CHARACTERIZATION OF INTERLEUKIN-5 RECEPTORS ON EOSINOPHILIC SUBLINES FROM HUMAN PROMYELOCYTIC LEUKEMIA (HL-60) CELLS

The T cell product interleukin 5 (IL 5) has been shown to be a key factor in the development and the maturation of the eosinophilic cell lineage. We report here on the detection of human IL5 receptors on eosinophilic sublines of the promyelocytic leukemia HL-60. Sodium butyrate, which initiates differentiation to mature eosinophils, also induces the appearance of high affinity (Kd 1-5 x 10 -11 M) IL5 binding sites on these cells. The receptors are specific for 11,5, since binding of radiolabeled ligand can only be inhibited with homologous or murine IL-5 and not by other cytokines. We further show that the receptors are functional, since 116 can stimulate the proliferation of these cells. Affinity crosslinking of surface-bound 1251 human IL-5 or 35S mouse IL5 identified two membrane polypeptides of ~60 and ~130 kD to which 1175 is closely associated. The presence of granuloryte/macrophage-colony-stimulating factor or tumor necrosis factor during butyrate induction decreased the expression of 11,5 binding sites compared with control cultures. The identification and characterization of human 1175 receptors on HL60 sublines should provide new insight into the role of this cytokine in eosinophil differentiation. © 1990, Rockefeller University Press., All rights reserved.