COMPARATIVE-STUDY OF GLYCOSPHINGOLIPID COMPOSITION IN MAMMALIAN LENSES

The carbohydrate epitope Gal alpha 1-3Gal-R (alpha-galactosyl epitope) , which is detectable by its binding with Bandeiraea simplicifolia-IB4 lectin, was found in glycosphingolipids (GSLs), both neutral and acid ic (gangliosides), from lens tissues of non-primate mammals, but not i n those of human senile cataracts and Old World monkeys. Instead, huma n cataractous and Old World monkey non-cataractous lenses expressed Le wis(x) (Le(x)) epitopes (Gal beta 1-4(Fuc alpha 1-3)GlcNAc-R) in neutr al GSLs. Sialylated Le(x) epitopes were found in rat and pig lenses as well as in human and Old World monkey lenses. Ganglio-series ganglios ides, consisting mainly of GM3, GM1, GD1a and GD3, were detected in a species-specific fashion. On the other hand, alpha-galactosyl epitopes were expressed in lens tissues only in water-insoluble proteins of no n-primate mammals, but Le(x) and sialylated Le(x) epitopes were not de tectable in lens proteins. Among the several mammalian lenses examined , humans and Old World monkeys showed similar GSL compositions, in par ticular the presence of Le(x) and sialylated Le(x) epitopes and the ab sence of alpha-galactosyl epitopes, in lens tissue.