Abstract
We examined the expression of eosinophilic granules, esterase activity and CD14 in a human eosinophilic cell line, EoL‐1. Unstimulated EoL‐1 cells were weakly positive for nonspecific esterase, but negative for surface CD14, and contained a few eosinophilic granule‐positive cells. A combination of G‐CSF and TNF‐α increased the eosinophilic granule‐containing cells, but failed to increase esterase activity or CD14 expression. IFN‐γ alone or in combination with TNF‐α enhanced nonspecific esterase activity but failed to induce CD14 expression or increase eosinophilic granule‐containing cells. dbcAMP increased eosinophilic granule‐containing cells, nonspecific esterase activity and CD14 expression. Specific esterase activity was not detected in any circumstances. EoL‐1 cells fractionated by density gradients or CD14 expression showed nonspecific esterase activity and CD14 expression in both the eosinophilic granule‐positive and negative cell populations. Forskolin and butyrate had a synergistic effect on CD14 induction and protein kinase A was suggested to play a role in dbcAMP‐induced CD14 expression. A protein kinase C activator, phorbol 12‐myristate 13‐acetate, did not increase eosinophilic granules, nonspecific esterase activity or CD14 experession in EoL‐1 cells. The results show that EoL‐1 cells can express nonspecific esterase and CD14, but the expression is not necessarily restricted to cells which have differentiated into the monocyte/macrophage lineage.