Interrogating Chagas antibody responses with high-throughput precision tools: towards a comprehensive catalog of ​ T. cruzi ​ antigens and epitopes across America.

RICCI A; RAMSEY J; ALTCHEH J; KESPER JR N; NOLAN M; DIOSQUE P; VILLAR JC; BUSCAGLIA CA; AGÜERO F

New Orleans, LA

Conferencia; 67th ASTMH Annual Meeting; 2018

American Society of Tropical Medicine and Hygiene

Using state of the art high-density peptide microarrays, we developed a highly multiplexedscreening array design containing ~2.8 million unique peptides derived from the completeproteomes of ​ Trypanosoma cruzi ​ strains CL-Brener (hybrid DTU TcVI; 19,668 proteins) andSylvio X10 (DTU TcI, 10,832 proteins). The full length of all 30,500 proteins encoded inthese genomes were scanned using 16mer peptides with an overlap of 12 residues betweeneach peptide. Using this platform, we screened sera pools from Chagas-positive and healthyvolunteers from several regions across America: Argentina, Brazil, Colombia, Mexico andthe United States. Screening of negative sera pools from healthy subjects allowed us todefine a background baseline of antibody-binding signal against peptides, as well as toidentify cross-reactive epitopes. Screening of Chagas-positive sera pools allowed us toidentify specific antibody-binding against ​ T. cruzi ​ peptides. Using a conservative signalthreshold to define antigenic peaks in proteins, our analysis led to the discovery of >4,500antigens (mostly novel), and to the identification of 22,747 antibody-binding peaks (epitopes)across all samples. Also, the comparative analysis of antibody-binding in different samplesallowed us to define a core set of pan-Chagas antigens and epitopes with reactivity in allhuman samples, as well as sets of unique/differential antigens (only reactive in onepopulation) or antigens with shared reactivity in a few samples (populations). In thepresentation we will highlight interesting cases of shared/differential antibody responses indifferent samples, and will discuss next steps to use this high-throughput platform todecompose the sera pools and gain insights into the seroprevalence of these epitopes ineach population. To the best of our knowledge this is the first proteome-wide catalog ofantigenic determinants for a human infectious disease.