Figure 1.

Blinatumomab: structure and mode of action.

Notes: (A) Blinatumomab contains the variable domains (V_H and V_L) of two different IgG molecules. It is constructed out of two scFv, each formed by a pair of the V_H and V_L from two IgG molecules binding CD3 and CD19. The two scFv proteins are connected with a flexible, nonimmunogenic linker made of 25 amino acids. (B) Blinatumomab in the presence of CD3- and CD19-positive cells leads to a very close linkage with multiple connections between the two different cell types. This close contact zone forms a cytolytic synapse mediating TCR activation: granzymes and perforin are exocytosed into the CD19 positive target cell inducing its apoptosis.

Abbreviations: scFv, single chain variable fragment; TCR, T-cell receptor.