A Korean biotech company has announced that it has succeeded in cloning a pig containing human genes, bringing them a step closer to transplanting pig organs into humans.
Dr Park Kwang-wook and his team at Mgenbio produced the world's first cloned pig with the human HLA-G gene, an immunity gene, which will help stop pig cells from being rejected after transplantation into humans.
Immune rejection is one of the main challenges of any organ transplant, especially between different species (xenotransplantation). The human immune system attacks foreign organs because it considers them invaders and the process has to be suppressed with heavy medication. HLA-G is a gene that protects a fetus from its mother's immune system during pregnancy, in the pig cells it will reduce the power of the human antibodies by 60-70 per cent. However, the team will need to modify another three to five genes related to the immune response before transplanting organs from cloned pigs becomes a real possibility.
Dr Park cloned the pig by injecting the HLA-G gene into the cell of a pig bred for organ transplants. The cell was then implanted into the womb of a surrogate pig, which gave birth to five piglets. All five pigs carried the HLA-G gene, although only one survived.
Dr Park, whose research is supported by the state-run National Livestock Research Institute, says the first commercial application of his work will be the treatment of patients with diabetes. Insulin-secreting cells from the pig's pancreas containing human immunity genes could be transplanted into human patients, leading to the first effective treatment of this incurable disease.