Modified antibody compositions, methods of making and using thereof
The present disclosure provides modified antibodies which contain an antibody or antibody fragment (AB) modified with a masking moiety (MM). Such modified antibodies can be further coupled to a cleavable moiety (CM), resulting in activatable antibodies (AAs), wherein the CM is capable of being cleaved, reduced, photolyzed, or otherwise modified. AAs can exhibit an activatable conformation such that the AB is more accessible to a target after, for example, removal of the MM by cleavage, reduction, or photolysis of the CM in the presence of an agent capable of cleaving, reducing, or photolyzing the CM. The disclosure further provides methods of making and using such modified antibodies and activatable antibodies.
1. An isolated polypeptide comprising a cleavable moiety (CM) comprising the amino acid sequence LSGRSDNH (SEQ ID NO: 271).
2. The isolated polypeptide of claim 1 , wherein the polypeptide comprises an antibody or antigen binding fragment thereof (AB) that binds a target.
3. The isolated polypeptide of claim 2 , wherein the CM is located within the polypeptide at a position that is at or near the N-terminus of the AB.
4. The isolated polypeptide of claim 2 , wherein the antigen binding fragment thereof is selected from the group consisting of a Fab fragment, a F(ab′) 2 fragment, a scFv, a scab, a dAb, a single domain heavy chain antibody, and a single domain light chain antibody.
5. The isolated polypeptide of claim 2 , wherein the CM is a substrate for a protease that is co-localized in a tissue with the target.
6. The isolated polypeptide of claim 2 , wherein the AB is linked to the CM.
7. The isolated polypeptide of claim 6 , wherein the AB is linked directly to the CM.
8. The isolated polypeptide of claim 6 , wherein the AB is linked to the CM via a linking peptide.
9. The isolated polypeptide of claim 2 , wherein the isolated polypeptide comprises a masking moiety (MM), wherein the MM has an equilibrium dissociation constant for binding to the AB which is greater than the equilibrium dissociation constant of the AB for binding to the target.
10. The isolated polypeptide of claim 9 , wherein the MM is a polypeptide of no more than 40 amino acids in length.
11. The isolated polypeptide of claim 9 , wherein the amino acid sequence of the MM is different from that of the target and is no more than 50% identical to the amino acid sequence of a natural binding partner of the AB.
12. The isolated polypeptide of claim 9 , wherein the MM does not interfere or compete with the AB for binding to the target in a cleaved state.
13. The isolated polypeptide of claim 9 , wherein the MM is linked to the CM such that the isolated polypeptide in an uncleaved state comprises the structural arrangement from N-terminus to C-terminus as follows: MM-CM-AB or AB-CM-MM.
14. The isolated polypeptide of claim 13 , wherein the isolated polypeptide comprises a linking peptide between the MM and the CM.
15. The isolated polypeptide of claim 13 , wherein the isolated polypeptide comprises a linking peptide between the CM and the AB.
16. The isolated polypeptide of claim 13 , wherein the isolated polypeptide comprises a first linking peptide (LP1) and a second linking peptide (LP2), and wherein the isolated polypeptide has the structural arrangement in the uncleaved state from N-terminus to C-terminus as follows: MM-LP1-CM-LP2-AB or AB-LP2-CM-LP1-MM.
17. The isolated polypeptide of claim 16 , wherein the two linking peptides need not be identical to each other.
18. The isolated polypeptide of claim 16 , wherein each of LP1 and LP2 is a peptide of about 1 to 20 amino acids in length.
19. The isolated polypeptide of claim 6 , wherein the isolated polypeptide comprises a masking moiety (MM), wherein the MM has an equilibrium dissociation constant for binding to the AB which is greater than the equilibrium dissociation constant of the AB for binding to the target.
20. The isolated polypeptide of claim 19 , wherein the MM is a polypeptide of no more than 40 amino acids in length.
21. The isolated polypeptide of claim 19 , wherein the amino acid sequence of the MM is different from that of the target and is no more than 50% identical to the amino acid sequence of a natural binding partner of the AB.
22. The isolated polypeptide of claim 19 , wherein the MM does not interfere or compete with the AB for binding to the target in a cleaved state.
23. The isolated polypeptide of claim 19 , wherein the MM is linked to the CM such that the isolated polypeptide in an uncleaved state comprises the structural arrangement from N-terminus to C-terminus as follows: MM-CM-AB or AB-CM-MM.
24. The isolated polypeptide of claim 23 , wherein the isolated polypeptide comprises a linking peptide between the MM and the CM.
25. The isolated polypeptide of claim 23 , wherein the isolated polypeptide comprises a linking peptide between the CM and the AB.
26. The isolated polypeptide of claim 23 , wherein the isolated polypeptide comprises a first linking peptide (LP1) and a second linking peptide (LP2), and wherein the isolated polypeptide has the structural arrangement in the uncleaved state from N-terminus to C-terminus as follows: MM-LP1-CM-LP2-AB or AB-LP2-CM-LP1-MM.
27. The isolated polypeptide of claim 26 , wherein the two linking peptides need not be identical to each other.
28. The isolated polypeptide of claim 26 , wherein each of LP1 and LP2 is a peptide of about 1 to 20 amino acids in length.