The present invention provides a method for the selection of bispecific single chain antibodies comprising a first binding domain capable of binding to an epitope of CD3 and a second binding domain capable of binding to the extracellular domain cell surface antigens with a high molecular weight extracellular domain. Moreover, the invention provides bispecific single chain antibodies produced by the use of the method of the invention, nucleic acid molecules encoding these antibodies, vectors comprising such nucleic acid molecules and methods for the production of the antibodies. Furthermore, the invention provides pharmaceutical compositions comprising bispecific single chain antibodies of the invention, medical uses of the same and methods for the treatment of diseases comprising the administration of bispecific single chain antibodies of the invention.
