Xeno antigen type 2 / Galili antigen triaose /Linear B-2 trisaccharide

Galα1-3Galβ1-4Glc (α-Gal epitope type I trisaccharide) is the core xenoantigen responsible for hyperacute rejection in xenotransplantation, appearing as a white lyophilized powder widely used in immunology and glycan research for anti-Gal antibody screening and tolerance induction studies. This trisaccharide, abundant on non-primate mammalian cells (pig, cow), elicits potent natural IgM/IgG responses in humans due to its absence post-α1,3-galactosyltransferase knockout ~25-30 million years ago; commercially synthesized enzymatically (>95% purity), it serves as a diagnostic tool for α-Gal syndrome, vaccine adjuvant, and pathogen mimicry target, blocking bacterial/viral adhesion while modulating inflammation; stable for years frozen, soluble in water, with key roles in cancer glycomimetics and organ transplant research.

Appearance

• White to off-white amorphous or crystalline lyophilized powder.​
• Highly water-soluble (>150 g/L); hygroscopic when exposed to air.​

Source

• Ubiquitous on pig/cow endothelial cells (~10^6 epitopes/cell); absent in Old World primates/humans.​
• Chemoenzymatic synthesis via α1,3-galactosyltransferase on lactose acceptors in E. coli.​

Molecular Weight and Structure

• 504.44 g/mol, formula C₁₈H₃₂O₁₆ (CID 11249135).​
• α-D-Gal p-(1→3)-β-D-Gal p-(1→4)-D-Glc p linear trisaccharide scaffold.​

Sugar Specificity

• High affinity for human anti-Gal IgM/G (KD ~10^-7 M); binds lectins GS-I B4, PNA.​
• Hydrolyzed by α-galactosidase A from mammalian lysosomes.​

Biological Activity

• Triggers complement activation/C3b deposition in xenografts; induces IL-10 T-regs.​
• Inhibits Shiga toxin; modulates allergy via IgE cross-reactivity.​

Purity and Microbial Contamination

• ≥98% by HPLC/NMR; endotoxins <5 EU/mg via LAL.​
• Sterile filtration; heavy metals <0.5 ppm, moisture <5%.​

Identity and Quality Control

• ¹H-NMR confirms α1-3 linkage (J 3.8 Hz); LC-ESI MS [M+Na]+ 527.2.​
• HPAEC-PAD for Gal:Gal:Glc (2:1:1); anomeric purity >99%.​

Shelf Life and Storage

• 3-5 years at -20°C lyophilized under argon.​
• Ambient short-term (months) if desiccated.​

Applications

• Xenotransplant tolerance assays; α-Gal syndrome diagnostics.​
• Cancer vaccines; anti-Gal therapeutics; glycan arrays.​

Key Characteristics

• Hyperantigenic potency (10^4x linear Gal); gastric-stable.​
• Precise xenoepitope mimic for antibody affinity studies.​

Citation Links

• https://pubchem.ncbi.nlm.nih.gov/compound/11249135​
• https://pmc.ncbi.nlm.nih.gov/articles/PMC2271034/​
• http://chemsynlab.com/en/product/41744-59-6.html​
• https://www.dextrauk.com/products/glycoconjugates/…​
• https://www.chemicalbook.com/ChemicalProductProperty_EN_CB412868636.htm​
• https://www.tcichemicals.com/CH/en/p/G0380​
• https://www.vulcanchem.com/product/VC212766​
• https://glycosmos.org/structure/Gal-a1-3Gal-b1-4Glc
• https://www.sigmaaldrich.com/…/Gal-alpha1-3-Gal
• https://pubmed.ncbi.nlm.nih.gov/?term=Galα1-3Galβ1-4Glc