Antibody composition-producing cell

1. A method of producing an antibody composition which comprises antibody molecules, wherein said method comprises culturing a mammalian cell that produces an antibody molecule, said mammalian cell having a decrease in, or an absence of, α1,6-fucosyltransferase activity,

wherein said decrease in, or absence of, α1,6-fucosyltransferase activity results from deleting a gene encoding α1,6-fucosyltransferase, or from mutating said gene to reduce or eliminate the α1,6-fucosyltransferase activity,

and wherein the antibody molecule has an Fc region comprising two complex-type and/or hybrid-type N-glycoside-linked sugar chains bound to the Fc region, wherein said sugar chains comprise a reducing terminal which contains an N-acetylglucosamine, and wherein at least one of said sugar chains does not contain fucose bound to the 6-position of the N-acetylglucosamine in the reducing terminal of the sugar chain.

2. The method of claim 1 , wherein at least 80% of the antibody molecules produced by said cell are non-fucosylated antibody molecules.

3. The method of claim 2 , wherein the antibody molecules in said composition consist essentially of the non-fucosylated antibody molecules.

4. The method of claim 2 , wherein the antibody molecules in said composition consist of the non-fucosylated antibody molecules.

5. A method of increasing the ratio of a non-fucosylated antibody molecule in an antibody composition, wherein said method comprises:

culturing a mammalian cell that produces an antibody molecule, said mammalian cell having a decrease in, or an absence of, α1,6-fucosyltransferase activity, thereby increasing the ratio of a non-fucosylated antibody molecule in an antibody composition; and

measuring the ratio of non-fucosylated antibody in the resulting composition,

wherein said decrease in, or absence of, α1,6-fucosyltransferase activity results from deleting a gene encoding α1,6-fucosyltransferase, or from mutating said gene to reduce or eliminate the α1,6-fucosyltransferase activity,

and wherein the antibody molecule has an Fc region comprising two complex-type and/or hybrid-type N-glycoside-linked sugar chains bound to the Fc region, wherein said sugar chains comprise a reducing terminal which contains an N-acetylglucosamine, and wherein at least one of said sugar chains does not contain fucose bound to the 6-position of the N-acetylglucosamine in the reducing terminal of the sugar chain.

6. The method of claim 5 , wherein at least 80% of the antibody molecules produced by said cell are non-fucosylated antibody molecules.

7. The method of claim 6 , wherein the antibody molecules in said composition consist essentially of the non-fucosylated antibody molecules.

8. The method of claim 6 , wherein the antibody molecules in said composition consist of the non-fucosylated antibody molecules.

9. A method of increasing the antibody-dependent cellular cytotoxicity (ADCC) of an antibody composition by increasing the ratio of a non-fucosylated antibody molecule in the antibody composition, wherein said method comprises:

culturing a mammalian cell that produces an antibody molecule, said mammalian cell having a decrease in, or an absence of, α1,6-fucosyltransferase activity, thereby increasing the antibody-dependent cellular cytotoxicity (ADCC) of an antibody composition; and

measuring ADCC activity of the resulting composition,

wherein said decrease in, or absence of, α1,6-fucosyltransferase activity results from deleting a gene encoding α1,6-fucosyltransferase, or from mutating said gene to reduce or eliminate the α1,6-fucosyltransferase activity,

and wherein the antibody molecule has an Fc region comprising two complex-type and/or hybrid-type N-glycoside-linked sugar chains bound to the Fc region, wherein said sugar chains comprise a reducing terminal which contains an N-acetylglucosamine, and wherein at least one of said sugar chains does not contain fucose bound to the 6-position of the N-acetylglucosamine in the reducing terminal of the sugar chain.

10. The method of claim 9 , wherein at least 80% of the antibody molecules produced by said cell are non-fucosylated antibody molecules.

11. The method of claim 10 , wherein the antibody molecules in said composition consist essentially of the non-fucosylated antibody molecules.

12. The method of claim 10 , wherein the antibody molecules in said composition consist of the non-fucosylated antibody molecules.

13. A method for producing an antibody with enhanced ADCC activity, comprising culturing an animal cell containing a DNA encoding an antibody, to allow said cell to produce the antibody, and recovering the antibody produced,

wherein said animal cell is modified, by a modification, to exhibit a reduced amount, or an absence, of N-glycoside-linked sugar chains containing fucose linked through an α-1,6 linkage, and wherein said animal cell produces antibodies that do not contain fucose linked through an α-1,6 linkage,

and wherein the antibody has an Fc region comprising two complex-type and/or hybrid-type N-glycoside-linked sugar chains bound to the Fc region, wherein said sugar chains comprise a reducing terminal which contains an N-acetylglucosamine, and wherein at least one of said sugar chains does not contain fucose bound to the 6-position of the N-acetylglucosamine in the reducing terminal of the sugar chain.

14. The method of claim 13 , wherein said modification causes a reduction in, or an absence of, at least one intracellular sugar nucleotide in said cell, said at least one intracellular sugar nucleotide being selected from the group consisting of: GDP-α4-keto-6-deoxymannose; GDP-α4-keto-6-deoxygalactose; and GDP-fucose.

15. The method of claim 13 , wherein said modification is the introduction into said cell, or the deletion from said cell, of an enzyme, said introduction or deletion causing a reduction in the amount, or an absence, of the at least one intracellular sugar nucleotide in said cell.

16. The method of claim 15 , wherein the enzyme is an enzyme which alters the structure of a substrate for an enzyme in a GDP-fucose synthesis pathway.

17. The method of claim 16 , wherein the enzyme in the GDP-fucose synthesis pathway is GDP-keto-6-deoxymannose 3,5-epimerase 4-reductase.

18. The method of claim 13 , wherein 20% or more of the total antibodies produced by said cell do not contain fucose linked through an α-1,6 linkage.

19. The method of claim 18 , wherein 50% or more of the total antibodies produced by said cell do not contain fucose linked through an α-1,6 linkage.

20. The method of claim 13 , wherein the cell is a CHO cell.