EXPRESSION OF HUMAN α-GALACTOSIDASE AND α1,2-FUCOSYLTRANSFERASE GENES MODIFIES THE CELL SURFACE GALα1,3GAL ANTIGEN AND CONFERS RESISTANCE TO HUMAN SERUM-MEDIATED CYTOLYSIS

Objective To explore the strategies which reduce the amount of xenoantigen Galα1, 3 Gal. Methods Human α-galactosidase gene and α 1,2-fucosyltransferase gene were transferred into cultured porcine vascular endothelial cells PEDSV.15 and human α-galactosidase transgenic mice were produced. The Galα 1,3Gal on the cell surface and susceptibility of cells to human antibody-mediated lysis were analyzed. Results Human α-galactosidase gene alone reduced 78% of Galα1,3Gal on PEDSV.15 cell surface while human α-galactosidase combined with α 1,2-fucosyltransferase genes removed Galα 1,3Gal completely. Decrease of Galα1,3Gal could reduce susceptibility of cells to human antibody-mediated lysis, especially during co-expression of α-galactosidase gene and α1,2-fucosyltransferase gene. RT-PCR indicated positive human α-galactosidase gene expression in all organs of positive human α-galactosidase transgenic F1 mice including heart, liver, kidney, lung, and spleen, the amount of Galα1,3Gal antigens on which was reduced largely. 58% of spleen cells from F1 mice were destroyed by complement-mediated lysis compared with 24% of those from normal mice. Conclusions Human α-galactosidase gene and α1,2-fucosyltransferase gene effectively reduce the expression of Galα1,3Gal antigens on endothelial cell surface and confers resistance to human serummediated cytolysis. The expression of human α-galactosidase in mice can also eliminate the Galα1,3Gal antigens in most tissues and decrease the susceptibility of spleen cells to human serum-mediated cytolysis.