The α-Galactosyl Carbohydrate Epitope in Pathogenic Protozoa.

The α-gal epitope, which refers to the carbohydrate α-d-Gal p -(1 → 3)-β-d-Gal p -(1 → 4)-d-GlcNAc-R, was first described in the glycoconjugates of mammals other than humans. Evolution caused a mutation that resulted in the inactivation of the α-1,3-galactosyltransferase gene. For that reason, humans produce antibodies against α-d-Gal p containing glycoproteins and glycolipids of other species. We summarize here the glycoconjugates with α-d-Gal p structures in Trypanosoma , Leishmania , and Plasmodium pathogenic protozoa. These were identified in infective stages of Trypanosoma cruzi and in Plasmodium sporozoites. In Leishmania , α-d-Gal p is linked differently in the glycans of glycoinositolphospholipids (GIPLs). Chemically synthesized neoglycoconjugates have been proposed as diagnostic tools and as antigens for vaccines. Several syntheses reported for the α-gal trisaccharide, also called the Galili epitope, and the glycans of GIPLs found in Leishmania , the preparation of neoglycoconjugates, and the studies in which they were involved are also included in this Review.