title: Production of IL-13 by human lung mast cells in response to Fcepsilon receptor cross-linkage.
abstract: BACKGROUND
  Cross-linkage of the high affinity Fcepsilon receptors (FcepsilonRI) on the surface of the mast cell by the allergen-IgE complex is a central event in the induction of allergic inflammatory reactions. However, the precise roles of human mast cells in the perpetuation of allergic inflammation is not well known. IL-13 plays an important role in the regulation of allergic inflammation, especially being involved in the induction of IgE synthesis.
  
  
  OBJECTIVE
  We investigated whether human lung mast cells have the capacity to produce IL-13 by cross-linking of the FcepsilonRI.
  
  
  METHODS
  Lung mast cells were purified by affinity magnetic selection with monoclonal antibody YB5.B8 against c-kit to achieve a final mast cell purity of more than 93%. Purified mast cells were precultured with human myeloma IgE (3 microg/mL) for 16 h before challenge with stem cell factor (SCF) (50 ng/mL) and anti-IgE (1 microg/mL). By RT-PCR, ELISA and immunocytochemistry, we evaluated the capacity of human lung mast cells to express and produce IL-13.
  
  
  RESULTS
  IgE-dependent activation of human lung mast cells caused an increase in IL-13 mRNA expression which persisted for up to 12 h. Immunoreactive IL-13 was detectable 24 h after activation of sensitized lung mast cells with SCF and anti-IgE in 6 of 13 non-asthmatic donors and a million of mast cells secreted 106.7 +/- 42.65 (mean +/- SE) pg of IL-13 into the culture supernatants. SCF alone induced 61.63 +/- 31.12 pg of IL-13 from 106 mast cells. This difference was statistically significant (P = 0.028, n = 13). Furthermore, we confirmed by immunocytochemistry that immunological activation induced an increase of intracellular IL-13.
  
  
  CONCLUSIONS
  These findings demonstrate the capacity of human lung mast cells to transcribe IL-13 after IgE-dependent activation and to synthesize and release IL-13.
authors.affiliation: The First Department of Internal Medicine, Gunma University, Faculty of Medicine, School of Medicine, Gunma, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Okayama
authors.forename: T
authors.initials: T
authors.lastname: Ishizuka
authors.forename: R
authors.initials: R
authors.lastname: Pawankar
authors.forename: C
authors.initials: C
authors.lastname: Ra
authors.forename: M
authors.initials: M
authors.lastname: Mori
mesh_terms: D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007150:Immunohistochemistry; D018793:Interleukin-13 / Q000096:biosynthesis* / Q000235:genetics; D007700:Kinetics; D008168:Lung / Q000166:cytology*; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017455:Receptors, IgE / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019089:Stem Cell Factor
chemical_list: D018793:Interleukin-13; D012333:RNA, Messenger; D017455:Receptors, IgE; D019089:Stem Cell Factor