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.
