Maternal effect on offspring immunity against hepatitis B virus

B型肝炎病毒（HBV）可导致严重的肝脏疾病，包括肝硬化和肝细胞癌 （HCC）。世界上大约有2.5亿人长期感染这种病毒， 每年造成50 - 100万人死亡。大多数慢性HBV携带者在生命早期从他们的父母那里获得病毒。 感染的母亲与母婴传播（即，垂直传播）， 从无关的感染者获得HBV（即，水平传播）通常会发展为自限性急性 感染为什么垂直传播导致慢性感染，而水平传播导致自我感染？ 有限的急性感染尚不清楚。我们最近的研究表明，母亲体内的HBV可以抑制抗- 她的孩子的HBV免疫力，以促进HBV在后者的持久性。HBV的宿主范围很窄， 极大地阻碍了它的研究。我们最近开发了一种小鼠模型来研究母体对 HBV在其后代中的持续存在。通过将雌性半合子HBV转基因小鼠与雄性幼稚小鼠杂交， 获得非转基因小鼠幼仔。当这些非转基因小鼠幼崽被注射HBV时， 通过流体动力学注射基因组DNA，HBV复制在小鼠肝脏中持续长达28周。 这与非转基因母亲所生的对照小鼠相反，后者在HBV感染3-4周后清除HBV。 DNA注射我们的进一步研究表明，母体HBV可以调节小鼠肝巨噬细胞的生长， 后代，其将经历M2极化以抑制HBV特异性CD 8 + T细胞， HBV进入小鼠肝脏。本应用程序的目标是继续我们之前的研究以进一步了解 母体对子代抗HBV免疫力的影响。具体来说，我们将确定母亲体内的HBV 影响后代的HBV特异性CD 8 + T细胞和肝巨噬细胞。我们还将确定 以及母亲HBV如何影响后代的髓源性抑制细胞（MDSC）以及可能的 MDSC在抑制后代抗HBV免疫中的作用。最后，我们将研究可能的 肠道菌群及其代谢产物，特别是丁酸对HBV复制和抗HBV免疫作用 的后代。这些研究将为我们了解这一机制提供重要信息。 HBV母婴传播后的持续存在，并促进新治疗方案的开发 慢性HBV患者。

Hepatitis B virus (HBV) can cause severe liver diseases including cirrhosis and hepatocellular carcinoma (HCC). There are approximately 250 million people in the world that are chronically infected by this virus, resulting in 0.5-1 million deaths every year. Most chronic HBV carriers acquired the virus early in life from their infected mothers. In contrast to the mother-to-child transmission (i.e., vertical transmission), patients who acquired HBV from unrelated inviduals (i.e., horizontal transmission) will usually develop self-limited acute infection. Why vertical transmission leads to chronic infection whereas horizontal transmission leads to self- limited acute infection was unclear. Our recent studies indicated that HBV in the mothers could suppress anti- HBV immunity in her children to promote HBV persistence in the latter. HBV has a very narrow host range, which has greatly hampered its research. We have recently developed a mouse model to study the maternal effect on HBV persistence in her offspring. By crossing female hemizygous HBV transgenic mice to male naïve mice, we obtained non-transgenic mouse pups. When these non-transgenic mouse pups were injected with the HBV genomic DNA by hydrodynamic injection, the HBV replication persisted in the mouse liver for up to 28 weeks. This is in contrast to control mice born to non-transgenic mothers, which cleared HBV after 3-4 weeks of HBV DNA injection. Our further studies indicated that maternal HBV could condition hepatic macrophages of the offspring, which would undergo M2 polarization to suppress HBV-specific CD8+ T cells after the introduction of HBV into the mouse liver. The goal of this application is to continue our previous studies to further understand the maternal effect on offspring immunity against HBV. Specifically, we will determine how HBV in the mother impacts HBV-specific CD8+ T cells and hepatic macrophages of the offspring. We will also determine whether and how maternal HBV affects the myeloid-derived suppressor cells (MDSCs) of the offspring and the possible roles of MDSCs in the suppression of anti-HBV immunity in the offspring. Finally, we will investigate the possible effect of gut microbiota and their metabolites, specifically butyric acid, on HBV replication and anti-HBV immunity of the offspring. The proposed studies will provide important information for us to understand the mechanism of HBV persistence after its mother-to-child transmission and facilitate the development of novel therapeutic options for chronic HBV patients.