Differentiation of a human myeloid cell line (HL-60) toward granulocyte- and macrophage-like cells: comparison of cell surface antigen expression.

Human hematopoietic pathways have been defined mainly by the analysis of cellular morphological changes because of the paucity of other meaningful markers. Monocolonal antibodies against human cell surface antigens offer the possibility of following changes in the expression of these molecules, in particular when combined with the use of cell lines able to differentiate in vitro if provided with an appropriate stimulus. The aim of this work was to correlate antigenic changes on the surface of differentiating myelomonocytoid cells with the disappearance or appearance of morphologically distinct cell types during hematopoietic differentiation. The promyelocytic leukemia-derived cell line HL60 was employed as an effective model system. This cell line 141 can be induced with retinoic acid to differentiate toward granulocytes [3], and after the addition of the phorbol ester TPA to HL-60 cells, they become macrophage-like [8]. The expression of surface antigens on these cells following the different types of induction treatment was analyzed with a panel of over 70 monoclonal antibodies [12], using indirect immunofluorescence and bacterial binding assays.