Expression of EPOR, G-CSFR, and their chimeric receptors EPOR/CD34 and G-CSFR/CD34 on the BaF3 or 32D or FDCP1 cell transfectants. BaF3 (a through d), 32D (e through h), or FDCP1 (i through l) cells were stably transfected with each receptor expression construct as indicated, and individual positive cell clones were selected by flow cytometry analyses. The vector-transfected cells (negative controls, open histograms) or the receptor-transfected cells (solid histograms) were stained with either anti-EPOR MoAb or the FITC-labeled G-CSF. The staining profiles of the transfected cells with an isotype-matched control MoAb are the same as those of negative controls, which are depicted as open histograms.