Abstract:To explore the mechanism of protective immunity against infection of Schistosoma japonicum induced by Sj26 and Sj23 gene transferred dendritic cells(DC),BALB/c mice were injected into ear pinna three times with Sj26 and Sj23 gene transferred DC(Group A),Sj26 gene transferred DC(Group B),Sj23 gene transferred DC(Group C),pcDNA3 transferred DC(Group D),untreated DC(Group E)and RPMI-1640(Group F),and then challenged with 40 cercariae of S.japonicum per mouse 2 weeks after the last immunization.Sera from mice were used to detect the levels of IgG antibody,IFN-γ and IL-4 by ELISA.The level of IFN-γ and IL-4 in the supernatants of spleen cells stimulated with soluble egg antigen(SEA)and ConA were quantified by sandwich ABC-ELISA.The proliferation of spleen cells were measured with the method of MTT.IgG antibody increased significantly in sera from group A mice at 2 weeks after the last immunization(P<0.001).It was found that the level of IL-4 in sera of each group mice were no significantly different before and after immunization.The levels of IFN-γ in sera of group A mice increased significantly at 2 weeks after the last immunization(P<0.01).In response to ConA and SEA,the level of IFN-γ in spleen cells from group A mice increased significantly,while the IL-4 secretion decreased significantly(compared with group F,P<0.001).The stimulating index of spleen cells from group A mice were higher than those of other groups in response to ConA and SEA(compared with group F,P<0.001).Sj26 and Sj23 gene transferred DC could induce both humoral and cellular immune responses contributed to its protective immunity.It is envident that Sj26 and Sj23 gene transferred DC could induce predominant Th1 type immune response which might play an important role in the protective immunity against infection of S.japonicum.