Immunohistochemical study of intermediate filament proteins on routinely processed, celloidin-embedded human temporal bone sections by using a new technique for antigen retrieval.

Although immunohistochemical studies of intermediate filament proteins have been carried out on temporal bone sections by using modified fixation/embedding techniques to preserve antigenicity, there have been no light microscopic studies concerning immunohistochemical staining on routinely formalin-fixed celloidin-embedded human temporal bone sections. A method for immunostaining routinely processed celloidin-embedded tissues would be extremely valuable in that it would permit study of the extensive collections of formalin-celloidin temporal bone specimens that exist in major centers of otopathologic research. Recently, we have developed a new technique which can be used to retrieve the antigenicity masked by formalin fixation and decalcification. This method requires immersing slides for 30 min at room temperature in a solution of saturated sodium hydroxide in methanol before immunostaining. Using this method, 45 celloidin-embedded human temporal bone sections were stained with monoclonal antibodies to keratin, vimentin, neurofilament, glial fibrillary acidic protein and desmin as primary antibodies using a sensitive streptavidin-biotin procedure. The results obtained by using this technique are at least equivalent to those obtained with modified fixatives, cryosections or immuno-electron microscopy. This new method may provide a useful approach for studying routinely processed, celloidin-embedded human temporal bone sections and open a new field in immuno-otopathology.