ANTIGEN PRESENTATION BY A CONTINUOUS HUMAN MICROVASCULAR ENDOTHELIAL-CELL LINE, HMEC-1, TO HUMAN T-CELLS

Endothelial cells line the vessels and lymphatics of the body, acting as a barrier between the blood and extravascular tissue. These cells a re, therefore, in a prime position to play a role in lymphocyte activa tion. Indeed, it has been shown that primary endothelial cells in cult ure are capable of presenting particulate and soluble antigens to T ce lls and that this response is not dependent on macrophages. Recently, we developed an immortalized line of human microvascular endothelial c ells, CDC/EU.HMEC- 1 (HMEC- 1). This endothelial line has the advantag e not only of being devoid of contaminating cells but also of being a continuous cell line and therefore not subject to a restricted number of useful passages. The focus of this study was to determine whether H MEC-I cells (like primary endothelial cells) could present antigen to T cells in the absence of macrophages. We demonstrate that a cloned an d purified endothelial cell line can independently provide all the nec essary signals for antigen-specific T-cell activation.