Study Of CpG Inducing A Th1-type Immune Response And Regulating The Egg-granuloma In Liver Tissue Of The Mice Infected With Schistosoma Japonicum

Recent studies show that granuloma is an irnmunopathology reaction with many kinds of inflammatory cells such as eosinophile granulocyte infiltrating which is mediated by Th2 predominant response induced by soluble egg antigen .To control granulomatous formation plays an important role in the development of liver fibrosis in the advanced period. Regulating Th1/Th2 immunodeviation is an effective method to control granuloma and relieve fibrosis. .It has been reported that oligodexynucleotides containing CpG motifs (immunostimulatory sequences,ISS) can activate the innate immunity to secret cytokines such as IFN-γ,IL-12 etc which can facilitate Th1 type immune response and inhibit Th2 type immune response. Animal experiments also showed that CpG could relieve granulomatous reaction through regulating Th2 type immune response induced by egg of Schistosoma mansoni .In this paper ,through observing the regulating effects on Th1/Th2 immunodeviation to interfere with CpG or N-CpG or NS in vitro or in vivo ,we probed the effects of CpG on eggs granulomatous formation and fibrosis.The results showed that in vitro CpG co-administered with SEA or ConA could significantly up-regulate the expression of IFN-γ and down-regulate the expression of IL-4.The Th2 differentiation index of the spleen lymphocyte was significantly reduced with the effect of CpG .It concluded that CpG can induce a Thl type immune response. In intern experiment ,we could see that the granuloma density in liver tissue of mices immunized with CpG was lower than the control groups, single-egg granulomas formed were smaller in volume in the liver tissue of mices treated with CpG compared with those of the control groups.Antibody such as IgG, IgG₂a,IgG₁ in serum was dectected,the level of IgG at 6and 8w was lower than the control groups .IgG2a /IgGi at 6w CpG group was higher than the control groups.lt showed that CpG could facilitate Thl type immune response .Together with the results , CpG as a new kind of immune mediator and a potential vaccine adjuvant has an important theoretic and practical value for finding a novel approach to control egg-granuloma and prevent advanced schistosomiasis.