Differentiation of a human eosinophilic leukemic cell line, EoL-1: characterization by the expression of cytokine receptors, adhesion molecules, CD95and eosinophilic cationic protein (ECP)

Purification of enough eosinophils for the study of allergic inflammation i s difficult because eosinophils comprise only a small percentage of circula ting leucocytes. A human eosinophilic leukemic cell line, EoL-1, has been c onsidered to be an in vitro eosinophilic model. In the present study, the s uitability of EoL-1 cells as an eosinophilic model was further investigated . EoL-1 cells were induced to differentiate by dibutyryl cyclic AMP (dbcAMP ). The expression of cell surface cytokines (IL-3, IL-5, GM-CSF) receptors, adhesion molecules (CD49d, CD11b): and CD95 (Fas) was investigated by flow cytometry. Expression of eosinophilic cationic protein (ECP) was determine d by fluorescence enzyme immunoassay (FEIA) and reverse transcription-polym erase chain reaction (RT-PCR). EoL-1 cells could be differentiated into eos inophilic vacuole-containing cells by dbcAMP. They were found to express ce ll surface IL-3 and GM-CSF receptors, CD95 and CD49d. Treatment with dbcAMP could induce the expression of CD11b but decrease the expression of CD95. Anti-CD95 antibody could induce their apoptosis. The differentiation of EoL -1 cells was accompanied by increase in release of ECP into the supernatant and total ECP synthesis. Differentiation of EoL-1 cells also up-regulated the expression of mRNA for ECP and its level was parallel to the total amou nt of ECP synthesis. By virtue of their expression of haematopoietic cytoki nes receptors, adhesion molecules, CD95, synthesis and release of ECP, EoL- 1 cells are suitable as an in vitro eosinophilic model for studying eosinop hilic functions. (C) 1999 Elsevier Science B.V. All rights reserved.