Dynamic changes of DC and T cell subsets in mice during Echinococcus multilocularis infection.

The aim of this study was to determine the dynamic changes of dendritic cell (DC) pheno-types and T cell in response to Echinococcus multilocularis (Em) infection in BALB/c mice. Mice comprised the control and Em-infected group. At day 0, 2, 7, 30, 60, 90 and 120 after infection, the size of larval cysts, the phenotype of DC and Th in splenocytes and the expression of CD40, CD86, TLR2 and TLR4, on DCs sulfur were examined. The results show that after 60 days' infection, larval cysts grow on the surface of liver, and they become larger over time. Compared with the control mice, MHC I and MHC II expressions on DC were significantly increased at day 7 (p < 0.05). At the same time, CD40, CD86, TLR2 and TLR4 increased rapidly, but after that they decreased gradually. At day 120, those markers were lower than in the control group. The ratio of CD4/CD8 was normal during 90 days of infection, while at day 120, a decline in CD4 T cell and increase in CD8 were foundleading to the inversion of the CD4/CD8 ratio. Our findings suggest that within the 120 days of Em infection, the major function of DC is to present antigens. Immune response is provided predominantly by Th1 cells, inducing host immune response against Em. However, after 120 days, DC matured and the function was suppressed. Furthermore, inversion of the CD4/CD8 ratio is beneficial to the growth of Em, thus favoring its immune evasion.