Tropism-modified adenoviral and adeno-associated viral vectors for gene therapy

One of the most rapidly advancing areas of gene therapy is vector development. For the majority of gene therapy procedures, efficient and selective transduction would provide safe and more effective treatments at optimal vector doses. Advances in vector targeting strategies have been rapid within the field of DNA-based viruses, particularly adenovirus (Ad) and more recently adeno-associated virus (AAV) based vectors. Vector targeting at the level of virus: cell interaction can be achieved using both non-genetic and genetic methodology. Non-genetic approaches typically utilise bispecific antibodies that both neutralise wild-type virus tropism and provide a new cell binding capacity. For genetic targeting strategies, the virus capsid can be engineered to express foreign ligands that target selected receptors in the absence or presence of additional modification to ablate the virus' natural tropism. This review covers technological advances that have led to targeting of Ad and AAV and highlights the potential for these 'designer' viruses for future gene-based therapeutics.