What Makes an "Ideal" Cell Line for Recombinant Adeno-Associated Virus Production?

Recombinant adeno-associated viruses (rAAVs) have been utilized extensively as the vector-of-choice for in vivo delivery of gene therapy products. Nonetheless, there are several disadvantages associated with current rAAV production systems, as they struggle to meet ever-growing clinical demands. To date, eight different host cell systems have been used to produce rAAVs, with particular cell lines possessing characteristics that make them more suitable for rAAV manufacturing than others. These traits, along with other modifications that have been shown to improve rAAV productivity, are reviewed here to develop a consensus on what an "ideal" cell line for rAAV production might look like. In doing so, we describe traits that will help to identify and deliver novel host cell systems that can support the widespread adoption of rAAV-based gene therapy products.