FDA had approved an intentional genomic alteration in animals for food uses or therapeutic uses, but not both – until last week. With some fanfare, FDA announced just such an approval of an alteration in a line of domestic pigs. The pigs are referred to as GalSafe because the alteration eliminates alpha-gal sugar (AGS) on the surface of their cells. Exposure to AGS can trigger severe allergic reactions in humans that are exposed to it in various ways, including inhalation, external contact, consumption, implantation, or injection. Because pigs can serve as a source of both food products and a variety of therapeutic products, such products can pose a hazard to AGS-allergic individuals. The alteration in GalSafe pigs neatly solves that problem by knocking out the gene that that codes for the enzyme that results in the production of AGS.
The development of allergy to AGS is an interesting story of its own, which the curious can delve into through this CDC web page, or for a deeper dive, this podcast. One key aspect of the story is the link between development of allergy to AGS and bites of the Lone Star tick, which has been the focus of years of research summarized here. Another key aspect is that AGS is present in the cells of and tissues of not just pigs, but also other nonprimate mammals. Thus, AGS-allergic individuals are potentially at risk from exposure to any product of mammalian origin. Because GalSafe technology can be applied in other mammals, it holds the promise of greatly expanding food and therapeutic options for AGS-allergic individuals.