Adenoviral and AAV-Mediated Gene Transfer to the Inner Ear: Role of Serotype, Promoter, and Viral Load on In Vivo and In Vitro Infection Efficiencies

The lack of effective treatments for many forms of hearing and vestibular disorders has produced interest in virally mediated gene therapies. However, to develop a gene therapy strategy that would successfully treat inner ear disorders, appropriate viral vectors capable of transfecting cochlear and support cells must be identified. While virally mediated gene transfer into the inner ear has been accomplished using herpes simplex type I virus, vaccinia virus, retroviruses, adenovirus, and adeno-associated virus (AAV), we will restrict our discussion to AAV and adenoviral vectors. Issues such as vector toxicity and load, viral serotype and backbone, and promoter specificity are discussed and contrasted for both in vivo vs. in vitro inner ear gene transfer.