The present invention relates to molecules, particularly polypeptides, moreparticularly immunoglobulins (e.g., antibodies), comprising a variant Fcregion, wherein said variant Fc region comprises at least one amino acidmodification relative to a wild-type Fc region, which variant Fc region bindsFc.gamma.RIIIA and/or Fc.gamma.RIIA with a greater affinity, relative to acomparable molecule comprising the wild-type Fc region. The molecules of theinvention are particularly useful in preventing, treating, or ameliorating oneor more symptoms associated with a disease, disorder, or infection. Themolecules of the invention are particularly useful for the treatment orprevention of a disease or disorder where an enhanced efficacy of effectorcell function (e.g., ADCC) mediated by Fc.gamma.R is desired, e.g. , cancer,infectious disease, and in enhancing the therapeutic efficacy of therapeuticantibodies the effect of which is mediated by ADCC.
