How to successfully screen random AAV display peptide libraries in vivo

Adeno-associated virus (AAV) has emerged as a very promising gene therapy vector. To enable tissue-directed gene expression, many artificially generated AAV variants have been established, often isolated from large pools of mutated capsids. Random peptide libraries displayed on AAV capsids have been used successfully to select vectors targeted to a given target cell or tissue in vitro and in vivo. However, the published methodology for screening of AAV libraries to isolate vectors with selective tissue tropism after intravenous administration in vivo has not been described in sufficient detail to address all critical steps. A step-by-step protocol is provided here.