Figure 1. Domain architecture of T cell-recruiting triplebody 19-3-19.

Triplebody 19-3-19 binds to the CD3ε chain of the TCR/CD3 complex via its central scFv and to two copies of CD19 on the surface of a malignant target cell via its two distal scFvs. The scFvs are connected by flexible (G₄S)₄-linkers (black lines), which gives the molecule a maximum computed span length (distance between the two distal binding sites) of 20 nm, when the flexible linkers are fully extended.