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Background Inflammatory bowel disease is an immunologically mediated disease. Notably, it is less common in countries where there is a greater risk of exposure to helminths. In our study, we examined the modulatory effect of the laminated layer extracted from the cyst wall of a helminth parasite, Echinococcus granulosus, on dextran sulfate sodium (DSS)-induced colitis in mice. Methods An acute colitis was induced in BALB/c mice using 2.5% w/v DSS in drinking water. The crude extract of E. granulosus laminated layer was injected intraperitoneally daily, starting 3 days before colitis induction. The Disease Activity Index was monitored daily, colon length and weight were measured and histological scores were evaluated. Nitric oxide (NO) and cytokine levels (interferon γ (IFN-γ), tumor necrosis factor α (TNF-α) and interleukin 10 (IL-10)) were assessed by enzyme-linked immunosorbent assay. In addition, the colonic expression of inducible nitric oxide synthase (iNOS) and nuclear factor-κB (NF-κB) was examined. Statistical analyses were performed by one-way analysis of variance and the survival rate was analyzed by the long rank test. Results Hydatid laminated layer pretreatment significantly improved the clinical symptoms and histological scores (*** p

Hydatidosis is characterized by the long-term coexistence of larvaEchinococcus granulosusand its host without effective rejection. Previous studies demonstrated nitric oxide (NO) production (in vivo and in vitro) during hydatidosis. In this study, we investigated the direct in vitro effects of NO species: nitrite (NO2−), nitrate (NO3−) and peroxynitrite (ONOO−) on protoscolices (PSCs) viability and hydatid cyst layers integrity for 24 hours and 48 hours. Our results showed protoscolicidal activity ofNO2−andONOO−24 hours and 3 hours after treatment with 320 μM and 80 μM respectively. Degenerative effects were observed on germinal and laminated layers. The comparison of the in vitro effects of NO species on the PSCs viability indicated thatONOO−is more cytotoxic thanNO2−. In contrast,NO3−has no effect. These results suggest possible involvement ofNO2−andONOO−in antihydatic action and point the efficacy of these metabolites as scolicidal agents.

Background Helminth parasites are highly antigenic and some types favour the generation or exacerbation of allergic responses by inducing strong Th2-type responses (with the production of cytokines, particularly IL-4). Moreover, recent data suggest that Arginase is involved in the pathogenesis of multiple aspects of allergic disease. In the present work, our aim is to study whether the parasite Echinococcus granulosus induces Th2-type response and whether this is beneficial for the host or not. Echinococcus g. infection, which induces hydatidosis, remains a serious parasitic disease in Algeria. In human, the larval form develops into large cysts especially in the liver and lungs. Methods We have investigated the effect of laminated-layer (accelullar layer of hydatic cyst) extract (LLs) on IL-4, and IFN-γ production and Arginase activity in culture performed with mononuclear cells (PBMC). These cells are prepared from peripheral blood of hydatic patients (before and after surgery) and healthy donors. Of note, IFN-γ (Th1 cytokine) downregulates Th2-derived cytokines (like IL-4) which are the best inducer of Arginase pathway. Finally, we have investigated the effects of LLs and IL-4 on protoscoleces (larval form of parasite) viability in PBMC-protoscoleces coculture. Results We have found that LLs enhanced IL-4 production and Arginase activity and reduced IFN-γ production by PBMC. Furthermore, LLs and IL-4 also enhanced parasite survival in PBMC-Parasite cocultures. Moreover, we have purified by chromatography one of the major antigenic protein in LLs: the fraction 4 (F4, 12kDa). This fraction has the same effect as LLs on Th1/Th2 balance. Interestingly, similar findings are observed in cultures and cocultures performed with PBMC of presurgical and postsurgical patient and healthy donors. Conclusions Taken together, our results suggest that the laminated layer of Echinococcus g. may promote allergic response in humans directly by inducting the Th2 pathway. Moreover, this response allows the parasite survival.

Background The effect of helminth infections on allergic diseases is still inconclusive. Several studies show that Treg cell induced by parasites down regulate the host Th2-mediated allergic response. However, some studies highlight the importance of alternative activated macrophages (AAM) in the pathogenesis of allergic diseases. This phenotype is also implicated in helminth survival. Our aim is to study the immunomodulatory effect of laminated layer (LL, accelullar layer of hydatic cyst) of the helminth Echinococcus granulosus. This infection remains a serious parasitic disease in Algeria.