCR6 were unaffected. Second, to investigate which chemokines and receptors were up-regulated during the inductive phase of colitis, we employed the CD4+CD45RBhigh T cell transfer model. At 4 and 8 weeks after reconstitution of Rag-2-/- mice the mRNA levels of IP-10, MCP-1, MDC, MIG, TARC, RANTES, CCR4 and CCR5 were significantly increased prior to the appearance of macroscopic lesions. Other chemokines and chemokine receptors were clearly associated with the acute phase of the disease when lesions were evident. The sum of our studies with these two models identifies chemokines that are expressed at constant levels, irrespective of inflammatory responses, and those that are specifically associated with acute and/or chronic stages of Th1-driven colitis.     

CC chemokine receptor 4 ligand production by bronchoalveolar lavage fluid cells in cigarette-smoke-associated acute eosinophilic pneumonia

We examined the production of macrophage-derived chemokine (MDC/CCL22) and thymus- and activation-regulated chemokine (TARC/CCL17) by bronchoalveolar lavage fluid (BALF) cells in cigarette-smoke-associated acute eosinophilic pneumonia (CS-AEP). The CC Chemokine Receptor 4 (CCR4) ligand levels in BALF from patients with CS-AEP were considerably higher than those in healthy volunteers and correlated well with Th2 cytokine levels. Interleukin-4 enhanced CCR4 ligand production. MDC expression was observed in CD68-positive cells from patients with CS-AEP and in healthy control smokers. In contrast, TARC expression in CD68- or CD1a-positive cells was detected only in CS-AEP. An in vivo cigarette smoke challenge test induced increases in CCR4 ligands in the BALF and in the cultured supernatant of BALF adherent cells. These results suggest that alveolar macrophages and dendritic cells contribute to the pathogenesis of CS-AEP by generating CCR4 ligands, probably in response to cigarette smoke.     

Cytokine/chemokine profiles contribute to understanding the pathogenesis and diagnosis of primary Sjögren's syndrome

To investigate the pathogenesis of localized autoimmune damage in Sjögren's syndrome (SS) by examining the expression patterns of cytokines, chemokines and chemokine receptors at sites of autoimmune damage. mRNA expression of these molecules in the labial salivary glands (LSGs) and peripheral blood mononuclear cells (PBMCs) from 36 SS patients was examined using a real‐time polymerase chain reaction‐based method. Subsets of the infiltrating lymphocytes and chemokines/chemokine receptors expression in the LSG specimens were examined by immunohistochemistry. Cytokines/chemokine concentrations in the saliva were analysed using flow cytometry or enzyme‐linked immunosorbent assay. mRNA expression of T helper type 1 (Th1) cytokines, chemokines and chemokine receptors was higher in LSGs than in PBMCs. In contrast, mRNA expression of Th2 cytokines, chemokines [thymus and activation‐regulated chemokine (TARC/CCL17), macrophage‐derived chemokine (MDC/CCL22)] and chemokine receptor (CCR4) was associated closely with strong lymphocytic accumulation in LSGs. Furthermore, TARC and MDC were detected immunohistochemically in/around the ductal epithelial cells in LSGs, whereas CCR4 was detected on infiltrating lymphocytes. The concentrations of these cytokines/chemokines were significantly higher in the saliva from SS patients than those from controls, and the concentrations of Th2 cytokines/chemokines were associated closely with strong lymphocytic accumulation in LSGs. These results suggest that SS might be initiated and/or maintained by Th1 and Th17 cells and progress in association with Th2 cells via the interaction between particular chemokines/chemokine receptors. Furthermore, the measurement of cytokines/chemokines in saliva is suggested to be useful for diagnosis and also to reveal disease status.     

Chemokines, chemokine receptors and allergy

Chemokines are a group of cytokines that are responsible for the influx of blood cells, including T and B lymphocytes, monocytes, neutrophils, eosinophils and basophils, in allergic and other inflammatory conditions. They function as G protein-coupled chemotactic factors which also activate the cells with which they interact. Certain chemokines function within the afferent arm of the immune system, in which antigen is processed and antibody formation initiated, and others are active within the effector pathways of cellular immunity and late-phase allergic reactions. Th2 lymphocytes, which are critical for allergy, employ the CC chemokine receptors CCR4 and CCR8 with the ligands thymus- and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC) and I-309, respectively. The chemokine receptor CCR3 and ligands monocyte chemoattractant protein (MCP)-3, MCP-4, regulated upon activation normal T cell expressed and secreted (RANTES) and eotaxins I and II are of particular relevance for the recruitment and activation of eosinophils. Th1 reactions depend upon interferon gamma-induced CXC chemokines interferon- inducible protein (IP)-10, interferon-inducible T cell-alpha chemoattractant (iTAC) and monokine induced by interferon-gamma (MiG), which bind to chemokine receptor CXCR3.     

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

Antichemokine immunotherapy for allergic diseases

Chemokines have emerged as critical regulators of leukocyte function and as such represent attractive new targets for the therapy of allergic diseases. Recent studies have revealed important roles for the chemokine family in both the afferent and efferent limbs of the immune system, orchestrating and integrating innate and acquired immune responses. A subset of chemokines including eotaxin-1 (also called CCL11), eotaxin-2 (CCL24), eotaxin-3 (CCL26), MCP (monocyte chemoattractant protein)-3 (CCL7), MCP (monocyte chemoattractant protein)-4 (CCL13), TARC (thymus- and activation-regulated chemokine) (CCL17), and MDC (macrophage-derived chemokine) (CCL22) are highly expressed in allergic inflammation and are regulated by T helper type 2 cytokines. Receptors for these chemokines, including CCR3 (CC chemokine receptor 3), CCR4 (CC chemokine receptor 4) and CCR8 (CC chemokine receptor 8) are expressed on key leukocytes associated with allergic inflammation, such as T helper type 2 cells, eosinophils, mast cells and basophils, establishing a subset of chemokine/chemokine receptors potentially important in allergic inflammation. Recent data using inhibitory antibodies and chemokine antagonists support the concept that interfering with this subset of chemokines and their receptors represents a new approach to allergy immunotherapy.     

Chemokine and chemokine receptor analysis reveals elevated interferon-inducible protein-10 (IP)-10/CXCL10 levels and increased number of CCR5+ and CXCR3+ CD4 T cells in synovial fluid of patients with enthesitis-related arthritis (ERA)

Chemokines and chemokine receptors play a major role in homing of cells to the site of inflammation. Enthesitis-related arthritis (ERA) is a chronic inflammatory arthritis and no data are available on chemokines and their receptors in ERA. Blood (20) and synovial fluid (SF) (11) was collected from patients with ERA, and peripheral blood (PB) was collected from 12 patients with polyarticular juvenile idiopathic arthritis (JIA), nine patients with systemic onset and 18 healthy controls. Chemokines [interleukin (IL)-10/CXCL10, thymus and activation-regulated chemokine (TARC)/CCL17 and regulated upon activation normal T cell expressed and secreted (RANTES)/CCL5] were measured in serum and SF. Chemokine receptor expression was measured by flow cytometry. There was no difference in blood CD4(+) T cells bearing CCR5, CCR4 and CXCR3 in ERA and healthy controls. In paired samples the median frequency of CCR5(+) CD4(+) T cells was higher in SF compared to PB (15.8 versus 3.9%, P < 0.005), as was the frequency of CXCR3(+) T cells (21.61% versus 12.46%, P < 0.05). Median serum interferon-inducible protein-10 (IP-10)/CXCL10 levels were higher in patients with ERA compared to controls (139 versus 93 pg/ml; P < 0.05). Further median SF IP-10/CXCL10 levels were higher than the serum levels (2300 pg/ml versus 139 pg/ml; P < 0.01). Serum levels of RANTES/CCL5 were higher in patients (150 ng/ml) compared to control (99 ng/ml; P < 0.01). The SF levels were significantly lower compared to serum (P < 0.05). TARC/CCL17 levels in SF were lower than serum. There is increased homing of CCR5 and CXCR3(+) CD4 cells to the SF. Increased SF levels of IP-10/CXCL10 may be responsible for this migration in patients with ERA.     

Serum thymus and activation-regulated chemokine, macrophage-derived chemokine and eotaxin as markers of severity of atopic dermatitis

BACKGROUND: Expression of CCR4 ligands, such as thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC), leads to preferential influx of T-helper (Th) 2-type lymphocytes to the lesional skin in atopic dermatitis (AD). Eotaxin, like the CCR3 ligand, is an important contributor of eosinophils recruitment in the course of AD. These chemokines are assumed to play an important role in the pathomechanism of AD. METHODS: In this study, the serum concentration of TARC, MDC, eotaxin and total immunoglobulin E (IgE) in AD patients and healthy people were compared. Correlation between the studied indices and activity of AD was established. Severity of AD was assessed according to the SCORAD score. The study comprised 44 healthy people and 43 patients with AD. The serum concentrations of TARC, MDC, eotaxin and IgE were measured with the use of enzyme-linked immunosorbent assay kits. RESULTS: The serum levels of TARC, MDC, eotaxin and IgE appeared to be significantly higher in patients with AD than in healthy people. A strong positive correlation was revealed between the levels of TARC, MDC, total IgE in serum of patients with AD and SCORAD. In contrast, no significant relationship was found for the serum eotaxin concentration and TARC, MDC, IgE or disease severity. CONCLUSION: Our findings indicate that TARC and MDC are actively involved in the pathogenesis of AD and their expression, opposite to that of eotaxin, is strongly associated with clinical picture of atopic dermatitis.     

Suppressive Effect on MDC and IP-10 Expression in Monocytes by Endocrine Disruptor Chemicals

The expression of chemokines is critical in leukocyte recruitment and inflammation, but the regulatory mechanisms involved remain incompletely defined. While endocrine disrupter chemicals (EDCs) are known to be ubiquitous in the environment and often associated with altered inflammatory response, their potential impact on chemokine expression in monocytes is at present unknown. To this end, the effects of EDCs on the expression of Th1- and Th2-related chemokines in a human monocytic cell line, THP-1, were investigated. THP-1 cells were pre-treated with varying concentrations of EDCs (nonylphenol and 4-octylphenol) with or without the addition of an estrogen receptor (ER) antagonist, ICI 182,780 and then stimulated by lipopolysaccharide (LPS). The levels of chemokines, CXCL10/ IFN-α-inducible protein 10 (IP-10, a Th1 chemokine) and monocyte-derived chemokine (MDC)/CCL22, a Th2 chemokine) were measured by ELISA. EDC-mediated signaling events and histone modifications were examined by the use of Western blotting and chromatin immunoprecipitation (ChIP) assay. Nonylphenol and 4-octylphenol were able to suppress LPS-induced MDC and IP-10 expression. This suppressive effect was not reversed by the addition of ICI 182,780. Nonylphenol and 4-octylphenol reduced LPS-induced activation of MAPK signaling pathway, MKK1/2 and ERK, concomitant with decreased levels of LPS-induced acetylated histone 4 (H4) at the IP-10 and MDC gene loci. Nonylphenol and 4-octylphenol suppressed LPS-induced MDC expression in monocytes via, at least in part, the MKK1/2-ERK MAPK pathway and histone H4 acetylation, but not the estrogen receptor.     

Chemokine production and leukocyte recruitment to the lungs of Paracoccidioides brasiliensis-infected mice is modulated by interferon-gamma

Chemokines and chemokine receptors play a role in cell recruitment during granulomatous inflammatory reactions. Here, we evaluated the expression of chemokines and chemokine receptors and their regulation by IFN-gamma in the course of Paracoccidioides brasiliensis (Pb) infection in mice. We found an association between KC and MIP-1alpha (CCL3) production and neutrophil infiltration in the lungs of Pb-infected mice during the early acute phase of infection. High levels of RANTES/CCL5, MCP-1/CCL2, IP-10/CXCL10, and Mig/CXCL9 simultaneously with mononuclear cell infiltration in the lungs was found. In the absence of IFN-gamma (GKO mice) we observed increased production of KC and MIP-1alpha and chronic neutrophilia. Moreover, we found a change in the chemokine receptor profiles expressed by wild-type (WT) versus GKO animals. Increased expression of CXCR3 and CCR5, and low levels of CCR3 and CCR4 were observed in the lungs of Pb-infected WT mice, whereas the opposite effect was observed in the lungs of GKO mice. Consistent with these results, infected cells from WT mice preferentially migrated in response to IP-10 (CXCR3 ligand), while those from GKO mice migrated in response to eotaxin/CCL11 (CCR3 ligand). These results suggest that IFN-gamma modulates the expression of chemokines and chemokine receptors as well as the kind of cells that infiltrate the lungs of Pb-infected mice.     

Stem cell factor and IgE-stimulated murine mast cells produce chemokines (CCL2, CCL17, CCL22) and express chemokine receptors

OBJECTIVE AND DESIGN: In the present study we investigated the effect of SCF and/or IgE on histamine, TNF-alpha and chemokines released from bone marrow-derived mast cells (BMMC) as well as chemokine receptor expression. MATERIAL AND METHODS: BMMC were derived from femoral bone marrow of CBA/J mice. The purity of BMMC was >98% after 3 weeks. BMMC (2.5 x 10(6) cells/well) were incubated in the presence or absence of either SCF, IgE plus DNP or a combination of SCF and IgE for 6 and 18 h. Cell-free supernatants were recovered to measure CC chemokines, TNF-alpha and histamine release utilizing ELISA assays. CC chemokine family receptors were detected by RT-PCR analysis, and confirmed using functional chemotactic assays. RESULTS: Histamine levels were comparable between SCF and IgE stimulated cells, whereas TNF-alpha production was significantly greater after IgE compared to SCF stimulation. SCF and/or IgE-stimulated BMMC released CC chemokines, CCL22 (MDC), CCL17 (TARC) and CCL2 (MCP-1). Increased mRNA expression of CCR1, CCR2, CCR3, and CCR5 was detected in SCF and IgE-stimulated BMMCs. Functional chemotactic assays confirmed the expression data. CONCLUSION: SCF and IgE can up-regulate the expression of chemokines and chemokine receptors on mast cells. Thus, SCF may play a significant role in their activation and inflammation during allergic responses.     

Cytokines and chemoattractants in allergic inflammation

It is now generally accepted type 2 T helper (Th2) cytokines and some chemoattractants play an essential role in the pathogenesis of the allergic inflammation. The effects of Th2 cytokines, such as interleukin (IL)-4, IL-5, IL-9, and IL-13, account for virtually all the pathophysiological manifestations of allergy and asthma. Moreover, both Th2 cells and the effector cells usually present in the areas of allergic inflammation (basophils, mast cells, and eosinophils) express chemoattractant receptors, such as CCR3, CCR4, CCR8 and CRTH2. Therefore, interactions of eotaxin(s), eotaxin/CCL11, RANTES/CCL5, and MCP-1/CCL2, MCP-2/CCL8, MCP-3/CCL7, MCP-4/CCL13 with CCR3 are responsible for the recruitment of basophils, eosinophils and mast cells, whereas interactions of CCR4 with MDC/CCL22 or TARC/CCL17, CCR8 with I-309/CCL1, and CRTH2 with prostaglandin D(2) play a critical role in the allergen-induced recruitment of Th2 cells in the target tissues of allergic inflammation. The demonstration that Th2-polarized responses against allergens represent the triggering event for the development of allergic diseases, together with the recognition that some chemoattractants are responsible for the recruitment of both Th2 cells and other effector cells of allergic inflammation, can provide the conceptual basis for the development of new therapeutic strategies in allergic conditions.