A double protein A-gold-silver staining method for tissue antigens in light microscopy.

A double staining method has been developed for light microscopic immunohistochemistry. The technique consists of a sequence of protein A-gold-silver procedures, in which the reaction products are visualized in black and brown colours. The results obtained in the rat pancreatic islets and adenohyophysis, in combination with a variety of histochemical controls, substantiate both the specificity and reliability of this method. The double staining method is simple and economical, since the two differently coloured reaction products are obtained by a common mechanism of colouration (physical development) using a single probe, protein A-gold.