In the BiTe and BiKe molecules, binding domains are two single-chain variable fragment (scFv) regions, arisen from mAbs, joined by a flexible peptide linker with affinities for both a selected leukemia associated antigen (e.g. CD33, CD19) as well as a selected target on an effector immune cell, like CD3 expressed on T-cells (in BiTes) or CD16 expressed on NK-cells (in BiKes) (62). Here, CD33 is linked to leukemia.