Immunogold Labelling of Cryosections and Cryofractures

In cell biological research the localization of particular molecules at the microscopical level has been an important aspect, leading to the development of a wide variety of cytochemical methods. These methods are based upon the property that specific markers can be coupled chemically to a wide variety of molecules, such as fluorescent markers for light microscopy and electron dense markers for electron microscopy. An important feature in cytochemistry concerns the specificity of the labelling and in this respect, the use of poly- and monoclonal antibodies caused a considerable improvement. The antibodies were bound to the various markers (both fluorescent and electron dense) and the molecules of interest were visualized via direct or two- or three-step labelling methods. Alternative methods use radioactively labelled compounds that can be visualized by autoradiography (Hayat 1972; Williams 1977; Wischnitzer 1981).