The properties of an Fc-containing protein, for example, an antibody, are controlled by altering the sialylation of the oligosaccharides in the Fc region. The modified Fc-containing proteins have therapeutic utility in diseases or conditions in which it is desirable to control the affinity for one or more of the FcgRI, FcgRIIA, and FcgRIIIA receptors, ADCC activity, macrophage or monocyte activation, serum half-life, and avidity.
