Search

We describe changes in antigen expression on HL60 cells with differentiation into granulocytes induced by all-trans retinoic acid (ATRA) or dimethylsulphoxide (DMSO), into monocytes by α1,25-dihydroxyvitamin D3 (D3), or into macrophages by 12-O-tetradecanoyl phorbol-13-acetate (TPA). Undifferentiated cells expressed CD13, CD14 (at a low level), CD15, CDw17, CD32, CD33, CD49e, CD63, CD64, CDw65, CD71 and CD87 antigens and bound the unclustered mAb D171 and Mo5. Differentiated and undifferentiated cells were negative for CD16, CD34, CD61, CD66abcde, CD68, CD88, CDw90 and CD93. Four panels of markers were identified whose expression changes significantly following differentiation. CD15, CD49e, CD63, CDw65, CD71 and mAb D171 and IGR-2,1A6 for DMSO; CD13, CD15, CDw17, CD49e, CD63, CDw65, CD71, CD87, CDw92 and mAb D171 and IGR-2,1A6 for ATRA; CD14, CD31, CD35, CD71, CD87, CDw92 and mAb D171 and BRIC18 for D3; CDw12, CD13, CD15, CD31, CD35, CD49e, CD71, CD87, CDw92 and mAb D171 for TPA. These will be useful for analyzing the pathways that regulate differentiation, whether the observed changes are consequences of differentiation or more direct effects of the inducers. HL60 cells provide a model for investigating the regulation of these antigens.

A wide range of different agents are capable of inducing the onset of HL-60 differentiation along the myeloid lineage. The diversity of these agents has made the analysis of the molecular mechanisms involved in the regulation of the onset and progress of terminal differentiation in these cells difficult. We have adapted the standard soft-agar cloning procedure to enable the single-step selection of clonal populations of spontaneously arising differentiation resistant HL-60 variants. This simple procedure which obviates the need for mutagenesis, long-term exposure to inducing agents or complex manipulations, optimises the chance of obtaining variants with a single lesion blocking the onset of differentiation. The analysis of two variants, HL-R5 and HL-D4, selected by this procedure for resistance to retinoic acid and DMSO, respectively, suggests the existence of different pathways used by the two agents which converge before the onset of terminal differentiation.