Myeloid U937 Skin Sensitisation Test

The MUSST 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. 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. In the MUSST test method, the modulation of the FITC-labeled anti-CD86 in U937 cells is measured by flow cytometry after a 48 hours exposure to test chemicals.