A line of transgenic pigs in which the expression of human decay‐accelerating factor by endothelial cells is increased in the presence of inflammatory stimuli

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‐α. 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 μg/ml), and 5–40‐fold in response to TNF‐α(10 ng/ml). In both normal and transgenic PAE the increase in expression of E‐selectin in response to TNF‐α 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‐α, 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‐α. A study of the time course of up‐regulation triggered by incubation with TNF‐α 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.