Clearance of abnormal IGA1 in IGA1 deposition diseases
The present invention relates to proteins which specifically bind to IgA1 and which have been modified to comprise either O- or N-linked glycans. The invention encompasses methods for decreasing IgA1, preferably abnormally glycosylated IgA1, in an individual by administering to the individual a glycan-modified IgA1 binding protein of the invention. The invention also encompasses a method for the treatment of a disease characterized by IgA1 deposition wherein a glycan-modified IgA1 binding protein is administered to an individual in need thereof.
1. An isolated antibody polypeptide which specifically binds IgA1, said polypeptide comprising one or both of (a) a naturally occurring or non-naturally occurring serine or threonine residue at the end of a CH1 domain, which serine or threonine residue has been artificially modified by addition of an O-linked glycan, and (b) a naturally occurring or non-naturally occurring asparagine residue at the end of a CH1 domain, which asparagine residue has been artificially modified by addition of an N-linked glycan;
(i) wherein the O-linked glycan has the following formula:
wherein, (Ser/Thr) is one of said one or more non-naturally occurring serine or threonine residues which has been modified by the addition of said O-linked glycan,
wherein S.A. is a sialic acid,
wherein, R 1 is H, (GalNAc) n , where n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10,
and wherein R 2 is H or S.A; and
(ii) wherein the N-linked glycan has a formula selected from the group consisting:
(a)
wherein (Asn) is one of said one or more non-naturally occurring asparagine residues which has been modified by the addition of said N-linked glycan,
wherein S.A. is a sialic acid;
wherein, R 1 is H, (GlcNAc) n , where n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10,
and wherein R 2 is H or S.A; or
(b) a biantennary structure having the formula:
wherein (Asn) is one of said one or more non-naturally occurring asparagine residues which has been modified by the addition of said N-linked glycan,
wherein S.A. is a sialic acid,
wherein R 1 is H, (GlcNAc) n , or (GlcNAc) n linked to mannose, wherein n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10,
wherein R 2 is H, mannose, (GlcNAc) n , or mannose linked to (GlcNAc) n , wherein n=1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
2. The isolated antibody polypeptide of claim 1 , wherein said antibody polypeptide is selected from the group consisting of a dAb, a Fab, an scFv, an Fv, or a disulfide-bonded Fv.
3. The isolated antibody polypeptide of claim 2 , wherein said Fab is of human origin.
4. The isolated antibody polypeptide of claim 2 , wherein said Fab is a fragment of a humanized chimeric monoclonal IgG.
5. The isolated antibody polypeptide of claim 1 , wherein said antibody polypeptide binds to the hinge region of IgA1.
6. The isolated antibody polypeptide of claim 2 , wherein said antibody polypeptide binds to the CH 2 —CH 3 region interface of IgA1.
7. The isolated antibody polypeptide of claim 1 , wherein said isolated antibody polypeptide specifically binds an IgA1 hinge region having the sequence TPPTPSPSTPPTPSPS (SEQ ID NO:12).
8. The isolated antibody polypeptide of claim 7 , wherein said isolated antibody polypeptide specifically binds to GalNAc residues on said hinge region.
9. The isolated antibody polypeptide of claim 1 , wherein said isolated antibody polypeptide binds to the J chain of a dimeric IgA.
10. The isolated antibody polypeptide of claim 1 , wherein said isolated antibody polypeptide is artificially modified by chemical conjugation.
11. A method of reducing the amount of IgA1 in an individual, comprising administering to said individual an isolated antibody polypeptide of claim 1 .
12. The method of claim 11 , wherein said IgA1 is abnormally glycosylated.
13. The method of claim 11 , wherein said antibody polypeptide is selected from the group consisting of a dAb, a Fab, an scFv, an Fv, or a disulfide-bonded Fv.
14. The method of claim 13 , wherein said Fab is of human origin.
15. The method of claim 13 , wherein said Fab is a fragment of a humanized chimeric monoclonal IgG.
16. The method of claim 13 , wherein said antibody polypeptide binds to the hinge region of IgA1.
17. The method of claim 16 , wherein said antibody polypeptide binds to the CH 2 —CH 3 region interface of IgA1.
18. The method of claim 11 , wherein said isolated antibody polypeptide specifically binds a IgA1 hinge region having the sequence TPPTPSPSTPPTPSPS (SEQ ID NO:12).
19. The method of claim 18 , wherein said isolated antibody polypeptide specifically binds to GalNAc residues on said hinge region.
20. The method of claim 11 , wherein said isolated antibody polypeptide binds to the J chain of a dimeric IgA.
21. The method of claim 11 , wherein said N-linked glycan has the following formula:
wherein (Asn) is one of said one or more non-naturally occurring asparagine residues which has been modified by the addition of said N-linked glycan;
wherein S.A. is a sialic acid;
wherein, R 1 is H, (GlcNAc ) n , where n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10;
and wherein R 2 is H or S.A.
22. The method of claim 11 , wherein said N-linked glycan is a biantennary structure having the formula:
wherein (Asn) is one of said one or more non-naturally occurring asparagine residues which has been modified by the addition of said N-linked glycan;
wherein S.A. is a sialic acid;
wherein R 1 is H, (GlcNAc ) n , or (GlcNAc) n linked to mannose, wherein n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10;
and wherein R 2 is H, mannose, (GlcNAc) n , or mannose linked to (GlcNAc) n , wherein n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.
23. A method for treatment of a disease characterized by IgA1 deposition, comprising administering to an individual in need thereof, an isolated antibody polypeptide of claim 1 .
24. The method of claim 23 , wherein said antibody polypeptide is selected from the group consisting of a dAb, a Fab, an scFv, an Fv, or a disulfide-bonded Fv.
25. The method of claim 23 , wherein said Fab is of human origin.
26. The method of claim 23 , wherein said Fab is a fragment of a humanized chimeric monoclonal IgG.
27. The method of claim 23 , wherein said antibody polypeptide binds to the hinge region of IgA1.
28. The method of claim 23 , wherein said antibody polypeptide binds to the CH 2 —CH 3 region interface of IgA1.
29. The method of claim 23 , wherein said isolated antibody polypeptide specifically binds a IgA1hinge region having the sequence TPPTPSPSTPPTPSPS (SEQ ID NO:12).
30. The method of claim 29 , wherein said isolated antibody polypeptide specifically binds to GalNAc residues on said hinge region.
31. The method of claim 23 , wherein said isolated antibody polypeptide binds to the J chain of a dimeric IgA.
32. The method of claim 23 , wherein said N-linked glycan has the following formula:
wherein (Asn) is one of said one or more non-naturally occurring asparagine residues which has been modified by the addition of said N-linked glycan;
wherein S.A. is a sialic acid;
wherein, R 1 is H, (GlcNAc) n , where n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10;
and wherein R 2 is H or S.A.
33. The method of claim 23 , wherein said N-linked glycan is a biantennary structure having the formula:
wherein (Asn) is one of said one or more non-naturally occurring asparagine residues which has been modified by the addition of said N-linked glycan;
wherein S.A. is a sialic acid;
wherein R 1 is H, (GlcNAc)., or (GlcNAc) n , linked to mannose, wherein n =1, 2, 3, 4, 5, 6, 20 7, 8, 9, or 10;
and wherein R 2 is H, mannose, (GlcNAc) n , or mannose linked to (GlcNAc) n , wherein n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.