Using CRISPR, researchers led by Harvard Medical School's George Church have deactivated retroviruses that lurk in the pig genome, a step that brings using pig organs in transplants closer to reality, the New York Times reports.
Because of their similar size to human organs, pig organs have long been eyed as a possible way to close the gap between supply and demand for organ transplants. However, the discovery of retroviruses in pig genomes that could infect human cells as well as of carbohydrates that line pig organs and mark them for attack by the human immune system has made their use challenging.
But Church and his colleagues, including ones from his company eGenesis, now report in Science that they inactivated porcine endogenous retroviruses (PERVs) in pig cell lines using CRISPR. They then used somatic cell nuclear transfer to generate pigs with inactivated PERVs. The Economist notes that half of the 30 PERV-free piglets were still alive four-and-a-half months after being born, about how old they'd have to be for organ harvesting.
Church says he and his colleagues are also working on developing piglets that lack the carbohydrates that trigger a response by the human immune system. By combining the two approaches, he hopes people can receive pig organs without having to take anti-rejection medications, the Times says.
"I am afraid that he may find these goals more difficult to achieve than he expects, but I would be happy to be mistaken," Columbia University's David Sachs tells the Times.