A Modified Adenosine Polyphosphatase Histochemical Method to Demonstrate Langerhans Cells in Fragile Epidermis

Adenosine polyphosphatase enzymes provide useful markers for epidermal Langerhans cells. Established adenosine polyphosphatase histochemical methods were refined and applied to demonstrate Langerhans cells in thin sheets of murine dorsal epidermis. The skin was supported during staining by attaching the keratinized surface to polyallyl diglycol carbonate “plastic” slides with cyanoacrylate adhesive and flattening it with pressure from a glass slide on the dermal surface. Optimal specific staining of dendritic Langerhans cells occurred after fixation of ethylenediaminetetraacetic acid-separated epidermal sheets in cacodylate buffered formaldehyde for 20 min and incubation, in the presence of magnesium and lead ions, with 9.36 × 10^-4 M adenosine diphosphate (ADP) for 45 min. Better definition of the cells was obtained with ADP as a substrate than with any concentration of adenosine triphosphate.