title: Chemokines induce eosinophil degranulation through CCR-3.
abstract: BACKGROUND
  Such CC chemokines as eotaxin and RANTES induce preferential eosinophil recruitment in allergic inflammation. They also elicit proinflammatory effector functions of eosinophils, such as enhanced adhesion and superoxide generation. Eosinophil degranulation by chemokines, however, has not been studied in detail.
  
  
  OBJECTIVE
  The purpose of this study was to identify chemokines and their corresponding receptors that induce eosinophil degranulation by using a panel of chemokines and blocking antibodies to candidate receptors.
  
  
  METHODS
  Highly purified eosinophils were preloaded with Fura-2 and stimulated with a panel of chemokine ligands for 14 known chemokine receptors: CCR1 to CCR8, CXCR1 to CXCR4, CX3CR1, and XCR1. Calcium influx was measured with fluorescence spectrometry. Eosinophils were also stimulated with the chemokines in the presence or absence of IL-5, and levels of eosinophil-derived neurotoxin were measured in the supernatant with RIA. Specific antibodies to chemokine receptors were used to block degranulation.
  
  
  RESULTS
  Calcium influx was induced by monocyte chemotactic protein (MCP) 1, MCP-3, MCP-4, RANTES, eotaxin, IL-8, and stromal cell-derived factor 1alpha, which are chemokines that bind several chemokine receptors. However, degranulation was induced only by CCR3 ligands, including MCP-3, MCP-4, RANTES, and eotaxin. Priming of eosinophils with IL-5 enhanced CCR3 ligand-induced degranulation but did not cause non-CCR3 ligands to induce eosinophil-derived neurotoxin release. An antibody against CCR3 significantly inhibited degranulation induced by CCR3 ligands, eotaxin, or RANTES.
  
  
  CONCLUSIONS
  These results suggest that chemokine-induced eosinophil degranulation, a major effector of eosinophil functions, is mediated through only CCR3, although some non-CCR3 ligands induce calcium influx in eosinophils. CCR3 may be an important target in the treatment of eosinophilic inflammation.
authors.affiliation: Department of Pediatrics, Mie National Hospital, Tsu, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fujisawa
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
authors.forename: H
authors.initials: H
authors.lastname: Nagase
authors.forename: J
authors.initials: J
authors.lastname: Atsuta
authors.forename: A
authors.initials: A
authors.lastname: Terada
authors.forename: K
authors.initials: K
authors.lastname: Iguchi
authors.forename: H
authors.initials: H
authors.lastname: Kamiya
authors.forename: Y
authors.initials: Y
authors.lastname: Morita
authors.forename: M
authors.initials: M
authors.lastname: Kitaura
authors.forename: H
authors.initials: H
authors.lastname: Kawasaki
authors.forename: O
authors.initials: O
authors.lastname: Yoshie
authors.forename: K
authors.initials: K
authors.lastname: Hirai
mesh_terms: D002118:Calcium / Q000097:blood; D015550:Cell Degranulation / Q000187:drug effects; D018925:Chemokines / Q000494:pharmacology*; D004804:Eosinophils / Q000166:cytology*; D006801:Humans; D054397:Receptors, CCR3; D019707:Receptors, Chemokine / Q000502:physiology*; D013997:Time Factors
chemical_list: C515350:CCR3 protein, human; D018925:Chemokines; D054397:Receptors, CCR3; D019707:Receptors, Chemokine; D002118:Calcium