MLO 0606 Cover Story.indd

Continues on page 12 This review is intended to provide the scientifi c community, in general, and the buying public, in particular, with information about the technical and fi nancial aspects of antigen retrieval (AR) — a procedure that has become an integral part of most immunohistochemical (IHC) staining protocols. Loosely defi ned, AR is a specimen pretreatment procedure that modifi es the molecular conformation of target proteins by exposing slide-mounted material, (sectioned tissue and other cellular preparations), to a heated buffer solution. This modifi cation process is necessary because, although aldehyde-based fi xatives are excellent for preserving cellular morphology, they also cause protein cross-linking, resulting in the inability of some protein epitopes to bind complementary antibodies. Antigen retrieval is commonly used in conjunction with enzyme digestion as a means of improving the reactivity of various antigens within IHCstaining reactions. Since a variety of techniques and devices have been used to perform AR, this review may be useful to individuals interested in identifying the most ideal method or instrument for their laboratories and may assist them in making betterinformed decisions. While a number of papers describing the advantages and disadvantages of various AR methods for specifi c applications have been published,1,2 few have compared the technical differences between methods,3 or objectively presented the capabilities and shortcomings of existing AR devices.