title: Interleukin-6 and tumour necrosis factor alpha are expressed by keratinocytes but not by Langerhans cells.
abstract: The presence of human cytokines was examined in parallel skin biopsies and epidermal single cell preparations obtained from normal individuals. Using biotin-avidin-peroxidase and immunofluorescence techniques and antibodies against recombinant cytokines, a granular intercellular/membrane-associated staining for interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF alpha), but not IL-1 alpha or beta, was observed. An epidermal cytoplasmic staining pattern was also detected, which was most pronounced using the anti-rIL-6 antiserum. In the epidermal single cell preparations, membrane-associated staining was detected for both IL-6 and TNF alpha. Double staining revealed that CD1-positive Langerhans cells (LC) failed to express any of the examined cytokines. In vitro binding of rIL-6 or rTNF alpha to skin sections and epidermal single cell preparations indicated that the cell surface-associated IL-6 and TNF alpha originally demonstrated on keratinocytes were truly membrane-bound. Finally, co-cultivation of epidermal cells with an IL-6 responsive cell line, B9, and testing of epidermal cell supernatants in this assay, indicated that the in vivo membrane-bound IL-6 had biological activity.
authors.affiliation: Department of Dermatology, University of California, San Francisco.
authors.forename: A
authors.initials: A
authors.lastname: Oxholm
authors.forename: M
authors.initials: M
authors.lastname: Diamant
authors.forename: P
authors.initials: P
authors.lastname: Oxholm
authors.forename: K
authors.initials: K
authors.lastname: Bendtzen
mesh_terms: D000328:Adult; D018949:Antigens, CD1; D000943:Antigens, Differentiation / Q000032:analysis; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis*; D015603:Keratinocytes / Q000737:chemistry*; D007801:Langerhans Cells / Q000737:chemistry*; D008297:Male; D013194:Staining and Labeling; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*
chemical_list: D018949:Antigens, CD1; D000943:Antigens, Differentiation; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha