title: Evaluation of selected biomarkers for the detection of chemical sensitization in human skin: a comparative study applying THP-1, MUTZ-3 and primary dendritic cells in culture.
abstract: Dendritic cells (DCs) exhibit the unique capacity to induce T cell differentiation and proliferation, two processes that are crucially involved in allergic reactions. By combining the exclusive potential of DCs as the only professional antigen-presenting cells of the human body with the well known handling advantages of cell lines, cell-based alternative methods aimed at detecting chemical sensitization in vitro commonly apply DC-like cells derived from myeloid cell lines. Here, we present the new biomarkers programmed death-ligand 1 (PD-L1), DC immunoreceptor (DCIR), IL-16, and neutrophil-activating protein-2 (NAP-2), all of which have been detectable in primary human DCs upon exposure to chemical contact allergens. To evaluate the applicability of DC-like cells in the prediction of a chemical's sensitization potential, the expression of cell surface PD-L1 and DCIR was analyzed. In contrast to primary DCs, only minor subpopulations of MUTZ-3 and THP-1 cells presented PD-L1 or DCIR at their surface. After exposure to increasing concentrations of nickel and cinnamic aldehyde, the expression level of PD-L1 and DCIR revealed much stronger affected on monocyte-derived DCs (MoDCs) or Langerhans cells (MoLCs) when compared to THP-1 and MUTZ-3 cells. Applying protein profiler arrays we further identified the soluble factors NAP-2, IL-16, IL-8 and MIP-1α as sensitive biomarkers showing the capacity to discriminate sensitizing from non-sensitizing chemicals or irritants. An allergen-specific release of IL-8 and MIP-1α could be detected in the supernatants of MoDCs and MoLCs and also in MUTZ-3 and THP-1 cells, though at much lower levels. On the protein and transcriptional level, NAP-2 and IL-16 indicated sensitizers most sensitively and specifically in MoDCs. Altogether, we have proven the reciprocal regulated surface molecules PD-L1 and DCIR and the soluble factors MIP-1α, NAP-2 and IL-16 as reliable biomarkers for chemical sensitization. We further show that primary DCs are significantly different in their phenotype and function compared to DC-like cell lines. Since they demonstrated higher absolute values and a broader range in biomarker expression, we propose that MoDCs represent an optimal and robust sensor test system well suited to identify and classify chemicals with an allergic potential.
authors.affiliation: German Federal Institute for Risk Assessment (BfR), Department of Product Safety, Berlin, Germany. Manuel.Hitzler@bfr.bund.de
authors.forename: Manuel
authors.initials: M
authors.lastname: Hitzler
authors.forename: Antje
authors.initials: A
authors.lastname: Bergert
authors.forename: Andreas
authors.initials: A
authors.lastname: Luch
authors.forename: Matthias
authors.initials: M
authors.lastname: Peiser
mesh_terms: D000171:Acrolein / Q000031:analogs & derivatives / Q000633:toxicity; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000485:Allergens / Q000633:toxicity*; D051940:B7-2 Antigen / Q000378:metabolism; D060890:B7-H1 Antigen / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism; D005054:Eugenol / Q000633:toxicity; D006801:Humans; D019410:Interleukin-16 / Q000235:genetics / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D007801:Langerhans Cells / Q000187:drug effects* / Q000378:metabolism; D037181:Lectins, C-Type / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D009532:Nickel / Q000633:toxicity; D012333:RNA, Messenger / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism; D023422:Skin Irritancy Tests; D001620:beta-Thromboglobulin / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000485:Allergens; D051940:B7-2 Antigen; D060890:B7-H1 Antigen; D015415:Biomarkers; C423236:CD274 protein, human; C497964:CD86 protein, human; C423004:CLEC4A protein, human; D019410:Interleukin-16; D016209:Interleukin-8; D037181:Lectins, C-Type; C493277:MAPKAP1 protein, human; D008562:Membrane Glycoproteins; C061615:PPBP protein, human; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D001620:beta-Thromboglobulin; D005054:Eugenol; D000171:Acrolein; D009532:Nickel; C012843:cinnamaldehyde
keywords: Biomarker; Contact allergy; DCIR; Dendritic cell; IL-16; MIP-1α; MUTZ-3; NAP-2; PD-L1; Sensitization assay; THP-1