Anti-human transferrin receptor antibody capable of penetrating blood-brain barrier

1. An anti-human transferrin receptor antibody, wherein the heavy chain variable region of the antibody comprises,

(a) CDR1 comprising the amino acid sequence of SEQ ID NO: 62 or SEQ ID NO: 63,

(b) CDR2 comprising the amino acid sequence of SEQ ID NO: 13 or SEQ ID NO: 14, and

(c) CDR3 comprising the amino acid sequence of SEQ ID NO: 15 or SEQ ID NO: 16, and the light chain variable region of the antibody comprises,

(a) CDR1 comprising the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprising the amino acid sequence of SEQ ID NO: 10.

2. The antibody according to claim 1 , wherein the framework region 3 of the heavy chain comprises the amino acid sequence of SEQ ID NO: 64.

3. The antibody according to claim 2 , wherein the heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 65.

4. The antibody according to claim 3 , wherein the heavy chain comprises the amino acid sequence of SEQ ID NO: 66 or SEQ ID NO: 68.

5. The antibody according to claim 1 , wherein the antibody comprises an amino acid sequence having sequence identity not lower than 80% to the amino acid sequence of the light chain variable region of SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21 or SEQ ID NO: 22, and in the light chain variable region of the antibody,

(a) CDR1 comprises the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprises the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprises the amino acid sequence of SEQ ID NO: 10.

6. The antibody according to claim 1 , wherein the antibody comprises an amino acid sequence having a sequence identity not lower than 90% to the amino acid sequence of the light chain variable region of SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21 or SEQ ID NO: 22, and in the light chain variable region of the antibody,

(a) CDR1 comprises the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprises the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprises the amino acid sequence of SEQ ID NO: 10.

7. The antibody according to claim 1 , wherein the antibody comprises an amino acid sequence modified from the amino acid sequence of the light chain variable region of SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21 or SEQ ID NO: 22 by the substitution, deletion or addition of 1 to 5 amino acids, in place thereof and in the light chain variable region of the antibody,

(a) CDR1 comprises the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprises the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprises the amino acid sequence of SEQ ID NO: 10.

8. The antibody according to claim 1 , wherein the antibody comprises an amino acid sequence modified from the amino acid sequence of the light chain variable region of SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21 or SEQ ID NO: 22 by the substitution, deletion or addition of 1 to 3 amino acids, and in the light chain variable region of the antibody,

(a) CDR1 comprises the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprises the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprises the amino acid sequence of SEQ ID NO: 10.

9. The antibody according to claim 1 , wherein the antibody comprises an amino acid sequence having sequence identity not lower than 80% to the amino acid sequence of the light chain of SEQ ID NO: 23, SEQ ID NO: 25, SEQ ID NO: 27 or SEQ ID NO: 29, and in the light chain variable region of the antibody,

(a) CDR1 comprises the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprises the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprises the amino acid sequence of SEQ ID NO: 10.

10. The antibody according to claim 1 , wherein the antibody comprises an amino acid sequence having sequence identity not lower than 90% to the amino acid sequence of the light chain of SEQ ID NO: 23, SEQ ID NO: 25, SEQ ID NO: 27 or SEQ ID NO: 29, and in the light chain variable region of the antibody,

(a) CDR1 comprises the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprises the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprises the amino acid sequence of SEQ ID NO: 10.

11. The antibody according to claim 1 , wherein the antibody comprises an amino acid sequence modified from the amino acid sequence of the light chain of SEQ ID NO: 23, SEQ ID NO: 25, SEQ ID NO: 27 or SEQ ID NO: 29 by the substitution, deletion or addition of 1 to 5 amino acids, and in the light chain variable region of the antibody,

(a) CDR1 comprises the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprises the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprises the amino acid sequence of SEQ ID NO: 10.

12. The antibody according to claim 1 , wherein the antibody comprises an amino acid sequence modified from the amino acid sequence of the light chain of SEQ ID NO: 23, SEQ ID NO: 25, SEQ ID NO: 27 or SEQ ID NO: 29 by the substitution, deletion or addition of 1 to 3 amino acids, and in the light chain variable region of the antibody,

(a) CDR1 comprises the amino acid sequence of SEQ ID NO: 6,

(b) CDR2 comprises the amino acid sequence of SEQ ID NO: 8, and

(c) CDR3 comprises the amino acid sequence of SEQ ID NO: 10.

13. The antibody according to claim 1 , wherein the antibody has an affinity to both the extracellular region of human transferrin receptor and the extracellular region of monkey transferrin receptor.

14. The antibody according to claim 13 , wherein the dissociation constant of its complex with the extracellular region of human transferrin receptor is not greater than 1×10 −10 M, and the dissociation constant of its complex with the extracellular region of monkey transferrin receptor is not greater than 1×10 −10 M.

15. The antibody according to claim 1 , wherein the antibody is Fab antibody, F(ab′) 2 antibody, or F(ab′) antibody.

16. The anti-human transferrin receptor antibody according to claim 1 , wherein the antibody is a single-chain antibody selected from the group consisting of scFab, scF(ab′), scF(ab′) 2 and scFv.

17. The antibody according to claim 16 , wherein the light chain and the heavy chain thereof are linked via a linker sequence.

18. The antibody according to claim 17 , wherein the heavy chain is linked, via a linker sequence, to the light chain on the C-terminal side of the light chain.

19. The antibody according to claim 17 , wherein the linker sequence consists of g 2 to 50 amino acid residues.

20. The antibody according to claim 19 , wherein the linker sequence is selected from the group consisting of the amino acid sequence Gly-Ser, the amino acid sequence Gly-Gly-Ser, the amino acid sequence Gly-Gly-Gly, the amino acid sequences set forth as SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, the amino acid sequence consisting of three consecutively linked amino acid sequences each set forth as SEQ ID NO: 3, and the amino acid sequence consisting of 2 to 10 of any of said amino acid sequences that are consecutively linked.

21. The antibody according to claim 16 , wherein the light chain is linked, via a linker sequence, to the heavy chain on the C-terminal side of the heavy chain.

22. A fusion protein comprising an anti-human transferrin receptor antibody and a different protein (A), wherein the anti-human transferrin receptor antibody is the antibody according to claim 1 , and the protein (A) is linked to the light chain of the antibody on the C-terminal side or the N-terminal side of the light chain.

23. The fusion protein according to claim 22 , wherein the protein (A) is linked, directly or via a linker, to the light chain on the C-terminal side or the N-terminal side of the light chain.

24. The fusion protein according to claim 22 , wherein the protein (A) is linked, via a linker, to the light chain on the C-terminal side or the N-terminal side of the light chain.

25. The fusion protein according to claim 24 , wherein the linker is a peptide consisting of 1 to 50 amino acid residues.

26. The fusion protein according to claim 25 , wherein the linker is a peptide comprising an amino acid sequence selected from the group consisting of a single glycine, a single serine, the amino acid sequence Gly-Ser, the amino acid sequence Gly-Gly-Ser, the amino acid sequence of SEQ ID NO: 3, the amino acid sequence of SEQ ID NO: 4, the amino acid sequence of SEQ ID NO: 5, and the amino acid sequence consisting of 2 to 10 of any of said amino acid sequences that are consecutively linked.

27. A method for the production of a fusion protein according to claim 22 , comprising a step of culturing mammalian cells transformed with an expression vector comprising a DNA fragment that is incorporated therein encoding the amino acid sequence of the fusion protein to let the mammalian cells secrete the fusion protein in the culture medium.

28. A fusion protein of an anti-human transferrin receptor antibody and a different protein (A), wherein the anti-human transferrin receptor antibody is the antibody according to claim 1 , and the protein (A) is linked to the heavy chain of the antibody on the C-terminal side or the N-terminal side of the heavy chain.

29. The fusion protein according to claim 28 , wherein the protein (A) is linked, directly or via a linker, to the heavy chain on the C-terminal side or the N-terminal side of the heavy chain.

30. The fusion protein according to claim 28 , wherein the protein (A) is linked, via a linker, to the heavy chain on the C-terminal side or the N-terminal side of the heavy chain.

31. The fusion protein according to claim 30 , wherein the linker sequence is a peptide consisting of 1 to 50 amino acid residues.

32. The fusion protein according to claim 31 , wherein the linker is a peptide comprising an amino acid sequence selected from the group consisting of a single glycine, a single serine, the amino acid sequence Gly-Ser, the amino acid sequence Gly-Gly-Ser, the amino acid sequence of SEQ ID NO: 3, the amino acid sequence of SEQ ID NO: 4, the amino acid sequence of SEQ ID NO: 5, and the amino acid sequence consisting of 2 to 10 of any of said amino acid sequences that are consecutively linked.

33. The fusion protein according to claim 28 , wherein the protein (A) is a protein originating from human.

34. The fusion protein according to claim 28 , wherein the protein (A) is selected from the group consisting of nerve growth factor (NGF), lysosomal enzymes, ciliary neurotrophic factor (CNTF), glial cell line-derived neurotrophic factor (GDNF), neurotrophin-3, neurotrophin-4/5, neurotrophin-6, neuregulin-1, erythropoietin, darbepoetin, activin, basic fibroblast growth factor (bFGF), fibroblast growth factor 2 (FGF2), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), interferon α, interferon β, interferon γ, interleukin 6, granulocyte-macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G-CSF), macrophage colony stimulating factor (M-CSF), cytokines, tumor necrosis factor α receptor (TNF-α receptor), PD-1 ligands, PD-L1, PD-L2 enzymes having β-amyloid-degrading activity, anti-β-amyloid antibody, anti-BACE antibody, anti-EGFR antibody, anti-PD-1 antibody, anti-PD-L1 antibody, anti-PD-L2 antibody, anti-HER2 antibody, anti-TNF-α antibody, and anti-CTLA-4 antibody.

35. The fusion protein according to claim 28 , wherein the protein (A) is a lysosomal enzyme, and the lysosomal enzyme is selected from the group consisting of α-L-iduronidase, iduronate 2-sulfatase, human acidic α-glucosidase, glucocerebrosidase, β-galactosidase, GM2 activator protein, β-hexosaminidase A, β-hexosaminidase B, N-acetylglucosamine-1-phosphotransferase, α-mannosidase, β-mannosidase, galactosylceramidase, saposin C, arylsulfatase A, α-L-fucosidase, aspartylglucosaminidase, α-N-acetylgalactosaminidase, acidic sphingomyelinase, α-galactosidase A, β-glucuronidase, heparan N-sulfatase, α-N-acetylglucosaminidase, acetyl CoA:α-α-glucosaminide N-acetyltransferase, N-acetylglucosamine-6-sulfate sulfatase, acid ceramidase, amylo-1,6-glucosidase, sialidase, palmitoyl protein thioesterase 1, tripeptidyl-peptidase 1, hyaluronidase 1, CLN1 and CLN2.

36. The fusion protein according to claim 28 , wherein the protein (A) is human iduronate 2-sulfatase, human acidic α-glucosidase, or human α-L-iduronidase.

37. A method for the treatment of a disease of the central nervous system accompanying Pompe's disease comprising parenterally administering a therapeutically effective amount of the fusion protein according to claim 36 to a patient with the disease.

38. A method for the treatment of a disease of the central nervous system accompanying Hurler syndrome or Hurler-Scheie syndrome, the method comprising parenterally administering a therapeutically effective amount of the fusion protein according to claim 36 to a patient with the disease.

39. The fusion protein according to claim 28 , wherein a human IgG Fc region or part thereof is introduced between the protein (A) and the antibody.

40. The fusion protein according to claim 39 , wherein the human IgG Fc region is linked, directly or via a linker sequence, to the protein (A) on the C-terminal side of the protein (A), and the heavy chain or the light chain of the antibody is linked, directly or via a linker sequence, to the human IgG Fc region on the C-terminal side of the human IgG Fc region.

41. The fusion protein according to claim 39 , wherein the human IgG Fc region comprises the amino acid sequence of SEQ ID NO: 70.

42. The fusion protein according to claim 41 , wherein the human IgG Fc region is linked, via a linker sequence, to a Fab heavy chain consisting of the amino acid sequence of SEQ ID NO: 61, and comprises the amino acid sequence of SEQ ID NO: 71 formed thereby.

43. A DNA fragment encoding the amino acid sequence of the fusion protein according to claim 28 .

44. A method for the production of a fusion protein according to claim 28 , comprising a step of culturing mammalian cells transformed with an expression vector comprising a DNA fragment that is incorporated therein encoding the amino acid sequence of the fusion protein to let the mammalian cells secrete the fusion protein in the culture medium.

45. A DNA fragment encoding the amino acid sequence of the anti-human transferrin receptor antibody according to claim 1 .

46. An expression vector comprising the DNA fragment according to claim 45 .

47. A mammalian cell transformed with the expression vector according to claim 46 .