A comparison of primary endothelial cells and endothelial cell lines for studies of immune interactions

The purpose of this study was to assess the suitability of using endothelia l cell (EC) lines for studies of endothelial/immune interactions. The immor tal human EC lines HMEC-1, ECV304 and EaHy926 were compared to human umbili cal vein endothelial cells (HUVEC) for constitutive and induced expression of surface antigens known to be involved in interactions with T cells. Thes e cell lines were also compared to HUVEC in transendothelial migration assa ys. Flow cytometry was used to measure cell surface expression of platelet/ endothelial cell adhesion molecule-1 (PECAM-1), intercellular adhesion mole cule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, ma jor histocompatibility complex (MHC) class I and MHC class II, CD40, CD95 ( fas) and lymphocyte function associated antigen-3 (LFA-3) before and after treatment with the cytokines tumour necrosis factor-alpha (TNF-alpha) and i nterferon-gamma (IFN-gamma). Polymerase chain reaction (PCR) was used to de tect expression of the MHC class II transactivator. Significant differences were found in the ability to respond to cytokines between HUVEC and the ce ll lines, the greatest differences being induction of VCAM-1 and E-selectin in response to TNF-or and induction of MHC class II antigens in response t o IFN-gamma. Thus unlike HUVEC, induction of VCAM-1 and E-selectin was not detectable on EaHy926 and ECV304 and barely detectable on HMEC-1. MHC class II antigens were not induced on ECV304 in response to IFN-gamma and nor wa s the class II transactivator (CIITA). Unlike HUVEC and the other cell line s, ECV304 were constitutively negative for PECAM-1. Constitutive and induce d expression of MHC class I, ICAM-1, LFA/3, CD40 and fas were most conserve d between the cell lines and showed little difference to HUVEC. The migrati on of peripheral blood mononuclear cells (PBMC) through all cell lines was significantly reduced compared to through HUVEC, suggesting that there is a functional difference between the cell lines with regard to interactions w ith lymphocytes. In conclusion this study has demonstrated significant diff erences in the ability of endothelial cell lines to respond to cytokines co mpared to primary HUVEC cultures. In particular ECV304 compares very poorly with HUVEC. Whether these differences are caused by immortalization proced ures or reflect heterogeneity of EC arising from different vascular beds is discussed.