title: Classification of sensitizing and irritative potential in a combined in-vitro assay.
abstract: We have developed a coculture system which in parallel indicates the sensitizing and irritative potential of xenobiotics. The assay is named loose-fit coculture-based sensitization assay (LCSA) and may be performed within 5 days. The system is composed of human monocytes that differentiate to a kind of dendritic cells by 2-day culturing in the presence of allogenic keratinocytes. The culture medium is enriched by a cocktail of recombinant cytokines. On day 3, concentration series of probes are added. On day 5, cells are harvested and analyzed for expression range of CD86 as a marker of sensitizing potential and for uptake of the viability stain 7-AAD as a marker of irritative potential. Estimation of the concentration required to cause a half-maximal increase in CD86 expression allowed quantification of sensitizing potential, and estimation of the concentration required to reduce viability to 50% allowed quantification of irritative potential. Examination of substances with known potential resulted in categorization of test scores. To evaluate our data, we have compared results with those of the validated animal-based sensitization test, the murine local lymph node assay (LLNA, OECD TG 429). To a large extent, results from LCSA and from LLNA achieved analogous grouping of allergens into categories like weak-moderate-strong. However, the new assay showed an improved capacity to distinguish sensitizers from non-sensitizers and irritants. In conclusion, the LCSA contains potential to fulfil the requirements of the EU's programme for the safety of chemicals "Registration, Evaluation, Authorization and Restriction of chemical substances" (REACH, 2006) to replace animal models.
authors.affiliation: Institute of Clinical Pharmacology and Toxicology, Charité, Berlin, Germany. reinhard.wanner@charite.de
authors.forename: Reinhard
authors.initials: R
authors.lastname: Wanner
authors.forename: Anna
authors.initials: A
authors.lastname: Sonnenburg
authors.forename: Maria
authors.initials: M
authors.lastname: Quatchadze
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schreiner
authors.forename: Matthias
authors.initials: M
authors.lastname: Peiser
authors.forename: Torsten
authors.initials: T
authors.lastname: Zuberbier
authors.forename: Ralf
authors.initials: R
authors.lastname: Stahlmann
mesh_terms: D000485:Allergens / Q000276:immunology / Q000633:toxicity*; D000818:Animals; D051940:B7-2 Antigen / Q000378:metabolism; D001681:Biological Assay; D002454:Cell Differentiation; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D017449:Dermatitis, Allergic Contact / Q000276:immunology; D006801:Humans; D007509:Irritants / Q000276:immunology / Q000633:toxicity*; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects; D051379:Mice; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D012130:Respiratory Hypersensitivity / Q000276:immunology; D015262:Xenobiotics / Q000276:immunology / Q000633:toxicity*
chemical_list: D000485:Allergens; D051940:B7-2 Antigen; D007509:Irritants; D015262:Xenobiotics