Antigen Retrieval Techniques

The vast majority of antigen retrieval studies have been applied to formalin fixed material. When aldehyde-based fixatives are used (e.g. formalin), inter- and intra-molecular cross links are produced with certain structural proteins which are responsible for the masking of tissue antigens. With aldehyde-based fixatives this adverse effect is thought to be due to the formation of methylene bridges between reactive sites on tissue proteins. These reactive sites include primary amines, amide groups, thiols, alcoholic hydroxyl groups and cyclic aromatic rings. The degree of masking of the antigenic sites depends upon the length of time of fixation, temperature, concentration of fixative and the availability of other nearby proteins able to undergo cross-linkages. In order to "unmask" these antigenic sites, a range of antigen retrieval techniques are available at our laboratories.