IL-1 up-regulates the expression of cytokine receptors on a factor-dependent human hemopoietic cell line, TF-1.

A factor-dependent human hemopoietic cell line, TF-1, requires interleukin 3 (IL-3) or granulocyte/macrophage colony-stimulating factor (GM-CSF) for its long-term growth. We have found that IL-4, IL-5, and IL-6 also support the growth of TF-1 and that IL-1 enhances the proliferative effect of these cytokines. Augmentation by IL-1 is associated with up-regulation of the receptors for IL-3, IL-5, GM-CSF, and erythropoietin (Epo). IL-1 increased the number of binding sites for IL-3 and Epo without changing their affinities. In contrast, IL-1 increased the number of high affinity binding sites for GM-CSF and IL-5, whereas the total number of binding sites was unchanged. Chemical crosslinking experiments indicated that the receptors for IL-3, IL-5, and GM-CSF were composed of two components and that the molecular masses of the larger components of these cytokine receptors were quite similar (120 kd). The enhanced expression of the larger components of the IL-3, IL-5, and GM-CSF receptors by IL-1 may be responsible for IL-1-induced up-regulation of these receptors. These observations are consistent with the model that the receptors for IL-3 and GM-CSF share a common component.