[EASL 2015]HBV特异性T细胞或可有效治疗慢性乙型肝炎

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最近新加坡临床科学研究所的S.Koh博士等的研究证实，1例HBsAg重排HCC患者的改造的HBV特异性T细胞过继转移引起HBsAg生成深度抑制(J Hepatology 2014. doi: 10.1016/j.jhep.2014.10.001.)。难以区分HBV抗T细胞的抗病毒作用与其杀伤作用，是影响这种免疫治疗应用于慢性HBV患者的障碍。第50届欧洲肝脏研究学会（EASL）年会上S.Koh博士公布的新的研究旨在发现一种能抑制病毒复制且没有肝毒性的HBV特异性T细胞，并分析这些T细胞介导的抗病毒机制。

研究方法

使用人淋巴细胞中的HBV-T细胞受体信使RNA电激法，我们生成了一种HBV特异性T细胞，其特点是具有不同的细胞活化和成熟期。这些独特的HBV特异性T细胞进行了2D和三三D体外检测，对其抑制病毒复制和/或溶解靶细胞的能力进行了分析。

研究结果

在不同设计的HBV特异性T细胞群中，我们选择了一种穿孔蛋白/ granzymelow HBV特异性T细胞，这种T细胞能够使HepG2.2.15病毒载量下降50％，而不会造成肝毒性，效靶比为1：3（2D和3D模型）。 HBV特异性识别后，这些休眠的幼稚（CD28 + CD27 +）T细胞可产生大量的细胞因子（IFN-γ，TNF-α，GM-CSF和淋巴毒素α和-β）。这些特殊的抗病毒机制分析提示，经典抗病毒细胞因子（IFN-γ，TNF-α，GM-CSF）和淋巴毒素β受体（LTBR）通路激活剂之间的特殊协同作用可介导抗病毒作用，但对非细胞病变作用无影响。

结论

生成一种能高效抑制HBV复制但不会直接杀死肝细胞的HBV特异性T细胞是有可能的。这代表了对慢性乙肝过继T细胞疗法有吸引力的一类细胞群。抗病毒细胞因子和/或LTBR活化对抗病毒活性的相对作用可能会导致HBV感染新靶向联合疗法的发展。

英文原文


ENGINEERED HBV-SPECIFIC T CELLS: DISENTANGLING ANTIVIRAL FROM KILLING CAPACITY (Abstrat No G04)

Authors：S. Koh1 , C.Y.L. Tham2, A.T. Tanoto2, A. Pavesi3, R.D. Kamm4,A. Bertoletti2. 1 Singapore Institute for Clinical Sciences A*STAR,2 Emerging Infectious Diseases Program, Duke-NUS Graduate Medical School, 3 Singapore MIT Alliance – SMART, Singapore, Singapore;4 Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, United States


Background and Aims: We have recently demonstrated that adoptive transfer of engineered HBV-specific T cells in a patient with HBsAg-productive HCC cause a profound inhbition of HBsAg production (J Hepatology 2014. doi: 10.1016/j.jhep.2014.10.001.). The difficulty to disentangle the antiviral effect of HBV T cells from their killing ability constitutes a barrier to the application of this immunotherapeutic approach in chronic HBV patients. Therefore, our aim was to produce HBV-specific T cells that can inhibit virus replication without hepatotoxicity and analyzed the antiviral mechanism mediated by these engineered T cells.

Methods: Using messenger RNA electroporation of HBV-T cell receptor in human lymphocytes, we produced HBV-specific T cells characterized by different activation and maturation stages. These distinct HBV-specific T cell populations were tested in 2 dimensional (2D) and 3D in vitro assays for their ability to inhibit HBV replication and/or lyse target cells.

Results: Among different engineered HBV-specific T cell populations, we selected a perforin/granzymelow HBV-specific T cells able to induce 50% drop in HBV viral load in HepG2.2.15 without causing detectable hepatotoxicity at an effector to target ratio of 1:3 (both in 2D and 3D models). After HBV-specific recognition, these resting naïve (CD28+CD27+) T cells produced a large range of cytokines (IFN-gamma, TNF-alpha, GM-CSF and lymphotoxin-alpha and -beta). Analysis of the specific antiviral mechanisms indicated that a specific synergy between classical antiviral cytokines (IFN-gamma, TNF-alpha, GM-CSF) and activator of lymphotoxin-b receptor (LTbR) pathway mediate the antiviral but non-cythopathic effect.

Conclusions: It is possible to produce HBV-specific T cells able to efficiently inhibit HBV replication without causing direct hepatocytes killing. This represents an attractive cell population for adoptive T cell therapy of chronic hepatitis B. The relative contribution of antiviral cytokines and/or LTbR activation to antiviral activity can lead to the development of new targeted combinatorial therapy in HBV infection.