Intermediate filaments in mouse taste bud cells.

The intermediate filaments in mouse taste bud cells were studied by immunocytochemistry using antikeratin antibodies, and by conventional electron microscopy. Taste bud cells (types I, II, and III) possessed less densely aggregated bundles of intermediate filaments than the surrounding epithelial cells. Type III cells, however, contained more densely aggregated bundles than type I or II cells. Basal cells in the taste buds showed aggregations of filaments as dense as those seen in the epithelial cells, although their bundles were more slender than those of the epithelial cells. The antibodies to keratins from the bovine muzzle and human stratum corneum stained all types of the taste bud cells as well as the surrounding epithelial cells. PKK2 antibody reacted with the surrounding epithelial cells, but did not react with the taste bud cells. These results show that keratins are present in both taste bud and surrounding epithelial cells, although the keratin subtype differs between those cells. This finding has led us to the supposition that all cell types comprising the taste buds--including type III (receptor) cells--originate from the epithelial cells surrounding the taste buds. It is also suggested that both keratin subtypes and aggregation patterns of intermediate filament bundles change during differentiation from surrounding epithelial cells to taste bud cells, and from basal cells in the taste buds to types I, II, or III cells.