Effect Of RhuIL-2 On T Cell Subset, NK Cells And Embroys Of Pregnant Mice Infected Toxoplasma Gondii

Objective: To study the effect of rhuIL-2 on embryos and the trend of T cell subsets and nature killer cells of spleen of pregnant mice infected with Toxoplasma gondii.Materials and methods: Pregnant mice at the day 0 of gestation were divided into four groups. Three groups mice were inoculated intraperitoneally (i.p.) 400 tachyzoites of RH strain at the day 8 of gestation .Two of three groups were administered two dose of rhuIL-2 500U and 2000U at the day-1, 0, 1 of infection respectively as low-dose-IL-2 administered group and high-dose-IL-2 administered group, the other one was only injected 0.2ml NS as experimental controls. The left one group was not infected and administered as blank controls. Mice per group were executed by cervical vertebra disjointing at the day 10, 12, 14, 16 of gestation. Anatomized the pregnant mice uteri and observed the embryos fetation and compared the difference of average live embryo ratio among groups.The placentae and fetuses of the pregnant mice executed at the day 12 of gestation fixed in formaldehyde and embedded were used for immunohistochemical staining of T. gondii antigen to observe the T. gondii infection under optical microscopy. Then calculatedthe rate of vertical transmission of T. gondii according to the fetuses' coloration. FASCAN was employed to detect the level of T cell subsets and NK cell of splencytes taken from all pregnant mice.Results and discussions: The immunhistochemical staining showed that T. gondii antigen had already occurred at the day 12 of gestation . It expressed in cytoplasm of placenta villa epithelium cell and the interface under the trophoblast. T. gondii antigen was also observed in the myometrium cells and decidua cells. When fetuses were infected, T. gondii antigen was expressed in tissue differentiation sections.The level of spleen CD4+ T cells of experimental controls was lower than that of blank controls (P<0. 01) at the day 10, 12, 14, 16 of gestation and increased mildly at the day 16 of gestation. The level of spleen CDS+ T cell maintained a higher level in all terms in contrast to blank controls (P<0. 05) . The ratio of CD4+and CD8+ T cell inversed from the day 10 to 14 of gestation and rose to 1. 20 at the day 16 of gestation , but was still lower than blank controls(P<0. 05) , which indicated the maladjustment of T cell subsets. After being infected T. gondii, the level of spleen NK cells of pregnant mice decreased strikingly and were lower than controls(P<0. 01) in all terms. These data suggested that the peripheral cellular immunity of pregnant mice infected T. gondii was suppressed, the maladjustment of T cell subsets and the falldown of NK cell were mostly the major factors of T. gondii vertical transmission.The live embryos rate of high dose rhuIL-2 group rose strikigly, the rate of the low dose group showed no difference with experimental controls. The rates of T. gondii vertical transmission of these two groups were lower than that of experimental group(P<0. 05) . Thus it indicated that a definite dose of rhuIL-2 could play a protective role of fetuses exposed to T.gondii infection. The spleen CD4+ T cell of pregnant mice administered high dose of rhuIL-2 was higher than that of experimental controls, could reach the level of blank controls, that of the low dose group showed no difference with experimental controls. The spleen CD8+ T cell of the two administered groups decreased strikingly in comparison with experimental controls. As a result, the rate of spleen CD4+ and CD8+T cell of the high dose group rose to the level of blank controls and was much higher than experimental controls, but the low dose group showed no difference with it. The nature killer cells of spleen of the high dose group increasing strikingly, differed from the infected group, which indicated that rhuIL-2 could promote the proliferation of NK cell.Conclusions: We have already constructed a model of T.gondii vertical transmission successfully and verified that the peripheral cellular immunity of pregnant mice...