Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital - Amager and Hvidovre, and Department of Immunology and Microbiolgy, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
Department of Molecular Diagnostics, Aalborg University Hospital and Clinical Institute, Aalborg University, Aalborg, Denmark.
J Hepatol. 2022 May;76(5):1051-1061. doi: 10.1016/j.jhep.2021.12.026. Epub 2022 Jan 4.
BACKGROUND & AIMS: A prophylactic vaccine is required to eliminate HCV as a global public health threat. We developed whole virus inactivated HCV vaccine candidates employing a licensed adjuvant. Further, we investigated the effects of HCV envelope protein modifications (to increase neutralization epitope exposure) on immunogenicity.
Whole virus vaccine antigen was produced in Huh7.5 hepatoma cells, processed using a multistep protocol and formulated with adjuvant (MF-59 analogue AddaVax or aluminium hydroxide). We investigated the capacity of IgG purified from the serum of immunized BALB/c mice to neutralize genotype 1-6 HCV (by virus neutralization assays) and to bind homologous envelope proteins (by ELISA). Viruses used for immunizations were (i) HCV5aHi with strain SA13 envelope proteins and modification of an O-linked glycosylation site in E2 (T385P), (ii) HCV5aHi(T385) with reversion of T385P to T385, featuring the original E2 sequence determined in vivo and (iii) HCV5aHi(ΔHVR1) with deletion of HVR1. For these viruses, epitope exposure was investigated using human monoclonal (AR3A and AR4A) and polyclonal (C211 and H06) antibodies in neutralization assays.
Processed HCV5aHi formulated with AddaVax induced antibodies that efficiently bound homologous envelope proteins and broadly neutralized cultured genotype 1-6 HCV, with half maximal inhibitory concentrations of between 14 and 192 μg/ml (mean of 36 μg/ml against the homologous virus). Vaccination with aluminium hydroxide was less immunogenic. Compared to HCV5aHi(T385) with the original E2 sequence, HCV5aHi with a modified glycosylation site and HCV5aHi(ΔHVR1) without HVR1 showed increased neutralization epitope exposure but similar immunogenicity.
Using an adjuvant suitable for human use, we developed inactivated whole HCV vaccine candidates that induced broadly neutralizing antibodies, which warrant investigation in further pre-clinical studies.
A vaccine against hepatitis C virus (HCV) is needed to prevent the estimated 2 million new infections and 400,000 deaths caused by this virus each year. We developed inactivated whole HCV vaccine candidates using adjuvants licensed for human use, which, following immunization of mice, induced antibodies that efficiently neutralized all HCV genotypes with recognized epidemiological importance. HCV variants with modified envelope proteins exhibited similar immunogenicity as the virus with the original envelope proteins.
需要开发预防性疫苗来消除丙型肝炎病毒（HCV）这一全球公共卫生威胁。我们利用已获许可的佐剂开发了全病毒灭活 HCV 疫苗候选物。此外，我们还研究了 HCV 包膜蛋白修饰（增加中和表位暴露）对免疫原性的影响。
全病毒疫苗抗原在 Huh7.5 肝癌细胞中产生，采用多步方案处理，并与佐剂（MF-59 类似物 AddaVax 或氢氧化铝）联合使用。我们研究了从免疫 BALB/c 小鼠血清中纯化的 IgG 中和基因型 1-6 HCV 的能力（通过病毒中和试验）和结合同源包膜蛋白的能力（通过 ELISA）。用于免疫的病毒为：（i）具有 SA13 包膜蛋白的 HCV5aHi 和 E2 中 O-连接糖基化位点（T385P）的修饰，（ii）T385P 回复为 T385 的 HCV5aHi(T385)，其特征为体内确定的原始 E2 序列，（iii）缺失 HVR1 的 HCV5aHi(ΔHVR1)。对于这些病毒，使用人类单克隆（AR3A 和 AR4A）和多克隆（C211 和 H06）抗体在中和试验中研究了表位暴露情况。
与 AddaVax 联合使用的经处理的 HCV5aHi 诱导的抗体能够有效地结合同源包膜蛋白，并广泛中和培养的基因型 1-6 HCV，半数抑制浓度在 14 至 192μg/ml 之间（针对同源病毒的平均值为 36μg/ml）。与氢氧化铝相比，铝佐剂的免疫原性较低。与具有原始 E2 序列的 HCV5aHi(T385)相比，具有修饰的糖基化位点的 HCV5aHi 和没有 HVR1 的 HCV5aHi(ΔHVR1)显示出增加的中和表位暴露，但免疫原性相似。
使用适合人类使用的佐剂，我们开发了灭活的全 HCV 疫苗候选物，这些候选物诱导了广泛中和抗体，值得进一步进行临床前研究。
需要针对丙型肝炎病毒（HCV）开发疫苗，以预防每年估计有 200 万例新感染和 40 万人死亡。我们使用已获许可用于人类的佐剂开发了全灭活 HCV 疫苗候选物，这些疫苗在免疫小鼠后诱导了抗体，能够有效地中和所有具有公认流行病学意义的 HCV 基因型。具有修饰的包膜蛋白的 HCV 变体表现出与具有原始包膜蛋白的病毒相似的免疫原性。
