Deng Guangying, Ge Jun, Liu Chao, Pang Jinke, Huang Zuxiong, Peng Jie, Sun Jian, Hou Jinlin, Zhang Xiaoyong
State key laboratory of organ failure research, Guangdong provincial key laboratory of viral hepatitis research, department of hepatology unit and infectious diseases, Nanfang hospital, Southern medical university, No. 1838, North Guangzhou avenue, 510515 Guangzhou, China.
State key laboratory of organ failure research, Guangdong provincial key laboratory of viral hepatitis research, department of hepatology unit and infectious diseases, Nanfang hospital, Southern medical university, No. 1838, North Guangzhou avenue, 510515 Guangzhou, China; Department of hepatology, affiliated infectious disease hospital, Fujian medical university, Fuzhou, China.
Clin Res Hepatol Gastroenterol. 2017 Sep;41(4):386-398. doi: 10.1016/j.clinre.2016.12.006. Epub 2017 Feb 21.
Toll-like receptor 8 (TLR8) plays an important role in controlling chronic viral infections. However, the role of TLR8 in chronic hepatitis B virus (HBV) infection is poorly understood. In this study, we aimed to investigate the expression and function of TLR8 in peripheral blood mononuclear cells (PBMCs) of chronic hepatitis B (CHB) patients and its alteration during peg-IFN-α-2a therapy.
We evaluated TLR8 expression and antiviral function in vitro by real-time RT-PCR and flow cytometry analysis using fresh PBMCs obtained from CHB patients compared to healthy controls. We also employed clinical cohorts to investigate TLR8 expression in response to peg-IFN-α-2a therapy.
TLR8 was mainly expressed in monocytes, and simulation with its ligand resulted in high levels of IFN-γ and TNF-α production. Compared with healthy controls, PBMCs obtained from CHB patients displayed reduced levels of TLR8 expression and IFN-γ, TNF-α and IL-12 induction. The exposure of HepG2.2.15 cells to conditioned medium from PBMCs stimulated by ssRNA40 strongly reduced the levels of HBV DNA, HBsAg and HBeAg, whereas the addition of IFN-γ or TNF-α neutralizing antibodies could block the antiviral effect. NK cells and T cells were the principal IFN-γ-producing lymphocytes after ssRNA40 stimulation, whereas monocytes were the primary source of TNF-α. Analysis of the temporal dynamics showed that patients who achieved a complete response sustained a significant higher level of TLR8 mRNA than those who did not achieve a complete response beginning at week 12 of peg-IFN-α-2a therapy.
TLR8 expression and function in PBMCs were impaired by chronic HBV infection. Higher TLR8 expression after treatment week 12 could potentially predict complete response to peg-IFN-α-2a therapy.
Toll样受体8（TLR8）在控制慢性病毒感染中发挥重要作用。然而，TLR8在慢性乙型肝炎病毒（HBV）感染中的作用尚不清楚。在本研究中，我们旨在探讨TLR8在慢性乙型肝炎（CHB）患者外周血单个核细胞（PBMC）中的表达和功能及其在聚乙二醇干扰素-α-2a治疗期间的变化。
我们通过实时逆转录聚合酶链反应（RT-PCR）和流式细胞术分析，使用从CHB患者获得的新鲜PBMC与健康对照相比，在体外评估TLR8表达和抗病毒功能。我们还采用临床队列研究TLR8在聚乙二醇干扰素-α-2a治疗反应中的表达。
TLR8主要表达于单核细胞，用其配体刺激可导致高水平的干扰素-γ（IFN-γ）和肿瘤坏死因子-α（TNF-α）产生。与健康对照相比，从CHB患者获得的PBMC显示TLR8表达水平降低，以及IFN-γ、TNF-α和白细胞介素-12（IL-12）诱导减少。将HepG2.2.15细胞暴露于经单链RNA40（ssRNA40）刺激的PBMC的条件培养基中，可强烈降低HBV DNA、乙肝表面抗原（HBsAg）和乙肝e抗原（HBeAg）水平，而添加IFN-γ或TNF-α中和抗体可阻断抗病毒作用。自然杀伤细胞（NK细胞）和T细胞是ssRNA40刺激后产生IFN-γ的主要淋巴细胞，而单核细胞是TNF-α的主要来源。时间动态分析表明，从聚乙二醇干扰素-α-2a治疗第12周开始，实现完全缓解的患者TLR8 mRNA水平显著高于未实现完全缓解的患者。
慢性HBV感染损害了PBMC中TLR8的表达和功能。治疗第12周后较高的TLR8表达可能预测对聚乙二醇干扰素-α-2a治疗的完全缓解。
