A Single Domain–Based Anti-Her2 Antibody Has Potent Antitumor Activities

Abstract Human epidermal growth factor receptor 2 (HER2) is overexpressed in approximately 20% to 30% of breast cancers and various other types of cancers, which plays a vital role in the cancer progression. Monoclonal antibodies targeting Her2 are now used in the clinic to treat Her2 overexpression cancer patients. However, relapse or resistance is frequent with the current therapies. To generate a new treatment avenue against Her2, we immunized and selected a specific anti-Her2 single domain antibody C3 for further studies. The C3-Fc antibody drove antibody-dependent cell-mediated cytotoxicity against Her2-positive tumor cells in vitro and resulted in potent antitumor growth in vivo . These data suggest that the C3-Fc antibody may provide an alternative avenue for Her2-positive cancer therapy.