The invention discloses a low-
immunogenicity iPSC
cell based on B2M
gene knockout and HLA-E
fusion protein knockin as well as a preparation method and application of the low-
immunogenicity iPSC
cell. According to the invention, a double-stranded
DNA template containing HLA-E
fusion protein is knocked into a B2M
gene knockout site in a targeted manner, and meanwhile, a B2M
signal peptide coding sequence is reserved. The double-stranded
DNA template of the HLA-E
fusion protein sequentially comprises a B2M left homologous arm, a CW3
enhancer, a G4S joint, a B2M non-
signal peptide, a G4S joint, an HLA-E non-
signal peptide, a bGH
polyadenylic acid signal and a B2M right homologous arm from upstream to downstream. The sequence of a left homologous arm of the B2M is SEQ ID NO: 12; the sequence of the CW3
enhancer is SEQ ID NO: 13; the sequences of the two discontinuous G4S joints are both SEQ ID NO: 14; the sequence of the B2M signal-free peptide is SEQ ID NO: 15; the sequence of the HLA-E non-
signal peptide is SEQ ID NO: 16; the sequence of a bGH
polyadenylic acid signal is SEQ ID NO: 17; and the sequence of the right homologous arm of the B2M is SEQ ID NO: 18. The left homologous arm and the right homologous arm are used for determining the position of a double-stranded
DNA template, the DNA of the left homologous arm is homologous with the 5'end sequence of a targeted DNA incision through fixed-point knock-in, and the DNA of the right homologous arm is homologous with the 3 'end sequence of the DNA incision.