Commensal microbiota is closely related to Hepatitis B virus (HBV) infection. Gut bacteria maturation accelerates HBV immune clearance in hydrodynamic injection (HDI) HBV mouse model. However, the effect of gut bacteria on HBV replication in recombinant adeno-associated virus (AAV)-HBV mouse model with immune tolerance remains obscure. We aim to investigate its role on HBV replication in AAV-HBV mouse model. C57BL/6 mice were administrated with broad-spectrum antibiotic mixtures (ABX) to deplete gut bacteria and intravenously injected with AAV-HBV to establish persistent HBV replication. Gut microbiota community was analyzed by fecal qPCR assay and 16S ribosomal RNA (rRNA) gene sequencing. HBV replication markers in blood and liver were determined by ELISA, qPCR assay and Western blot at indicated time points. Immune response in AAV-HBV mouse model was activated through HDI of HBV plasmid or poly(I:C) and then detected by quantifying the percentage of IFN-γ/CD8 T cells in the spleen flow cytometry as well as the splenic IFN-γ mRNA level qPCR assay. We found that antibiotic exposure remarkably decreased gut bacteria abundance and diversity. Antibiotic treatment failed to alter the levels of serological HBV antigens, intrahepatic HBV RNA transcripts and HBc protein in AAV-HBV mouse model, but contributed to HBsAg increase after breaking of immune tolerance. Overall, our data uncovered that antibiotic-induced gut bacteria depletion has no effect on HBV replication in immune tolerant AAV-HBV mouse model, providing new thoughts for elucidating the correlation between gut bacteria dysbiosis by antibiotic abuse and clinical chronic HBV infection.

中文翻译：

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抗生素诱导的肠道细菌消耗对 HBV 免疫耐受小鼠模型中的 HBV 复制没有影响

共生微生物群与乙型肝炎病毒（HBV）感染密切相关。在水动力注射 (HDI) HBV 小鼠模型中，肠道细菌成熟可加速 HBV 免疫清除。然而，在具有免疫耐受性的重组腺相关病毒（AAV）-HBV小鼠模型中，肠道细菌对HBV复制的影响仍不清楚。我们的目的是研究其对 AAV-HBV 小鼠模型中 HBV 复制的作用。对 C57BL/6 小鼠施用广谱抗生素混合物 (ABX) 以消除肠道细菌，并静脉注射 AAV-HBV 以建立持续的 HBV 复制。通过粪便 qPCR 检测和 16S 核糖体 RNA (rRNA) 基因测序分析肠道微生物群落。在指定时间点通过 ELISA、qPCR 测定和蛋白质印迹测定血液和肝脏中的 HBV 复制标记物。通过HBV质粒或poly(I:C)的HDI激活AAV-HBV小鼠模型的免疫反应，然后通过量化脾脏流式细胞仪中IFN-γ/CD8 T细胞的百分比以及脾脏IFN-γ来检测mRNA 水平 qPCR 测定。我们发现抗生素暴露显着降低了肠道细菌的丰度和多样性。抗生素治疗未能改变 AAV-HBV 小鼠模型中血清学 HBV 抗原、肝内 HBV RNA 转录物和 HBc 蛋白的水平，但在破坏免疫耐受后导致 HBsAg 升高。总体而言，我们的数据发现，抗生素诱导的肠道细菌耗竭对免疫耐受的 AAV-HBV 小鼠模型中的 HBV 复制没有影响，为阐明抗生素滥用引起的肠道细菌生态失调与临床慢性 HBV 感染之间的相关性提供了新的思路。