Surface Mucin-1 does not play a role in dendritic cell migration

Mucin-1 (MUC1) is a transmembrane glycoprotein that is upregulated upon maturation of dendritic cells (DC) in vitro or in vivo. One of the proposed functions of surface expressed MUC1 is its involvement in migration of cells. We hypothesized that MUC1 is involved in DC migration since mature DC (mDC) are highly migratory cells and MUC1 is upregulated on the surface of DC upon maturation. In this study we cultured DC using two maturation cocktails, one cocktail containing IL-4, GM-CSF, TNFalpha, PGE2, IL-1 beta and IL-6 (TP1,6-DC) and the other IL-13, GM-CSF, Ribomunyl and IFN-gamma (RI-DC). Both maturation cocktails render DC with a similar surface phenotype including CCR7 expression, but only the former induces a migratory capacity of DC to a CCL19 gradient. To analyze the role of surface-expression of MUC1 on TP1,6-DC, that are capable of migration, expression of MUC1 was prevented by adding an anti-MUC1 antibody (Ab) during the maturation process. Compared with matured DC in the absence of the Ab, no difference was observed in chemokine-induced migratory behaviour between the MUC1+ and MUC1- DC populations in a standard Transwell chemotaxis assay, nor in organotypic cultures. Our data clearly demonstrate that surface MUC1 on DC does not influence intrinsic cell-motility, nor is it involved in cell-cell and cell-matrix dependent migration.