CD33 and leukemia: CD16-directed BiKEs CD16 × CD19 and CD16 × CD33 and TriKE CD16 × CD22 × CD19 were shown to specifically stimulate NK cell activation via CD16, which triggers NK cell cytolytic activity and secretion of cytokines to attack CD19+, CD33+, and CD19+CD22+ lymphoma and leukemia, respectively (Gleason et al., 2012; Nagato et al., 2017).