T Cell Subtypes Changes Of Liver And Mesenteric Lymph Node (MLN) In Mice Infected By Schistosoma Japonicum

Schistosomiasis is a serious disease to human and animals' health, the main reason for this disease is the eggs deposited in liver and intestine tissue leading to the egg granuloma and fibrosis. In animal models of Schistosome infection, the host immune response experiences a process from an acute phase of Th1 cellular immune responses to the chronic phase of Th2 humoral immune response. Eggs deposited in tissue can release the SEA which causes the T cell mediated immune response, the process is mediated by the Th1-type cells, along with increasing the IFN-γand other cytokines and causing the host acute inflammatory response. 6 to 8 weeks after infection, Th2 type cytokines IL-4, IL-5, IL-10 is gradually increased, causing the host Th2-type humoral immune response, the shift of the Th1/Th2 axis and the host Th2-type humoral immune response. Objective:Observing and discussing the changes of the T cells and their subsets in Schistosoma japonicum infected C57BL/6 mouse's liver and mesenteric lymph node on the single cell level at different stages by flow cytometry.Methods:1. 40 female C57BL/6 mice were divided into two groups, infection group and normal group. Each mouse in infection group was experimentally infected percutaneously with 40 cercariae.2. Mice were narcotized on week 4, 6 and 8 after infection. Precava was cut, steriled NS was used to remove blood from liver through ventriculus sinister injection. Then, the liver and the mesenteric lymph node were harvested.3. Make single mononuclear cell solution of the mesenteric lymph node and liver, then stimulated it with PMA plus Ionomycin. Cells were fixed, permeabilized and stained with specific conjugated mAbs. Data was analyzed by flow cytometer.4. Histopathologic sections of liver were obtained, HE stained and observed.Results:1. After Schistosomes infection, the liver granuloma was forming gradually, and the normal liver structure was destroyed obviously.2. After Schistosomes infection, C57BL/6's mesenteric lymph node became bigger, and the mesenteric lymph node cells became more.3. In the liver, during the infection 8 weeks, the percentage of the IL-2~+ cell, IFN-γ~+ cell, IL-4~+ cell, IL-10+ cell and IL-17~+ cell in CD4~+ cells were increasing. The proportion of the IL-17~+ cell reached the highest level on week 6, but decreased on week 8. 4. In the mesenteric lymph node, during the infection 8 weeks, the percentage of the IFN-γ~+ cell, IL-4~+ cell, IL-5~+ cell in CD4~+ cells was increasing. The proportion of the IL-17~+ cell reached the highest level on week 6, but decreased on week 8.5. In liver, the percentage of IFN-γ~+ cell in CD8+ cells reached 43.6 % on week 6 after infection and then decreased in the following days. In the mesenteric lymph node, the proportion of IFN-γ~+ cell in CD8+ cells was keeping decreasing on week 8 after infection.Conclusion1. After Schistosomes infection, C57BL/6's mesenteric lymph node cells became more and numerous eggs were assembled in the liver causing the inflammation response.2. After infected with S. japonicum, percentages Th (Th1, Th2 and Th17) and CTL of liver and mesenteric lymph node changed at different stage.