The Role Of SHLA-G On The Abnormal Pregnant Outcome Induced By Toxoplasma Gondii Infection

Objective: To research the role of sHLA-G on the adverse pregnancy outcomesinduced by Toxoplasma gondii. Methods:1. Experiments in vivo: Establish theinfection animal model of pregnant C57BL/6mice in vivo. The pregnant mice weredivided into normal control group and the infected group. The mice of the infectedgroup were injected intraperitoneally with400Toxoplasma gondii tachyzoites on the8th day of gestation; The control group were injected intraperitoneally with PhosphateBuffered Saline at the same time; All the mice were anaesthetized and decapitated on14th day, the pregnancy outcome was recorded. Separating the uterus and placenta totest the concentration of Qa-2from the superantant of placenta with ELISA and detecting the inhibitory receptor NKG2A expressed on decidual NK cell with flow cytometry.2. Experiments in vitro: Establish BeWo cell system for vitro experiment，and setthe normal control group and infectioned group respectively. To detect the non-classicsoluble leucocyte antigen G (sHLA-G) of BeWo supernatant with ELISA; Establishingdecidual NK cells system and set the normal group and the infected group, within theinfected group to establish three groups，the control group，sHLA-G intervention groupand sHLA-G-neutralizing antibodies group，todetect the inhibitory receptor KIR2DL4of decidual NK cells using flow cytometry. Results:1. in vivo: The pregnant mice ofcontrol group showed normal life phenomenon，the placentas and fetuses of normalgroup showed uniform size，normal blood supply and flesh red; The pregnant mice ofinfection group showed abnormal Vital signs，for example santding instability，bodytemperature drops，the placentas and fetuses had bad blood supply，the average weightof placenta or fetuses decreased. Compared with normal control，the concentration ofQa-2increased significantly (P <0.05)， the expression of NKG2A of infected decidualNK cells also increased significantly compared to the controls(P <0.05).2. In vitroexperiment: Compared with control group，the sHLA-G level of infected BeWo supernatant increased significantly (P <0.05); Compared with the control group，theexpression of KIR2DL4in the sHLA-G-intervention group increased (P <0.05);Compared with sHLA-G intervention group， the expression of KIR2DL4in thesHLA-G-neutralizing antibodies group decreased significantly (P <0.05). Conclusionwe confirmed that infection by toxoplasma can lead to rise sHLA–G secretion duringmaternal-fetal interface through experiments in vivo and in vitro. The increasedsHLA-G can lead to its receptor KIR2DL4up-regulate.sHLA-G and its receptorKIR2DL4(NKG2A) are a pair of important immune molecules involving in immunetolerance during maternal-fetal interface.The overexpression of sHLA-G andKIR2DL4could damage the placenta barrier.This causes the toxoplasma gondii to crossthe placenta barrier easily，and lead to adverse pregnancy outcomes，such as fetalabnormalities，miscarriage，stillbirth.