Figure 1.

(A) Schematic describing the difference between canonical ADCC with a mAb (top), and ADCC with a bsAb. A mAb binds to CD16 via its low affinity Fc to drive ADCC. With a bsAb, the high affinity of the scFvs tethered to the heavy chains, together with increased avidity from their binding two CD16 receptors on the NK cell potentially drives higher efficacy. This specific activation of NK cells results in lysis of the infected target via production of cytolytic granules.

(B) Schematic describing bsAb and mAb constructs (top) and the ORFs encoding these antibodies in the plasmids used for transfection (bottom).

(C) IgG-Fv bispecific antibodies (bsAbs) and corresponding stump-binding monoclonal antibodies (mAbs) were expressed in Expi293 cells, and purified by size exclusion chromatography on an S200 column after an initial protein A purification step. IgG-Fvs (~200kD, blue) elute earlier than IgGs (~150kD, purple) as expected.