An in vitro assay to screen for the sensitizing potential of xenobiotics.

We are developing a new, animal-free assay for determination of the sensitizing potential of a substance. The design of this assay is based on current immunological knowledge of the pathogenesis of allergic contact dermatitis. It integrates human dendritic cells and keratinocytes, which are both known to be critically involved in vivo. The read-out system uses molecular responses typically occurring after an encounter of the skin with contact allergens. The assay provides concentration-response information, by which the relative ability of a chemical to induce sensitization can be predicted. Additionally, the assay defines the border-concentration of general toxicity of a substance. Weak allergens and even prohaptens are detectable. We have called the assay LCSA, loose-fit coculture-based sensitization assay.