Immunohistochemical analysis of the olfactory mucosa by use of antibodies to brain proteins and cytokeratin.

The present study deals with the immunohistochemical detection of four brain-derived proteins and cytokeratin in the normal olfactory mucosa of humans and guinea pigs. Neurofilament protein immunoreactivity was found in the olfactory vesicles, dendrites, and perikaryon of receptor cells, and in thick nerve bundles located deep in the lamina propria. The antiserum to neuron-specific enolase (NSE) selectively stained olfactory receptor cells throughout the length of the bundles. The NSE immunoreactivity also was recognized in nerve bundles of various sizes throughout the lamina propria. Glia-specific S-100 protein immunoreactivity was present in Bowman's glands as well as in all nerve bundles in the lamina propria, but not in any cellular elements constituting the olfactory epithelium. Immunoreactivity for spot-35 protein, which was considered to be specific for cerebellar Purkinje cells, was found in flasklike cells (microvillar cells) occurring near the free surface of the epithelium. The basal cells in the olfactory and respiratory epithelium were stained positively with a cytokeratin antiserum.