title: Selective induction of interleukin-12 in reconstructed human epidermis by chemical allergens.
abstract: Keratinocytes play an important role in skin inflammatory and immunological reactions through the release of cytokines and response to them. These cells have been shown to direct T-cell priming by producing cytokines such as interleukin (IL)-10 and IL-12. The purpose of this work was to explore the potential use of IL-12 production to discriminate between skin irritants and contact allergens in vitro. Initially, a reconstituted human epidermis was treated with a known human skin irritant, sodium lauryl sulphate (SLS), and a known human contact allergen, 1-chloro-2,4-dinitrobenzene (DNCB). The expression of IL-12p40 was assessed at specific time intervals by the semi-quantitative reverse transcriptase-polymerase chain reaction (rt-PCR). The data obtained indicated that only DNCB induced an up-regulation of IL-12p40. This up-regulation occurred after exposure to DNCB for 3 hours. Importantly, the application of SLS or vehicles did not induce IL-12 mRNA up-regulation. An increase in total IL-12 protein content was detected in supernatants of allergen-stimulated, but not vehicle-stimulated, reconstituted epidermis. To confirm these results, the effects of benzalkonium chloride, oxazolone and eugenol were assessed. At concentrations that resulted in equivalent IL-1α release, only contact allergens increased IL-12 expression, which confirmed the previous results. These data suggest that IL-12, which is crucial for T-helper type 1 cell responses, could be a useful marker for discriminating between contact allergens and irritants.
authors.affiliation: Center for Cosmetic Toxicology, Institute of Pharmacological Sciences, Via Balzaretti 9, 20133 Milan, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Corsini
authors.affiliation: Center for Cosmetic Toxicology, Institute of Pharmacological Sciences, Via Balzaretti 9, 20133 Milan, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Limiroli
authors.affiliation: Center for Cosmetic Toxicology, Institute of Pharmacological Sciences, Via Balzaretti 9, 20133 Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Marinovich
authors.affiliation: Laboratoire de Recherche Fondamentale de L'Oréal, 93600 Aulnay-sous-Bois, France.
authors.forename: C
authors.initials: C
authors.lastname: Cohen
authors.affiliation: Laboratoire de Recherche Fondamentale de L'Oréal, 93600 Aulnay-sous-Bois, France.
authors.forename: R
authors.initials: R
authors.lastname: Roguet
authors.affiliation: Center for Cosmetic Toxicology, Institute of Pharmacological Sciences, Via Balzaretti 9, 20133 Milan, Italy.
authors.forename: C L
authors.initials: CL
authors.lastname: Galli