Molecular characterization of thioredoxin peroxidases 1 from Trichinella spiralis and its potential in generating protective immunity.

BACKGROUND

Trichinella spiralis remains a significant food-borne parasitic threat with no licensed vaccine available. This study evaluated the vaccine potential of T. spiralis thioredoxin peroxidase 1 (Ts-TPx1).

METHODS

Recombinant Ts-TPx1 (rTs-TPx1) was expressed, purified, and characterized. Mice were immunized intraperitoneally with rTs-TPx1 plus ISA206, ISA206 alone, or PBS, and subsequently challenged orally with T. spiralis larvae. Systemic and intestinal immune reponses, protection efficacy, intestianl barrier function, and pathological changes in the murine intestine and diaphragm muscle were subsequently assessed.

RESULTS

Ts-TPx1 belongs to the 2-Cys peroxiredoxin  family. Native Ts-TPx1 is expressed across key lifecycle stages, predominantly localizing to the parasite surface and stichosome. rTs-TPx1 immunization elevated serum levels of Ts-TPx1-specific IgG, IgG1, and IgG2a, with IgG1 levels higher than IgG2a, and increased splenocyte secretion of specific INF-γ and IL-4. The vaccine conferred significant protection, reducing intestinal adult worm burden by 65.0% and muscle larval burden by 61.8%. It also enhanced intestinal mucosal immunity, as evidenced by increased sIgA and Muc2 levels, and ameliorated intestinal and diaphragm muscle pathology.

CONCLUSIONS

rTs-TPx1 immunization elicited specific intestinal mucosal immunity and Th2-biased mixed Th1/Th2 systemic protective response, establishing it as a promising vaccine candidate against Trichinella infection.