Immunochemical and immunocytochemical localization of S-100 antigen in normal human skin

Abstract

The S-100 antigen¹ is generally considered to be unique to the nervous system, where it is found primarily in the cytoplasm and nucleus of glial cells, both in soluble and bound form^2,3. It belongs to the family of acidic Ca²⁺-binding proteins⁴. In phylogenesis, S-100 conserves a close immunological relationship between different species, and during ontogenesis the pattern of its accumulation parallels the functional maturation of the nervous system^2,3, although its biological role remains to be clarified. Recently, S-100 has been found in cells of non-nervous organs (interstitial cells of the pineal gland⁵, stellate cells of the adenohypophysis^6,7 and satellite cells of the adrenal medulla⁸), and in cultured malignant human melanomas⁹. We report here the presence of S-100 in normal human skin, where the antigen seems to be located specifically in melanocytes and in cells with morphological features of Langerhans cells.