title: A plasmacytoid dendritic cell (CD123+/CD11c-) based assay system to predict contact allergenicity of chemicals.
abstract: A predictive allergenicity test system for assessing the contact allergenicity of chemicals is needed by the cosmetic and pharmaceutical industry to monitor product safety in the marketplace. Development of such non-animal alternative assay systems for skin sensitization and hazard identification has been pursued by policy makers and regulatory agencies. We investigated whether phenotypic and functional changes to a subset of dendritic cells (DC), plasmacytoid DC (pDC), could be used to identify contact allergens. To achieve this goal, normal human DC were generated from CD34+ progenitor cells and cryopreserved. Frozen DC were thawed and the pDC fraction (CD123+/CD11c-) was harvested using FACS sorting. The pDC were cultured, expanded, and exposed to chemical allergens (N=26) or non-allergens (N=22). Concentrations of each chemical that resulted in >50% viability was determined using FACS analysis of propidium iodide stained cells using pDC from 2 to 5 donors. Expression of the surface marker, CD86, which has been implicated in dendritic cell maturation, was used as a marker of allergenicity. CD86 expression increased (> or =1.5-fold) for 25 of 26 allergens (sensitivity=96%) but did not increase for 19 of 22 non-allergens (specificity=86%). In a direct comparison to historical data for the regulatory approved, mouse local lymph node assay (LLNA) for 23 allergens and 22 non-allergens, the pDC method had sensitivity and specificity of 96% and 86%, respectively, while the sensitivity and specificity of the LLNA assay was 83% and 82%, respectively. In conclusion, CD86 expression in pDC appears to be a sensitive and specific indicator to identify contact allergenicity. Such an assay method utilizing normal human cells will be useful for high throughput screening of chemicals for allergenicity.
authors: MatTek Corporation, Ashland, MA 01721, United States. sayehunie@mattek.com
authors: Seyoum
authors: S
authors: Ayehunie
authors: Maureen
authors: M
authors: Snell
authors: Matthew
authors: M
authors: Child
authors: Mitchell
authors: M
authors: Klausner
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000633:toxicity*; D000826:Animal Testing Alternatives; D000818:Animals; D000911:Antibodies, Monoclonal; D001681:Biological Assay; D018845:CD11 Antigens / Q000276:immunology*; D002478:Cells, Cultured; D004396:Coloring Agents; D003358:Cosmetics / Q000737:chemistry / Q000633:toxicity*; D003713:Dendritic Cells / Q000187:drug effects*; D017449:Dermatitis, Allergic Contact / Q000276:immunology*; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D005312:Fetal Blood / Q000166:cytology; D005434:Flow Cytometry; D006801:Humans; D053650:Interleukin-3 Receptor alpha Subunit / Q000276:immunology*; D008070:Lipopolysaccharides / Q000633:toxicity; D023441:Local Lymph Node Assay; D051379:Mice; D014677:Pharmaceutical Vehicles; D015203:Reproducibility of Results; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D000485:Allergens; D000911:Antibodies, Monoclonal; D018845:CD11 Antigens; D004396:Coloring Agents; D003358:Cosmetics; D053650:Interleukin-3 Receptor alpha Subunit; D008070:Lipopolysaccharides; D014677:Pharmaceutical Vehicles; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue