Anti-galactose-α-1,3-galactose immunoglobulin (Anti-α-Gal)

Anti-galactose-α-1,3-galactose (anti-α-Gal) immunoglobulins are naturally occurring antibodies found in humans, apes, and Old World monkeys, constituting approximately 1% of total serum IgG (Galili, 2013). These antibodies are produced in response to α-Gal epitopes present on gut microbiota, as humans lack the α-1,3-galactosyltransferase enzyme necessary to synthesize this carbohydrate (Machado et al., 2021). They are the primary mediators of hyperacute rejection in xenotransplantation, where they recognize α-Gal on the surface of non-primate mammalian cells, such as those from pigs (Cooper et al., 2015). Furthermore, anti-α-Gal IgE is responsible for alpha-gal syndrome, a unique red meat allergy often initiated by tick bites that sensitize the host to the α-Gal epitope (Commins et al., 2011). In therapeutic contexts, these antibodies can be harnessed to target cancer cells that have been enzymatically or genetically modified to express α-Gal epitopes, thereby inducing an immune-mediated anti-tumor response (Galili, 2023). They also interact with certain drugs like cetuximab, which contains α-Gal on its Fab portion, potentially leading to severe hypersensitivity reactions in patients with pre-existing anti-α-Gal IgE (Chung et al., 2008).

Other names

Anti-Gal antibodiesAnti-alpha-gal antibodiesNatural anti-Gal antibodiesAnti-Gal

Therapeutic strategies targeting these immunoglobulins involve the use of soluble α-Gal mimetics or polymers to neutralize and deplete circulating antibodies to prevent xenograft rejection, or the modification of tumor cells with α-Gal epitopes to redirect these antibodies to trigger complement-mediated lysis and antibody-dependent cellular cytotoxicity against the cancer (Galili, 2023; Cooper et al., 2015).