The performance of an in vitro skin sensitisation test, IL-8 Luc assay (OECD442E), and the integrated approach with direct peptide reactive assay (DPRA)

J Toxicol Sci. 2018;43(12):741-749. doi: 10.2131/jts.43.741.


In all current in vitro skin sensitisation assays, DMSO is used to dissolve water-insoluble chemicals. However, our previous study suggested the superiority of the modified IL-8 Luc assay (mIL-8 Luc), in which X-VIVOTM 15 is used to dissolve chemicals, over the original assay using DMSO (oIL-8 Luc). In this study, to confirm the superiority of the mIL-8 Luc, we first increased the number of chemicals examined and demonstrated the superiority of the mIL-8 Luc, in which the mIL-8 Luc provided 87.6% of sensitivity, 74.2% of specificity, and 84.6% of accuracy. Next, to clarify the cause of false negative judgment by the mIL-8 Luc, we examined the effects of physical properties of chemicals on judgment. The results demonstrated that high molecular weight, high LogKo/w, or poor water solubility, did not cause false negative judgment. When it was accepted as an OECD test guideline, the criteria of the mIL-8 Luc to determine sensitisers were modified to further decrease false negative judgment by poor solubility. By applying the new criteria, the test guideline IL-8 Luc assay (tgIL-8 Luc) improved sensitivity but decreased specificity and increased the number of chemicals that cannot be judged. To overcome this problem, we examined a simple combination of the tgIL-8 Luc with direct peptide reactive assay (DPRA), which could improve specificity and decrease the number of the chemicals that cannot be judged. These data suggest that the tgIL-8 Luc is a promising in vitro skin sensitisation assay in combination with other in vitro or in chemico methods.

Keywords: Alternative method; Contact dermatitis; Luciferase assay; Sensitisation test; Skin sensitisation.

MeSH terms

  • Animal Testing Alternatives*
  • Biological Assay
  • Dermatitis, Allergic Contact*
  • Genes, Reporter
  • Glyceraldehyde-3-Phosphate Dehydrogenases / genetics
  • Haptens / toxicity*
  • Humans
  • Interleukin-8 / genetics
  • Luciferases / genetics
  • Peptides
  • Skin Tests*
  • THP-1 Cells


  • Haptens
  • Interleukin-8
  • Peptides
  • Luciferases
  • Glyceraldehyde-3-Phosphate Dehydrogenases