Knockout of porcine genes contributing to rejection

"Knockout of porcine genes contributing to rejection" refers not to a single molecular target, but rather **a collection of genetic engineering strategies** used in the field of xenotransplantation. The goal is **to eliminate specific pig genes that encode cell-surface molecules recognized by the human immune system as foreign**, which would otherwise trigger rapid organ rejection after transplantation into humans or non-human primates. The most prominent targets for knockout include: **1. GGTA1 (alpha 1,3-galactosyltransferase):** - Responsible for synthesizing the α-Gal epitope, which is highly immunogenic in humans and causes hyperacute rejection. - GGTA1 knockout ("GalT-KO") pigs lack this antigen, significantly reducing immediate antibody-mediated graft loss[3][5]. **2. CMAH (cytidine monophosphate-N-acetylneuraminic acid hydroxylase):** - Produces NeuGc sialic acid; inactive in humans. - Its presence on pig cells can provoke an immune response; knockout reduces this risk[2]. **3. B4GALNT2 (beta 1,4-N-acetylgalactosaminyltransferase 2):** - Synthesizes the SDa blood group antigen. - Also targeted for deletion due to its role as an xenoantigen recognized by human antibodies[1][8]. In addition, other modifications may include knocking out swine leukocyte antigen class I/II molecules or introducing human transgenes that inhibit complement activation/coagulation dysfunction. These combined knockouts are essential steps toward making pig organs more compatible with human recipients by minimizing both humoral and cellular components of graft rejection. However, "knockout" here describes **a process applied across multiple gene targets**, not one discrete protein/receptor. Because "Knockout of porcine genes contributing to rejection" does not refer specifically enough to any one molecule or receptor—and instead describes a broad category—it should be flagged as incorrect if used as an individual therapeutic target name. > “Numerous research groups have made significant progress in identifying the key genetic modifications [in pigs]… These include elimination of porcine xenoantigens…” [5] > “Natural antibodies directed against carbohydrate antigens on pig cells presented one… obstacle… Discovery… precipitated efforts to produce pigs without α‑1,3‑galactosyltransferase.” [1] > “α‑Galactosyltransferase knockout pigs were produced... This achievement was a milestone... More xeno-antigens have been identified later.” [3]

Other names

Porcine gene knockouts for xenotransplantationGenetic modifications to reduce xenograft rejectionKnockout of pig xenoantigen genes

Not applicable; this is not a drug target but rather a set of genetic modifications intended to remove immunogenic antigens from donor pigs[1][2][3].