title: Unsaturated compounds induce up-regulation of CD86 on dendritic cells in the in vitro sensitization assay LCSA.
abstract: Unsaturated compounds are known to cause false-positive reactions in the local lymph node assay (LLNA) but not in the guinea pig maximization test. We have tested a panel of substances (succinic acid, undecylenic acid, 1-octyn-3-ol, fumaric acid, maleic acid, linoleic acid, oleic acid, alpha-linolenic acid, squalene, and arachidonic acid) in the loose-fit coculture-based sensitization assay (LCSA) to evaluate whether unspecific activation of dendritic cells is a confounder for sensitization testing in vitro. Eight out of 10 tested substances caused significant up-regulation of CD86 on dendritic cells cocultured with keratinocytes and would have been classified as sensitizers; only succinic acid was tested negative, and squalene had to be excluded from data analysis due to poor solubility in cell culture medium. Based on human data, only undecylenic acid can be considered a true sensitizer. The true sensitizing potential of 1-octyn-3-ol is uncertain. Fumaric acid and its isomer maleic acid are not known as sensitizers, but their esters are contact allergens. A group of 18- to 20-carbon chain unsaturated fatty acids (linoleic acid, oleic acid, alpha-linolenic acid, and arachidonic acid) elicited the strongest reaction in vitro. This is possibly due to the formation of pro-inflammatory lipid mediators in the cell culture causing nonspecific activation of dendritic cells. In conclusion, both the LLNA and the LCSA seem to provide false-positive results for unsaturated fatty acids. The inclusion of T cells in dendritic cell-based in vitro sensitization assays may help to eliminate false-positive results due to nonspecific dendritic cell activation. This would lead to more accurate prediction of sensitizers, which is paramount for consumer health protection and occupational safety.
authors.affiliation: Institute of Clinical Pharmacology and Toxicology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Thomas Armin
authors.initials: TA
authors.lastname: Frohwein
authors.affiliation: Institute of Clinical Pharmacology and Toxicology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Sonnenburg
authors.affiliation: Department of Dermatology and Allergy, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Zuberbier
authors.affiliation: Institute of Clinical Pharmacology and Toxicology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Stahlmann
authors.affiliation: Institute of Clinical Pharmacology and Toxicology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany. dr.max.schreiner@gmail.com.|Department of Internal Medicine (Abt. I), Bundeswehrkrankenhaus Berlin, Scharnhorststraße 13, 10115, Berlin, Germany. dr.max.schreiner@gmail.com.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schreiner
mesh_terms: D000818:Animals; D051940:B7-2 Antigen / Q000378:metabolism*; D018920:Coculture Techniques / Q000379:methods; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology; D005189:False Positive Reactions; D005231:Fatty Acids, Unsaturated / Q000276:immunology* / Q000633:toxicity; D006168:Guinea Pigs; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D023441:Local Lymph Node Assay; D012882:Skin Tests / Q000379:methods*; D019802:Succinic Acid / Q000276:immunology / Q000633:toxicity; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D051940:B7-2 Antigen; C497964:CD86 protein, human; D005231:Fatty Acids, Unsaturated; D019802:Succinic Acid
keywords: Coculture; Dendritic cells; Keratinocytes; Regulative toxicology; Sensitization assay