U-SENS™ - Myeloid U937 Skin Sensitisation Test

The U-SENS assay supports the discrimination between sensitizing and non-sensitizing chemicals. It addresses one of the biological mechanisms described under key event 3 (events in dendritic cells (DC)) of the skin sensitization Adverse Outcome Pathway (AOP) by measuring the induction of the CD86 protein marker in U937 cells.

The U937 cells are human myeloid cells used as surrogate model for DCs. U937 is a cell line established from a diffuse histiocytic lymphoma with the advantage of higher stability and the easiness of maintenance compared to human-blood derived DCs. Although being of monocytic origin, U937 cells have shown DC-like responses following exposure to sensitizers including the up-regulation of surface marker (e.g. CD86) and cytokine production (e.g. TNF-a). The up-regulation of CD86 plays important roles in the induction of Allergic Contact Dermatitis (ACD). The CD86 protein marker is a costimulatory factor which is upregulated in mature DCs and plays a pivotal role in antigen presentation and subsequent T cell priming. It is one of the most frequently used biomarkers in in vitro assays indicating DC activation and has been shown to be the most suitable and robust marker in U937 cells.

In the U-SENS™ test method, the modulation of the CD86 membrane marker in U937 cells is measured by flow cytometry after a 45 hours exposure to test chemicals.