Aortic endothelial cell cultures (PAE) from four lines of pigs transgenic for human decay-accelerating factor (hDAF) have been used to study the response to the inflammatory stimuli bacterial lipopolysaccharide (LPS) and recombinant human TNF-alpha. Human umbilical vein endothelial cells (HUVEC) and PAE from normal, non-transgenic pigs were used as controls. The expression of hDAF and E-selectin on the cell surface was determined by flow cytometry. After overnight incubation, HUVEC, normal and transgenic PAE increased the relative expression of E-selectin 2-5-fold in response to LPS (25 mu g/ml), and 5-40-fold in response to TNF-alpha (10 ng/ml). In both normal and transgenic PAE the increase in expression of E-selectin in response to TNF-alpha was maximal at 4 hr and significantly decreased after 20 hr. There was no significant increase in DAF expression by HUVECs in response to LPS or TNF-alpha, and three of the four lines of transgenic pigs studied did not increase expression of hDAF in response to either stimulus. However, endothelial cells from the transgenic line A74 exhibited a dose-dependent increase in expression of hDAF in response to LPS and TNF-alpha. A study of the time course of up-regulation triggered by incubation with TNF-alpha showed that, in contrast to the up-regulation of E-selectin, hDAF expression continued to increase for at least 3 days. This response may afford additional protection to organs from this line of transgenic pigs.
