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

项目总结 卡波西肉瘤相关疱疹病毒(KSHV)已被国际组织列为直接致癌物 癌症研究机构，因为它能引起卡波西肉瘤(KS)和两种罕见的 B细胞淋巴瘤。KS经常发生在医源性或HIV/AIDS诱导的免疫抑制的个体中。 到目前为止，还没有获得许可的KSHV疫苗可以预防初次感染和随后的恶性肿瘤。 我们在这项应用中的目标是优化关键的KSHV糖蛋白(GPS)的包含，这些糖蛋白是 参与上皮细胞、内皮细胞、成纤维细胞和B细胞进入多价亚单位候选疫苗 可刺激中和抗体(NAB)免疫反应，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关于KSHV的NCI K01 CA184388-05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。值得注意的是，我们和其他人 还表明，抗KSHV糖蛋白K8.1、Gb和Gh/Gl的单抗和多克隆抗体都可以 在体外中和不同允许的人类细胞感染KSHV。在这一成功的基础上，我们有 产生的含有对病毒至关重要的四种糖蛋白的四价病毒样颗粒(KSHV-LP) 条目(K8.1、GB和Gh/Gl)。在这项应用中，我们将使用野生型和人源化的小鼠和普通的 毛猴(Callithrix Jacchus)模型检验纯化的KSHV-LPs直接或 通过用改良的痘苗病毒安卡拉载体(MVA-KSHV-LP)免疫将产生强大的保护性NAB 对KSHV感染及其相关恶性肿瘤的反应。我们建议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，这是其他儿童的典型情况 疱疹病毒，为疫苗接种和抗KSHV糖蛋白的抗体打开了一扇机会之窗 K8.1、Gb、Gh/gl可中和KSHV感染。此外，人源化小鼠的容忍性和 绒猴对KSHV的感染为测试候选疫苗提供了一个理想的平台。因此，一种多价疫苗 诱导预防性中和抗体反应不仅将是一种非常有价值的候选疫苗 预防KSHV感染不仅对预防KSHV相关疾病至关重要。我们会 基于以下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 IND申请I期临床试验的先决条件数据。从长远来看，我们方法的成功 将向市场推出一种有可能降低全球KSHV+发病率的新疫苗 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 在发展中国家或从KSHV血清阳性率为10%的发达国家根除KSHV。

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%.