Production process for antibody composition

• US 20040132140A1
• Filed: 04/09/2003
• Published: 07/08/2004
• Est. Priority Date: 04/09/2002
• Status: Abandoned Application

• Current Assignee: Kyowa Hakko Kirin Company Limited (Kirin Holdings Company Limited)
• Original Assignee: Kyowa Hakko Kogyo Company Limited (Kirin Holdings Company Limited)
• Inventors: Kinoshita, Satoko, Kamachi, Reiko, Yamano, Kazuya, Satoh, Mitsuo, Kanda, Yutaka, Mori, Katsuhiro, Iida, Shigeru
• Application Number:
  US10/409,616
• Publication Number:
  US 20040132140A1
• Time in Patent Office: Days
• US Class Current: 435/70.21
• CPC Class Codes: A61K 39/395 Antibodies agglutinins A61K38/36 ; as drug carriers A61K47/50; Immunoglobulins; Immune serum, e.g. antilymphocytic serum
• CPC Class Codes: A61P 29/00 Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
• CPC Class Codes: A61P 31/04 Antibacterial agents
• CPC Class Codes: A61P 31/12 Antivirals
• CPC Class Codes: A61P 31/14 for RNA viruses
• CPC Class Codes: A61P 35/00 Antineoplastic agents
• CPC Class Codes: A61P 37/02 Immunomodulators
• CPC Class Codes: A61P 37/04 Immunostimulants
• CPC Class Codes: A61P 37/08 Antiallergic agents antiasthmatic agents A61P11/06; ophthalmic antiallergics A61P27/14
• CPC Class Codes: A61P 43/00 Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• CPC Class Codes: A61P 9/00 Drugs for disorders of the cardiovascular system
• CPC Class Codes: C07K 16/00 Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies antibodies with enzymatic activity, e.g. abzymes C12N9/0002
• CPC Class Codes: C07K 16/2866 against receptors for cytokines, lymphokines, interferons
• CPC Class Codes: C07K 16/2896 against molecules with a "CD"-designation, not provided for elsewhere
• CPC Class Codes: C07K 2317/24 containing regions, domains or residues from different species, e.g. chimeric, humanized or veneered
• CPC Class Codes: C07K 2317/41 Glycosylation, sialylation, or fucosylation
• CPC Class Codes: C07K 2317/732 Antibody-dependent cellular cytotoxicity [ADCC]
• CPC Class Codes: C12N 15/1137 against enzymes viral enzymes C12N15/1131; receptors C12N15/1138
• CPC Class Codes: C12N 2310/14 interfering N.A.
• CPC Class Codes: C12N 2310/53 partially self-complementary or closed
• CPC Class Codes: C12N 9/1051 : Hexosyltransferases (2.4.1)
• CPC Class Codes: C12Y 204/01068 : Glycoprotein 6-alpha-L-fucosyltransferase (2.4.1.68), i.e. FUT8

Abstract

A process for producing an antibody composition using a cell, which comprises using a cell resistant to a lectin which recognizes a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α-bond in a complex N-glycoside-linked sugar chain, and a cell used for the process.

Claims

1. A process for producing an antibody composition using a cell, which comprises using a cell resistant to a lectin which recognizes a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain.

2. The process according to claim 1, wherein the cell is a cell in which the activity of a protein selected from the group consisting of the following (a), (b) and (c) is decreased or deleted:

(a) an enzyme protein relating to synthesis of an intracellular sugar nucleotide, GDP-fucose;

(b) an enzyme protein relating to modification of a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain;

(c) a protein relating to transport of an intracellular sugar nucleotide, GDP-fucose, to the Golgi body.

3. The process according to claim 2, wherein the enzyme protein relating to modification of a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain is α

1,6-fucosyltransferase.

4. The process according to claim 2 or 3, wherein the activity of the protein is decreased or deleted by a technique selected from the group consisting of (a) to (d):

(a) a gene disruption technique which comprises targeting a gene encoding the protein;

(b) a technique for introducing a dominant negative mutant of a gene encoding the protein;

(c) a technique for introducing mutation into the protein;

(d) a technique for suppressing transcription and/or translation of a gene encoding the protein.

5. The process according to claim 4), wherein the technique for suppressing transcription and/or translation of a gene encoding the protein is an RNAi method.

6. The process according to any one of claims 3 to 5, wherein the α

1,6-fucosyltransferase is a protein encoded by a DNA selected from the group consisting of (a) to (h) or a protein selected from the group consisting of the following (i) to (n);

(a) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

79;

(b) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

80;

(c) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

81;

(d) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

82;

(e) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

79 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(f) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

80 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(g) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

81 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(h) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

82 under stringent conditions and encodes a protein having an a α

1,6-fucosyltransferase activity;

(i) a protein comprising the amino acid sequence represented by SEQ ID NO;

91;

(j) a protein comprising the amino acid sequence represented by SEQ ID NO;

92;

(k) a protein which comprises an amino acid sequence in which at least one amino acid is deleted, substituted, inserted and/or added in the amino acid sequence represented by SEQ ID NO;

91 and has an α

1,6-fucosyltransferase activity;

(l) a protein which comprises an amino acid sequence in which at least one amino acid is deleted, substituted, inserted and/or added in the amino acid sequence represented by SEQ ID NO;

92 and has an α

1,6-fucosyltransferase activity;

(m) a protein which comprises an amino acid sequence having a homology of at least 80% with the amino acid sequence represented by SEQ ID NO;

91 and has an α

1,6-fucosyltransferase activity;

(n) a protein which comprises an amino acid sequence having a homology of at least 80% with the amino acid sequence represented by SEQ ID NO;

92 and has an α

1,6-fucosyltransferase activity.

7. The process according to claim 5 or 6, wherein the RNAi method is a method in which a double-stranded RNA comprising an RNA selected from the group consisting of (a) to (d) and its complementary RNA and being capable of decreasing the amount of mRNA of α

1,6-fucosyltransferase is introduced into or expressed in the cell;

(a) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

79;

(b) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

80;

(c) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

81;

(d) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

82.

8. The process according to claim 7, wherein the double-stranded RNA comprising an RNA selected from the group consisting of (a) to (d) and its complementary RNA is introduced into or expressed in the cell to thereby decrease the amount of mRNA of α

1,6-fucosyltransferase and provide the cell with the resistance to a lectin which recognizes a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain;

(a) an RNA comprising the nucleotide sequence represented by SEQ ID NO;

83;

(b) an RNA comprising the nucleotide sequence represented by SEQ ID NO;

84;

(c) an RNA which comprises a nucleotide sequence in which one or a few nucleotides are deleted or added in the nucleotide sequence represented by SEQ ID NO;

83 and has substantially the same RNAi activity as the RNA represented by SEQ ID NO;

83;

(d) an RNA which comprises a nucleotide sequence in which one or a few nucleotides are deleted or added in the nucleotide sequence represented by SEQ ID NO;

84 and has substantially the same RNAi activity as the RNA represented by SEQ ID NO;

84.

9. The process according to claim 7 or 8, wherein the double-stranded RNA is introduced into the cell by using a vector into which a DNA corresponding to the RNA according to claim 7 or 8 and its complementary DNA are inserted.

10. The process according to any one of claims 1 to 9, wherein the cell is resistant to at least one lectin selected from the group consisting of the following (a) to (d):

(a) a Lens culinaris lectin;

(b) a Pisum sativum lectin;

(c) a Vicia faba lectin;

(d) an Aleuria aurantia lectin.

11. The process according to any one of claims 1 to 10, wherein the cell is a cell into which a gene encoding an antibody molecule is introduced.

12. The process according to claim 11, wherein the antibody molecule is selected from the group consisting of the following (a) to (d):

(a) a human antibody;

(b) a humanized antibody;

(c) an antibody fragment comprising the Fc region of (a) or (b);

(d) a fusion protein comprising the Fc region of (a) or (b).

13. The process according to claim 11 or 12, wherein the antibody molecule belongs to an IgG class.

14. The process according to any one of claims 1 to 13, wherein the antibody composition has a higher antibody-dependent cell-mediated cytotoxic activity than an antibody composition produced by its parent cell.

15. The process according to claim 14, wherein the antibody composition having a higher antibody-dependent cell-mediated cytotoxic activity has a higher ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end in the sugar chain among total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition than an antibody composition produced by its parent cell.

16. The process according to claim 15, wherein the ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end through α

-bond is 20% or more of total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition.

17. The process according to claim 15 or 16, wherein the sugar chain in which fucose is not bound is a sugar chain in which 1-position of fucose is not bound to 6-position of N-acetylglucosamine in the reducing end in the complex N-glycoside-linked sugar chain through α

-bond.

18. The process according to any one of claims 1 to 17, wherein the cell is selected from the group consisting of a yeast, an animal cell, an insect cell and a plant cell.

19. The process according to any one of claims 1 to 18, wherein the cell is a mouse myeloma cell.

20. The process according to claim 19, wherein the mouse myeloma cell is NS0 cell or SP2/0-Ag14 cell.

21. The process according to any one of claims 1 to 18, wherein the cell is selected from the group consisting of the following (a) to (g):

(a) a CHO cell derived from a Chinese hamster ovary tissue;

(b) a rat myeloma cell line YB2/3HL.P2.G11.16Ag.20 cell;

(c) a BHK cell derived from a Syrian hamster kidney tissue;

(d) a hybridoma cell which produces an antibody;

(e) a human leukemic cell line Namalwa cell;

(e) an embryonic stem cell;

(g) a fertilized egg cell.

70. An antibody composition produced by the process according to any one of claims 1 to 21.

73. A medicament comprising as an active ingredient the antibody composition according to any one of claims 70 to 72.

74. The medicament according to claim 73, which is a diagnostic agent, an preventing agent or a treating agent for tumor-accompanied diseases, allergy-accompanied diseases, inflammatory-accompanied diseases, autoimmune diseases, cardiovascular diseases, viral infection-accompanied diseases or bacterial infection-accompanied diseases.

81. Use of the antibody composition according to any one of claims 70 to 72 in the manufacture of the medicament according to claim 73 or 74.

22. A cell into which a gene encoding an antibody composition is introduced, which is resistant to a lectin which recognizes a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain.

23. The cell according to claim 22, wherein the activity of a protein selected from the group consisting of the following (a), (b) and (c) is more decreased or deleted than its parent cell:

(a) an enzyme protein relating to synthesis of an intracellular sugar nucleotide, GDP-fucose;

(b) an enzyme protein relating to modification of a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain;

(c) a protein relating to transport of an intracellular sugar nucleotide, GDP-fucose, to the Golgi body.

24. The cell according to claim 23, wherein the enzyme protein relating to modification of a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain is α

1,6-fucosyltransferase.

25. The cell according to claim 23 or 24, wherein the activity of the protein is decreased or deleted by a technique selected from the group consisting of (a) to (d):

(a) a gene disruption technique which comprises targeting a gene encoding the protein;

(b) a technique for introducing a dominant negative mutant of a gene encoding the protein;

(c) a technique for introducing mutation into the protein;

(d) a technique for suppressing transcription and/or translation of a gene encoding the protein.

26. The cell according to claim 25, wherein the technique for suppressing transcription and/or translation of a gene encoding the protein is an RNAi method.

27. The cell according to any one of claims 24 to 26, wherein the α

1,6-fucosyltransferase is a protein encoded by a DNA selected from the group consisting of (a) to (h) or a protein selected from the group consisting of the following (i) to (n);

(a) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

79;

(b) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

80;

(c) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

81;

(d) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

82;

(e) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

79 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(f) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

80 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(g) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

81 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(h) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

82 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(i) a protein comprising the amino acid sequence represented by SEQ ID NO;

91;

(j) a protein comprising the amino acid sequence represented by SEQ ID NO;

92;

(k) a protein which comprises an amino acid sequence in which at least one amino acid is deleted, substituted, inserted and/or added in the amino acid sequence represented by SEQ ID NO;

91 and has an α

1,6-fucosyltransferase activity;

(l) a protein which comprises an amino acid sequence in which at least one amino acid is deleted, substituted, inserted and/or added in the amino acid sequence represented by SEQ ID NO;

92 and has an α

1,6-fucosyltransferase activity;

(m) a protein which comprises an amino acid sequence having a homology of at least 80% with the amino acid sequence represented by SEQ ID NO;

91 and has an α

1,6-fucosyltransferase activity;

(n) a protein which comprises an amino acid sequence having a homology of at least 80% with the amino acid sequence represented by SEQ ID NO;

92 and has an α

1,6-fucosyltransferase activity.

28. The cell according to claim 26 or 27, wherein the RNAi method is a method in which a double-stranded RNA comprising an RNA selected from the group consisting of (a) to (d) and its complementary RNA and being capable of decreasing the amount of mRNA of α

1,6-fucosyltransferase is introduced into or expressed in the cell;

(a) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

79;

(b) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

80;

(c) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

81;

(d) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

82.

29. The cell according to claim 28, wherein the double-stranded RNA comprising an RNA selected from the group consisting of (a) to (d) and its complementary RNA is introduced into or expressed in the cell to thereby decrease the amount of mRNA of α

1,6-fucosyltransferase and provide the cell with the resistance to a lectin which recognizes a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain;

(a) an RNA comprising the nucleotide sequence represented by SEQ ID NO;

83;

(b) an RNA comprising the nucleotide sequence represented by SEQ ID NO;

84;

(c) an RNA which comprises a nucleotide sequence in which one or a few nucleotides are deleted or added in the nucleotide sequence represented by SEQ ID NO;

83 and has substantially the same RNAi activity as the RNA represented by SEQ ID NO;

83;

(d) an RNA which comprises a nucleotide sequence in which one or a few nucleotides are deleted or added in the nucleotide sequence represented by SEQ ID NO;

84 and has substantially the same RNAi activity as the RNA represented by SEQ ID NO;

84.

30. The process according to claim 28 or 29, wherein the double-stranded RNA is introduced into the cell by using a vector into which a DNA corresponding to the RNA according to claim 28 or 29 and its complementary DNA are inserted.

31. The cell according to any one of claims 22 to 30, wherein the cell is resistant to at least one lectin selected from the group consisting of the following (a) to (d):

(a) a Lens culinaris lectin;

(b) a Pisum sativum lectin;

(c) a Vicia faba lectin;

(d) an Aleuria aurantia lectin.

32. The cell according to any one of claims 22 to 31, wherein the antibody molecule is selected from the group consisting of the following (a), (b), (c) and (d):

(a) a human antibody;

(b) a humanized antibody;

(c) an antibody fragment comprising the Fc region of (a) or (b);

(d) a fusion protein comprising the Fc region of (a) or (b).

33. The cell according to any one of claims 22 to 32, wherein the antibody molecule belongs to an IgG class.

34. The cell according to any one of claims 22 to 33, wherein the antibody composition has a higher antibody-dependent cell-mediated cytotoxic activity than an antibody composition produced by its parent cell.

35. The cell according to claim 34, wherein the antibody composition having a higher antibody-dependent cell-mediated cytotoxic activity has a higher ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end in the sugar chain among total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition than an antibody composition produced by its parent cell.

36. The cell according to claim 35, wherein the ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end through α

-bond is 20% or more of total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition.

37. The cell according to claim 35, wherein the sugar chain in which fucose is not bound is a sugar chain in which 1-position of fucose is not bound to 6-position of N-acetylglucosamine in the reducing end in the complex N-glycoside-linked sugar chain through α

-bond.

38. The cell according to any one of claims 22 to 37, wherein the cell is selected from the group consisting of a yeast, an animal cell, an insect cell and a plant cell.

39. The cell according to any one of claims 22 to 37, wherein the cell is a mouse myeloma cell.

40. The cell according to claim 39, wherein the mouse myeloma cell is NS0 cell or SP2/0-Ag14 cell.

41. The cell according to any one of claims 22 to 38, wherein the cell is selected from the group consisting of the following (a) to (g):

(a) a CHO cell derived from a Chinese hamster ovary tissue;

(b) a rat myeloma cell line YB2/3HL.P2.G11.16Ag.20 cell;

(c) a BHK cell derived from a Syrian hamster kidney tissue;

(d) a hybridoma cell which produces an antibody;

(e) a human leukemic cell line Namalwa cell;

(f) an embryonic stem cell;

(g) a fertilized egg cell.

42. A process for producing an antibody composition, which comprises culturing the cell according to any one of claims 22 to 41 in a medium to form and accumulate an antibody composition in a culture;

and recovering the antibody composition from the culture.

43. The process according to claim 42, which produces an antibody composition having a higher antibody-dependent cell-mediated cytotoxic activity than an antibody composition produced by its parent cell.

44. The process according to claim 43, wherein the antibody composition having a higher antibody-dependent cell-mediated cytotoxic activity has a higher ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end in the sugar chain among total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition than an antibody composition produced by its parent cell.

45. The process according to claim 44, wherein the ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end through α

-bond is 20% or more of total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition.

46. The process according to claim 44 or 45, wherein the sugar chain in which fucose is not bound is a sugar chain in which 1-position of the fucose is not bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain.

71. An antibody composition produced by the process according to any one of claims 42 to 46.

47. A mouse myeloma cell resistant to a lectin which recognizes a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain.

48. The mouse myeloma cell according to claim 47, wherein the activity of a protein selected from the group consisting of the following (a), (b) and (c) is more decreased or deleted than its parent cell:

(a) an enzyme protein relating to synthesis of an intracellular sugar nucleotide, GDP-fucose;

(b) an enzyme protein relating to modification of a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain;

(c) a protein relating to transport of an intracellular sugar nucleotide, GDP-fucose, to the Golgi body.

49. The mouse myeloma cell according to claim 48, wherein the enzyme protein relating to modification of a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain is α

1,6-fucosyltransferase.

50. The mouse myeloma cell according to claim 48 or 49, wherein the activity of the protein is decreased or deleted by a technique selected from the group consisting of (a) to (d):

(a) a gene disruption technique which comprises targeting a gene encoding the protein;

(b) a technique for introducing a dominant negative mutant of a gene encoding the protein;

(c) a technique for introducing mutation into the protein;

(d) a technique for suppressing transcription and/or translation of a gene encoding the protein.

51. The mouse myeloma cell according to claim 50, wherein the technique for suppressing transcription and/or translation of a gene encoding the protein is an RNAi method.

52. The mouse myeloma cell according to any one of claims 49 to 51, wherein the α

1,6-fucosyltransferase is a protein encoding a DNA selected from the group consisting of (a) to (h) or a protein selected from the group consisting of the following (i) to (n);

(a) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

79;

(b) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

80;

(c) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

81;

(d) a DNA comprising the nucleotide sequence represented by SEQ ID NO;

82;

(e) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

79 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(f) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

80 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(g) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

81 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(h) a DNA which hybridizes with a DNA comprising the nucleotide sequence represented by SEQ ID NO;

82 under stringent conditions and encodes a protein having an α

1,6-fucosyltransferase activity;

(i) a protein comprising the amino acid sequence represented by SEQ ID NO;

91;

(j) a protein comprising the amino acid sequence represented by SEQ ID NO;

92;

(k) a protein which comprises an amino acid sequence in which at least one amino acid is deleted, substituted, inserted and/or added in the amino acid sequence represented by SEQ ID NO;

91 and has an α

1,6-fucosyltransferase activity;

(l) a protein which comprises an amino acid sequence in which at least one amino acid is deleted, substituted, inserted and/or added in the amino acid sequence represented by SEQ ID NO;

92 and has an α

1,6-fucosyltransferase activity;

(m) a protein which comprises an amino acid sequence having a homology of at least 80% with the amino acid sequence represented by SEQ ID NO;

91 and has an α

1,6-fucosyltransferase activity;

(n) a protein which comprises an amino acid sequence having a homology of at least 80% with the amino acid sequence represented by SEQ ID NO;

92 and has an α

1,6-fucosyltransferase activity.

53. The mouse myeloma cell according to claim 51 or 52, wherein the RNAi method is a method in which a double-stranded RNA comprising a RNA selected from the group consisting of (a) to (d) and its complementary RNA and being capable of decreasing the amount of mRNA of α

1,6-fucosyltransferase is introduced into or expressed in the cell;

(a) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

79;

(b) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

80;

(c) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

81;

(d) an RNA corresponding to a DNA comprising a nucleotide sequence of continuous 10 to 30 nucleotides in the nucleotide sequence represented by SEQ ID NO;

82.

54. The mouse myeloma cell according to claim 51, wherein the double-stranded RNA comprising an RNA selected from the group consisting of (a) to (d) and its complementary RNA is introduced into or expressed in the cell to thereby decrease the amount of mRNA of α

1,6-fucosyltransferase and provide the cell with the resistance to a lectin which recognizes a sugar chain in which 1-position of fucose is bound to 6-position of N-acetylglucosamine in the reducing end through α

-bond in a complex N-glycoside-linked sugar chain;

(a) an RNA comprising the nucleotide sequence represented by SEQ ID NO;

83;

(b) an RNA comprising the nucleotide sequence represented by SEQ ID NO;

84;

(c) an RNA which comprises a nucleotide sequence in which one or a few nucleotides are deleted or added in the nucleotide sequence represented by SEQ ID NO;

83 and has substantially the same RNAi activity as the RNA represented by SEQ ID NO;

83;

(d) an RNA which comprises a nucleotide sequence in which one or a few nucleotides are deleted or added in the nucleotide sequence represented by SEQ ID NO;

84 and has substantially the same RNAi activity as the RNA represented by SEQ ID NO;

84.

55. The mouse myeloma cell according to claim 50 or 51, wherein the double-stranded RNA is introduced into the cell by using a vector into which a DNA corresponding to the RNA according to claim 53 or 54 and its complementary DNA are inserted.

56. The mouse myeloma cell according to any one of claims 47 to 55, wherein the cell is resistant to at least one lectin selected from the group consisting of the following (a) to (d):

(a) a Lens culinaris lectin;

(b) a Pisum sativum lectin;

(c) a Vicia faba lectin;

(d) an Aleuria aurantia lectin.

57. The mouse myeloma cell according to any one of claims 47 to 56, wherein the mouse myeloma cell is selected from the group consisting of the following (a) and (b):

(a) NS0 cell;

(b) SP2/0-Ag14 cell.

58. The cell according to any one of claims 47 to 57, wherein the mouse myeloma cell is a cell into which a gene encoding an antibody molecule is introduced.

59. The cell according to claim 58, wherein the antibody molecule is selected from the group consisting of the following (a), (b), (c) and (d):

(a) a human antibody;

(b) a humanized antibody;

(c) an antibody fragment comprising the Fc region of (a) or (b);

(d) a fusion protein comprising the Fc region of (a) or (b).

60. The cell according to claim 58 or 59, wherein the antibody molecule belongs to an IgG class.

61. The cell according to any one of claims 58 to 60, wherein the antibody composition has a higher antibody-dependent cell-mediated cytotoxic activity than an antibody composition produced by its parent cell.

62. The cell according to claim 61, wherein the antibody composition having a higher antibody-dependent cell-mediated cytotoxic activity has a higher ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end in the sugar chain among total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition than an antibody composition produced by its parent cell.

63. The cell according to claim 62, wherein the ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end through α

-bond is 20% or more of total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition.

64. The cell according to claim 62, wherein the sugar chain in which fucose is not bound is a sugar chain in which 1-position of fucose is not bound to 6-position of N-acetylglucosamine in the reducing end in the complex N-glycoside-linked sugar chain through α

-bond.

65. A process for producing an antibody composition, which comprises culturing the cell according to any one of claims 58 to 64 in a medium to form and accumulate an antibody composition in the culture;

and recovering the antibody composition from the culture.

66. The process according to claim 65, which produces an antibody composition having a higher antibody-dependent cell-mediated cytotoxic activity than an antibody composition produced by its parent cell.

67. The process according to claim 66, wherein the antibody composition having a higher antibody-dependent cell-mediated cytotoxic activity has a higher ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end in the sugar chain among total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition than an antibody composition produced by its parent cell.

68. The process according to claim 67, wherein the ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end through α

-bond is 20% or more of total complex N-glycoside-linked sugar chains bound to the Fc region in the antibody composition.

69. The process according to claim 67 or 68, wherein the sugar chain in which fucose is not bound is a sugar chain in which 1-position of fucose is not bound to 6-position of N-acetylglucosamine in the reducing end in the complex N-glycoside-linked sugar chain through α

-bond.

72. An antibody composition produced by the process according to any one of claims 65 to 69.

75. A double-stranded RNA comprising an RNA selected from the group consisting of (a) to (d) and its complementary RNA:

(a) an RNA comprising the nucleotide sequence represented by SEQ ID NO;

83;

(b) an RNA comprising the nucleotide sequence represented by SEQ ID NO;

84;

(c) an RNA which comprises a nucleotide sequence in which one or a few nucleotides are deleted or added in the nucleotide sequence represented by SEQ ID NO;

83 and has substantially the same RNAi activity as the RNA represented by SEQ ID NO;

83;

(d) an RNA which comprises a nucleotide sequence in which one or a few nucleotides are deleted or added in the nucleotide sequence represented by SEQ ID NO;

84 and has substantially the same RNAi activity as the RNA represented by SEQ ID NO;

84.

76. A DNA corresponding to the RNA according to claim 75 and its complementary DNA.

77. The DNA according to claim 76, the DNA corresponding to the RNA is the nucleotide sequence represented by SEQ ID NO:

63 or 64.

78. A recombinant DNA comprising the DNA according to claim 76 or 77 and its complementary DNA.

79. The recombinant DNA according to claim 78, which is constructed for expressing the double-stranded RNA according to claim 75.

80. A transformant obtainable by introducing the recombinant DNA according to claim 78 or 79 into a cell.