The IgG form of antibodies is suitable for the majority of immunodetection procedures and is the most cost effective. Horseradish peroxidase (HRP) conjugates are prepared by a modified Nakane and Kawaoi procedure . Peroxidase conjugates are commonly used for immunohistochemistry, Western blotting, and ELISA. Affinity purification anti-horseradish peroxidase and conjugates are available for detection of horseradish peroxidase antigen or for signal amplification of HRP-containing reagents. For immunostaining of mammalian cells, an advantage of using anti-horseradish peroxidase is reduced background, since the antibody does not recognize the endogenous peroxidase-like enzymes found in those cells.