Open AccessReversed Immunoglycomics Identifies α-Galactosyl-Bearing Glycotopes Specific for Leishmania major Infection
Author(s) -
Alba L. Montoya,
Victoria Macleod Austin,
Susana Portillo,
Irodiel Vinales,
Roger A. Ashmus,
Igor L. Estevao,
Sohan R. Jankuru,
Yasser Alraey,
Waleed S. Al-Salem,
Álvaro Acosta-Serrano,
Igor C. Almeida,
Katja Michael
Publication year - 2021
Publication title -
jacs au
Language(s) - English
Resource type - Journals
ISSN - 2691-3704
DOI - 10.1021/jacsau.1c00201
Subject(s) - glycan , leishmania , trypanosoma cruzi , biology , antibody , antigen , leishmaniasis , heterologous , immunofluorescence , cutaneous leishmaniasis , virology , parasite hosting , immunology , microbiology and biotechnology , glycoprotein , biochemistry , gene , world wide web , computer science
All healthy humans have high levels of natural anti-α-galactosyl (α-Gal) antibodies (elicited by yet uncharacterized glycotopes), which may play important roles in immunoglycomics: (a) potential protection against certain parasitic and viral zoonotic infections; (b) targeting of α-Gal-engineered cancer cells; (c) aiding in tissue repair; and (d) serving as adjuvants in α-Gal-based vaccines. Patients with certain protozoan infections have specific anti-α-Gal antibodies, elicited against parasite-derived α-Gal-bearing glycotopes. These glycotopes, however, remain elusive except for the well-characterized glycotope Galα1,3Galβ1,4GlcNAcα, expressed by Trypanosoma cruzi . The discovery of new parasitic glycotopes is greatly hindered by the enormous structural diversity of cell-surface glycans and the technical challenges of classical immunoglycomics, a top-down approach from cultivated parasites to isolated glycans. Here, we demonstrate that reversed immunoglycomics, a bottom-up approach, can identify parasite species-specific α-Gal-bearing glycotopes by probing synthetic oligosaccharides on neoglycoproteins. This method was tested here seeking to identify as-yet unknown glycotopes specific for Leishmania major , the causative agent of Old-World cutaneous leishmaniasis (OWCL). Neoglycoproteins decorated with synthetic α-Gal-containing oligosaccharides derived from L. major glycoinositolphospholipids served as antigens in a chemiluminescent enzyme-linked immunosorbent assay using sera from OWCL patients and noninfected individuals. Receiver-operating characteristic analysis identified Gal p α1,3Gal f β and Gal p α1,3Gal f β1,3Man p α glycotopes as diagnostic biomarkers for L. major- caused OWCL, which can distinguish with 100% specificity from heterologous diseases and L. tropica- caused OWCL. These glycotopes could prove useful in the development of rapid α-Gal-based diagnostics and vaccines for OWCL. Furthermore, this method could help unravel cryptic α-Gal-glycotopes of other protozoan parasites and enterobacteria that elicit the natural human anti-α-Gal antibodies.