However what parts of kidney and which renal cell renalase is expressed in are not clear yet. In order to obtain high sensitive anti-renalase antibody, this study used DNA immunization which is an established laboratory technique that has been done successfully. Study was conducted using self-made anti-renalase monoclonal antibody, and findings were consistent with the literature, that is, renalase was expressed in both glomeruli and renal tubule [1] . Further in vitro testing showed renalase expressed in mesangial cells, podocytes and tubular epithelial cells, especially only tubular epithelial cells can secrete renalase to the supernatant. Therefore, tubular epithelial cells may be the major cells that can secrete renalase. Such observation has not been reported. These study findings indicate that anti-renalase monoclonal antobodies used in this study could identify natural renalase protein and it is a good experiment tool.