Upregulation of Toll-like receptor 2 and nuclear factor-kappa B expression in experimental colonic schistosomiasis.

Role of different mediators was described in the development of the granulomatous response and fibrosis observed in intestinal schistosomiasis. However, both Toll-like receptor 2 (TLR2) and nuclear factor kappa B (NF-κB) have not yet been investigated in intestinal schistosomiasis. This study aimed to characterize the role of TLR2 and NF-κB in the pathogenesis of intestinal schistosomiasis. Experimental animals were divided into two groups; group I: non-infected control group and group II: mice infected subcutaneously with S. mansoni cercariae. Colon samples were taken from infected mice, every two weeks, starting from the 6th week postinfection (PI) till 18th week PI. Samples were subjected to histopathological and immunohistochemical studies. Colon of S. mansoni infected mice showed histopathological changes in the form of mucosal degeneration, transmural mononuclear cellular infiltration and granulomas formation. Immunostained sections revealed significant increase in TLR2 and NF-κB positive cells in all layers of the colon, cells of the granuloma and those of the lymphoid follicles 10 weeks PI. All these changes decreased gradually starting from 12 weeks PI onward to be localized focally at 18 weeks PI. In conclusion, recruitment and activation of inflammatory cells to the colonic mucosa in intestinal schistosomiasis are multifactorial events involving TLR2 that can trigger the NF-κB pathways. Hence, down-regulation of both TLR2 and NF-κB could be exploited in the treatment of colonic schistosomiasis.

FoxP3+ T regulatory cells and immunomodulation after Schistosoma mansoni egg antigen immunization in experimental model of inflammatory bowel disease.

To assess the effect of Schistosoma mansoni egg antigen immunization on the immunomodulation in dextran sodium sulfate (DSS) induced colitis as an experimental model of IBD in comparison to non immunization and healthy control. The study was performed on 180 mice; 25 healthy control, 15 to identify the inflammatory peak of DSS, 25 received DSS for 7 days; 90 infected with S. mansoni cercariae to collect eggs for antigen preparation, and 25 immunized with the prepared antigen then received DSS course. Disease activity index, macroscopic & microscopic inflammatory scores, FoxP3+ T regulatory cell count, myeloperoxidase activity, and Th1/Th2 cytokine profile were compared in studied groups. Immunization induced both FoxP3+ T(regs) and Th2 cytokines to establish a state of immune homeostasis and create a quiescent steadier immune response to DSS. S. mansoni egg antigen succeeded in acting like a prophylactic helminthic therapy as it has a profitable modulatory effect on DSS-induced colitis model.