Minicircle-DNA

Abstract

The use of plasmid DNA in clinical applications is anticipated to increase significantly in the years to come as DNA vaccines and non-viral gene therapies have entered phase three clinical trials and are already approved for use. Therefore, employing appropriate plasmids that are specifically suited for the production of DNA pharmaceuticals becomes an aspect of major importance. Especially safety issues have to be carefully reconsidered and adequately addressed. The presence of bacterial backbone sequences in conventional plasmids is one of the major drawbacks in this regard. These sequences reduce the overall efficiency of the DNA agent and, most important, they represent a biological safety risk in clinical applications. Typically, bacterial backbone sequences consist of an antibiotic selection marker, an origin of replication and unmethylated bacterial CpG motifs. This report gives a short introduction in problems and drawbacks associated with these elements and focuses on the production of plasmid derived DNA agents devoid of bacterial backbone sequences by site-specific recombination and subsequent purification by DNA interaction affinity chromatography (minicircle-DNA).