Infection grade determines intestinal immune reaction in Schistosomiasis

Introduction Schistosomiasis is one of the most common parasitic diseases worldwide with over 200 million infections. It is caused by trematodes of the genus Schistosoma, that mature, pair and lay eggs into intestinal veins (S. mansoni) of the host. The eggs can be trapped in capillary vessel, where they cause inflammatory reactions, predominantly in the liver and intestine. We aimed to analyze the effect of S. mansoni infection on the immune response in intestinal tissues.

Methods Female hamsters were infected with S. mansoni cercariae of both sexes (bisex) or with cercariae of one sex (monosex control without egg deposition). The worms were rinsed out of the hosts circulation by perfusion and subsequently counted, while the egg-load was counted in KOH-digested tissue. Th1 and Th2 specific cytokines were analyzed by RT-qPCR.

Results Compared to the control-groups (monosex and not infected), IL-4, IL-10, and IFNγ were induced in bisex-infected hamsters. In this group a positive correlation between the Th1 cytokine IFNγ and worm burden was observed. Interestingly, IL-5 mRNA expression levels did not show any group differences, but an inverse correlation between egg load and IL-5 expression.

Conclusion Our results suggest that the bisex-infection with S. mansoni caused a Th1 response and Th2 response in the intestine. There is evidence that the Th1 response is associated with the number of worm burden, whereas the inverse correlation of IL-5 with egg load may suggest that the Th2 response depends on the time of egg production and development of immune tolerance.

Publikationsverlauf

Artikel online veröffentlicht:
26. Januar 2022