Antibody composition-producing cell

A method for producing an antibody composition, said method comprising culturing a cell in a cell culture medium to produce and accumulate an antibody composition in the culture;

• and recovering the antibody composition from the culture,
• wherein said cell is a mammalian cell into which a gene encoding an antibody molecule is introduced, and wherein said mammalian cell produces the antibody composition comprising an antibody molecule having complex N-glycoside-linked sugar chains bound to the Fc region, wherein among the total complex N-glycoside-linked sugar chains bound to the Fc region in the composition, the ratio of a sugar chain in which fucose is not bound to N-acetylglucosamine in the reducing end in the sugar chain is 20% or more,
• wherein said mammalian cell is resistant to a lectin which recognizes a sugar chain in which the 1-position of fucose is bound to the 6-position of N-acetylglucosamine in the reducing end through an α-bond in the complex N-glycoside-linked sugar chain,
• wherein said lectin resistance results from decreasing or deleting the activity of an enzyme in said cell, said enzyme being selected from the group consisting of (a)-(d):
• (a) GDP-mannose 4,6-dehydratase;
• (b) GDP-keto-6-deoxymannose 3,5-epimerase, 4-reductase;
• (c) GDP-beta-L-fucose pyrophosphorylase;
• and
• (d) α1,6-fucosyltransferase,
• and wherein said antibody composition has greater antibody-dependent cellular cytotoxicity activity than an antibody composition produced by expressing said gene in the parent mammalian cell that has not had the activity of the enzyme selected from the group of (a)-(d) decreased or deleted and that is not resistant to said lectin.