GRANULOCYTE-COLONY-STIMULATING FACTOR-RECEPTOR MEDIATED CELL-GROWTH AND DIFFERENTIATION

Granulocyte colony-stimulating factor (G-CSF) can elicit different bio logical responses through interaction with its receptor (G-CSFR). A se ries of G-CSFR expressing clones were established from WEHI-3B D+ myel omonocytic leukemia cells and interleukin-3 (IL-3) dependent Ba/F3 pre B cells by transduction of a G-CSFR cDNA. The overexpression of the G- CSFR from the expression vector promoted differentiation in WEHI-3B D cells exposed to G-CSF while, in contrast, the cytokine supported gro wth in Ba/F3 cells transfected with the expression plasmid in the abse nce of IL-3. Western blotting, immunoprecipitation and cell surface la beling with Na[I-125] followed by immunoprecipitation with an anti-G-C SFR antibody revealed different patterns of detected proteins in these two cell lines, implying that different forms of the G-CSFR were gene rated which produced distinct biological responses and/or that differe nt cell-type specific signal transducers were involved in the producti on of cellular differentiation or growth.