Applications of rAAV
rAAV as Research Tool
In vivo Over-expression
rAAV was first used to deliver a neomycin resistant gene into mammalian cells. Afterward, rAAV has been used in research as a gene transfer tool. Over-expression of a target gene in mammalian cells via rAAV has a unique advantage. For example, rAAV can obtain long-term expression without genome-integration in vivo, whereas lentivirus has limited tissue tropism and raises the concern of genome-integration, though it can express genes long term. Adenoviruses are transient expression vectors but it often causes severe immune response, which may affect or hide the correct phenotype of the transgene. In contrast, rAAV can transfer target genes into almost all tissues in animals depending on different serotypes and promoter-specificity. After the realization that synthesis of complemented second-strand of AAV is the bottle-neck for in vivo transduction efficiency, McCarty and colleagues invented a double-stranded (self-complementary) AAV, which contains a modified ITR unable to be cut by Rep protein; in turn the self-complementary single stranded DNA can form the double-stranded DNA [ 1 ]. We generated “K” serial ssAAV entry vectors with 14 kinds of promoters for targeting universal or specific organs or cell types, and “KD” serial dsAAV (scAAV) with 12 kinds of promoter to drive customized genes.
In vivo Knock-Out
In vivo Activation
In vivo Knock-Down
rAAV as Clinical Trials Vector for Gene Therapy
The first rAAV clinical success came from several groups that used rAAV-rpe65 to cure Leber congenital amaurosis (LCA) caused by homozygous recessive rpe65 deficiency . After the rAAV-RPE65 was injected sub-retinally into one eye of each patient, significant recovery of vision was observed in some of them.
Currently, world-widely more than 200 clinical-trials are completed or ongoing.
For a complete list of rAAV clinical trials, please click the below weblink
2. Terence R Flotte, et al., Human gene therapy 7 (9), 1145-1159 (1996)
3. WW Hauswirth et al., Human gene therapy 19 (10), 979-990 (2008)