Binding characteristics and proliferative action of purified granulocyte colony-stimulating factor (G-CSF) on normal and leukemic human promyelocytes.

The binding of purified 125I-labeled murine granulocyte colony stimulating factor (125I-G-CSF) to normal and leukemic human cells was examined. Normal neutrophils and their precursors demonstrated specific labeling with 125I-G-CSF, whereas eosinophils, lymphocytes, and erythroid cells did not. Normal human promyelocytes demonstrated the highest binding among hemopoietic cells. Human myeloid leukemic cells also demonstrated consistent specific labeling with 125I-G-CSF. Normal promyelocytes and chronic myeloid leukemia promyelocytes demonstrated only transient clonal proliferation in vitro when stimulated by G-CSF, but this was not always the case with acute promyelocytic leukemic cells. The qualitative responsiveness of normal and leukemic cells to G-CSF was very similar despite heterogeneity in receptor numbers on individual cells. A subset of acute promyelocytic leukemic cells appeared unresponsive to stimulation by GM-CSF.