[Migration of monocytes and granulocytes in co-culture with endothelial cells]

The interaction of leucocytes and endothelial cells was analyzed in a co-culture system using time-lapse video microscopy. Isolated granulocytes or monocytes/macrophages were added to confluent endothelial cell cultures. The migratory behavior of the blood cells was subsequently analyzed using video direct visualization and morphometry. Using this technology the active migration of blood cells through the confluent endothelial layer in both directions could be shown. While granulocytes migrated several times through the endothelium in both directions, monocytes migrated from the top of the endothelial layer underneath the endothelial cells and remained there. The migratory speed of granulocytes was with 1166 microns/h about twice as fast as the speed of monocytes with 608 microns/h. The differentiation between the migratory speed of granulocytes on top or underneath the endothelial cells revealed a marked acceleration underneath the endothelial cells with a speed of 1519 microns/h compared to 671 microns/h on top of the endothelium. These results led to speculation that special extracellular matrix components produced by the endothelial cells activate the migratory behavior of blood cells.