Specific Recognition of β-Galactofuranose-Containing Glycans of Synthetic Neoglycoproteins by Sera of Chronic Chagas Disease Patients
Alba L. Montoya,
Eileni R. Gil,
Emily L. Heydemann,
Igor L. Estevao,
Bianca E. Luna,
Cameron C. Ellis,
Sohan R. Jankuru,
Belkisyolé Alarcón de Noya,
Oscar Noya,
Maria Paola Zago,
Igor C. Almeida,
Katja Michael
Affiliations
Alba L. Montoya
Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Eileni R. Gil
Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Emily L. Heydemann
Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Igor L. Estevao
Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Bianca E. Luna
Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Cameron C. Ellis
Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Sohan R. Jankuru
Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Belkisyolé Alarcón de Noya
Sección de Inmunología, Instituto de Medicina Tropical, Facultad de Medicina, Universidad Central de Venezuela, Caracas 1041-A, Venezuela
Oscar Noya
Sección de Inmunología, Instituto de Medicina Tropical, Facultad de Medicina, Universidad Central de Venezuela, Caracas 1041-A, Venezuela
Maria Paola Zago
Instituto de Patología Experimental, Facultad de Ciencias de la Salud, Universidad Nacional de Salta (UNSa)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Salta 4400, Argentina
Igor C. Almeida
Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Katja Michael
Department of Chemistry and Biochemistry, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
Chagas disease (CD) can be accurately diagnosed by detecting Trypanosoma cruzi in patients’ blood using polymerase chain reaction (PCR). However, parasite-derived biomarkers are of great interest for the serological diagnosis and early evaluation of chemotherapeutic efficacy when PCR may fail, owing to a blood parasite load below the method’s limit of detection. Previously, we focused on the detection of specific anti-α-galactopyranosyl (α-Gal) antibodies in chronic CD (CCD) patients elicited by α-Gal glycotopes copiously expressed on insect-derived and mammal-dwelling infective parasite stages. Nevertheless, these stages also abundantly express cell surface glycosylphosphatidylinositol (GPI)-anchored glycoproteins and glycoinositolphospholipids (GIPLs) bearing nonreducing terminal β-galactofuranosyl (β-Galf) residues, which are equally foreign to humans and, therefore, highly immunogenic. Here we report that CCD patients’ sera react specifically with synthetic β-Galf-containing glycans. We took a reversed immunoglycomics approach that entailed: (a) Synthesis of T. cruzi GIPL-derived Galfβ1,3Manpα-(CH2)3SH (glycan G29SH) and Galfβ1,3Manpα1,2-[Galfβ1,3]Manpα-(CH2)3SH (glycan G32SH); and (b) preparation of neoglycoproteins NGP29b and NGP32b, and their evaluation in a chemiluminescent immunoassay. Receiver-operating characteristic analysis revealed that NGP32b can distinguish CCD sera from sera of healthy individuals with 85.3% sensitivity and 100% specificity. This suggests that Galfβ1,3Manpα1,2-[Galfβ1,3]Manpα is an immunodominant glycotope and that NGP32b could potentially be used as a novel CCD biomarker.
