Directed Evolution of AAV Mutants for Enhanced Gene Delivery

Gene therapy vehicles must be engineered to overcome numerous barriers that limit delivery efficiency. These barriers arise at every step of the delivery process, including the transit of the vector from injection to a cell surface, re ceptor binding and uptake, intracellular trafficking, and nuclear entry. The gene transfer properties of the highly promising adeno-associated viral (AAV) vector at each step are determined by its capsid structure. Previous capsid modifications that alter AAV tropism, as well as the existence of multiple AAV serotypes, suggests that the AAV capsid is reasonably plastic. We have taken advantage of this remarkable capsid plasticity to generate a large mutant AAV library