Abstract: A method of enhancing the antibody-dependent cellular cytotoxicity (ADCC) of a human or humanized CD19 antibody is disclosed. The antibody is produced in the presence of a beta.(1,4)-N-acetylglucosaminyltransferase III (GnTIII) enzyme, under conditions effective to produce in the antibody, an Fc fragment characterized by Asn297-linked oligosaccharides containing (i) at least 60% N-acetylglucosamine bisecting oligosasccharides, and (ii) at least 10% non-fucosylated N-acetylglucosamine bisecting oligosaccharides. Also disclosed is an anti-CD19 antibody, a composition produced by the method, a treatment method for cancers associated with malignant B-lineage cells, such as chronic lymphocytic leukemia, Non-Hodgkin lymphoma, and acute lymphoblastic leukemia, and a treatment method for autoimmune disease.

Abstract: Bispecific antibody derivatives are disclosed which are comprised of a first region which binds to a first antigen and a second region which binds to a second antigen different from the first antigen. The first and second regions of the bispecific antibody are each stabilized by an additional internal disulfide bridge, and connected by a flexible polypeptide linker. The bispecific antibody is devoid of an Fc portion and is encoded as a single chain-sequence.