1. Department of Pediatrics and Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA.
2. Howard Hughes Medical Institute, Philadelphia, PA 19104, USA.
3. Gene Therapy and Vaccine Program, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
4. Department of Pediatrics, Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.