Figure 6
From: Design of a trans protease lentiviral packaging system that produces high titer virus
Titer results for the 5, 6, and 7 plasmid systems with the SIN lentiviral vector. (A) Diagram showing the structure of the SIN lentiviral vector which contains the following safety features: a 400 bp deletion in the U3 region of the 3' LTR, a complete deletion of the 3' LTR U5 region replaced by an ideal termination/polyadenylation sequence, and two stops placed within the packaging signal (Ψ) to prevent the production of unwanted transcripts. This vector also contains an unmodified 5' LTR, the central polypurine tract, RRE, and GFP driven by an EF1α promoter. (B) NIH3T3 and Jurkat cells were infected with serial dilutions of viral supernatants produced using a SIN lentiviral vector along with the 5, 6, or 7 plasmid packaging systems. Titers were determined by monitoring transduced cells for the production of GFP by FACS. For NIH3T3 cells the mean titer with the 5 plasmid system, shown in blue, was 3.1 × 106 TU/ml, the 6 plasmid system, shown in green, 3.4 × 105 TU/ml, and the 7 plasmid system with and without the optimized Gag, shown in light and dark pink, 6.0 × 105 TU/ml, and 1.0 × 106 TU/ml, respectively. ** p = 0.009 (6P versus 7P-Opt), *** p < or = 0.0002 (6P versus 7P, 7P-Opt versus 7P, 5P versus 6P, and 5P versus 7P-Opt, 5P versus 7P). For Jurkat cells the mean titer for the 5 plasmid system, shown in blue, was 2.5 × 107 TU/ml, the 6 plasmid system, shown in green, 2.7 × 106 TU/ml, the 7 plasmid system with and without the optimized Gag, shown in light and dark pink, 5.5 × 106 and 6.9 × 106 TU/ml, respectively. * p = 0.01 (6P versus 7P-Opt), *** p < 0.0001 (6P versus 7P, 5P versus 6P, and 5P versus 7P-Opt, 5P versus 7P). Error bars represent SEM, data represents 6 independent experiments (N = 6), statistical analysis was determined by unpaired t-test using Prism 4 software.