DEVELOPMENT OF HEPATITIS C VIRUS-LIKE PARTICLES AS CANDIDATE HCV VACCINE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 目前，没有预防感染丙型肝炎病毒的疫苗可用，这种流行病在全球范围内继续有增无减。本研究的目的是开发一种由类丙型肝炎病毒颗粒组成的候选丙型肝炎病毒疫苗，并在黑猩猩模型中评价该疫苗的免疫原性。用含有佐剂和免疫刺激复合体的丙型肝炎病毒VLP疫苗免疫4只丙型肝炎病毒天然黑猩猩。接种疫苗的动物已经接受了传染性丙型肝炎病毒的攻击，以确定疫苗预防感染的效果。 在昆虫细胞中产生的含有丙型肝炎病毒结构蛋白(核心、E1和#2)的重组丙型肝炎病毒样颗粒(丙型肝炎病毒样颗粒)与假定的丙型肝炎病毒粒子相似，能够在小鼠和狒狒体内诱导强大而广泛的体液和细胞免疫反应。在这里，我们提出了关于丙型肝炎病毒脂蛋白在黑猩猩体内的免疫原性和保护性免疫诱导的证据。用丙型肝炎病毒脂蛋白或丙型肝炎病毒脂蛋白加AS01B佐剂免疫黑猩猩(每组2只)。免疫后，所有动物均产生了丙型肝炎病毒特异的免疫应答，包括干扰素、IL-2、CD_4和CD_8~+T细胞，以及针对CORE、E1和#2的增殖淋巴细胞应答。当用丙型肝炎病毒感染性疫苗攻击时，一只黑猩猩在攻击后第三周和第四周出现一过性病毒血症，病毒滴度较低(103-104拷贝/毫升)。另外三只黑猩猩感染了更高水平的病毒血症(每毫升104到105个拷贝)，但在挑战10周后，它们的病毒水平变得无法量化(每毫升103个拷贝)。在丙型肝炎病毒攻击后，所有四只黑猩猩的外周和肝内T细胞以及对丙型肝炎病毒结构蛋白的增殖反应都显著增加。这些T细胞和增殖反应与丙型肝炎病毒RNA水平的下降相一致。4只初生黑猩猩感染了相同的丙型肝炎病毒疫苗，其中3只持续感染，病毒血症在105-106拷贝/毫升之间。我们的研究表明，在黑猩猩模型中，丙型肝炎病毒-LP免疫诱导了丙型肝炎病毒特异性的细胞免疫反应，可以控制丙型肝炎病毒的攻击。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. At the present time, no vaccines to prevent infection with HCV are available and the epidemic continues unabated worldwide. The objectives of this study are to develop a candidate HCV vaccine consisting of HCV-like particles and to evaluate the immunogenicity of the vaccine in the chimpanzee model. Four HCV na¿ve chimpanzees were immunized with HCV-VLP vaccine formulated with adjuvants and immunostimulatory complexes. The vaccinated animals have been challenged with infectious HCV to determine the efficacy of the vaccine preventing infection. Recombinant hepatitis C virus (HCV)-like particles (HCV-LPs) containing HCV structural proteins (core, E1, and #2) produced in insect cells resemble the putative HCV virions and are capable of inducing strong and broad humoral and cellular immune responses in mice and baboons. Here, we present evidence on the immunogenicity and induction of protective immunity by HCV-LPs in chimpanzees. Chimpanzees (two in each group), were immunized with HCV-LPs or HCV-LPs plus AS01B adjuvant. After immunizations, all animals developed an HCV-specific immune response including IFN-¿+, IL-2+, CD4+, and CD8+ T cell and proliferative lymphocyte responses against core, E1, and #2. Upon challenge with an infectious HCV inoculum, one chimpanzee developed transient viremia with low HCV RNA titers (103 to 104 copies per ml) in the third and fourth weeks after the challenge. The three other chimpanzees became infected with higher levels of viremia (104 to 105) copies per ml), but their viral levels became unquantifiable (103 copies per ml) 10 weeks after the challenge. After the HCV challenge, all four chimpanzees demonstrated a significant increase in peripheral and intrahepatic T cell and proliferative responses against the HCV structural proteins. These T cell and proliferative responses coincided with the fall in HCV RNA levels. four na¿ve chimpanzees were infected with the same HCV inoculum, and three developed persistent infection with higher viremia in the range of 105 to 106 copies per ml. Our study suggests that HCV-LP immunization induces HCV-specific cellular immune responses that can control HCV challenge in the chimpanzee model.