Abstract: The present application provides a multispecific antibody and preparation method and use thereof. The multispecific antibody comprises: a) a Fab fragment specifically binding to a first antigen, wherein the Fab fragment consists of a light chain and CH1 and a variable region of a heavy chain; b) a first peptide linker with the N-terminal end fused to the heavy chain; c) a second peptide linker with the N-terminal end fused to the light chain, wherein only one disulfide bond can be formed between the first and the second peptide linkers, and each of the first and the second peptide linkers is independently selected from the group consisting of a peptide linker comprising any of the sequences as set forth in SEQ ID NO.1-2, wherein X represents any amino acid other than Cys, or is absent.

Abstract: Provided are an anti-claudin 18.2 (CLDN18.2) antibody and use thereof. Also provided are a chimeric antibody and a humanized antibody of the anti-CLDN18.2 antibody. These antibodies have high affinity for human CLDN18.2 proteins, and are promising antibody molecules for preventing and/or treating CLDN18.2 related diseases, such as CLDN18.2-related tumors.

Abstract: The present application provides a multispecific antibody and preparation method and use thereof. The multispecific antibody comprises: a) a Fab fragment specifically binding to a first antigen, wherein the Fab fragment consists of a light chain and CH1 and a variable region of a heavy chain; b) a first peptide linker with the N-terminal end fused to the heavy chain; c) a second peptide linker with the N-terminal end fused to the light chain, wherein only one disulfide bond can be formed between the first and the second peptide linkers, and each of the first and the second peptide linkers is independently selected from the group consisting of a peptide linker comprising any of the sequences as set forth in SEQ ID NO.1-2, wherein ×represents any amino acid other than Cys, or is absent. The antibody can be readily produced by recombinant expression and can simultaneously target two different antigens or different epitopes of the same antigen, or multiple epitopes of more different antigens.

Abstract: The present application provides a fusion protein, a method for preparing such fusion proteins and use thereof. The fusion protein comprises a Fab fragment capable of binding specifically to 4-lBB molecules and comprises CD40L capable of binding specifically to CD40 molecules; the N-terminus of the first CD40L is connected to the C-terminus of the light chain or heavy chain of the Fab fragment by means of a first peptide linker. The fusion protein of the CD137 antibody and CD40L of the present application is capable of binding specifically to CD40, has the effects of inducing dendritic cell maturation, activating lymphocytes, etc., and can be used for treating tumors and immune-related diseases; Meanwhile, the fusion protein of the CD137 antibody and CD40L can target 4-lBB and activate the signal transduction pathway of 4-lBB to enhance immune responses.

Abstract: The present application provides a fusion protein, containing: an anti-CD137 antibody capable of specifically binding to a CD137 molecule or an antigen binding fragment thereof; an anti-CD3 antibody capable of specifically binding to a CD3 molecule or an antigen binding fragment thereof; and a first peptide linker and a second peptide linker. The present application also provides a nucleic acid encoding the fusion protein, an expression vector containing the nucleic acid, a host cell containing the nucleic acid or the expression vector, a method for preparing the fusion protein, a pharmaceutical composition containing the fusion protein, and a use of the fusion protein.