Ultrastructural observation on Langerhans cells in the rat gingival epithelium.

Abstract

The present study was carried out to investigate ultrastructurally Langerhans cells in the rat gingival epithelium. The gingivae of lower incisors of 15 Wistar rats were examined by electron microscopy. The results were as follows: Langerhans cells were observed mainly in the lower prickle‐cell layer of the gingival epithelium. On rare occasions Langerhans cells were also found in the basal and granular layers. The average number of Langerhans cells per 100 cells in the prickle‐cell layer was 1.0 cell. Usually Langerhans cells had clear cytoplasms and convoluted or indented nuclei, although sometimes the cells exhibited round nuclei. The clear cytoplasm contained a moderately developed Golgi apparatus and a small number of rough surfaced endoplasmic reticulum, free ribosomes, mitochondria, and lysosomes, but it lacked tonofilaments. Birbeck granules were often found in close vicinity of the Golgi apparatus. The average number of Birbeck granules per one Langerhans cell was 4.3 granules. The cell membrane of Langerhans cells had no junctional complexes like desmosomes. The degeneration of keratinocytes adjacent to Langerhans cells was observed in a few specimens.