Obtaining recombinant renalase protein and preparation of monoclonal antibodies are the essential steps for the study of renalase's function, expression and distribution in renal tissues and cells. Recently we have been using recombinant renalase protein produced by prokaryotic expression system to develop monoclonal antibodies, and we also have tried to use recombinant protein produced by eukaryotic expression systems such as baculovirus etc, to develop monoclonal antibodies. However, obtaining large volume of eukaryotic expressed recombinant renalase protein has not been such an easy task [5, 6] .