Effect of expression of hGMβcchimera with or without hβc in FDCP-mix cells.
(A) Analysis of receptor subunit expression. Parental and hGM/βc transfected cells were analyzed for expression of the extracellular domain of the (i) hGM Rα and (ii) hβcsubunit using a 2-step labeling procedures and flow cytometry. The solid gray histogram represents the cell autofluorescence obtained in the absence of antibody staining. Representative histograms are shown for labeling obtained in the presence of secondary antibody only (gray) and in the presence of both primary and secondary antibody (black). (B) Effects on cellular proliferation. Cells expressing hGM/βc (○) and hGM/βc, hβc(●) were cultured in hGM-CSF (1 ng/mL) for 14 days. Cellular viability was assessed at intervals and the results are expressed as viable cell number (× 105/mL) and are mean ± SEM from 3 experiments. The results obtained with the wild-type hGM Rα,βc are shown for comparison (■). (C) Effect of activation of hGM/βc expressed alone or in combination with the hβc subunit on cell morphology. (i) hGM/βc cells, (ii) hGM/βc,hβc, and (iii) wild-type hGM Rα, hβc were cultured in hGM-CSF (1 ng/mL) for 7 days and photomicrographs were prepared following May-Grünwald-Giemsa staining of cytospin preparations. The morphology of cells cultured in the presence of murine cytokines (G/M Diff conditions), which promote myeloid development, are shown for comparison for (iv) hGM/βccells and (v) hGM/βc,βc and (vi) wild-type hGM Rα, hβc. Results are shown from an experiment representative of 3. Bar is 10 μm.
