The Langerhans cell in hairless mouse epidermis.

Hairless mouse epidermis was separated from the underlying dermis using a 2 h incubation in 20 mM ethylenediaminetetraacetic acid (EDTA). The basal epidermis, thus exposed, was then examined using scanning electron (SEM), transmission electron (TEM), and light microscopy (LM). Sheets were also stained for: (i) Langerhans cell adenosine triphosphatase (ATPase), beta-glucuronidase, and la antigens; and, (ii) melanocyte 3,4-dihydroxyphenylalanine (DOPA)-oxidase. A regular distribution of protruding dendritic cells was observed superficial to the basal epidermis. These external dendritic cells were identified as Langerhans cells on the basis of subcellular morphology and distribution in the TEM. ATPase staining was Langerhans cell specific. The Langerhans cell population in hairless mouse epidermis was large, and evenly distributed in the interfollicular epidermis and the outer root sheath of degenerate hair follicles. The melanocyte population, in comparison, was negligibly small (4-5 cells per mm2).