Adenovirus-mediated gene transfer of triple human complement regulating proteins (DAF, MCP and CD59) in the xenogeneic porcine-to-human transplantation model

In this study, the adenovirus-mediated gene transfer of triple human complement regulating proteins was investigated in xenogeneic pig liver perfusion. The porcine liver was perfused in situ at 4 °C under a pump-driven veno-venous shunt of the portal vein and inferior vena cava, with 5 to 15×1011 plaque-forming units (pfu) of adenovirus vector (group 1: AxCALacZ; 2: AxCACD59; 3: AxCACD59 + AxCADAF; 4: AxCACD59 + AxCADAF + AxCAMCP) for 1 h (for each, n=3). The livers were harvested 24 h after gene transfer and then were reperfused ex-vivo with fresh human blood for 2 h. In immunohistochemical staining, each complement regulating protein (CRP) showed a distribution similar to that of the LacZ expression. The C3 levels in the perfusate were also maintained at higher levels in group 4 from 60 to 120 min after reperfusion (C3: 85% to 95% of the initial level) than in groups 1 to 3 (C3: 80% to 90% of the initial level) from 60 to 120 min after reperfusion. The complement deposition on the porcine liver [C3, membrane attack component (MAC)] decreased significantly more in group 4 than in groups 1 to 3. In conclusion, the adenovirus-mediated multiple gene transfer of human CRPs (hCRPs) was found to effectively suppress the complement activation in xenogeneic pig liver perfusion.