990. Transduction of Pancreatic Islets with Pseudotyped Adeno-Associated Virus: Effect of Viral Capsid

Abstract

Recombinant adeno-associated viral (rAAV) vectors currently show promise for islet gene therapy. In the presence of complementing AAV2 Rep proteins, AAV2 genomes can be pseudotyped with other serotype capsids to assemble infectious virions. Using this pseudotyping strategy, AAV2 genomes carrying the GFP reporter gene were encapsidated into AAV1, AAV2, and AAV5 capsids. The utility of cross-packaged AAV1, AAV2, and AAV5 capsid-mediated transduction to murine and human pancreatic islets was evaluated. These pseudotyped rAAV vectors all showed some ability to transduce both human and murine pancreatic islets. The transduction efficiency of rAAV vector was dependent on the cross-packaged capsid. Pseudotyped rAAV2/1 based vectors transduced murine islets at greater efficiency than either rAAV2/2 or rAAV2/5 vectors. For human islet transduction, the rAAV2/2 vector was more efficient than rAAV2/1 or rAAV2/5 vectors. The vector capsids permit species specific transduction. rAAV2/2 transduced human islets more efficiently than murine islets, while rAAV2/1 transducted murine islets more efficiently than human islets. Pseudotyped rAAV transduced islet grafts maintained normal function in vitro, reversed diabetes in vivo, and expressed transgenic product persistently in vivo. These studies provide a methodologic framework for evaluating the function of pseudotyped rAAV.