Abstract: The present invention relates to antibodies or fragments thereof that specifically bind Fc?RIIB, particularly human Fc?RIIB, with greater affinity than said antibodies or fragments thereof bind Fc?RIIA, particularly human Fc?RIIA. The present invention also provides the use of an anti-Fc?RIIB antibody or an antigen-binding fragment thereof, as a single agent therapy for the treatment, prevention, management, or amelioration of a cancer, preferably a B-cell malignancy, particularly, B-cell chronic lymphocytic leukemia or non-Hodgkin's lymphoma, an autoimmune disorder, an inflammatory disorder, an IgE-mediated allergic disorder, or one or more symptoms thereof. The invention provides methods of enhancing the therapeutic effect of therapeutic antibodies by administering the antibodies of the invention to enhance the effector function of the therapeutic antibodies. The invention also provides methods of enhancing efficacy of a vaccine composition by administering the antibodies of the invention.

Abstract: The present invention relates to molecules, preferably soluble (i.e., not membrane bound) polypeptides, most preferably soluble fusion polypeptides comprising the extracellular soluble regions of an Fc&ggr;R, derivatives and analogs thereof, and nucleic acids encoding same. Molecules of the invention are particularly useful for the treatment, management, or prevention of, or amelioration of one or more symptoms of, an autoimmune disease, especially for ameliorating serum platelet deficiency associated with immune thrombocytopenic purpura. The invention provides methods and compositions for enhancing the therapeutic efficacy of standard, current or experimental therapies for an autoimmune disease by administering a molecule of the invention.

Abstract: CD16A binding proteins useful for the reduction of a deleterious immune response are described. In one aspect, humanized anti-CD16A antibodies, optionally lacking effector function, are used for treatment of immune disorders such as idiopathic thrombocytopenic purpura and autoimmune hemolytic anemia.