Large-Scale Generation of Plasmids that Express Type I Interferon

Large-scale preparations of plasmid DNA encoding cytokine cassettes are continuously gaining in importance in many areas of gene-therapy (1 ) including DNA vaccinations with plasmid cytokine adjuvants (2 –4 ), tumor research (5 ), and treatment of infectious diseases (6 ,7 ). Small-scale plasmid preparations (approx 10–100 μg DNA) usually result in adequate yields, whereas large-scale (>1 mg DNA) preparations of plasmid DNA can result in disproportionally small yields of DNA. We have found that using Terrific broth (TB) rather than Luria-Bertani (LB) broth in available kits significantly (approx fivefold) increases plasmid DNA yields (see Note 1 ). This suggestion is especially true for low or very low copy plasmids. In this chapter, we give an overview of different plasmid purification techniques commonly used, and describe advantages and disadvantages for each method.