The human promyelocytic leukemia cell line HL-60 is reactive with an antiserum raised against normal human granulocytes (AGS). Immunoprecipitation with AGS on [ S]methioninelabeled HL-60 cell lysates with subsequent analysis by NaDodSO4/polyacrylamide slab gel electrophoresis shows a major antigenic doublet with molecular weights-of 88,000 and 86,000, together with some minor antigens of lower molecular weight. Upon stimulation with dimethyl sulfoxide or 12-O-tetradecanoylphorbol 13-acetate, which induces HL-60 to differentiate to mature granulocytes or monocytes/macrophages, respectively, this antigenic doublet disappears. 12-O-Tetradecanoylphorbol 13-acetate induces the synthesis of an antigen, molecular weight 83,000, reactive with an antimonocyte serum. Neutrophil-specific alloantigens were not detected on HL-60 or its differentiated derivatives.With the aid of the appropriate human antisera in leukoagglutination or indirect immunofluorescence assays, several neutrophil-specific alloantigen systems have been detected on human granulocytes (1-4). In addition, neutrophil-specific xenogeneic antisera have been produced (5-7).Recently, a human leukemic cell line (HL-60) has been established from the peripheral blood of a patient with acute promyelocytic leukemia, which shows myeloid characteristics (8). Morphologically, the cultured HL-60 cells are predominantly promyelocytes, although some mature myelocytic cells are also present. Furthermore, cells of this cell line can be induced to differentiate in culture. Incubation with dimethyl sulfoxide (Me2SO) induces HL-60 to maturate into myelocytes and granulocytes (9) which have acquired functional properties characteristic of these cells (10). In contrast, the phorbol ester 12-0-tetradecanoylphorbol 13-acetate (TPA) induces differentiation ofHL-60 along the monocyte/macrophage pathway, with a concomitant increase in phagocytic capacity and adherence to plastic surfaces (11).Other cell lines of putative myeloid origin include K562 (12) which, by both immunological (13) and biochemical (14) criteria, is an erythroleukemic cell line, and the early myeloid cell line KG-1, which expresses the HLA-DR antigen (15, 16). The relatively mature character of HL-60 is further evidenced by its lack of HLA-DR antigen normally present on myeloblasts (17).In this study, antigens present on HL-60 at its various stages of differentiation were detected by immunofluorescence with a set of reagents that included xenogeneic-antisera with specificity for granulocytes and monocytes, respectively. We further analyzed these antigens by immunoprecipitation on radioactively labeled cell lysates, followed by NaDodSOjpolyacrylamide gel electrophoresis. This study has potentially important consequences for analysis of antigens on leukemic cells present in patients with chronic myeloid leukemia and acute myeloblastic leukemia.
MATERIALS AND METHODS Cell Lines and Conditions for Growth and Differentiation.The continuous suspension cell lines used in this study were HL-60 (8), K562 (12), ...