| abstract |
The present invention provides an antibody or an antigen-binding fragment thereof that binds to CD25 and its use in the preparation of a cancer therapeutic drug, the antibody or its antigen-binding fragment comprising a light chain variable region and a heavy chain variable region containing a specific complementarity determining region sequence Area. The antibody or antigen-binding fragment has one or more of the following advantages: enhanced CD25 protein binding ability, enhanced CD25 protein affinity, enhanced CD25-expressing cell killing ability, reduced PBMC activation inhibition, enhanced in vivo tumor growth inhibition ability, enhanced tumor killing in vivo, enhanced ability to reduce Treg cell numbers, or enhanced ability to increase effector T cell numbers. |