Bi-specific digoxigenin binding antibodies
This invention relates to bispecific antibodies and antibody fragments against a target protein and a hapten, wherein the hapten is PEG or biotin, most preferably digoxigenin, methods for their production, their use as a delivery platform for therapeutic or diagnostic agents, pharmaceutical compositions containing said antibodies, and uses thereof.
1. A bi-specific antibody specific against a digoxigenin (DIG) and a target protein, comprising a first antigen-binding site that binds to said DIG and a second antigen-binding site that binds to a target protein, wherein the DIG is conjugated to a nucleic acid, wherein said first antigen-binding site comprises: (a) a heavy chain variable domain of SEQ ID NO: 2 or SEQ ID NO:3, wherein SEQ ID NO:3 comprises mutations of S49A, 157A and A60P; and (b) a light chain variable domain of SEQ ID NO: 5 or SEQ ID NO: 1.
2. The bispecific antibody of claim 1 , comprising
a) a monospecific bivalent antibody consisting of two full length antibody heavy chains and two full length antibody light chains whereby each chain comprises only one variable domain,
b) two peptide-linkers,
c) two monospecific monovalent single chain antibodies, each comprising said first antigen-binding site, wherein each single chain antibody consists of an antibody heavy chain variable domain, an antibody light chain variable domain, and a single-chain-linker between said antibody heavy chain variable domain and said antibody light chain variable domain; and optionally, said single chain antibodies are linked to the same terminus (C- or N-terminus) of the monospecific bivalent antibody heavy chains or, alternatively to the same terminus of the monospecific bivalent antibody light chains.
3. The bi-specific antibody of claim 1 , wherein said antigen-binding site specifically binding to DIG comprises a heavy chain Fd-Fragment (V H and Ch1) of SEQ ID NO: 4 or SEQ ID NO: 36 and an L-chain of SEQ ID NO: 6 or SEQ ID NO: 37.
4. The bi-specific antibody of claim 1 , wherein said first antigen-binding site specifically binds to DIG, and wherein said first antigen-binding site comprises a heavy chain Fd-Fragment (V H and CH1) of SEQ ID NO: 4 or SEQ ID NO: 36 and an L-chain of SEQ ID NO: 6 or SEQ ID NO: 37.
5. The bi-specific antibody of claim 1 , wherein the antibody is humanized.
6. The bi-specific antibody of claim 1 , wherein the target protein is a cell surface antigen.
7. The bi-specific antibody of claim 6 , wherein the cell surface antigen is a tumor antigen.
8. The bi-specific antibody of claim 1 , wherein the target protein is selected from the group consisting of Her2, IGFI R, CD22, CD33, LeY, VEGFRI.
9. The bi-specific antibody of claim 1 , wherein the nucleic acid is a therapeutic or diagnostic agent.
10. The bi-specific antibody of claim 1 , wherein the nucleic acid is a double-stranded RNA.
11. The bi-specific antibody of claim 1 , wherein the nucleic acid is conjugated to a transfection reagent.
12. The bi-specific antibody of claim 11 , wherein the transfection reagent is a liposomal transfection reagent or a transfecting peptide.
13. The bi-specific antibody of claim 1 , wherein the nucleic acid is coupled to an endosome escape or a disruption module.
14. The bi-specific antibody of claim 13 , wherein the nucleic acid is coupled to a peptide which mediates endosome escape or disruption.
15. The bi-specific antibody of claim 13 , wherein the endosome escape or disruption modules comprises a dynamic polyconjugate (DPC).
16. The bi-specific antibody of claim 9 , wherein the diagnostic agent is a digoxigenated Cy5-labeled nucleic acid.
17. A pharmaceutical composition comprising the bi-specific antibody of claim 1 coupled to a digoxigenated therapeutic or diagnostic nucleic acid.