Multivalent immunoglobulin-based bioactive assemblies
The present invention concerns methods and compositions for stably tethered structures of defined compositions, which may have multiple functionalities and/or binding specificities. Preferred embodiments concern hexameric stably tethered structures comprising one or more IgG antibody fragments and which may be monospecific or bispecific. The disclosed methods and compositions provide a facile and general way to obtain stably tethered structures of virtually any functionality and/or binding specificity. The stably tethered structures may be administered to subjects for diagnostic and/or therapeutic use, for example for treatment of cancer or autoimmune disease. The stably tethered structures may bind to and/or be conjugated to a variety of known effectors, such as drugs, enzymes, radionuclides, therapeutic agents and/or diagnostic agents.
1. A hexameric stably tethered structure comprising an IgG antibody attached to two AD2 moieties of SEQ ID NO: 4 and four antigen-binding antibody fragments of the same or different IgG with each fragment attached to a DDD2 moiety of SEQ ID NO: 2; the AD2 moieties bound to the DDD2 moieties.
2. The structure of claim 1 , wherein the AD2 moieties are covalently attached to the DDD2 moieties by disulfide bonds.
3. The structure of claim 1 , wherein the four antibody fragments are Fab fragments.
4. The structure of claim 3 , wherein the IgG antibody and each of the Fab fragments binds to the same antigenic epitope.
5. The structure of claim 3 , wherein the IgG antibody binds to a first antigenic epitope and the Fab fragments bind to a second antigenic epitope.
6. The structure of claim 1 , wherein the antibody or the antibody fragments are human, humanized or chimeric.
7. The structure of claim 3 , wherein the Fab fragments are selected from the group consisting of the Fab fragments of humanized antibody hMN-14 that binds to CEA, humanized antibody hA20 that binds to CD20, humanized antibody hLL2 that binds to CD22, humanized antibody hL243 that binds to HLA class II, humanized antibody hCC49 that binds to TAG-72, humanized antibody hLL1 that binds to CD74, humanized antibody hPAM4 that binds to MUC 1, humanized antibody hRS7 that binds to EGP-1, humanized antibody hR1 that binds to IGF1R, anti-CD 14, anti-CD 111, adalimumab, infliximab, omalizumab, palivizumab and humanized antibody hMN-15 that binds to CEA.
8. The structure of claim 1 , wherein the antibody fragments are selected from the group consisting of Fab, Fab′, Fv, sFV and scFV antibody fragments.
9. The structure of claim 1 , further comprising one or more effectors or carriers conjugated to the structure by either covalent or non-covalent linkage.
10. The structure of claim 5 , wherein the IgG antibody and the antibody fragments bind to the antigen combinations of CD20/CD22; CD20/CD74; CD20/HLA-DR; CD22/CD74; CD22/HLA-DR; CD74/HLA-DR; CD74/CEA or HLA-DR/CEA.
11. A hexameric stably tethered structure comprising an JgG antibody attached at its C-terminal end to two AD2 moieties of SEQ ID NO: 4and four Fab fragments of the same or different IgG antibody with each Fab fragment attached at its C-terminal end to a DDD2 moiety of SEQ ID NO: 2 the AD2 moieties bound to the DDD2 moieties.
12. The hexameric stably tethered structure of claim 11 , wherein the IgG antibody and the four Fab fragments bind to CD20.
13. The hexameric stably tethered structure of claim 12 , wherein the IgG antibody is a humanized A20 (hA20) antibody and the four Fab fragments are Fab fragments of a humanized A20 (hA20) antibody.
14. The hexameric stably tethered structure of claim 11 , wherein the IgG antibody and the four Fab fragments bind to CD22.
15. The hexameric stably tethered structure of claim 14 , wherein the IgG antibody is epratuzumab (hLL2) and the four Fab fragments are Fab fragments of epratuzumab (hLL2).
16. The hexameric stably tethered structure of claim 11 , wherein the IgG antibody binds to CD22 and the four Fab fragments bind to CD20.
17. The hexameric stably tethered structure of claim 16 , wherein the IgG antibody is epratuzumab (hLL2) and the four Fab fragments are Fab fragments of hA20.
18. The hexameric stably tethered structure of claim 11 , wherein the IgG antibody binds to CD22 and the four Fab fragments bind to carcinoembryonic antigen (CEA).
19. The hexameric stably tethered structure of claim 18 , wherein the IgG antibody is epratuzumab (hLL2) and the four Fab fragments are Fab fragments of a humanized MN-14 (hMN-14) antibody.
20. The hexameric stably tethered structure of claim 11 , wherein the IgG antibody binds to CD20 and the four Fab fragments bind to CD22.
21. The hexameric stably tethered structure of claim 20 , wherein the IgG antibody is hA20 and the four Fab fragments are Fab fragments of epratuzumab.
22. The hexameric stably tethered structure of claim 11 , wherein the IgG antibody binds to CD20 and the four Fab fragments bind to CEA.
23. The hexameric stably tethered structure of claim 22 , wherein the IgG antibody is hA20 and the four Fab fragments are Fab fragments of hMN-14.