Dendritic Cell Migration Assay for distinguishing sensitizers from non-sensitizers (including irritants)

The Dendritic Cell Migration Assay (DCMA) is an in vitro method for the identification of sensitisers based on the evaluation of Denditric Cells migration. It is designed for dichotomous classification (S/NS) and does not provide additional information on potency.

DCMA addresses the migration of Langerhans Cells (LC) from the epidermis to the regional lymph nodes which is considered to be one of the key events involved in the induction of skin sensitization. The migration is associated with increased levels of the CXCR4 receptor and decreased levels of the CCR5 receptor on maturing LC, and with increased secretion of the chemokine CXCL12 by dermal fibroblasts. Driven by the CXCR4-CXCL12 interaction, the maturing LCs eventually travel from the dermis to the lymph nodes where they prime T cells and induce sensitization.

This process is mimicked in vitro using human keratinocyte and fibroblast cultures in a two compartment test system, and is simplified by replacing the fibroblasts by the recombinant counterparts of the chemokines involved (CXCL12 and CCL5). The test is based on the human myelomonocytic cell line MUTZ-3 which was identified as the human dendritic cell-like cell line that is closest to human monocyte derived DC (high functional relevance). MUTZ-3 cells are differentiated into immature MUTZ-LC. They are then fluorescently labelled with CSFE.

On the basis of the differential migration (amount of fluorescent MUTZ-LC entering the lower transwell) skin and lung sensitisers are discriminated from non-sensitisers and irritants. If the chemical is a sensitizer, MUTZ-LC will mature, up-regulate CXCR4 and preferentially migrate towards CXCL12. If the chemical is an irritant, no up-regulation of CXCL12 occurs, CCR5 expression is maintained and MUTZ-LC preferentially migrate towards CCL5.