The effect of complement regulatory protein expression on pig endothelial cells to porcine endogenous retrovirus lyses by human sera

Abstract

Introduction Expression of human complement regulatory proteins (CRP) on pig endothelial cells (PEC) has been useful to avoid hyperacute rejection by human sera. On the other hand, porcine endogenous retrovirus (PERV) from PEC transfectants with CRP may acquire resistance to human sera. In this study, we investigated the effects of the transfected CRP on PERV neutralization and/or lysis by human sera. Methods cDNA of membrane cofactor protein (MCP: CD46), decay accelerating factor (DAF: CD55), and CD59 were transfected to PEC lines by lipofection. The expressions of these CRPs were verified by FACS analysis. The PEC lines with human CRPs were then transfected with the LacZ gene and PERV subtype B (PERV-B) to investigate PERV infectivity by LacZ pseudotype assay. Culture supernates of PEC were inoculated to HEK293 cells with or without 10% human sera. The inoculated 293 cells were then histochemically stained to count the LacZ-positive blue foci and calculated the rate of reduction of LacZ-positive cells by serum. Results PERV from the PEC with DAF or CD59 showed a resistance to human sera compared with those of control PEC (DAF: 59.6% ± 5.3%, CD59: 61.1% ± 3.9% vs control: 31.3% ± 3.6%; P < .01). However, PEC with MCP did not cause such an effect (28.8% ± 2.5%). Conclusions While expression of DAF and CD59 on PEC changed its PERV responsiveness to human sera, MCP did not improve it.