KSHV Subunit Vaccine Candidates to Elicit Potent Humoral Immune Reponses against KSHV Infection

项目摘要 卡波西肉瘤相关疱疹病毒（KSHV）已被国际分类为直接致癌物。 癌症研究机构，因为它能够引起卡波西肉瘤（KS）和两种罕见类型的肉瘤 B细胞淋巴瘤KS常发生在医源性或HIV/AIDS诱导的免疫抑制个体中。 到目前为止，还没有获得许可的KSHV疫苗可以预防原发性感染和随后的恶性肿瘤。 我们在本申请中的目标是优化关键KSHV糖蛋白（gps）的包含， 参与上皮、内皮、成纤维细胞和B细胞进入的多价亚单位疫苗候选物， 可以刺激中和抗体（nAb）免疫应答，以预防或限制KSHV感染和KSHV+ 体内的癌症此应用程序基于我最近完成的NCI K 01 CA 184388 -05对KSHV的研究 进入机制和疫苗开发。最近，我们发现在体外，KSHV糖蛋白gH是 对于上皮细胞、内皮细胞和成纤维细胞的病毒感染是必需的，但对B细胞不是必需的。特别是，我们和其他 还表明，抗KSHV糖蛋白K8.1、gB和gH/gL的单克隆和多克隆抗体均能 在体外中和多种允许的人细胞的KSHV感染。在这一成功的基础上，我们 产生的四价病毒样颗粒（KSHV-LPs），其中包含病毒关键的四种糖蛋白， 条目（K8.1、gB和gH/gL）。在本申请中，我们将使用野生型和人源化小鼠以及常见的 绒猴（Callithrix jacchus）模型来检验纯化的KSHV-LP直接或间接递送的假设。 通过用修饰的安卡拉牛痘载体（MVA-KSHV-LPs）免疫将引发强保护性nAb 对KSHV感染及其相关恶性肿瘤的反应。我们提案的前提是建立在强大的 有证据表明：1）KSHV感染不会发生在儿童早期，这是典型的其他 疱疹病毒，为疫苗接种打开了机会之窗，2）针对KSHV糖蛋白的抗体 K8.1、gB和gH/gL能中和KSHV感染。此外，人源化小鼠和 绒猴对KSHV感染的耐受性为测试候选疫苗提供了一个理想的平台。因此，多价疫苗 诱导预防性中和抗体反应的疫苗不仅是一种宝贵的候选疫苗， 预防KSHV感染，而且在预防KSHV相关疾病方面也至关重要。我们将 基于三种临床前动物模型，为我们的候选KSHV疫苗的安全性提供证据， I期临床试验IND申请的先决条件数据。从长远来看，我们方法的成功 将向市场推出一种新疫苗，有可能降低KSHV+的全球发病率 恶性肿瘤（> 44，000例/年），以及限制KSHV感染和相关恶性肿瘤的可能性 在发展中国家或在KSHV血清阳性率<10%的发达国家根除它们。

PROJECT SUMMARY Kaposi sarcoma-associated herpesvirus (KSHV) has been classified as a direct carcinogen by the International Agency for Research on Cancer because of its ability to cause Kaposi sarcoma (KS) and two rare types of B-cell lymphoma. KS frequently occurs among iatrogenic or HIV/AIDS-induced immunosuppressed individuals. To date, there is no licensed KSHV vaccine that can prevent primary infection and subsequent malignancies. Our objective in this application is to optimize the inclusion of key KSHV glycoproteins (gps), which are involved in epithelial, endothelial, fibroblast and B-cell entry, into multivalent subunit vaccine candidates that can stimulate neutralizing antibody (nAb) immune responses to prevent or limit KSHV infection and KSHV+ cancers in vivo. This application builds on my recently completed NCI K01 CA184388-05 research on KSHV entry mechanisms and vaccine development. Recently, we showed that in vitro, the KSHV glycoprotein gH is essential for viral infection of epithelial, endothelial, and fibroblasts cells, but not B cells. Notably, we and other have also shown that both monoclonal and polyclonal Abs to KSHV glycoproteins K8.1, gB, and gH/gL can neutralize KSHV infection of diverse permissive human cells in vitro. Building on this success, we have generated quadrivalent virus-like particles (KSHV-LPs) incorporating the four glycoproteins critical for viral entry (K8.1, gB and gH/gL). In this application we will use wild-type and humanized mice and common marmoset (Callithrix jacchus) models to test the hypothesis that purified KSHV-LPs delivered directly or through immunization with a modified vaccinia Ankara vector (MVA-KSHV-LPs) will elicit robust protective nAb responses to KSHV infection and its associated malignancies. The premise of our proposal is built on strong evidence that 1) infection with KSHV does not occur during early childhood, as is typical for other herpesviruses, opening a window of opportunity for vaccination and 2) Abs against the KSHV glycoproteins K8.1, gB, and gH/gL can neutralize KSHV infection. Furthermore, the permissiveness of humanized mice and marmosets to KSHV infection offers an ideal platform to test candidate vaccines. Thus, a polyvalent vaccine that induces prophylactic neutralizing Abs responses will not only be an invaluable candidate vaccine in preventing KSHV infection, but also of utmost importance in preventing KSHV-associated diseases. We will provide evidence for the safety of our candidate KSHV vaccine based on three pre-clinical animal models as prerequisite data for an IND application for a phase I clinical trial. In the long term, the success of our approach will introduce a new vaccine to the market with a potential for reducing global incidence of KSHV+ malignancies (>44,000 cases/year), and the possibility of limiting KSHV infection and associated malignancies in developing countries or eradicating them from developed countries where KSHV seroprevalence is <10%.