Antibodies, compositions comprising such antibodies, and uses thereof in thetreatment of diseases such ascancer are described, in which the antibodies are observed to bind to aphosphatidylserine (PS)-coated ELISAplate in an ELISA conducted in the presence of 10% serum. Hybridomas and hostcells producing suchantibodies, as well as nucleic acids and expression vectors encoding suchantibodies are also provided.Antibodies described herein include antibody 3G4, deposited as ATCC AccessionNumber PTA 4545, andchimeric 3G4 antibodies comprising human antibody constant regions.