CD4～+CD25～+ T Cells Can Down-regulate Immune Response And The Hepatic Egg Granuloma Formation Of Mice In Infection With Schistosoma Japonicum

At present, one of the most important challenges to the population living in an endemic area with schistosomiasis japonica is the long-term persistence of pathogen in the host and no strong protective immunity against the parasites. Thus, reinfection is difficult to be resisted. Studies in human populations and experimental models showed that the specific host immunity to schistosome is gradually down-regulated with the development of schistosomiasis, which is similar to other chronic infections, including tuberculosis and leishmaniasis. Recently, growing evidences have been presented to support the association between the chronic infections and CD4~+CD25~+ regulatory T cells. But to date, most data concentrated on the role of CD4~+CD25~+ regulatory T cells in autoimmunity diseases while the functions of these cells in schistosomiasis japonica are unclear. Our previous study has proved that there are some associations between the down-regulated immunity of chronic infections and CD4~+CD25~+ regulatory T cells.Our study focused on the role of CD4~+CD25~+ regulatory T cells during S.japonicum chronic infection.