High-Titer Stocks of Adeno-Associated Virus from Replicating Amplicons and Herpes Vectors

The adeno-associated virus (AAV) is a nonpathogenic member of the Parvoviridae family (for review,see ref. 1 ) Recently this virus has gained considerable interest and has been developed as a gene delivery vector (2 ). Six primate AAV serotypes (designated AAV types 1–6) have so far been identified and characterized in the literature (3 ,4 ). The most extensively studied of these isolates is AAV type 2. The vast majority of the transduction studies have been carried out using recombinant vectors (rAAV) based on serotype 2. These studies have shown that rAAV2 has the ability to transduce a wide range of both dividing and nondividing cells, achieving efficient long-term gene expression in vivo in a variety of tissues including retina (5 ), muscle (6 ), central nervous system (7 ), and liver (8 ). The range of tissues transduced by recombinant AAV vectors based on other serotypes is currently being investigated by several laboratories (9 ). It is hoped that rAAV vectors produced from these serotypes may prove to be useful for the transduction of tissues that are poorly infected by AAV2.