LEUKOTRIENE RECEPTORS IN HL-60 CELLS DIFFERENTIATED INTO EOSINOPHILS,MONOCYTES AND NEUTROPHILS

The expression of leukotriene B-4 (LTB(4)) and leukotriene D-4 (LTD(4) ) receptors was determined, by binding assay, in HL-60 cells different iated into the monocyte/macrophage, neutrophil, and eosinophil lineage s. Monocyte/macrophage- and neutrophil-differentiated cells developed specific LTB(4) receptors with high affinities (K-d = 1.27 nM and 2.65 nM, respectively) and low affinities (K-d = 26.41 nM and 55.63 nM, re spectively). These receptors were functional and specific as indicated by the ability of LTB(4) to elicit an increase in intracellular calci um concentration antagonised by specific antagonists. Eosinophil-diffe rentiated cells developed mainly LTD(4) receptors (K-d = 41.91 nM), an d stimulation with LTD(4) induced an increase in intracellular calcium that was antagonised by a specific LTD(4) antagonist. These results s how, for the first time, that eosinophil-differentiated HL-60 cells ex press specific functional LTD(4) receptors. These cells could be used for the study of the actions of peptidoleukotrienes on eosinophils, an d for studies on the molecular mechanisms regulating LTD(4) receptor e xpression.