KERATIN IMMUNOCYTOCHEMISTRY IN THE LINGUAL MUCOSA OF RATS

The role of the intermediate filaments in the specialized cells of sensory receptors, and their distribution and chemical composition have not been adequately studied. The exception to this rule is the human Merkel's cells, for which it has been shown that the intermediate filaments consist of cytokeratins, 8, 18, and 19 [3]. By contrast with the mechanoreceptors, special investigations devoted to the problem of organization of the cytoskeleton and its role in chemoreceptor cells are virtually only just beginning. It was shown in [4] that intermediate filaments in taste bud cells from foliate papillae of the rabbit tongue consist of keratin. Rashbass suggested that the keratin of the intermediate filaments of taste bud cells and of the tonofilaments of the surrounding epithelium differ in their antigenic properties. A detailed study of the distribution of intermediate filaments in different types of rodent taste bud cells was undertaken in [5]. It was shown that taste bud cells have less dense concentrations of intermediate filaments than cells of the surrounding epithelium. A comparative study of the content of intermediate filaments in different types of taste bud cells showed that type III chemoreceptor cells contain the largest number of them. Monoclonal antibodies against human and porcine keratin with mol.wt. of 40 to 65 kD from normal and transformed epithelia from different parts of the body did not give an immunocytochemical reaction selectively with taste buds. In the present investigation monoclonal antibodies were chosen against rat cytokeratins, giving a positive immunocytochemical reaction with lingual taste bud cells of the same species and not interacting with cytokeratins of the surrounding epithelium of the lingual mucosa. Meanwhile, an immunocytochemical study of the exocrine glands, connected with the taste buds, was undertaken for the first time with the aid of these same monoclonal antibodies against cytokeratins. Interest in these structures is due to the existing ideas regarding their role as the source of precursors for taste bud cells [1].