Described are mono- and multivalent scFv-antibodies comprising the binding sites specific for the human T cell marker CD3. These antibodies are strongly immunosuppressive and do not cause a significant release of cytokines. Furthermore, polynucleotides encoding said antibodies are described as well as vectors comprising said polynucleotides, host cells transformed therewith and their use in the production of said antibodies. Pharmaceutical compositions containing any of the above mentioned polynucleotides, antibodies or vectors are useful for immunotherapy, preferably against acute transplant rejections. <；IMAGE>；
