A novel pentaglycosylceramide in ostrich liver, IV4-beta-Gal-nLc(4)Cer, with terminal Gal(beta 1-4)Gal, a xenoepitope recognized by human natural antibodies

Thin layer chromatograms of ostrich liver neutral glycosphingolipids were i mmunostained with human sera. In addition to the expected staining of the F orssman pentaglycosylceramide by some sera, more polar and less abundant un known glycolipids could be stained. Among them, the shortest carbohydrate c hain glycolipid was purified and structurally characterized by mass spectro metry, proton NMR and methylation analysis, It was a novel pentaglycosylcer amide of the neolactoseries terminated with the Gal(beta 1-4)Gal determinan t which is not expressed in mammalian species, Human antibodies affinity-pu rified on a synthetic Gal(beta 1-4)Gal(beta 1-4)Glc-Sepharose column recogn ized the newly characterized Gal(beta 1-4)Gal-terminated pentaglycosylceram ide, and, in addition, longer chain glycolipids. Occurrence of antibodies d irected at the Gal(beta 1-4)Gal epitope was studied by ELISA on 108 human s era, Anti-Gal(beta 1-4)Gal antibodies were predominantly IgM, and their dis tribution was similar to that of antiGal(alpha 1-3)Gal and anti-Forssman Ig Ms, It was concluded that anti-Gal(beta 1-4)Gal are natural antibodies, not previously identified in man. They can be considered as xenoantibodies dir ected at species which express Gal(beta 1-4)Galterminated carbohydrate chai ns.