'The kidney came from a pig engineered by the biotech company eGenesis, which removed three genes involved in potential rejection of the organ. In addition, seven human genes were inserted to enhance human compatibility. Pigs carry retroviruses that may infect humans, and the company also inactivated the pathogens'
I wrote about current strategies for the use of pigs in #xenotransplantation for Nature Medicine last year.
"Pigs are, prima facie, a good organ source. They are abundant, their overall physiology is very similar to that of humans, as is their size (in this case, size matters), and they can be bred under conditions that limit exposure to pathogens (UAB houses their donor pigs in a germ-free facility). Grafting pig kidneys into our close relatives, old-world monkeys and apes, held a nasty surprise: the organs were immediately rejected. One photograph of a pig kidney recovered from a baboon at 10 minutes after transplantation shows a blackened lump that resembles more a disaster in a French kitchen than standard organ rejection. This hyperacute reaction is caused by pre-existing 'natural' antibodies directed against pig α-gal (the response is so potent that it can compromise even decellularized cardiac valve xenografts)."
