ABSTRACT
Nakene and Pierce, in 1966, first proposed that enzymes be used in the place of fluorochromes as labels for antibodies. Horseradish peroxidase (HRP) is the enzyme label most widely employed. The immunoperoxidase technique permits the demonstration of antigens in various types of cells and fixed tissues. This method has certain advantages that include the following: (1) the use of conventional light microscopy; (2) the stained preparations may be kept permanently, (3) the method may be adapted for use with electron microscopy of tissues, and (4) counterstains may be employed. The disadvantages include the following: (1) the demonstration of relatively minute positively staining areas is limited by the resolution of the light microscope; (2) endogenous peroxidase may not have been completely eliminated from the tissue under investigation; and (3) diffusion of products results from the enzyme reaction away from the area where antigen is localized.
