Figure 1.

Ceramide pentahexoside (CPH) (left) and ceramide decahexoside (CDecaH) (right) as representative α-gal glycolipids. CPH is the most abundant glycolipid in rabbit RBC and is presented as a schematic α-gal glycolipid with five carbohydrates. CDecaH is a glycolipid with 10 carbohydrate branched chain. α-gal epitopes (Galα1-3Galβ1-4GlcNAc-R) are marked by the broken line rectangles. The terminal α-galactosyl (Gal) is linked α1,3 to the penultimate Gal of the carbohydrate chain by the glycosylation enzyme α1,3galactosyltransferase (α1,3GT). The carbohydrate chain is linked to the lipid portion (ceramide) embedded in the cell membrane via the two fatty acid tails. Anti-Gal binding to α-gal epitopes is presented as schematic IgG molecules. α-gal glycolipids in rabbit RBC (with the exception of ceramide heptahexoside) increase in size in increments of five carbohydrates, each forming an additional branch that is capped by α-gal epitopes.