The XS106 cell: a Langerhans' cell surrogate with a selective type 2 phenotype.

ABSTRACT

Epidermal Langerhans' cells (LC) play important roles in initiating and regulating cutaneous immune responses. However, LC comprise less than 3% of all epidermal cells and consequently are difficult to study ex vivo. In the current investigations, we have examined the utility of the XS106 cell line, a dendritic cell (DC) line derived from mouse epidermis, as a surrogate for LC. Membrane marker expression, type 1- and type 2-associated chemokine production, and migration patterns have been characterised following treatment of XS106 cells with a range of toll-like receptor (TLR) ligands. Comparisons have been made with mouse bone marrow-derived DC- and LC-derived ex vivo. Like BMDC, XS106 cells expressed generic DC markers, in addition to displaying higher levels of skin DC markers compared with BMDC. XS106 cells and LC-enriched epidermal fractions both displayed higher constitutive expression of type 2-associated chemokines than type 1 chemokines. Furthermore, although treatment with a range of TLR ligands induced cytokine secretion by XS106 cells, only type 2 TLR ligands increased membrane marker expression of major histocompatibility complex class II and co-stimulatory molecules. Moreover, type 1-associated TLR ligands failed to induce selective type 1 chemokine secretion by XS106 cells. XS106 cells also displayed functional similarity to LC, migrating in response to chemokines that are known to induce the migration of LC. On the basis of membrane marker expression and selective type 2 polarisation XS106 cells provide a useful surrogate for LC.