title: Activation of murine epidermal TCR-gamma delta+ T cells by keratinocytes treated with contact sensitizers.
abstract: The vast majority of TCR gamma delta+, CD4-, CD8- T cells resident in the adult mouse epidermis expresses tissue-specific V-region genes (V gamma 3/V delta 1) in the absence of junctional diversity. The role this unique T cell population plays in the immune surveillance of the skin is not clear. It has been shown that dendritic epidermal T cells (DETC) were activated by stressed keratinocytes and that stimulated DETC produced, for example, a keratinocyte-specific growth factor. To investigate whether DETC are involved in the induction of a contact allergy, we examined the influence of contact sensitizers and nonsensitizing contact irritants on the DETC response toward epidermal symbionts. We show that 9 of 15 cloned DETC are specifically activated, apparently in a non-MHC-restricted way, to proliferate in the presence of keratinocytes or unseparated epidermal cells, which were treated with a sensitizing agent either in vivo or in vitro. All seven tested contact sensitizing substances activated all of the reactive DETC, while keratinocytes/epidermal cells treated with nonsensitizing irritants were as nonstimulatory as vehicle controls. We demonstrate that direct cell to cell contact of DETC and stimulatory keratinocytes/epidermal cells was required and that the TCR was involved in the induction of DETC proliferation. This specific reactivity of DETC toward keratinocytes or epidermal cells pretreated with a contact sensitizer may be indicative of participation of epidermal T cells in the induction of a contact sensitivity and points to a possible role of DETC in the skin immune system.
authors.affiliation: Department of Dermatology, Johannes Gutenberg University, Mainz, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Huber
authors.forename: P
authors.initials: P
authors.lastname: Descossy
authors.forename: R
authors.initials: R
authors.lastname: van Brandwijk
authors.forename: J
authors.initials: J
authors.lastname: Knop
mesh_terms: D000818:Animals; D001565:Benzoates; D019817:Benzoic Acid; D002450:Cell Communication; D002455:Cell Division; D003877:Dermatitis, Contact / Q000276:immunology*; D004139:Dinitrofluorobenzene; D000078404:Epidermal Cells; D004817:Epidermis / Q000276:immunology*; D015603:Keratinocytes / Q000166:cytology / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D010853:Picryl Chloride; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D001565:Benzoates; D016692:Receptors, Antigen, T-Cell, gamma-delta; D019817:Benzoic Acid; D004139:Dinitrofluorobenzene; D010853:Picryl Chloride