Anti-galactose-alpha-1,3-galactose immunoglobulin M antibody (Anti-αGal IgM)

Anti-αGal IgM antibodies are naturally occurring antibodies found in humans, apes, and Old World monkeys, directed against the carbohydrate epitope galactose-alpha-1,3-galactose (α-Gal) (Galili U., 2013, Immunol Cell Biol). This epitope is synthesized by the enzyme alpha-1,3-galactosyltransferase, which is active in most mammals but was evolutionarily inactivated in the human lineage (Cooper DKC, et al., 2015, World J Transplant). These antibodies, primarily of the IgM isotype, are produced throughout life in response to α-Gal-expressing bacteria in the gastrointestinal tract and constitute a significant portion of the human natural antibody repertoire. In the field of xenotransplantation, anti-αGal IgM is the primary driver of hyperacute rejection, as it binds to α-Gal on the vascular endothelium of porcine organs, triggering the classical complement pathway and causing rapid graft failure. Therapeutic strategies targeting these antibodies include the use of soluble α-Gal mimetics like GAS914 to neutralize circulating IgM or the use of immunoadsorption columns to physically deplete them from the bloodstream (Katopodis AG, et al., 2002, J Clin Invest). Additionally, while IgE is the primary mediator of the alpha-gal syndrome (red meat allergy), IgM levels are often monitored as part of the broader immune response to the carbohydrate (Commins SP, et al., 2011, J Allergy Clin Immunol).

Other names

Anti-Gal IgMAnti-alpha-galactosyl IgMNatural anti-Gal antibodiesAnti-alpha-1,3-galactose IgMAnti-Gal alpha 1-3 Gal IgM

Neutralization of circulating antibodies through competitive binding with soluble alpha-gal epitopes or physical removal from plasma via immunoadsorption.