Definition

A preparation of allogeneic, off-the-shelf natural killer (NK) cells, derived from umbilical cord blood (UCB) and ex vivo-expanded, that expresses a high-affinity variant of CD16, with potential immunostimulatory and antineoplastic activities. Upon administration, UCB-derived CD16-expressing NK cells AB-101 lyse tumor cells. NK cells AB-101 also secrete pro-inflammatory cytokines, which further stimulate an anti-tumor immune response. Upon coadministration with tumor-targeting monoclonal antibodies, the Fab moiety of the antibodies bind to the tumor-associated antigens (TAAs) expressed on tumor cells and the Fc moiety of the antibodies bind to CD16 expressed on NK cells AB-101. This leads to NK cell activation, cytokine secretion and antibody-dependent cellular cytotoxicity (ADCC). CD16, also known as Fc-gamma receptor III, is normally expressed on the surface of NK cells, neutrophils, monocytes and macrophages, and plays a key role in initiating ADCC. It is often downregulated in certain cancers, thereby inhibiting the anti-tumor immune response.