INTERACTIONS OF DENDRITIC CELLS WITH FIBRONECTIN AND ENDOTHELIAL-CELLS

We studied the phenotypic characteristics of spontaneously migrated sk in dendritic cells (sDC) and monocyte-derived dendritic cells (moDC), generated under different culture conditions, and their interactions w ith fibronectin (FN) and endothelial cells. Monocyte-derived dendritic cells were obtained after culturing monocytes with granulocyte-macrop hage colony-stimulating factor (GM-CSF) (800 U/ml) and interleukin-4 ( IL-4) (500 U/ml) with either 10% fetal bovine serum (FBS) or 10% allog eneic human serum (HS). Regardless of the type of serum used: the majo rity of moDC expressed human leucocyte antigen-DR (HLA-DR) and CD86. O n day 5 of incubation, 20-67% of moDC cultured in the presence of HS ( HS-moDC) expressed CD1a, b and c versus 94-97% when cultured in the pr esence of FBS (FBS-moDC). DC showed a differential gradient of adhesio n to FN: FBS-moDC > HS-moDC > sDC a monocytes. Both FBS-moDC and HS-mo DC were strongly positive for CD49e (alpha 5-integrin) and CD29 (beta 1-integrin) but negative for CD49d (alpha 4-integrin). A monoclonal an tibody (mAb) against CD49e blocked the adhesion of both types of moDC to FN. Although both FBS-moDC and HS moDC attached to endothelium (a 7 6% and 63% increase, respectively), only HS-moDC were able to migrate through non-activated endothelium. Overall, these results suggest that spontaneously migrated sDC are less adherent to FN than moDC, that HS and FBS induce differences in CD1 expression, that HS-moDC are less a dhesive to FN and endothelial cells but more motile than FBS-moDC, and that alpha 5 beta 1-integrin is the molecule involved in moDC adhesio n to FN.