Induction of differentiation into monocyte/macrophage cell lineage of a human eosinophilic leukaemia cell line EoL‐1 by simultaneous stimulation with tumour necrosis factor‐α and interferon‐γ

Abstract

Human myeloid leukaemia cell lines have been shown to differentiate into distinct cell lineages in vitro in response to several differentiation-inducing agents. A human eosinophilic leukaemia cell line, EoL-1, has been shown to differentiate into mature eosinophilic granulocytes by treatment with the culture supernatant of a human T-cell line, HIL-3. In this study we have studied whether the EoL-1 cell line has potential to differentiate into cell lineage other than eosinophils. We found that EoL-1 cells cultured in the presence of tumour necrosis factor (TNF)-alpha (10 u/ml) and interferon (IFN)-gamma (1000 u/ml) for 2-4 d differentiated into macrophage-like cells in morphology, and expressed CD14 antigen on their cell surface. It is possible that the small subpopulation of EoL-1 cells which contains non-specific esterase (NSE) activity may be preferentially differentiated by TNF-alpha and IFN-gamma. To clarify this issue, we have cloned the EoL-1 cell line and obtained NSE negative and positive sublines. Both EoL-1 sublines differentiated into monocyte/macrophage-like cells, because: (a) EoL-1 sublines were induced to express CD14 antigen, and (b) they attached firmly to the plastic wells; (c) after differentiation they became strongly positive for NSE staining, and secreted TNF-alpha in response to the stimulation with lipopolysaccharide; and (d) they exhibited potent phagocytic activity. Therefore, we found that the EoL-1 cell line has the ability to differentiate not only into mature eosinophilic cells but also into monocyte/macrophage cell lineage, suggesting that EoL-1 cells represent immature cells with ability to differentiate into multiple cell lineages.