Double chimeric antigen receptor (CAR) modified T lymphocyte and preparation method thereof

The invention belongs to the biotechnology field and relates to a double chimeric antigen receptor (CAR) modified T lymphocyte and a preparation method thereof. A CAR-L with low affinity and a CAR-H with high affinity are constructed, are used for identifying two tumor-associated antigens respectively, respectively contain a CD3zeta sequence and a costimulatory molecule (CM) signal sequence and are simultaneously transfected into the T lymphocyte, and the modified T lymphocyte can be effectively activated only by simultaneously identifying the two tumor-associated antigens, thus reinforcing the targeting of the CAR-T lymphocyte in killing tumors and reducing the damages to normal tissues.