Abstract: In the discovery phase of IL-5-targeted drugs, in order to assess the blocking activity of the drug candidates, it is necessary to establish a cell line with high signal-to-noise ratio and good reproducibility for the assay depending on IL-5 proliferation. TF-1 growth is completely dependent on IL-3 or GM-CSF, while IL-5 shares βc receptors with IL-3 and GM-CSF. GM-CSF-dependent TF-1 cell line was used in this study. GM-CSF, a growth factor essential for TF-1 cell growth, was replaced with IL-5, and the serum content was reduced for cell domestication and culture passaging. By 35 days of cell domestication and 3-5 times of reduced FBS passages in culture, 14 monoclonal cell lines were obtained by the limited dilution method. FACS assays were performed on 14 cell lines, 9 of which had elevated IL-5Rα expression. IL-5 proliferation assay was performed on the cell lines with IL-5Rα overexpression, and the results showed that monoclonal clones obtained with 6% FBS were more sensitive to IL-5 stimulation compared to monoclonal clones obtained with 8% FBS. The optimal cell number for the cell proliferation assay was 2×104cells/well, the brand of FBS was Gibco at a concentration of 3%. The signal-to-noise ratio and Emax of dose-response curve of IL-5-dependent TF-1 cells against IL-5 were 3.19 and 2.15 respectively. The TF-1-9E3 could be used for the biological activity assay of IL-5 and blocking assay of IL-5 and IL-5Rα.

Key words: IL-5, TF-1细胞, 增殖, 阻断活性, 细胞驯化