Figure 1.

Protease-activated antibody (pro-antibody) design and construction. A pro-antibody is constructed by tethering a peptide (mask) that blocks the antibody’s binding site to the antibody N-terminus via a flexible linker containing a protease substrate. A scFv-Fc fusion was used for simplicity. Masking attenuates binding activity until selective substrate cleavage releases the mask and fully restores antibody-binding activity.