90. Evaluation of Novel Gene Transfer Vectors Derived from Infectious Molecular Clones of Primate AAVs

We recently isolated and characterized a diverse array of novel primate AAVs from human and nonhuman primate (NHP) tissues through either PCR-based molecular rescue of proviral sequences or direct rescue and cloning of infectious virus genomes from tissues or primary cell cultures. In the present study, we focus on evaluating gene transfer vectors derived from infectious molecular clones of novel primate AAVs. Our study revealed that, in comparison with recombinant AAV2 genomes, packaging efficiency of recombinant AAV8 and AAVrh.39 genomes was significantly reduced, when trans-plasmids carrying both rep and cap genes from AAV8 and AAV rh.39, respectively, and Adhu5 helper plasmid were used for triple transfection of 293 cells. We speculated that incompatibility between replication and packaging of those novel primate vectors and helper gene functions from Adhu5 could be one of the causes for the deficiency. Identification and optimization of appropriate helper adenovirus with most likely a simian origin could be one of the strategies to overcome the packaging difficulty.