Antibody preparations with reduced hydrophobic interactions between Fc side chains and sugar residues of the oligosaccharide backbone present in the CH2 regions of the Fc and/or increased hydrophilic reactions between Fc side chains and sugar residues in the CH2 regions of the Fc-containing protein compared to a wild-type antibody, are prepared by enzymatic treatment, expression under certain conditions, use of particular host cells, and contact with serum. These antibody preparations resist cleavage by proteases, such as papain, ficin, bromolein, pepsin, a matrix metalloproteinase, such as MMP-7, neutrophil elastase (HNE), stromelysin (MMP-3) and macrophage elastase (MMP-12), and glycosylation modification enzymes.
