Expression of the Chemokine Receptor CCR3 on Human Mast Cells

220

150

Eotaxin and eotaxin-2, acting through CCR3, are potent eosinophil chemoattractants both in vitro and in animal models. In this study we examined the capacity of eotaxin and eotaxin-2 to recruit eosinophils and other inflammatory cells in vivo in human atopic and nonatopic skin. Skin biopsies taken after intradermal injection of eotaxin and eotaxin-2 were examined by immunohistochemistry. Allergen- and diluent-challenged sites were used as positive and negative controls. Eotaxin and eotaxin-2 produced a dose- and time-dependent local eosinophilia of comparable intensity in both atopic and nonatopic individuals. This was associated with an acute wheal and flare response at the site of injection and development of a cutaneous late phase reaction in a proportion of subjects. There was an accompanying decrease in mast cell numbers. Both chemokines also induced the accumulation of basophils and an unexpected early infiltration of neutrophils. Macrophages were prominent at the 24-h point. Although there was surface CCR3 expression on neutrophils in whole blood, we were unable to demonstrate any functional neutrophil responses to eotaxin in vitro. Thus, intradermal injection of eotaxin and eotaxin-2 in humans induced infiltration of eosinophils and other inflammatory cells as well as changes consistent with CC chemokine-induced mast cell degranulation.

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Eotaxin (CCL11) and Eotaxin-2 (CCL24) Induce Recruitment of Eosinophils, Basophils, Neutrophils, and Macrophages As Well As Features of Early- and Late-Phase Allergic Reactions Following Cutaneous Injection in Human Atopic and Nonatopic Volunteers

Menzies‐Gow

Ying

Sabroe

et al. 2002

220

150

“…Eotaxin-2 and eotaxin-3 are only distantly related to eotaxin-1 because they are only ϳ30% identical in sequence and are located on different chromosomes (19,20). The specific activity of all eotaxins is mediated by the selective expression of the eotaxin receptor, CCR3, a seven-transmembrane spanning, G protein-coupled receptor, primarily expressed on eosinophils (21,22), while noted on a subset of Th2 cells (23) and mast cells in humans (24), little is known about the expression of CCR3 on cells other than eosinophils in the mouse. Notably, the eotaxin chemokines cooperate with IL-5 in the induction of tissue eosinophilia.…”

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confidence: 99%

The Eotaxin Chemokines and CCR3 Are Fundamental Regulators of Allergen-Induced Pulmonary Eosinophilia

Pope

Zimmermann²,

Stringer

et al. 2005

224

193

The eotaxin chemokines have been implicated in allergen-induced eosinophil responses in the lung. However, the individual and combined contribution of each of the individual eotaxins is not well defined. We aimed to examine the consequences of genetically ablating eotaxin-1 or eotaxin-2 alone, eotaxin-1 and eotaxin-2 together, and CCR3. Mice carrying targeted deletions of these individual or combined genes were subjected to an OVA-induced experimental asthma model. Analysis of airway (luminal) eosinophilia revealed a dominant role for eotaxin-2 and a synergistic reduction in eotaxin-1/2 double-deficient (DKO) and CCR3-deficient mice. Examination of pulmonary tissue eosinophilia revealed a modest role for individually ablated eotaxin-1 or eotaxin-2. However, eotaxin-1/2 DKO mice had a marked decrease in tissue eosinophilia approaching the low levels seen in CCR3-deficient mice. Notably, the organized accumulation of eosinophils in the peribronchial and perivascular regions of allergen-challenged wild-type mice was lost in eotaxin-1/2 DKO and CCR3-deficient mice. Mechanistic analysis revealed distinct expression of eotaxin-2 in bronchoalveolar lavage fluid cells consistent with macrophages. Taken together, these results provide definitive evidence for a fundamental role of the eotaxin/CCR3 pathway in eosinophil recruitment in experimental asthma. These results imply that successful blockade of Ag-induced pulmonary eosinophilia will require antagonism of multiple CCR3 ligands.

“…This receptor is highly expressed on eosinophils (3,8,9), and all three eotaxins have been shown to be potent eosinophil chemoattractants in vitro (2, 5-7, 10 -12). More recently, CCR3 has been detected on other cell types, including basophils, mast cells, and a subpopulation of Th2 cells (13)(14)(15). As all of these cell types are involved in allergic inflammatory reactions, it is hypothesized that the eotaxins play an important role in coordinating the recruitment of all of these cell types to sites of allergic inflammation.…”

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confidence: 99%

Eotaxin-2 Generation Is Differentially Regulated by Lipopolysaccharide and IL-4 in Monocytes and Macrophages

Watanabe

Jose

Rankin

2002

The eotaxins are a family of CC chemokines that coordinate the recruitment of inflammatory cells, in particular eosinophils, to sites of allergic inflammation. The cDNA for eotaxin-2 (CC chemokine ligand 24) was originally isolated from an activated monocyte library. In this study, we show for the first time that peripheral blood monocytes generate bioactive eotaxin-2 protein constitutively. Eotaxin-2 production was significantly up-regulated when monocytes were stimulated with the proinflammatory cytokine IL-1β and the microbial stimuli, LPS and zymosan. In contrast, the Th2 cytokines, IL-4 and IL-13, and the proinflammatory cytokine, TNF-α, acting alone or in combination, did not enhance the generation of eotaxin-2 by monocytes. Indeed, IL-4 suppressed the generation of eotaxin-2 by LPS-stimulated monocytes. Although other chemokines, including macrophage-inflammatory protein-1α, monocyte chemoattractant protein-1, macrophage-derived chemokine, and IL-8 were generated by monocytes, eotaxin-1 (CC chemokine ligand 11) could not be detected in the supernatants of monocytes cultured in the presence or absence of any of the stimuli used in the above experiments. Furthermore, human dermal fibroblasts that produce eotaxin-1 did not generate eotaxin-2 under basal conditions or when stimulated with specific factors, including IL-4, IL-13, TNF-α, and LPS. When monocytes were differentiated into macrophages, their constitutive generation of eotaxin-2 was suppressed. Moreover, IL-4, but not LPS, up-regulated the production of eotaxin-2 by macrophages. Taken as a whole, these results support a role for macrophage-derived eotaxin-2 in adaptive immunity, with a Th2 bias. In contrast, a role for monocyte-derived eotaxin-2 is implicated in innate immunity.