RECEPTOR INSERTION INTO FACTOR-DEPENDENT MURINE CELL-LINES TO DEVELOP SPECIFIC BIOASSAYS FOR MURINE G-CSF AND M-CSF AND HUMAN GM-CSF

cDNAs encoding the receptors for murine G-CSF, M-CSF or human GM-CSF were inserted into the murine hemopoietic continuous cell lines Ba/F3 or FDC-P1 and sublines selected that were then responsive to proliferative stimulation by these growth factors. When used in microwell assays the Ba/F3 G-CSF receptor-expressing cell line was able to detect 100 pg G-CSF per mi, the Ba/F3 M-CSF receptor-expressing cell line 100-400 pg M-CSF per mi and the EDC-P1 line expressing the alpha- and beta-chains of the human GM-CSF receptor detected 5-10 pg/ml of GM-CSF in test material. These cell lines appear satisfactory for use as selective bioassays for these colony stimulating factors in material potentially containing a mixture of growth factors.