Cytochemical identification of ATPase-positive langerhans cells in EDTA-separated sheets of mouse epidermis.

Sheets of epidermis for incubation to demonstrate ATPase activity were obtained from specimens of mouse footpad using EDTA as the separation medium. The use of EDTA in place of the NaBr method previously described, resulted in a greatly reduced incubation time, precise localization of reaction product and preservation of ultrastructural detail. A population of closely and regularly spaced ATPase-positive dendritic cells was demonstrated by light microscopy. Electron microscopy demonstrated that, with short incubation times, reaction product was found only in the extracellular space adjacent to dendritic cells, the majority of which possessed the typical ultrastructural features of Langerhans cells.