Proteomic analysis and functional characterization of excretory-secretory products from adult Toxocara canis: insights into parasite-host interactions

Background: Toxocara canis is a globally distributed zoonotic nematode with significant public health implications. While previous studies have explored the excretory-secretory (ES) proteins of third-stage larvae (L3) and the non-protein components of adult excretory-secretory products (ESPs), a comprehensive molecular characterization of ES proteins from adult T. canis remains lacking.

Methods: ES proteins from female and male adult T. canis were profiled using an Orbitrap Astral mass spectrometer. Proteins with differential abundance (PDAs) between sexes were analyzed for subcellular localization, transcription factor, conserved domain, GO term and KEGG pathway enrichment. Immune-interacting ES proteins were identified via co-immunoprecipitation (Co-IP) followed by mass spectrometry.

Results: A total of 2,513 ES proteins were identified, including 1,516 shared between female and male adults. Among these, 180 proteins were upregulated and 310 were downregulated between sexes. Additionally, 292 and 117 proteins were uniquely expressed in females and males, respectively. Many ES proteins were enriched in key signaling pathways, including PI3K-Akt, Rap1, MAPK, and JAK-STAT. Co-IP analysis revealed 150 immune-interacting ES proteins, such as 14-3-3-like protein 2, 26 S protease regulatory subunit, tubulin, heat shock protein 70, and Enolase. Importantly, 74 proteins were common to both the Co-IP and direct proteomic datasets.

Conclusions: This study provides the first comprehensive proteomic profile of ES proteins from adult T. canis, including those interacting with host immune components. These findings enhance our understanding of parasite-host interactions and offer promising targets for novel therapeutic interventions against zoonotic toxocariasis.

Toxocara canis; Co-immunoprecipitation; Excretory-secretory products; Proteomics; Toxocariasis.