Wang Rong, Xu Aizhang, Zhang Xueying, Wu Jie, Freywald Andrew, Xu Jianqing, Xiang Jim
Cancer Research Cluster, Saskatchewan Cancer Agency, Saskatoon, Saskatchewan, Canada S7N4H4.
School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E5.
Cell Mol Immunol. 2017 Jun;14(6):529-545. doi: 10.1038/cmi.2016.23. Epub 2016 Jun 6.
CD8 cytotoxic T lymphocyte (CTL) exhaustion is a chief issue for ineffective virus elimination in chronic infectious diseases. We generated novel ovalbumin (OVA)-specific OVA-Texo and HIV-specific Gag-Texo vaccines inducing therapeutic immunity. To assess their therapeutic effect in chronic infection, we developed a new chronic infection model by i.v. infecting C57BL/6 mice with the OVA-expressing adenovirus AdVova. During chronic AdVova infection, mouse CTLs were found to express the inhibitory molecules programmed cell-death protein-1 (PD-1) and lymphocyte-activation gene-3 (LAG-3) and to be functionally exhausted, showing a significant deficiency in T-cell proliferation, IFN-γ production and cytolytic effects. Naive CD8 T cells upregulated inhibitory PD-ligand 1 (PD-L1), B- and T-lymphocyte attenuator and T-cell anergy-associated molecules (Grail and Itch) while down-regulating the proliferative response upon stimulation in mice with chronic infection. Remarkably, the OVA-Texo vaccine counteracted T-cell anergy and converted CTL exhaustion. The latter was associated with (i) the upregulation of a marker for CTL functionality, diacetylated histone-H3 (diAcH3), (ii) a fourfold increase in CTLs, occurring independent of host DCs or CD4 T cells, and (iii) the restoration of CTL IFN-γ production and cytotoxicity. In vivo OVA-Texo-stimulated CTLs upregulated the activities of the mTORC1 pathway-related molecules Akt, S6, eIF4E and T-bet, and treatment of the CTLs with an mTORC1 inhibitor, rapamycin, significantly reduced the OVA-Texo-induced increase in CTLs. Interestingly, OVA-Texo-mediated CD40L signaling played a critical role in the observed immunological effects. Importantly, the Gag-Texo vaccine induced Gag-specific therapeutic immunity in chronic infection. Therefore, this study should have a serious impact on the development of new therapeutic vaccines for human immunodeficiency virus (HIV-1) infection.
CD8细胞毒性T淋巴细胞（CTL）耗竭是慢性传染病中病毒清除无效的主要问题。我们研发了新型的卵清蛋白（OVA）特异性OVA-Texo疫苗和HIV特异性Gag-Texo疫苗，可诱导治疗性免疫。为评估它们在慢性感染中的治疗效果，我们通过静脉注射用表达OVA的腺病毒AdVova感染C57BL/6小鼠，建立了一种新的慢性感染模型。在慢性AdVova感染期间，发现小鼠CTL表达抑制性分子程序性细胞死亡蛋白-1（PD-1）和淋巴细胞激活基因-3（LAG-3），且功能耗竭，表现为T细胞增殖、IFN-γ产生和细胞溶解作用明显不足。在慢性感染小鼠中，初始CD8 T细胞上调抑制性PD-配体1（PD-L1）、B和T淋巴细胞衰减器以及T细胞无反应相关分子（Grail和Itch），同时下调刺激后的增殖反应。值得注意的是，OVA-Texo疫苗抵消了T细胞无反应并逆转了CTL耗竭。后者与以下因素有关：（i）CTL功能标志物二乙酰化组蛋白-H3（diAcH3）的上调；（ii）CTL增加四倍，这一增加独立于宿主树突状细胞（DC）或CD4 T细胞；（iii）CTL的IFN-γ产生和细胞毒性恢复。体内OVA-Texo刺激的CTL上调了mTORC1途径相关分子Akt、S6、eIF4E和T-bet的活性，用mTORC1抑制剂雷帕霉素处理CTL可显著降低OVA-Texo诱导的CTL增加。有趣的是，OVA-Texo介导的CD40L信号在观察到的免疫效应中起关键作用。重要的是，Gag-Texo疫苗在慢性感染中诱导了Gag特异性治疗性免疫。因此，本研究应对人类免疫缺陷病毒（HIV-1）感染新型治疗性疫苗的开发产生重大影响。
