CD16a (FcγRIIIa) mediates the antibody dependent cellular cytotoxicity (ADCC) and is important for anti-tumor activities of many therapeutic antibodies. Bispecific antibody targeting natural killer (NK) cells has been studied for cancer therapy. In this work, anti-CD16a single-domain antibodies were identified from hCD16a immunized camel. Bispecific antibodies are then constructed by fusing these single domain antibodies with an anti-CEA single domain antibody. These bispecific antibodies can recruite NK cells to kill CEA-positive tumor cells, and inhibit tumor growth in vivo, suggesting that these anti-CD16a single domain antibodies are powerful tools to engaging NK cells for cancer therapy.
Keywords: CD16a; CEA; VHH; bispecific antibody; phage display; single domain antibody.