Abstract: The present invention provides an antibody binding a human tumor-associated calcium signal sensor 2 (Trop-2) protein or fragments thereof, and use of the antibody or fragments thereof in preventing or treating diseases. The antibody or fragments thereof of the present invention can effectively bind to the human Trop-2 protein, and have internalization activity, and the internalization activity is enhanced after ADC drug labeling, and the in vivo efficacy and safety of a mouse model are not lower than those of a control antibody.

Abstract: Provided are an antibody and a preparation method therefor. The antibody is, such as a humanized anti-human CD47 monoclonal antibody or fragment thereof, and a bispecific antibody targeting PD-L1 and CD47 or an antigen-binding fragment thereof. The bispecific antibody comprises two heavy chains and two light chains, variable regions of the two heavy chains are heterologous, and variable regions of the two light chains have similar sequences. The provided bispecific antibody has the light chains having the similar sequences, thus solving the technical problem of light and heavy chain mismatch during an assembly process of bispecific antibodies.

Abstract: In view of the technical problem that TGF-? RH and a fusion protein thereof are prone to degradation and breakage during the process of recombinant expression, provided are a TGF-? RII mutant and a fusion protein thereof. Compared with the extracellular region of the wild-type TGF-? RII of SEQ ID NO: 6, the TGF-? RII mutant has a mutation selected from Gln at position 6, Asp at position 12 and Gly at position 20. The TGF-? RII mutant is capable of binding to TGF-?. Compared to wild-type TGF-? RII, the TGF-? RII mutant has less breakage and/or degradation during recombination expression. It is convenient for large-scale production of antibodies/the TGF-? RII bifunctional protein with a more stable quality.

Abstract: Provided are a single variable domain antibody targeting a human programmed death ligand 1 (PD-L1) and a derivative thereof. A single variable domain antibody 2-2F2 specific for human PD-L1 is identified and obtained by extracting PBMCs from a camel immunized with human PD-L1, constructing a phage surface displayed VHH antibody library, and screening said VHH antibody library. On said basis, a chimeric antibody chF2 and a humanized modified antibody hzF2 variant are prepared. The hzF2 variant possesses affinity comparable or even superior to that of the original single variable domain antibody 2-2F2, can block the binding of PD-1 to PD-L1 in vitro, and can inhibit tumor growth in an in vivo experiment on tumor-bearing mice.

Abstract: The present invention provides an antibody binding to programmed cell death protein 1 (PD-1) or a fragment thereof and a use of the antibody or a fragment thereof in preventing or treating a tumor or cancer. The antibody or a fragment thereof of the present invention can effectively block the interactions of PD-1/PD-L1 and PD-1/PD-L2 and has a unique antigen binding epitope and unique properties in terms of efficacy and safety.