HETEROGENEOUS RESPONSES OF HUMAN ENDOTHELIAL-CELLS TO TUMOR-NECROSIS-FACTOR WITH RESPECT TO GROWTH-INHIBITION

The response of human arterial endothelial cells (ECs) to tumor necrosis factor (TNF) was compared to that of venous ECs. It was found that arterial ECs were more susceptible to TNF induced inhibition of growth and colony formation by TNF than venous ECs. In addition, synergistic effect of TNF with interferon-gamma (IFN-gamma) was more evident in arterial ECs. Little difference, however, was identified in the characteristics of TNF receptors between arterial and venous ECs; the dissociation constant (Kd) was 0.35 nM and the number of receptors/cell was approximately 5,000. This indicates that different susceptibility of ECs to TNF is not due to these characters of TNF receptors. In conclusion, ECs are heterogeneous in the responsiveness to TNF depending on the sites of origins.