| Objective:To study on the expression of the Fc gamma receptor Ⅲ(FcyRⅢ) in Hofbauer cells in maternal placental villi tissues infected by HBV, and to study the relationship between the level of FcyRⅢ in Hofbauer cells and the loads of HBV in hosts, and to investigate the role of FcyRⅢ in mediating HBV intrauterine infection.Methods:The fresh peripheral blood samples from fifty-five pregnant women and the fresh pregnant woman abortion placental villus tissues from sixty cases with HBV infection were all collected in our affiliated hospital and a teaching hospital. The peripheral blood mononuclear cells (PBMCs) in maternal and relevant cord blood mononuclear cells (CBMCs) in newborns were conventionally isolated by Ficoll-Hypaque medium. The loads of HBV-DNA in peripheral blood of maternal and cord blood of newborns were both detected by PCR. With pancreatic enzyme, EDTA digestive juices combined digest fresh villi tissues, the preparation of cell suspension would be made by completely the culture medium composed of RPMI1640liquid, so that the Hofbauer cells could be separated with Ficoll Hypaque and Percoll density gradient centrifugation, respectively. The activity of newly isolated and purification Hofbauer cells must be detected by trypan blue staining. The Hofbauer cells purified suspension was adjusted to the concentration of (1-2) x106/mL with1640complete medium and then detected the loads of HBV-DNA in Hofbauer cells by PCR. The total RNA from separation and purification of Hofbauer cells suspension were extracted by Trizol reagent and the reversed transcription into complementary DNA as soon as possible, so that the level of CD16(FcyRⅢ) mRNA in Hofbauer cells could be tested. The ratio of lg cDNA/lg GAPDH was regarded as the ultimate level of CD16mRNA so as to reduce the influence on amplified efficiency of cDNA and other factors. The comparative analysis of relationship between the expression of FcyRⅢ mRNA and the loads of HBV-DNA had been set up in pregnant women. The expression of CD16in Hofbauer cells in fresh placenta villi tissues was synchronously observed by HE staining and immunohistochemical staining, and further analyzed of the relationship with HBV infection levels in hosts. In addition, the expression of FcyRⅢ in Hofbauer cells in placenta of different types of maternal HBV infection also analyzed and compared in parallel. Results:The positive rates and loads of HBV-DNA in PBMCs of the term birth mothers with HBeAg(+) and their newborns were all higher than those in HBeAg(-). The significantly difference had been confirmed (P<0.05). Among them, the higher positive detection rates of HBV-DNA in the neonatal serum and CBMCs were set up in the pregnant women with high loads of HBV-DNA in the PBMCs of pregnant women. There were higher positive rates of HBV, such as46.4%(13/28), and higher loads of HBV-DNA in Hofbauer cells in the early abortion villus tissues. Comparison of HBV-DNA positive rates in Hofbauer cells of chorionic villus in pregnant women with positive and negative of HBeAg, the difference had been statistically significant (P<0.05). The further results showed that the levels of CD16(FcyRlII) mRNA in Hofbauer cells with positive of HBV-DNA obviously increased after detection of PCR, so that the statistically significant was difference comparing with the group with negative of HBV-DNA in Hofbauer cells (P<0.05). A good correlation (r=0.65, P<0.05) between the expression of CD16mRNA loads of HBV-DNA in Hofbauer cells also had been established. The expression of CD16mRNA in Hofbauer cells with positive of HBV-DNA was significantly higher than those in negative of HBV-DNA, there was significantly difference between the two groups (P<0.05). The results of cell immunohistochemical staining showed that the expression of CD16in the HBV infection pregnant women abortion villus Hofbauer cells and normal controls were observed under the microscope, and many brown granules could be seen on the surface of cell membrane and in cytoplasm. Interestingly, the results of streptavidin-perosidase (SP) immunohistochemical staining showed that the number of Hofbauer cells also had been increased and the immune coloring of CD16had been enhanced in HBV infection villus tissues than those in normal controls. The similar results were visible in pregnant women abortion villus Hofbauer cells with positive of HBV-DNA. The expression of FcyRlII mRNA of Hofbauer cells in placenta was increased, there was high significant difference between in HBV infection of placenta than that of normal control group (P0.05). It is noteworthy that the expression of FcyRⅢ mRNA of Hofbauer cells was increased in the intrauterine infection group than that in the none intrauterine infection group, the difference was statistically significant (P<0.05).Conclusion:Hofbauer cells, also known as a type of novel macrophages in placenta, usually are located in the villous stroma and adjacent to the fetal blood vessels, and play a key role in the resistance to microbial pathogens invasion. However, during the process of the resistance to multiple microbial pathogens, Hofbauer cells, regarded as a group of non-specific immune cells, can also be infected by HBV. The HBV infection in Hofbauer cells may be positive correlated to expression of HBeAg and HBV-DNA loads in the pregnant women. The FcyRⅢ, also known as an important immune molecules CD16on the membrane surface of Hofbauer cells, is common regarded as the important sign of cellular activation and associated with the loads of HBV-DNA in the pregnant women. Many brown granules can be seen on the surface of Hofbauer cell membrane and in cytoplasm by SP immunohistochemical staining. The expression intensity of brown granules is positively correlated with the replication level of HBeAg and loads of HBV-DNA. After Hofbauer cells infected by HBV, a cascade of signal transduction system in cells can be activated so that the expression of Fc gamma receptor Ⅲ on surface of Hofbauer cells can be enhanced subsequently. The cellular immunity or transcription of lymphokines can be caused by FcyRIII combining with immune complex from maternal circulation, such as HBsAg-anti-HBsAg immune complex, so that the HBV intrauterine infection also can be mediated. |
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