Performance of a novel in vitro assay for skin sensitization based on activation of T lymphocytes

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Fenxia Hou
Caihong Xing
Bin Li
Juan Cheng
Wei Chen

Abstract

There are currently no skin sensitization assays based on T cell activation. We built a novel in vitro test to assess T cell activation and assessed its performance to discriminate skin sensitizers from non-sensitizers using 52 reference chemicals. Jurkat Clone E6-1 human T lymphocytes were exposed to a series of concentrations of test substances for 24 hours and CD69 expression was measured as a marker of early T cell activation by flow cytometry. Most sensitizers tested induced an increased relative fluorescence intensity (RFI) of CD69 on the T cells, which was linearly correlated with the tested concentrations, indicating a statistically significant causal link between sensitizer concentration and increase of CD69 expression. CD69 RFI ≥ 1.5 was determined as the positive criterion for skin sensitizer classification when cell viability ≥ 50%. The sensitivity (79.4%), specificity (88.9%) and accuracy (82.7%) of our test for the 52 tested reference chemicals showed a good predictivity for skin sensitizers. Results were reproduced in at least two repeats, and the concurrent positive control, 2 μg/mL 2,4-dinitrochlorobenzene, was found positive in all 25 independent runs conducted, indicating in-house reproducibility. The EC1.5 value, i.e., the concentration at which a test chemical induces a CD69 RFI of 1.5, may be used to categorize skin sensitization potency of a chemical. This work may contribute to the development of an in vitro assay for skin sensitization based on the activation of T cells.

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How to Cite
Hou, F., Xing, C., Li, B., Cheng, J. and Chen, W. (2020) “Performance of a novel in vitro assay for skin sensitization based on activation of T lymphocytes”, ALTEX - Alternatives to animal experimentation, 37(3), pp. 451-468. doi: 10.14573/altex.2001312.
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