Development of masked therapeutic antibodies to limit off-target effects
In one embodiment, a masked monoclonal antibody (mAb) is provided, the mAb, encoded by a nucleic acid sequence or an amino acid sequence molecule comprising a signal sequence, a masking epitope sequence, a linker sequence that is cleavable by a protease specific to a target tissue; and an antibody or a functional fragment thereof. In another embodiment, a masked monoclonal antibody (mAb) is provided, which includes a therapeutic mAb and a mask, the mask comprising protein A and protein L attached by a protease cleavable linker.
1. A cross-masked monoclonal antibody (mAb) complex comprising:
(1) a first masked mAb comprising:
(a) a first masking epitope comprising amino acid residues 23-198 of SEQ ID NO:5 as shown in FIG. 14 ;
(b) a first linker that is cleavable by a protease specific to a target tissue, wherein the protease is matrix metalloproteinase-9 (MMP-9); and
(c) a first antibody or a first antigen-binding fragment thereof that binds EGFR, wherein the antibody is cetuximab, and
(2) a second masked mAb comprising:
(a) a second masking epitope comprising amino acid residues 23-198 of SEQ ID NO:6 as shown in FIG. 15 ;
(b) a second linker that is cleavable by the protease specific to the target tissue, wherein the protease is MMP-9; and
(c) a second antibody or a second antigen-binding fragment thereof that binds EGFR, wherein the antibody is matuzumab.
2. The cross-masked mAb complex of claim 1 , wherein the first masked mAb and the second masked mAb form a dimer by occlusion of the first and second antigen recognition sites by the second and first masking epitopes, respectively.
3. The cross-masked mAb complex of claim 1 , wherein the first linker and the second linker comprise the amino acid sequence VPLSLYS (SEQ ID NO:3).
4. The cross-masked mAb complex of claim 3 , wherein the first linker and the second linker comprise the amino acid sequence SEQ ID NO: 4 or SEQ ID NO: 7.
5. The cross-masked mAb complex of claim 1 , wherein the first masked mAb comprises a first signal sequence and the second masked mAb comprises a second signal sequence.
6. The cross-masked mAb complex of claim 5 , wherein the first masked mAb comprises the amino acid sequence of SEQ ID NO:5.
7. The cross-masked mAb complex of claim 5 , wherein the first masked mAb is encoded by the nucleic acid sequence of SEQ ID NO:1.
8. The cross-masked mAb complex of claim 5 , wherein the second masked mAb comprises the amino acid sequence of SEQ ID NO:6, wherein the amino acid sequence of SEQ ID NO: 6 comprises amino acid P at position 175 and N at position 176.