title: Tracking human contact allergens: from mass spectrometric identification of peptide-bound reactive small chemicals to chemical-specific naive human T-cell priming.
abstract: Modification of proteins by reactive small chemicals is a key step in the activation of chemical-specific T cells in allergic contact dermatitis (ACD). However, an integrated approach to characterize both the precise nature of chemically modified proteins and the chemical-specific T cells is currently lacking. Here, we analyze the molecular conditions for adduct formation of the strong human contact sensitizer 2,4-dinitrochlorobenzene (DNCB) and its water-soluble form, 2,4-dinitrobenzenesulfonic acid (DNBS), with both an all amino acid-containing model peptide (± Cys) and the protein human serum albumin (HSA). Mass spectrometric detection and quantification revealed thiol-dependent peptide adduct formation at all pH values found in human skin layers. Highest modification rates were obtained with DNBS. Accordingly, DNBS- but not DNCB-modified human immature dendritic cells (iDC) induced in vitro primary human T-cell responses as did 2,4,6-trinitrobenzenesulfonic acid-modified iDC as measured by dinitrophenyl (DNP)- and trinitrophenyl (TNP)-specific T-cell proliferation and interferon gamma (IFN-γ) production in CD4(+) and CD8(+) T-cell subsets. Moreover, DNP-modified HSA protein effectively induced primary T-cell responses when processed by iDC. Thus, an integrated approach that combines efficient skin-related in chemico coupling analyses with an in vitro T-cell priming assay can be used to predict in vivo reactions of chemical contact allergens with extracellular and cellular proteins. This strategy supports the development of chemical-specific in vitro assays that are urgently required in predictive hazard identification and risk assessment of allergenic and nonallergenic chemicals.
authors.affiliation: Laboratory of Immunology & Proteomics, Department of Dermatology and University Medical Center Mannheim, University of Heidelberg, 68167 Mannheim, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Dietz
authors.forename: Philipp R
authors.initials: PR
authors.lastname: Esser
authors.forename: Sonja S
authors.initials: SS
authors.lastname: Schmucker
authors.forename: Irina
authors.initials: I
authors.lastname: Goette
authors.forename: Anne
authors.initials: A
authors.lastname: Richter
authors.forename: Martina
authors.initials: M
authors.lastname: Schnölzer
authors.forename: Stefan F
authors.initials: SF
authors.lastname: Martin
authors.forename: Hermann-Josef
authors.initials: HJ
authors.lastname: Thierse
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000378:metabolism*; D001557:Benzenesulfonates / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D003877:Dermatitis, Contact; D004137:Dinitrochlorobenzene / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D010446:Peptide Fragments / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*
chemical_list: D000485:Allergens; D001557:Benzenesulfonates; D004137:Dinitrochlorobenzene; D010446:Peptide Fragments; C001073:2,4-dinitrobenzenesulfonic acid