Strategies in Immunolabelling

Abstract

Albert Coons (Coons et al, 1941) began the science of immunocytochemistry when, in the light microscope, he demonstrated the possibility of localising tissue substances with fluorescent antibodies. Since then numerous ingenious markers have been attached to antisera and other macromolecules in order to identify tissue and cellular substances both in the light and the electron microscope. Ferritin (Singer, 1959) was the first EM marker, followed by enzymes, the most efficient of which for EM proved to be horse-radish peroxidase (Nakane and Pierce, 1966), because diaminobenzidine (DAB), one of its chromogens, could be made electron dense with osmium (Seligman et al, 1968). Peroxidase/DAB has unique properties making it a useful LM marker with EM potential. Colloidal gold was introduced as an EM immunocytochemical marker by Faulk and Taylor (1971), although its value as an electron dense tracer had been established by Feldherr and Marshall (1962). Its versatility and simplicity of manufacture and use rapidly established it as the EM marker of choice. Today, imunocolloidal gold and immunoperoxidase/DAB make up the bulk of immunolabelling methods and are summarised and compared in Fig. 6.