Table 1.
Genetically modified pigs currently available for xenotransplantation researcha
| Gal antigen deletion or “masking”‘ |
| α1,3-galactosyltransferase gene-knockout (GTKO) |
| Human H-transferase gene expression (expression of blood type O antigen) |
| Endo-beta-galactosidase C (reduction in Gal antigen expression) |
| Complement regulation by human complement-regulatory gene expression |
| CD46 (membrane cofactor protein) |
| CD55 (decay-accelerating factor) |
| CD59 (protectin or membrane inhibitor of reactive lysis) |
| Anticoagulation and anti-inflammatory gene expression or deletion |
| Human tissue factor pathway inhibitor (TFPI) |
| Human thrombomodulin |
| Human CD39 (ectonucleoside triphosphate diphosphohydrolase-1) |
| von Willebrand factor (vWF)-deficient (natural mutant) |
| Suppression of cellular immune response by gene expression or downregulation |
| Porcine CTLA4-Ig (Cytotoxic T-Lymphocyte Antigen 4 or CD152) |
| LEA29Y (Inhibition of the B7/CD28 co-stimulatory pathway of T-cell activation) |
| CIITA-DN (MHC class II transactivator-knockdown, resulting in swine leukocyte antigen class II knockdown) |
| Human TRAIL (tumor necrosis factor-alpha-related apoptosis-inducing ligand) |
| HLA-E/human β2-microglobulin (inhibits human natural killer cell cytotoxicity) |
| Human CD47 (for species-specific CD47-signal regulatory protein-alpha natural interaction on macrophages) |
| Human FAS ligand (CD95L) |
| Human GnT-III (N-acetylglucosaminyltransferase III) gene |
| Anticoagulation, anti-inflammatory, and anti-apoptotic gene expression |
| Human A20 (tumor necrosis factor-alpha-induced protein 3) |
| Human heme oxygenase-1 (HO-1) |
| Human TNFRI-Fc (tumor necrosis factor-alpha receptor I-Fc) |
| Prevention of porcine endogenous retrovirus (PERV) activation |
| PERV siRNA |
a
Modified from Cooper DKC208.
Pigs with combinations of genetic modification, for example, GTKO with added transgenes are available.