1. Center for Cellular Immunotherapies and the Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5156, USA.
2. Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA 98109, USA.
3. Division of Immunology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, Netherlands.