title: The Influence of IgE on Cultured Human Mast Cells.
abstract: OBJECTIVE
  The mast cell plays a pivotal role in the human immune response. Crosslinking of 2 IgE molecules bound to the high affinity IgE receptor (FcεRI) on the surface of the mast cell results in mast cell degranulation and the release of several proinflammatory mediators. Patients with type-I allergy have increased levels of IgE in the blood compared to healthy individuals.
  
  
  METHODS
  In a 6-week culture system of stem cells to human mast cells we investigated the effect of the concentration of IgE. The mast cells were cultured with different concentrations of IgE for the last 10 days of the maturation period. It was observed how the IgE concentration affects the histamine release, FcεRI density on the mast cell surface and the concentration of other mediators.
  
  
  RESULTS
  A clear correlation between IgE concentration in culture medium and the release of histamine upon activation was observed. It showed a bell-shaped dose response curve, with maximal response around an IgE-concentration of 250 ng/mL. Furthermore, the sensitivity of the mast cells and surface density of FcεRI on mast cell surface was also influenced by the IgE concentration in the culture medium.
  
  
  CONCLUSIONS
  IgE in the culture medium during the last 10 days of mast cell maturation influences the release of the preformed mediator histamine after mast cell activation and the density of FcεRI on the mast cell surface. The release of the de novo synthetized mediator prostaglandin D2 and the expression of chymase and tryptase are not influenced by IgE in culture medium.
authors.affiliation: Pediatric Research Lab, Aarhus University Hospital, Denmark.
authors.forename: Pernille Munk
authors.initials: PM
authors.lastname: Frandsen
authors.forename: Inge Jacoba Maria Kortekaas
authors.initials: IJ
authors.lastname: Krohn
authors.forename: Hans Jürgen
authors.initials: HJ
authors.lastname: Hoffmann
authors.forename: Peter Oluf
authors.initials: PO
authors.lastname: Schiøtz
keywords: FcεRI; Human mast cell; IgE; allergy; histamine; hygiene hypothesis; parasite infection; prostaglandin D2