Chagas disease (CD) is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. The parasite’s cell surface is covered by highly immunogenic glycoconjugates. One of the previously identified immunodominant glycotopes is the disaccharide Galα(1,3)Galβ, which is the terminal moiety of a significant number of O-glycans expressed on glycosylphosphatidylinositol-anchored mucins of the infective stage of T. cruzi. The Galα(1,3)Galβ glycotope triggers high levels of protective T. cruzi-specific anti-α-Gal antibodies in infected individuals. Here, we have synthesized the mercaptopropyl glycoside of that glycotope and conjugated it to recombinant inactive tetanus toxoid protein or ovalbumin using different crosslinkers, including succinimidyl iodoacetate and sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, to afford immunogens suitable for eliciting IgG antibodies in the alpha-1,3-galactosyltransferase-knockout mouse model. As negative controls, 2-mercaptoethanol (2-ME) was conjugated to these carrier proteins. The average number of disaccharide or 2-ME conjugated per protein molecule was determined by MALDI-TOF-MS. The antigenicity of the neoglycoproteins was confirmed by chemiluminescent enzyme-linked immunosorbent assay using sera of chronic CD patients. This work provides the materials needed for studying the effect of different carrier proteins and crosslinkers on the murine immune response to these neoglycoconjugates.

Synthesis of neoglycoproteins as potential biomarkers and vaccines for Chagas disease

2019 Spring National Meeting

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