Institute of Virology, School of Medicine, Technical University of Munich/Helmholtz Centre Munich, Munich, Germany.
Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Ege University, Izmir, Turkey.
Front Immunol. 2022 Nov 3;13:1029214. doi: 10.3389/fimmu.2022.1029214. eCollection 2022.
Despite the availability of an effective prophylactic vaccine, 820,000 people die annually of hepatitis B virus (HBV)-related liver disease according to WHO. Since current antiviral therapies do not provide a curative treatment for the 296 million HBV carriers around the globe, novel strategies to cure HBV are urgently needed. A promising approach is the redirection of T cells towards HBV-infected hepatocytes employing chimeric antigen receptors or T-cell engager antibodies. We recently described the effective redirection of T cells employing a second-generation chimeric antigen receptor directed against the envelope protein of hepatitis B virus on the surface of infected cells (S-CAR) as well as bispecific antibodies that engage CD3 or CD28 on T cells employing the identical HBV envelope protein (HBVenv) binder. In this study, we added a trispecific antibody comprising all three moieties to the tool-box. Cytotoxic and non-cytolytic antiviral activities of these bi- and trispecific T-cell engager antibodies were assessed in co-cultures of human PBMC with HBV-positive hepatoma cells, and compared to that of S-CAR-grafted T cells. Activation of T cells the S-CAR or by either a combination of the CD3- and CD28-targeting bispecific antibodies or the trispecific antibody allowed for specific elimination of HBV-positive target cells. While S-CAR-grafted effector T cells displayed faster killing kinetics, combinatory treatment with the bispecific antibodies or single treatment with the trispecific antibody was associated with a more pronounced cytokine release. Clearance of viral antigens and elimination of the HBV persistence form, the covalently closed circular (ccc) DNA, through cytolytic as well as cytokine-mediated activity was observed in all three settings with the combination of bispecific antibodies showing the strongest non-cytolytic, cytokine-mediated antiviral effect. Taken together, we demonstrate that bi- and trispecific T-cell engager antibodies can serve as a potent, off-the-shelf alternative to S-CAR-grafted T cells to cure HBV.
尽管有有效的预防性疫苗，但根据世界卫生组织的数据，每年仍有 82 万人死于乙型肝炎病毒（HBV）相关肝病。由于目前的抗病毒疗法不能为全球 2.96 亿名乙型肝炎病毒携带者提供治愈方法，因此迫切需要新的方法来治愈乙型肝炎病毒。一种有前途的方法是利用嵌合抗原受体或 T 细胞衔接抗体将 T 细胞重新定向到感染乙型肝炎病毒的肝细胞。我们最近描述了利用针对乙型肝炎病毒表面抗原的第二代嵌合抗原受体（S-CAR）以及与相同的乙型肝炎病毒包膜蛋白（HBVenv）结合的结合物结合的 CD3 或 CD28 的双特异性抗体有效地重新定向 T 细胞。在这项研究中，我们在工具盒中添加了一种包含所有三个部分的三特异性抗体。在人 PBMC 与 HBV 阳性肝癌细胞的共培养物中，评估了这些双特异性和三特异性 T 细胞衔接抗体的细胞毒性和非细胞毒性抗病毒活性，并与 S-CAR 移植的 T 细胞进行了比较。S-CAR 或通过结合 CD3 和 CD28 的双特异性抗体或三特异性抗体的组合激活 T 细胞，可特异性消除 HBV 阳性靶细胞。虽然 S-CAR 移植的效应 T 细胞显示出更快的杀伤动力学，但双特异性抗体的组合治疗或三特异性抗体的单一治疗与更明显的细胞因子释放相关。在所有三种设置中，通过细胞溶解和细胞因子介导的活性，均观察到清除病毒抗原和消除共价闭合环状（ccc）DNA 的乙型肝炎病毒持续形式，其中双特异性抗体的组合显示出最强的非细胞毒性、细胞因子介导的抗病毒作用。总之，我们证明了双特异性和三特异性 T 细胞衔接抗体可以作为 S-CAR 移植的 T 细胞的有效、现成的替代物来治愈乙型肝炎病毒。
