Relevance of sulfated sugars as main components of cruzipain, the major cysteine proteinase of Trypanosoma Cruzi. Synthesis of new conjugates sulfated sugar – BSA

J KOVENSKY; M. POURCELOT; M LANDONI; L.L. SOPRANO; D.M. ACOSTA; V G DUSCHAK; A S COUTO

Tokio

Simposio; XXV International Carbohydrate Symposium; 2010

Chagas disease, also known as American Trypanosomiasis constitutes a major health problem in most of Latin America. The World Health Organization has estimated that some 16-18 million people are infected throughout the American continent, and that more than 100 million are exposed to the risk of infection. The parasitic protozoan Trypanosoma cruzi, causative agent of the disease, contains a major cysteine proteinase, cruzipain (Cz). The presence of sulfated high-mannose type oligosaccharides in its C-terminal domain was identified as a new striking feature of this molecule, responsible for most antibodies in natural and experimental infections. In order to study the involvement of sulfates in immune recognition, different sulfated and non-sulfated molecules were coupled to BSA using two strategies: a) the sugar derivative was treated with ammonium carbamate and coupled through the resulting glycosylamine; b) in a few synthetic steps, a linker containing an azide group was introduced. This methodology was used for the preparation of new conjugates containing GlcNAc, GlcN6S, GlcNS, GlcNAc, and uronic acids. The sugar/protein ratio in the conjugate was determined by UV-MALDI-TOF MS. Ongoing assays using specific anti-sulfate antibodies will help to elucidate the involvement of sulfates in the antigenicity and cross reactivity of the molecule and/or in the immunopathology of Chagas disease.