active agent and medicament containing them for preventing or combating graft has organ rejection in humans

This medicament is characterized in that it comprises a monoclonal antibody capable of binding to the receptor for interleukin 2 gene carried by lymphocytes and having the property of not being cytotoxic in vitro, even in the presence of complement while inhibiting the cell proliferation induced by interleukin-2, in particular the 33B3.1 antibody.