Abstract: Disclosed are an anti-B7-H7 antibody or an antigen-binding fragment thereof, a preparation method therefor and the use thereof. The anti-B7-H7 antibody or antigen-binding fragment thereof of the present invention has high affinity and high biological activity for B7-H7, and can effectively block the binding of B7-H7 to a receptor CD28H thereof and the binding of B7-H7 to a receptor KIR3DL3 thereof; furthermore, the anti-B7-H7 antibody or antigen-binding fragment thereof only specifically binds to B7-H7 without cross-reacting with other member proteins of the B7 family, and has good stability; in addition, the anti-B7-H7 antibody or antigen-binding fragment thereof shows strong in vivo anti-tumor activity.

Abstract: Provided are a bispecific antibody and use thereof. The bispecific antibody comprises a B7-H4-targeting antigen-binding domain and a 4-1BB-targeting antigen-binding domain. The bispecific antibody has one or two or three sites for binding to 4-1BB, along with a novel fully human B7-H4 antibody. The bispecific antibody specifically binds to tumor cells by targeting B7-H4, reducing toxicity induced by 4-1BB activation. In addition, the bispecific antibody of the present invention comprises a human Fc fragment, and thus retains the binding of Fc to FcRn and has a longer half-life.