Immunoperoxidase is a type of immunostain used in molecular biology, medical research, and clinical diagnostics. In particular, immunoperoxidase reactions refer to a sub-class of immunohistochemical or immunocytochemical procedures in which the antibodies are visualized via a peroxidase-catalyzed reaction.
Immunohistochemistry and immunocytochemistry are methods used to determine in which cells or parts of cells a particular protein or other macromolecule are located. These stains use antibodies to bind to specific antigens, usually of protein or glycoprotein origin. Since antibodies are normally invisible, special strategies must be employed to detect these bound antibodies. In an immunoperoxidase procedure, an enzyme known as a peroxidase is used to catalyze a chemical reaction to produce a coloured product.
Simply, a very thin slice of tissue is fixed onto glass, incubated with antibody or a series of antibodies, the last of which is chemically linked to peroxidase. After developing the stain by adding the chemical substrate, the distribution of the stain can be examined by microscopy.