CpG REDUCED PLASMIDS AND VIRAL VECTORS

摘要

Unmethylated plasmid DNA vectors are a major contributor to the inflammatory response associated with gene delivery. Results of clinical studies where CF subjects were subjected to either aerosolized liposomes alone or cationic lipid:DNA complexes indicated that bacterial derived plasmid DNA may be inflammatory. Additionally, unmethylated CpG dinucleotides have been shown to be immunostimulatory and are present at a much higher frequency in bacterially-derived plasmid DNA compared to vertebrate DNA. The invention provides for methods of modulating the immunostimulatory response to gene delivery by modifying the plasmid delivered to the cell. The plasmid is modified to reduce or eliminate the immunostimulatory response in order to preserve the efficacy of gene transfer but reduce the associated toxicity. In a preferred embodiment, the invention provides for a method of reducing inflammatory response to gene delivery by methylating CpG motifs of the plasmid vector and/or removing CpG motifs of the plasmid vector.