Antibody population uniformly including antibodies having left-right asymmetric sugar chain, and method for producing same

Provided are: a method for producing an antibody population uniformly including antibodies having a left-right asymmetric sugar chain; and a uniform antibody population of antibodies having a left-right asymmetric sugar chain, which is obtained by said method. This method for producing an antibody population, which uniformly includes antibodies in which N-type complex sugar chains bound to asparagines (Asn) at the 297th positions in CH domains of Fc regions of two heavy chains on the left and right sides of an antibody are sugar chains having different structures, comprises: (i) a step for cleaving, by endo-β-N-acetylglucosaminidase (ENGase), sugar chains bound to two heavy chains on the left and right sides of the antibody in an antibody composition, and purifying and isolating antibodies in which sugar chains of both heavy chains are cleaved; (ii) a step for mixing a population of the antibodies in which sugar chains of both heavy chains are cleaved and which are obtained in step (i), any oxazolined sugar chain X or a sugar derivative which generates oxazoline and of which the sugar chain is a sugar chain X, and ENGase which is modified so as to suppress sugar chain cleavage activity and improve sugar chain transfer activity, to produce antibodies in which the sugar chain X is bound to only one heavy chain among two heavy chains on the left and right sides, and purifying and isolating the antibodies; and (iii) a step for mixing the antibodies in which the sugar chain X is bound to only one heavy chain among two heavy chains on the left and right sides and which are obtained in step (ii), an oxazolined sugar chain Y having a structure different from that of the sugar chain X or a sugar derivative which generates oxazoline and of which the sugar chain is a sugar chain Y, and ENGase which is modified so as to suppress sugar chain cleavage activity and improve sugar chain transfer activity, to produce antibodies in which the sugar chain Y is bound to the other heavy chain among the two heavy chains on the left and right sides and the sugar chains bound to the two heavy chains on the left and right sides are sugar chains having different structures, and purifying and isolating the antibodies.