A second generation murine CD19 CAR with a CD28 costimulatory domain36 was retrovirally transduced into syngeneic murine T cells and administered to mice bearing E2a:PBX leukaemia following lymphodepletion (radiation or cyclophosphamide), resulting in long-term remissions with persistence of functional CAR-T cells (Supplementary Fig. 2). The gene discussed is CD28; the disease is leukemia.