Man, apes and Old World monkeys differ from other mammals in the expression of a-galactosyl epitopes
(Galili et al. (1988) J. Biol. Chem. 263: 17755). All human sera
contain a large amount of naturally occurring antibody (anti-Gal) which binds to
oligosaccharides terminating in the disaccharide Gala1-3Gal (Galili et al. (1985) J. Exp. Med. 162: 573). These antigens (termed Galili antigens) are established
as major xenoantigens on pig endothelium and are thus responsible for initiating the
hyperacute rejection of pig organs by Old World primates and humans. In the future
development of xenotransplantation, these compounds are of primary significance.
It is thought that the full structure to which human anti-pig antibodies bind is the
pentasaccharide Gala1-3Galb1-4GlcNAcb1-3Galb1-4Glc.
Dextra has manufactured a series of oligosaccharides terminating in Gala1-3Gal including the pentasaccharide and linear B-6
(Lee at al. (1998) Transplantation 66(8)) to facilitate the study of
hyperacute rejection. They also make an extensive series of glycoconjugates in which
oligosaccharides are linked to proteins and lipids.
