Adenoassociated Virus Vectors
Adenoassociated virus (AAV) based vectors are derived from a non-pathogenic parvovirus. AAV are thought to be naturally defective, because of their requirement for co-infection with a helper virus, such as Ad or HSV, for a productive infection. The single stranded 4.7 kB DNA genome is packaged in a 20 nm particle. AAV is not associated with any known disease and induces very little immune reaction when used as a vector. For applications requiring a relatively small transgene, AAV vectors are very attractive, but the small insert capacity limits their utility for applications requiring a large transgene.