Patient Plasma-Based Immunoproteomics Reveals Novel Echinococcus granulosus Antigens for Diagnosis of Cystic Echinococcosis.

Cystic echinococcosis (CE), a parasitic disease caused by Echinococcus granulosus (Eg), remains prevalent in underdeveloped pastoral regions. Current diagnostic methods for CE primarily rely on imaging techniques, whereas serological tests still require significant improvement. To address this challenge, we have developed an immunoproteomics workflow to identify novel diagnostic Eg antigens. Our approach involved extracting proteins from CE surgical tissues, which were then recognized by patient plasma through immunoblotting and subsequently identified using mass spectrometry. Applying stringent criteria to evaluate Eg protein antigenicity, we selected 25 candidates for expression, and 18 recombinant proteins demonstrated enhanced immunoreactivity with CE patient plasma. Further validation led to the identification of a novel panel comprising eight Eg recombinant antigens, which exhibited superior diagnostic capabilities with sensitivities ranging from 91.26% to 99.09% and specificities ranging from 95% to 97%. This panel was tested in a large-scale study involving 1068 plasma samples collected from patients with ultrasound-confirmed CE (+) and healthy controls. Our findings introduce a set of novel Eg antigens with significant potential for improving CE clinical diagnosis, particularly in its early stages. This research not only advances our understanding of CE immunology but also offers promising tools for enhancing disease detection and management in affected populations.