The invention belongs to the technical field of
biology, and discloses a polypeptide containing two
chimeric antigen receptor structures,
nucleic acid for coding the polypeptide, a modified
T lymphocyte, and a preparation method and application of the
T lymphocyte. The polypeptide provided by the invention contains the two
chimeric antigen receptor (CAR) structures, wherein one
chimeric antigen receptor structure specifically targets a tumor
cell, and the other one specifically targets a normal B
lymphocyte, so that a CAR-
T cell is effectively amplified through recognizing the B
lymphocyte ofa
blood circulation system, and more CAR-T cells arrive at a
solid tumor part so as to specifically kill the tumor
cell for improving a
treatment effect on the
solid tumor. The polypeptide further comprises an ScFv structure of an anti-PD-L1
monoclonal antibody, and the CAR-T cells can simultaneously secrete a PD-L1
monoclonal antibody which interdicts an immunosuppressive action medicated by a PD1 / PDL1
signal pathway and
T cell failure, so that the
treatment effect on the
solid tumor is improved, the
functional activity of immune cells
in vivo is prolonged at the same time, and finally the
tumor recurrence is retarded and even avoided.