Abstract: Provided is an anti-CD3 antibody or antigen-binding fragment thereof specifically binding to human and non-human primate CD3. The anti-CD3 antibody or antigen-binding fragment thereof has increased or decreased affinity and can achieve the purpose of increasing drug efficacy or reducing toxicity. When forming a bispecific antibody, selective adaptation can be performed according to different targets, providing a flexible adaptation scheme for drug development. In addition, provided are a conjugate, fusion, bispecific antibody, or pharmaceutical composition of the anti-CD3 antibody or antigen-binding fragment thereof. Further provided are a nucleic acid encoding the antibody, a host cell comprising the nucleic acid, a method for preparing the antibody, and a use of the foregoing CD3-binding antibody in preventing or treating cancer, an infectious disease, or an autoimmune disease in a subject.

Abstract: The invention relates to a method for preparing a homodimer protein mixture by using repulsive interaction of charges. The method comprises the step of replacing part of residues with the opposite-charged residues, so that different proteins or antibodies are unfavorable to forming heterodimers due to the repulsive interaction between like charges, while same proteins or antibodies are favorable to forming homodimers due to attractive interaction between opposite charges. The homodimer protein mixture obtained according to the method of the invention can simultaneously act on different epitopes of the same target, and simultaneously inhibit the effects of a plurality of antigens by binding to the antigens from different sources, thereby providing a new approach towards immunological diagnosis and treatment of tumors and other diseases.

Abstract: The invention relates to a method for preparing a homodimer protein mixture by using repulsive interaction of charges. The method comprises the step of replacing part of residues with the opposite-charged residues, so that different proteins or antibodies are unfavorable to forming heterodimers due to the repulsive interaction between like charges, while same proteins or antibodies are favorable to forming homodimers due to attractive interaction between opposite charges. The homodimer protein mixture obtained according to the method of the invention can simultaneously act on different epitopes of the same target, and simultaneously inhibit the effects of a plurality of antigens by binding to the antigens from different sources, thereby providing a new approach towards immunological diagnosis and treatment of tumors and other diseases.