The invention provides a CAR-NK
cell for knocking out KIR2DL5 targeting HER2 as well as a preparation method and application of the CAR-NK
cell, and belongs to the technical field of
genetic engineering.The CAR-NK
cell is obtained by adopting a
chimeric antigen receptor with HER2 as a target spot to infect an NK cell and then knocking out a KIR2DL5
gene; the
chimeric antigen receptor taking the HER2 as the target spot comprises an HER2 single-chain
antibody; the
nucleic acid artificial sequence of the HER2 single-chain
antibody is as shown in SEQ ID NO. 2. According to the application disclosed by the invention, the interaction of KIR2DL5-PVR is blocked by knocking out NK cell immune checkpoints, so that tumor
immune escape is avoided, and the activity of killing
tumor cells by CAR-NK cells is remarkably enhanced; according to the invention, by optimizing the
nucleic acid artificial sequence of HER2, the
secretion ability of CAR-NK cell factors, the tumor killing efficiency and the in-vivo inhibition effect on tumors can be improved.