title: Development of an in vitro method to estimate the sensitization induction level of contact allergens.
abstract: No standardized in vitro methods to assess potency of skin sensitizers are available. Recently, we standardized a procedure which combines the epidermal equivalent potency assay with assessment of IL-18 to provide a single test for identification and classification of skin sensitizers. This current study aimed to extend tested chemicals, and to provide a simple in vitro method for estimation of the expected sensitization induction level interpolating in vitro EC50 and IL-18 SI2 values to predict LLNA EC3 and/or human NOEL from standards curves generated using reference contact allergens. Reconstituted human epidermis was challenged with 14 chemicals not previously tested benzoquinone, chlorpromazine, chloramine T, benzyl salicylate, diethyl maleate, dihydroeugenol, 2,4-dichloronitrobenzene, benzyl cinnamate, imidazolidinyl urea, and limonene as contact sensitizers while benzyl alcohol, isopropanol, dimethyl isophthalate and 4-aminobenzoic acid as non-sensitizers in the LLNA. Where for benzyl salicylate and benzyl cinnamate no sensitization was observed in human predictive studies, positive responses to benzyl alcohol and dimethyl isophthalate were reported. The proposed method correlates better with human data, correctly predicting substances incorrectly classified by LLNA. With the exception of benzoquinone (interference with both MTT and IL-18 ELISA), and chloramine T (underestimated in the interpolation), a good estimation of LLNA EC3 and in vivo available human NOEL values was obtained.
authors.affiliation: Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Galbiati
authors.affiliation: Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Papale
authors.affiliation: Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Marinovich
authors.affiliation: Department of Dermatology, VU University Medical Centre, Amsterdam, The Netherlands; Department of Oral Cell Biology, ACTA, Amsterdam, The Netherlands.
authors.forename: Sue
authors.initials: S
authors.lastname: Gibbs
authors.affiliation: 3Rs Management and Consultancy, Denmark.
authors.forename: Erwin
authors.initials: E
authors.lastname: Roggen
authors.affiliation: Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy. Electronic address: emanuela.corsini@unimi.it.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Corsini
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000592:standards; D002138:Calibration; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D017449:Dermatitis, Allergic Contact / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D003877:Dermatitis, Contact / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004817:Epidermis / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D020382:Interleukin-18 / Q000378:metabolism; D007509:Irritants / Q000633:toxicity*; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D023441:Local Lymph Node Assay; D008297:Male; D051379:Mice; D019055:No-Observed-Adverse-Effect Level; D012015:Reference Standards; D015203:Reproducibility of Results; D018570:Risk Assessment; D023422:Skin Irritancy Tests / Q000379:methods* / Q000592:standards
chemical_list: D020382:Interleukin-18; D007509:Irritants
keywords: 3D model; Contact allergens; Contact hypersensitivity; In vitro; Potency; Reconstituted human epidermis