Langerhans cell surface densities in rat oral mucosa and human buccal mucosa.

We determined surface densities of Langerhans cells (LCs) in rat oral mucosa and human buccal mucosa by enumerating ATPase-positive dendritic cells in epithelial whole mounts. For the rat, mean surface densities per mm2 were 160 in anterior buccal mucosa, 640 in posterior buccal mucosa, 430 in the palate and 340 in the tongue. Human buccal mucosa showed a density of 890 cells per mm2. We conclude that LC densities in oral mucosa approximate those of external body sites, making them available in numbers sufficient to accomplish their postulated antigen-presenting functions.