Fusion protein dimer using antibody fc region as backbone and use thereof

Abstract

Provided is a fusion protein dimer using an antibody Fc region as the backbone, comprising a first and a second polypeptide chain. The first polypeptide chain comprises a first antibody Fc region and one or more single-domain antibodies fused to the first antibody Fc region. The second polypeptide chain comprises a second antibody Fc region and one or more single domain antibodies fused to the second antibody Fc region. The first polypeptide chain and/or the second polypeptide chain further comprise a cytokine fused to the Fc region of the respective antibody. Further provided is use of the fusion protein dimer in preparing an immunotherapeutic drug for treating tumors. The Fc fusion protein heterodimer not only increases the activity of a single domain antibody, but also significantly improves the biological activity of a cytokine. Further, by means of the targeting specificity of the antibody, the targeted transport of the cytokine is effectively enhanced, and cytotoxicity is attenuated, thereby obtaining better anti-tumor potential.