[Review: recent studies on a human eosinophilic leukemia cell line, EoL as an experimental model of eosinophils]

Recently, a human eosinophilic leukemia cell line, EoL was established from an eosinophilic leukemia patient. EoL-1 cells have the cytohistologic features of myeloblasts under normal culture conditions, and they can be induced to differentiate into eosinophilic granule-containing cells but not into other lineage cells under several culture conditions and are therefore considered to be committed precursors of eosinophils. Furthermore, EoL-1 cells can also be induced to differentiate functionally to show PAF-induced Ca2+ influx and actin polymerization. On the other hand, EoL-3 cells show constitutive expression of Fc epsilon RII, Fc gamma RII, LFA-1 and ICAM-1 on their cell surface. The EoL cells may provide new information on some aspects of the signal transduction mechanisms involved in the proliferation, differentiation and activation of eosinophils.