Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.
Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, Germany.
J Hepatol. 2019 Oct;71(4):673-684. doi: 10.1016/j.jhep.2019.06.005. Epub 2019 Jun 14.
BACKGROUND & AIMS: Immunosuppressed patients with chronic hepatitis E virus infection (cHEV), who are ineligible or have failed current treatment with off-label ribavirin, are a potential target population for T cell-based therapy. T cell responses are important for viral control. Herein, we aimed to identify human leukocyte antigen (HLA)-A2 restricted HEV-specific CD8+ T cell epitopes and T cell receptors (TCR) targeting these epitopes, as the basis for a redirected TCR treatment approach for patients with cHEV.
HEV genotype 3 overlapping peptide pools were used to screen HEV-specific CD8+ T cell immune responses in HLA-A2+ patients with acute HEV infection and healthy donors, by intracellular cytokine staining. CD8+ T cells targeting the identified epitopes were sorted for sequencing of the TCR repertoires by next generation sequencing. Messenger RNA encoding these TCRs were introduced into lymphocytes of healthy donors and patients with cHEV through TCR redirection. TCR-engineered lymphocytes were evaluated for Dextramer®-binding capacity, target sensitivity and cytotoxicity against peptide-loaded T2 cells.
HEV-specific responses were observed across open reading frame (ORF)1 and ORF2 of the HEV genome in patients with acute resolving HEV infection. HLA-A2-restricted HEV-specific CD8+ T cell epitopes targeting the HEV RNA helicase and RNA-dependent RNA polymerase were selected for functional studies. Introduction of HEV-specific TCRs into lymphocytes of immunocompetent donors and patients with chronic hepatitis E enabled the lymphocytes to bind HEV Dextramers, secrete multiple cytokines and exert cytotoxicity in a target-specific manner.
We identified TCRs that target HEV-specific CD8+ T cell epitopes, and characterized their immune properties, which may have clinical potential in future T cell-based therapy.
Patients who are immunosuppressed are vulnerable to developing chronic liver disease following infection with hepatitis E virus (HEV). To-date, there is no approved therapy for chronic hepatitis E. Interferon-α and ribavirin are off-label treatment options, but their applications are limited by side effects. Thus, immunotherapy, more specifically T cell-based therapy, may be an alternative approach. We designed T cell receptor-engineered T cells that effectively conferred immune cells, taken from patients with chronic hepatitis E, with the ability to recognize virus-specific epitopes and mediate killing of target cells in vitro.
慢性戊型肝炎病毒（HEV）感染的免疫抑制患者不适合或已对利巴韦林进行了非适应证治疗且治疗失败，是 T 细胞为基础的治疗的潜在目标人群。T 细胞应答对病毒控制很重要。在此，我们旨在鉴定人白细胞抗原（HLA）-A2 限制的 HEV 特异性 CD8+ T 细胞表位和针对这些表位的 T 细胞受体（TCR），作为针对慢性 HEV 患者的定向 TCR 治疗方法的基础。
通过细胞内细胞因子染色，使用 HEV 基因型 3 重叠肽池筛选急性 HEV 感染的 HLA-A2+患者和健康供体中的 HEV 特异性 CD8+ T 细胞免疫应答。针对鉴定出的表位的 CD8+ T 细胞进行下一代测序的 TCR 库的测序。通过 TCR 重定向将编码这些 TCR 的信使 RNA 导入健康供体和慢性 HEV 患者的淋巴细胞中。评估 TCR 工程化淋巴细胞对 Dextramer®结合能力、对负载肽的 T2 细胞的靶敏感性和细胞毒性。
在急性 HEV 感染患者中，观察到 HEV 全基因组 ORF1 和 ORF2 中存在 HEV 特异性反应。选择针对 HEV RNA 解旋酶和 RNA 依赖性 RNA 聚合酶的 HLA-A2 限制的 HEV 特异性 CD8+ T 细胞表位进行功能研究。将 HEV 特异性 TCR 导入免疫功能正常的供体和慢性乙型肝炎患者的淋巴细胞中，使淋巴细胞能够结合 HEV Dextramers，以特异性方式分泌多种细胞因子并发挥细胞毒性。
我们鉴定了靶向 HEV 特异性 CD8+ T 细胞表位的 TCR，并对其免疫特性进行了描述，这可能在未来的 T 细胞为基础的治疗中有临床潜力。
感染戊型肝炎病毒（HEV）后，免疫抑制患者易发生慢性肝病。迄今为止，尚无批准用于慢性乙型肝炎的治疗方法。干扰素-α和利巴韦林是适应证外的治疗选择，但由于副作用，其应用受到限制。因此，免疫疗法，更具体地说是 T 细胞为基础的疗法，可能是一种替代方法。我们设计了 T 细胞受体工程化 T 细胞，这些细胞有效地赋予来自慢性乙型肝炎患者的免疫细胞识别病毒特异性表位并介导体外杀伤靶细胞的能力。
