Adeno-associated virus (AAV) vectors in gene therapy

Viral vectors based on the adeno-associated virus (AAV) hold a great promise in the gene therapy field, given a number of unique features they potentially display. Among the appealing features of wild type AAV, are the absence of pathogenic effects in humans, the broad tissue tropism, the resistance to solvents and to extreme conditions of pH and temperature, the capacity of infecting both dividing and quiescent cells, and the capacity of integrating in a specific site of human chromosome 19. With this respect, the first applications of these vectors for gene transfer of therapeutic genes appear very promising. However, several open questions still need to be addressed, mostly concerning the elucidation of the molecular requirements for infectiveness, the identification of the cellular proteins which mediate viral replication and site-specific integration, and the development of stable packaging cell lines for the preparation of high titer viral stocks.