Plasmid DNA vaccine vector design: Impact on efficacy, safety and upstream production

• Published in: Biotechnology advances 2009-07, Vol.27 (4), p.353-370
• Main Authors: Williams, James A., Carnes, Aaron E., Hodgson, Clague P.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Biotechnology; DNA vaccine; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Fermentation; Fundamental and applied biological sciences. Psychology; Gene Expression; Gene therapy; Genetic Therapy - methods; Genetic Therapy - standards; Genetic Vectors; Humans; Mammals; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Plasmid; Plasmids; Vaccines, DNA - genetics; Vaccines, DNA - immunology; Vector
• ISSN: 0734-9750; 1873-1899
• DOI: 10.1016/j.biotechadv.2009.02.003

Critical molecular and cellular biological factors impacting design of licensable DNA vaccine vectors that combine high yield and integrity during bacterial production with increased expression in mammalian cells are reviewed. Food and Drug Administration (FDA), World Health Organization (WHO) and European Medical Agencies (EMEA) regulatory guidance's are discussed, as they relate to vector design and plasmid fermentation. While all new vectors will require extensive preclinical testing to validate safety and performance prior to clinical use, regulatory testing burden for follow-on products can be reduced by combining carefully designed synthetic genes with existing validated vector backbones. A flowchart for creation of new synthetic genes, combining rationale design with bioinformatics, is presented. The biology of plasmid replication is reviewed, and process engineering strategies that reduce metabolic burden discussed. Utilizing recently developed low metabolic burden seed stock and fermentation strategies, optimized vectors can now be manufactured in high yields exceeding 2 g/L, with specific plasmid yields of 5% total dry cell weight.