How was initial development of CAR-T cell therapy?

For cancer 1. Blood is collected from the cancer patient by leukapheresis 2. T cells are selected by purification on Ab coated beads. 3. T cells are transfected virally or nonvirally with a CAR molecule and expanded in vitro 4. Modified T-cells are reinfused to the patient with or without combined chemotherapy. 5. T cells bind to antigen-expressing tumor cells and kill them