The present invention relates to molecules, particularly polypeptides, moreparticularlyimmunoglobins (e.g., antibodies), comprising a variant Fc region, wherein saidvariant Fc regioncomprises at least one amino acid modification relative to a wild-type Fcregion, which variant Fc regionbinds Fc.gamma.RIIIA and/or Fc.gamma.RIIA with a greater affinity, relative toa comparable molecule comprisingthe wild-type Fc region. The molecules of the invention are particularlyuseful in preventing, treating,or ameliorating one or more symptoms associated with a disease, disorder, orinfection. The moleculesof the invention are particularly useful for the treatment or prevention of adisease or disorder where anenhanced efficacy of effector cell function (e.g., ADCC) mediated byFc.gamma.R is desired, e.g., cancer,infectious disease, and in enhancing the therapeutic efficacy of therapeuticantibodies the effect of whichis mediated by ADCC.
