Abstract: Provided is an anti-B7-H4 antibody containing a VH, wherein the VH contains the following CDRs or a mutation thereof: CDR1 as shown in the amino acid sequence of SEQ ID NO: 4 or 5, CDR2 as shown in the amino acid sequence of SEQ ID NO: 15, and CDR3 as shown in the amino acid sequence of SEQ ID NO: 24 or 25, and wherein the mutation is an insertion, deletion or substitution of 3, 2 or 1 amino acid(s) in the amino acid sequences of the CDRs. The antibody has the activity of binding to human B7-H4 and cynomolgus monkey B7-H4. The antibody still retains the activity of binding to human B7-H4 and cynomolgus monkey B7-H4 when prepared into a B7-H4×CD3 bispecific antibody, and has a strong killing effect on tumor cells. The antibody induces a very low expression of nonspecific cytokines such as IL-6 and IFN-?, and exhibits a strong in vivo anti-tumor activity.

Abstract: Provided are a B7H4-targeting antibody or a variant thereof, and a bispecific antibody containing the B7H4-targeting antibody, wherein the B7H4-targeting antibody comprises a light chain variable region and a heavy chain variable region. The variant has an amino acid mutation in the light chain variable region or heavy chain variable region of the antibody and can maintain the function of the antibody. The B7H4-targeting antibody has the activity of binding to human B7H4 and cynomolgus macaque B7H4, and does not cross-react with other B7 family members. The B7H4-targeting antibody exhibits good anti-tumor activity, T-cell activation activity and internalization activity in in-vivo and in-vitro experiments, and is more suitable for use as an ADC drug. Further provided is a bispecific antibody targeting B7H4 and CD3, which has a longer half-life, retains good stability and hydrophilicity, and reduces toxicity while ensuring efficacy.