Proliferation, Differentiation And Immune Inhibitory Ability Of Immune Cells Of Mice Stimulated By Adult Worm Antigen And Egg Antigen Of Schistosoma Japonicum

In China, schistosomiasis is still one of the major public health problems today. Schistosomiasis is a chronic helminth infection, which cause varying immune response due to different antigens in the different stages of infection. Shistosome adult worm antigen (SWA) and egg antigen (SEA) are two major antigen components during the course of schistosomiasis infection. In infection, These two types of antigen co-exist and lead to complicate results of host immune responses together. In order to investigate and compare the different effects of SWA and SEA of Schistosoma japonicum on host immune effection (against infection or damage host organs), the proliferation and differentiation of the spleen cells and CD4~+T cells of mice in response to SWA or SEA stimulation were investigated both in vivo and in vitro. Then, the apoptosis of CD4~+T cells and the induction of CD4~+C25~+Treg cells which their suppresive cytokines in response to SWA or SEA were detected both in vivo and in vitro to investigate and compare the different effects of SWA and SEA of Schistosoma japonicum on immunoregulation (immunosuppression). Results showed that the proliferation of slpeen cells and CD4~+T cells of mice in response to SEA stimulation increased significantly higher than that in response to SWA stimulation (P<0.05). Th flow cytometry analysis showed that higher productions of IL-4 and IL-17 in slpeen cells and splenic CD4~+T cells were observed under SEA stimulation, instead of SWA stimulation (P<0.05), whereas SWA induced a significantly higher production of IFN-γthan that in the SEA group (P<0.05). Also, our results found that the apoptosis of CD4~+T cells in both SWA group and SEA group were significantly increased, but there was no statistical significance between SWA group and SEA group (p>0.05). SEA induced higher proportion of CD4~+CD25~+FOXP3~+T cells, a stronger suppressive activity of CD4~+CD25~+T cells which produced higher levels of IL-10 and TGF-β, than that in the SWA group (P<0.05). These results suggest that the proliferation and differentiation of Th2 cells and Th17 cells in spleen cells and CD4~+T cells in response to SEA stimulation are significantly more than those in response to SWA stimulation, and SEA also significantly enhanced the immunosuppression activity of CD4~+CD25~+T cells. However, the significantly higher levels of Th1 cells were only observed under SWA induction.In conclusion, our study reveals that compared with SWA, SEA preferentially induces the immune effection including anti-infection and immunopathological damage, meanwhile SEA also plays more important role in the development of immunosuppression during chronic infection of schistosomiasis. Futhermore, our findings contributes to the schistosomiasis prevention (vaccine development) and treatment (the control of immune pathology), and further contribute to construction of an immune-model based on schistosome or its SWA and SEA antigen, which can be widely used in other immune-related diseases researches.