MORPHOLOGICAL ASPECTS OF ENDOTHELIAL CELL-MONOCYTE INTERACTIONS IN CULTURE

Monocytes obtained from the blood of healthy volunteers were added to cultures of bovine aortic endothelial cells (BAEC) at increasing time intervals (from 1 h to 24 h). Cultures of BAEC without the added blood elements were used as controls. The ultrastructural features of cellu lar interactions were studied by transmission electron microscopy. Aft er 4 h, in the co-cultured endothelial cells focal cytoplasmic lesions appeared in the areas where activated monocytes were strictly in cont act. Adhering monocytes frequently appeared apoptotic. After 24 h, pse udopod-like cytoplasmic projections originating from the endothelial c ells gave rise to areas of close contact between the BAEC and the mono cytes. These data reveal until now unknown endothelial cell taxis towa rd blood cells.