The combination cDNA/genomic TH gene therapy was further investigated with THLs carrying

both 877 and prgTH3 plasmids (Figures 5(b) and 5(c)). The striatal TH enzyme activity was significantly higher with the combination gene therapy as compared to clone 877 alone at 10 days after injection, and it was significantly higher as compared to Inhibitors,research,lifescience,medical prgTH3 alone at 3 and 6 days after injection (Figure 5(b)). The combination therapy also produced a parallel reduction in apomorphine rotation behavior (Figure 5(c)). The rotation behavior was significantly reduced with combination gene therapy as compared to clone 877 alone at 10 days after injection, and it was significantly reduced as compared to prgTH3 alone at 3 days after injection. Table 3 Tyrosine hydroxylase (TH) in Inhibitors,research,lifescience,medical brain and apomorphine-induced contralateral rotation after intravenous injection of gene therapy with TH expression plasmids. In summary, combination gene therapy is superior to single cDNA gene therapy. The combination gene therapy using both short-acting cDNA-derived TH transgene and long-acting genomic-derived TH transgene provides a more sustained therapeutic Inhibitors,research,lifescience,medical duration in experimental PD as compared to single gene therapy using either cDNA-derived

or genomic-derived transgene. 6. Long-Term Treatment with THL Akt inhibitor Plasmid DNA-based gene therapy with THL technology involves episomal gene expression and must be given on a chronic basis, which raises concerns about potential toxic side effects

from chronic repeat THL dosing. A 6-week toxicological study was conducted with Inhibitors,research,lifescience,medical repeated weekly intravenous administration of THLs carrying a 7kb expression plasmid encoding for rat TH and targeted with either the OX26 MAb to the rat TfR or with the mouse IgG2a isotype control antibody [49]. Animals were divided into 3 treatment groups: (a) saline, (b) 5ug DNA/week of the THLs targeted with the TfRMAb, and (c) 5ug DNA/week of the THLs targeted with Inhibitors,research,lifescience,medical the nonspecific isotype control IgG2a antibody. At the end of 6 weeks of chronic weekly treatment, there was no measurable differences in the 3 groups with respect to body weights, 14 serum chemistries (Table 4), or organ histology of brain, liver, spleen, kidney, heart, or lung. The immunocytochemistry showed no evidence of inflammation in brain using out antibodies that react with multiple components of the immune system [49]. These results demonstrate the lack of toxicity of chronic dosing of MAb-targeted THLs carrying plasmid DNA. Table 4 Summary of serum chemistry in long-term treatment with THLs. 7. Formulation of THL The efficiency of gene delivery to the brain and gene expression in target cells with THLs may be potentially enhanced by optimizing the formulation of THLs.