AAV DJ/8-GFAP-mCherry

Adeno-associated viruses (AAVs) hold promise as vectors for human gene therapy. Gene therapy involves the delivery of DNA to target cells with the goal of alleviating genetic disease or alleviating genetic susceptibility, for example, by providing a fully functional replacement for a mutated gene. Dozens of clinical trials have safely exploited the power of AAV vectors, with demonstrated efficacy in the treatment of congenital blindness and Parkinson's disease, as well as promising results in factor IX therapy for hemophilia B and other diseases.

The current study focuses on AAV-DJ, a variant that first demonstrated the value of gene shuffling in vector development. From a hybrid library of eight AAV serotypes, variants were first selected for in vitro delivery into a human hepatoma cell line (which has a low natural tolerance to AAV) and then tested for resistance to human antisera. After five passages in the presence of mixed human antisera (IVIG) with neutralizing activity against multiple serotypes, 96 clones were sequenced and enriched for a single AAV-2/8/9 chimera that had >85% sequence identity to the parental strain and differed from its closest relative (AAV-2) by 60 capsid amino acids (8%). AAV-DJ has the desired enhanced hepatocyte targeting, combining the best features of AAV-2 with those of AAV-8 and AAV-9. Like AAV-2, it is able to effectively transduce multiple cell types in vitro, but has a specific liver tropism in vivo, and like AAV-8 and AAV-9, it is better able to evade immune neutralization and effectively deliver more therapeutic DNA.