Autologous T cells engineered to express an anti-CD19 chimeric antigen receptor with 4-1BB costimulatory and CD3ζ signaling domains. Upon binding CD19 on B-cell malignancies, CAR signaling triggers T-cell activation, proliferation, and cytotoxic effector functions (perforin/granzyme release and cytokine secretion), resulting in targeted lysis of CD19-positive cells and antitumor activity.