To develop T-cell therapies for B-cell malignancies we have developed a chimeric antigen receptor (CAR) which when expressed on the cell surface redirects T-cell specificity for CD19, a B-lineage cell-surface antigen. We have undertaken a series of systematic experiments to improve the ability of these CAR+ T cells to persist after adoptive transfer based on conditional expression of interleukin-2 (IL-2) which is a potent cytokine that can prolong T-cell persistence. ...