7.1.3 Adeno Associated Viruses AAV

This type requires coinfection with either adenovirus or herpes simplex virus (HSV). The genome is double stranded DNA molecule and contains a palindrome sequence at each end, referred to as inverted tandem repeats (ITR). These ITR are important for integration to a specific site on chromosome No. 19 in human.  AAV have advantages over other virus system in that they are not naturally pathogenic, they are capable of infecting nondividing cells, they show longer lasting expression (up to 6 months in animal models) in addition to its specificity to integrate to specific sites on chromosome 19. They also lack of initiating and immune response. Unfortunately, they cannot incorporate genes larger than 5kb. Several trials for cystic fibrosis gene therapy have been carried out using this vector.