Figure 1.

Enhanced transduction efficiency of lentivirus-based vectors coprecipitated on 293T cells. A Effect of CaCl₂ concentration. To achieve the desired concentration 2 M CaCl₂ was added. Standard conditions for this study were 60 min for formation of lentivirus and calcium phosphate (CaPi) complex before addition to cells, and application of lentivirus-based vectors with or without CaPi coprecipitates to cells for 120 min. B Effect of duration of complex formation before addition to cells. Lentivirus-based vectors and CaPi complex were incubated for various durations before they were applied to cells. Standard conditions for this study were a CaCl₂ concentration of 4 mM and exposure of cells to lentivirus-based vectors CaPi coprecipitates for 120 min. C Effect of serum. Lentivirus-based vectors with CaPi coprecipitates were formed in the presence (+) or absence (−) of 10% fetal calf serum. Standard conditions for this study were 4 mM CaCl₂ and 60 min of complex formation. Coprecipitates were applied to cells for 120 min. Transduction efficiency was determined as described in the Methods section. Values are expressed as mean ± SE of three independent experiments. TU Tranducing units