母婴传播是乙肝病毒的主要传播途径。国内外指南推荐对高病毒载量的乙肝孕妇在妊娠晚期进行抗病毒干预以进一步减少母婴传播。然而，妊娠期抗病毒干预停药后肝炎活动的免疫学机制以及对新生儿训练后免疫的影响等重要问题，目前尚不明确。本项目以HBsAg+，HBeAg+孕妇为研究对象建立队列，在妊娠期及产后对孕妇及其婴儿进行随访。根据孕妇是否接受抗病毒干预分为干预组和对照组，使用流式细胞术、多重细胞因子检测、PCR阵列等技术分析母婴免疫学指标。主要研究内容包括（1）妊娠期抗病毒干预对母体免疫系统的影响及其与分娩后肝炎活动的关系;（2）妊娠期抗病毒干预对新生儿训练免疫及乙肝免疫接种效果的影响;（3）分析新生儿训练后免疫与母婴传播的相关性。本项目的开展，不仅有助于深入理解妊娠期抗病毒干预阻断母婴传播的免疫学机制，而且可以为优化阻断母婴传播的公共卫生策略提供科学依据，从而有利于进一步降低母婴传播的发生率。

Mother-to-infant transmission is the major mode of HBV transmission. It has been shown that antiviral intervention during the third trimester in pregnant women with high HBV load can effectively block HBV mother-to-infant transmission, given combination prophylaxis of HB vaccine and HB immunoglobulin for infants. However, several important issues related to antiviral intervention are still unresolved, such as mechanism underlying hepatic flare after antiviral discontinuation, and the influence of antiviral intervention on trained immunity of infants born to HBV+ mothers. In this project, we will establish study cohort of pregnant women with chronic HBV infection and follow up the mothers and their infants during pregnancy and after birth. According to recommendation in guideline, antiviral intervention will be suggested to pregnant women with high HBV load. Therefore, pregnant women in the cohort will be divided into two groups, intervention group and control group according to their willingness to accept antiviral intervention. The immunity of mothers and their infants will be analyzed by flow cytometry, multiple cytokine assay, and PCR array, etc. This project will focus on: (1) the impact of antiviral intervention during pregnancy on the immunity of mother and the relationship between antiviral intervention and hepatic flare pOstpartum; (2) Influence of antiviral intervention during pregnancy on the trained immunity and prophylactic efficacy of hepatitis B vaccination in infants; (3) corelation between trained immunity of newborns and mother-to-infant transmission. To study immunological issues related to antiviral intervention during pregnancy will not only be helpful to understand the immunological mechanism of preventing mother-to-infant transmission, but also provide scientific evidence for optimization of the public health strategy for preventing mother-to-infant transmission, therefore, will be benefical for further reduce the rate of mother-to-infant transmission.