Infigen of DeForest, Wis., and BioTransplant of Charlestown, Mass., recently announced the birth of three pigs that mark the next stop on road toward xenotransplantation. The minipigs are clones derived from previous research (J. Betthauser et al., "Production of cloned pigs from in vitro systems," Nat Biotech, 18:1055-9, 2000) as well as knockouts for alpha-1,3-galactosyltransferase (GGTA1), which normally places a particular carbohydrate onto cell surfaces. "Human cells do not have this carbohydrate on their surfaces, and thus reject tissues whose cells do. Knocking out GGTA1 prevents the addition of this carbohydrate," explains Erik J. Forsberg, Infigen's vice president of development.
The pigs, no-named but numbered, aren't the first swine to serve as a bridge to transplantation. In 1997, 19-year-old Robert Pennington survived acute liver failure long enough to undergo a transplant, thanks to Sweetie Pie, a 15-week-old, 118-pound pig. Pennington's blood was cleansed as it circulated through the pig's disembodied ...
