KERATINS AS MARKERS OF DIFFERENTIATED TASTE CELLS OF THE RAT

Cytokeratins in taste buds were immunocytochemically evaluated with mo noclonal antibodies. In each of six different epithelial sites in the rat oral cavity, intragemmal cells of taste buds were immunoreactive f or keratin polypeptides 8, 18, and 19, as well as for keratin 7, which has not been previously reported in taste buds. Keratin-18-like immun oreactivity was present in fewer than half of the intragemmal cells, w hereas all intragemmal cells were immunopositive for keratins 7, 8, an d 19. Apart from some salivary duct cells, no other cells in the tongu e were immunoreactive for any of these four keratins. Morphological an d immunocytochemical profiles indicate that taste buds are islets of s imple epithelium embedded in an expanse of stratified squamous epithel ium. These simple epithelial cells and their keratins are nerve-depend ent, since denervation eliminated all four keratins and replaced elong ated taste cells of the vallate papilla with stratified squamous epith elium. We conclude that antibodies against keratins 7, 8, or 19 are us eful markers for intragemmal cells in studies of taste bud development , degeneration, regeneration, turnover and tissue culture.