DEVELOPMENTAL-STUDY OF DISTRIBUTION AND FREQUENCY OF LANGERHANS CELLS IN RELATION TO FORMATION OF PATTERNING IN MOUSE TAIL EPIDERMIS

[摘要] The strucrure of mouse tail epidermis was investigated from day 15 of embryonic development and a qualitative and quantative analysis of the localization of Langerhans cells was carried out using the ATPase method. Langerhans cells occurred exclusively in regions where a granular layer was present in the developing epidermis. The appearance of both a granular layer and evenly distributed Langerhans cells was noted for the 1st time at embryonic days 16-17. At postnatal day 3 the number of Langerhans cells and the thickness of the granular layer was increased although the characteristic scale-interscale pattern of adult mouse tail skin was not yet outlined. This occurred 1st around postnatal day 9 and was characterized by a gradual reduction of the granular layer in the regions surrounding the forming scales. The same areas were occupied by Langerhans cells. This pattern of distribution was maintained in the adult animal. Repeated treatment of adult mouse tail skin with vitamin A resulted in a conversion of the p-keratotic epidermis into an o-keratinizing one, so that a granular layer was present throughout the whole epidermis. Langerhans cells could clearly be demonstrated in the scale regions.