[In vitro differentiation and Fc receptor expression of eosinophils]

Eosinophils express Fc gamma R II, together with some, if any, Fc gamma R I or Fc gamma R III. Fc epsilon R II is thought to be expressed only on the hypodense subpopulation of eosinophils. Dibutyryl cyclic AMP (dbcAMP) and gamma interferon (IFN-gamma) enhanced Fc gamma R II expression on both peripheral eosinophils and eosinophils derived in vitro by IL-5 from cord blood monoclear cells. IFN-gamma also enhanced Fc gamma R III expression on peripheral eosinophils only and not on IL-5-generated eosinophils. dbcAMP suppressed the IFN-gamma-induced Fc gamma R III expression on peripheral eosinophils. Other cytokines tested did not show any effect on Fc gamma R or Fc epsilon R II expression. These results suggest that expression of Fc gamma R subclasses and Fc epsilon R II on eosinophils is regulated differently and that cAMP and IFN-gamma play important roles in the regulation of Fc gamma R expression.