Galactose-alpha-1,3-galactose (alpha-Gal) (alpha-Gal)

Galactose-alpha-1,3-galactose (alpha-Gal) is a carbohydrate epitope expressed on the glycoproteins and glycolipids of non-primate mammals but is absent in humans due to the evolutionary loss of the alpha-1,3-galactosyltransferase enzyme (Galili, 2013, Journal of Immunology Research). Because of constant exposure to alpha-Gal-expressing bacteria in the gut, humans naturally produce high titers of anti-alpha-Gal IgM and IgG antibodies (Machado et al., 2021, Journal of Biomedical Science). The HyperAcute-Renal vaccine (Tergenpumatucel-L) utilizes this natural immunity by engineering allogeneic renal cancer cells to express alpha-Gal epitopes on their surface (Lumos Pharma, 2024). Upon administration, the pre-existing anti-alpha-Gal antibodies bind to the vaccine cells, initiating complement-mediated lysis and antibody-dependent cellular cytotoxicity (ADCC). This hyperacute rejection creates an inflammatory environment that recruits and activates antigen-presenting cells, which then engulf the vaccine cell debris and present tumor-associated antigens to the patient's T-cells (NCI Drug Dictionary). This mechanism is designed to overcome the immunosuppressive environment of the tumor and induce a systemic, long-lasting anti-tumor immune response against the patient's own cancer cells.

Other names

alpha-1,3-galactosyl epitopeGal-alpha-1,3-Galalpha-Gal epitopeGalalpha1-3Galalpha-Gal carbohydrate

Induction of hyperacute rejection of vaccine cells via pre-existing anti-alpha-Gal antibodies to enhance tumor antigen presentation.