Effect of cell surface concentration of human DAF on transgenic pig aortic endothelial cells on the degree of protection afforded against human complement deposition.

Abstract

Cultures of hDAF transgenic porcine aortic endothelial cells (TPAEs) with levels of cell surface hDAF expression between 2000 and 300 000 molecules per cell have been used to determine the relationship between expression of hDAF and protection from human complement deposition in an in vitro model. At concentrations below 45 000 molecules per cell, the relationship between hDAF expression and degree of protection conferred is linear. Concentrations of 123 000 molecules per cell and higher give maximal protection (60% reduction of susceptibility to neat human serum) in this model. It is concluded that increasing hDAF expression above that displayed by the A74 line of hDAF transgenic pigs (240 000 +/- 15 000 molecules per cell) would not confer any additional benefit.