Glossary / Life sciences and medicine
Carbohydrate antigen
A sugar chain on the cell surface that the immune system uses as a target. In xenotransplantation the key example is α-Gal, present in pigs but absent in humans.
In 1988 Uri Galili and colleagues showed that α-Gal, a sugar chain on the cells of most mammals, is missing only in humans, apes and Old World monkeys — which instead carry large amounts of antibody against it[1]. A pig organ placed in a human is destroyed by that antibody within minutes to hours (hyperacute rejection).
In 2002 pigs lacking the gene that makes this sugar were produced[2], making xenotransplantation a realistic research target. Today's donor pigs typically have three such sugar-making genes removed.
Related terms
- XenotransplantationTransplanting organs or tissues from animals into humans. Today the main candidates are kidneys and hearts from genetically modified pigs.
- Antibody-mediated rejectionRejection in which the recipient produces antibodies against a transplanted organ, and those antibodies attack the organ's blood vessels and gradually impair it.
Sources
- U. Galili, S. B. Shohet, E. Kobrin, et al., “Man, apes, and Old World monkeys differ from other mammals in the expression of alpha-galactosyl epitopes on nucleated cells,” J. Biol. Chem. 263, 17755–17762 (1988).
- L. Lai, D. Kolber-Simonds, K.-W. Park, et al., “Production of α-1,3-Galactosyltransferase Knockout Pigs by Nuclear Transfer Cloning,” Science 295, 1089–1092 (2002).