Langerhans Cells and Extra‐Epidermal Dendritic Cells

Abstract

S‐100 protein was demonstrated in the cytoplasm of dendritic cells (DCs) in normal and pathologic lymphoid tissues and epidermis in man and several other species. The presence of S‐100) protein served to distinguish these cells from other mononuclear cells, most importantly from those of macrophage/histiocyte lineage. Fractionation procedures to isolate and enrich suspensions of DCs were coupled with immunocytochemical techniques to identify S‐100‐positive cells. Langerhans cells in the epidermis and in aural cholesteatomata and nodal, splenic, and thymic interdigitating cells were S‐100‐positive. Lymph node and splenic follicular dendritic cells (except in rats) were negative, indicating that this DC may be a separate cell type.