Monocyte long-term cultivation on microvascular endothelial cell monolayers: morphologic and phenotypic characterization and comparison with monocytes cultured on tissue culture plastic.

Human monocytes were cultured on monolayers of a newly established microvascular endothelial cell strain. As compared to monocytes cultured on plastic, these endothelium-"derived" monocytes (EDM) showed distinct morphology, higher motility, and different antigen-expression pattern for several surface markers, as detected by cytofluorimetry. The MO-1- and the Leu-M1-marker were maintained on EDMs while they were lost on plastic-cultured cells. The MAX 1-26-termed markers failed to increase on EDMs, in contrast to plastic-cultured monocytes. For seven additional markers, expression after two weeks in vitro was higher on EDMs than on plastic-cultured monocytes. Functionally EDMs showed typical monocyte/macrophage behavior and were easily removable from the culture system for further experimentation. Our data suggest that monocytes cultured on microvascular endothelial cells are maintained for several weeks in a more physiologic state than monocytes cultured on plastic.