The surface glycoconjugates of trypanosomatid parasites

Abstract

Insect–transmitted protozoan parasites of the order Kinetoplastida, suborder Trypanosomatina, includeTrypanosoma brucei(aetiological agent of African sleeping sickness),Trypanosoma cruzi(aetiological agent of Chagas’ disease in South and Central America) andLeishmaniaspp. (aetiological agents of a variety of diseases throughout the tropics and sub–tropics). The structures of the most abundant cell–surface molecules of these organisms are reviewed and correlated with the different modes of parasitism of the three groups of parasites. The major surface molecules are all glycosylphosphatidylinositol (GPI)–anchored glycoproteins, such as the variant surface glycoproteins ofT. bruceiand the surface mucins ofT. cruzi, or complex glycophospholipids, such as the lipophosphoglycans and glycoinositolphospholipids of the leishmanias. Significantly, all of the aforementioned structures share a motif of Manα1–4GlcNα1–6–myo–inositol–1–HPO4–lipid and can therefore be considered to be members of a GPI superfamily.