Anti-galactose-alpha-1,3-galactose immunoglobulin G (Anti-α-Gal IgG)

Anti-α-Gal IgG antibodies are naturally occurring antibodies found in humans, apes, and Old World monkeys, constituting approximately 1% of circulating immunoglobulins (Galili, 2013, Immunology and Cell Biology). These antibodies are directed against the carbohydrate epitope galactose-alpha-1,3-galactose (α-Gal), which is synthesized by the enzyme α-1,3-galactosyltransferase in non-primate mammals but is absent in humans due to the evolutionary inactivation of the GGTA1 gene (Machado et al., 2021, Frontiers in Immunology). Humans develop high titers of anti-α-Gal IgG through continuous exposure to α-Gal-like structures on gut microbiota. These antibodies are the primary mediators of hyperacute rejection in xenotransplantation and play a significant role in alpha-gal syndrome, a delayed allergic reaction to mammalian meat (Commins et al., 2011, JACI). Additionally, they are responsible for hypersensitivity reactions to drugs like cetuximab, which contains α-Gal epitopes on its heavy chain (Chung et al., 2008, NEJM). Therapeutic research also explores utilizing these antibodies to target α-Gal-coated tumor cells to induce immune-mediated destruction (Galili, 2023, Antibodies). Management of these antibodies is crucial in the development of animal-derived medical products and the engineering of alpha-gal-deficient donor animals.

Other names

Anti-Gal antibodiesAnti-alpha-galactosyl antibodiesAnti-Gal IgGNatural anti-Gal

Binding to the galactose-alpha-1,3-galactose epitope on foreign cells or therapeutic proteins, leading to complement activation, opsonization, or hypersensitivity reactions (Galili, 2013, Immunology and Cell Biology).