Bispecific antibody targeting Frizzled-7 and PD-L1 as well as preparation method and application of bispecific antibody

The invention relates to a bispecific antibody targeting Frizzled-7 and PD-L1 as well as a preparation method and application of the bispecific antibody. The bispecific antibody is an antibody with a pestle mortar structure, which is composed of a mutant of a targeted PD-L1 antibody Atezolizumab and a mutant of a full-length antibody SHH002-hu1 of humanized anti-Fzd7, wherein the amino acid sequences of a kappa 1 light chain L1, a kappa 2 light chain L2, a heavy chain H1 and a heavy chain H2 of the bispecific antibody are respectively shown as SEQ ID NO.1-4. Compared with the prior art, the bispecific antibody prepared by the invention blocks a Wnt/beta-catenin signal channel, inhibits the proliferation, invasion and migration of Fzd7 + tumor cells and recovers the infiltration level of T cells in a tumor microenvironment by combining with an Fzd7 receptor on the surface of the tumor cells, and on the other hand, the bispecific antibody can be used for improving the immunologic activity of the tumor cells by