Chemotactic capabilities of HL-60 human myeloid leukemia cells differentiated to eosinophils

HL-60 human myeloid leukemia cells can be induced to differentiate into cells with many of the morphological, biochemical, and functional features of mature neutrophils, monocyte/macrophages, and eosinophils. HL-60 neutrophils are known to respond to several chemotactic compounds, but similar data do not exist for HL-60 eosinophils. We studied the chemotactic capabilities of eosinophil-differentiated HL-60 cells using a blind-well chamber technique. HL-60 eosinophils responded to the specific eosinophilotactic tetrapeptides Ala-Gly-Ser-Glu, Val-Gly-Asp-Glu, and Val-Gly-Ser-Glu; to the formylated tripeptide N-formyl-L-Met-L-Leu-L-Phe (fMLP); and to extracts estrogen-treated rat uteri, which contain an eosinophilotactin. Concentration optima for chemotaxis of HL-60 eosinophils were similar to those for normal human and rodent eosinophils. Neutrophil-differentiated HL-60 cells responded only to fMLP, whereas undifferentiated HL-60s showed no chemotactic ability. The time course of development of chemotactic competence paralleled other developmental changes in HL-60 eosinophilic differentiation, suggesting a common control mechanism. We conclude that the ability to respond to specific eosinophilotactic compounds is a feature of HL-60 cells that have differentiated to eosinophils and that this cell line may be used as a model system in studies of eosinophil chemotaxis.