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Skimune Chem

Chem Assay

Skimune®Chem is a safety assessment tool for use in testing cosmetics or household products. Skimune®Chem is a non-animal human in vitro skin explant assay capable of determining if the test chemical has the potential to provoke an immune response and react with the skin causing histological damage symptomatic of skin allergy.

The assay can distinguish between sensitising and non-sensitising chemicals in the absence of animal testing, predicating which chemicals would cause skin sensitisation in vivo. The assay can be used for relative potency assessment of chemicals to determine threshold doses for the induction of skin sensitisation or to distinguish high and low potency compounds. There are several key parameters required for a chemical to induce skin sensitisation; 1)the activation of dendritic cells and proliferation of T cells and 2)an induced cytokine response. We therefore offer additional fast evaluation screening assays to measure T cell proliferation and cytokine release in conjunction with the Skimune®Chem assay. The data from the different assays is integrated to provide a precise report of the potential risk of the test chemical to induce skin allergy.

Figure 1. T cell proliferation assay showing T cell responses to sensitisers or non-sensitisers. Dotted line indicates negative control threshold for T cell proliferation activity. Histological images show immune response damage in skin tissue in response to exposure to a sensitiser compared to a non-sensitiser (negative response).

We have compared the results of our assay against the current EU ‘gold standard’ mouse model for safety testing, the mouse local lymph node assay (LLNA) and determined a strong correlation. In addition Skimune®Chem is able to report on chemicals not detected in the mouse model eg nickel sulphate.

Skimune™ – LLNA

Number of positive LLNA chemicals = 21 Skimune® prediction of positive chemicals = 21

Number of negative LLNA chemicals = 20 Skimune® prediction of negative chemicals = 19

95% sensitivity, 95% specificity and 95% concordance

Ref:
Ahmed SS, Wang XN, Fielding M, Kerry A, Dickinson II, Munuswamy R, Kimber I, Dickinson AM (2016) An in vitro human skin test for assessing sensitization potential. J. of Appl. Toxicol, 36, 669-84