Figure 4.

Generation of VSV-G and cocal LV packaging cell lines. (a) Diagram highlighting the steps and plasmids used toward the generation of lentiviral vector (LV) packaging/producer cell lines. Stable expression was achieved by plasmid DNA transfection followed by selection with the respective drugs. (b) LV titer determined by flow cytometry for single cocal and VSV-G packaging clones (open circles) or from bulk cells (red bar). Unconcentrated titer is given as infectious units/ml (IU/ml). (c) Unconcentrated (1×) and concentrated (100×) LV titers obtained from the best producer cocal or VSV-G clones identified in b grown in 15-cm plates. Mean titers are from one representative experiment using four different dilutions of the vector for transduction. Error bars show SE of the mean. (d) Stability of cocal and VSV-G packaging cell lines as determined by unconcentrated titers produced following long-term culture. To induce LV production, the PGK.eGFP transfer plasmid was transiently transfected into cocal or VSV-G packaging cells.