Abstract: Related is a single-domain antibody targeting 4-1BB, a fusion protein thereof, a pharmaceutical composition and a use thereof. Specifically, the related single-domain antibody comprises one heavy chain variable region, and the amino acid sequences of CDR1-CDR3 contained in the heavy chain variable region are as shown in any item in table B, respectively. The single-domain antibody can bind to human 4-1BB and at the same time cross-bind to cynomolgus 4-1BB; in addition, with the help of external cross-linking, T cells are activated, which have excellent anti-tumor activity and safety.

Abstract: The invention relates to a novel antibody and an antibody fragment thereof specifically binding to a B-cell maturation antigen (BCMA), and particularly relates to a fully humanized single-chain variable fragment (scFv). The invention further relates to a nucleic acid encoding the antibody, a vector, and a host cell expressing the nucleic acid. Furthermore, the invention also relates to a composition containing the antibody described herein, and use thereof in treatment and diagnosis.

Abstract: The present invention relates to an anti-4-1BB-anti-PD-L1 bispecific antibody, and a pharmaceutical composition and the use thereof. Specifically, the present invention relates to a bispecific antibody, which comprises a first protein functional region targeting 4-1BB and a second protein functional region targeting PD-L1 or PD-1, wherein the first protein functional region is a single-domain antibody against 4-1BB; and the second protein functional region is an anti-PD-L1 antibody, anti-PD-1 antibody, anti-CTLA-4 antibody or anti-HER-2 antibody, or an antigen-binding fragment thereof. The bispecific antibody has the function of blocking the binding of PD-L1 to a receptor PD-1, and binds to 4-1BB on an immune cell, such that the immune cell activity in a tumor microenvironment is activated and the effect of inhibiting tumor occurrence and development is improved more effectively.

Abstract: Provided is a complementary determining region (CDR) of a VHH chain of an anti-PD-L1 single-domain antibody, wherein the CDR of the VHH chain includes the following: CDR1 with an amino acid sequence as shown in SEQ ID NO:5n+1; CDR2 with an amino acid sequence as shown in SEQ ID NO:5n+2, or CDR2 with an amino acid sequence having an sequence identity of greater than 85% with a sequence as shown in SEQ ID NO:2; and CDR3 with an amino acid sequence as shown in SEQ ID NO: 5n+3; wherein, each n is independently 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15.

Abstract: The invention relates to a novel antibody and an antibody fragment thereof specifically binding to a B-cell maturation antigen (BCMA), and particularly relates to a fully humanized single-chain variable fragment (scFv). The invention further relates to a nucleic acid encoding the antibody, a vector, and a host cell expressing the nucleic acid. Furthermore, the invention also relates to a composition containing the antibody described herein, and use thereof in treatment and diagnosis.