Fig. 4 Transfection efficiencies of dendritic poly(L-lysine)s into CHO cells (A) and cytotoxic activity of KG6 (B). (A) The cells were incubated with DNA-complex containing 2.5 ƒĘg of plasmid DNA and dendritic poly(L-lysine) at a C/A ratio of 4.0 for 3 h at 37Ž. Harvesting of the cells and luciferase assays were performed 48 h after transfection. (B) Cytotoxic activities of KG6 and SuperFect^R alone and their complexes with plasmid DNA at a C/A ratio of 4.0. Cell viabilities were evaluated by MTT assay. Open bar indicates cell viability in the presence of the plasmid DNA alone.