The present invention provides a glycosylation engineered mammalian host cell that expresses a recombinant antibody comprising an IgG Fc region containing N-linked oligosaccharides, wherein said host cell has been genetically modified to regulate the increased expression of at least one enzyme selected from the group consisting of ²(1,4)-N-acetylglucosaminyltransferase III, ²(1,4)-N-acetylglucosaminyltransferase V, and mannosidase II, wherein said recombinant antibody has an increased proportion of GlcNAc residues in the Fc region relative to the proportion of fucose residues and has increased Fc-mediated cellular cytotoxicity compared to the corresponding antibody produced by the same host cell that has not been genetically modified.
