VSV-based Therapeutic Papilloma Vaccine

描述（由申请人提供）：人乳头瘤病毒（HPV）感染子宫颈引发宫颈癌的发展。疫苗接种有可能通过预防原发性HPV感染和消除持续病变来预防宫颈癌。理想的疫苗既能产生治疗性免疫，也能产生保护性免疫。开发治疗性疫苗的最佳动物模型是兔乳头瘤病毒(CRPV)-兔模型。表达外源病毒蛋白的活重组水疱性口炎病毒（rVSV）已经成功地保护动物免受几种人类病毒的攻击。我们最近生成了一种表达CRPV E6肿瘤抗原的rVSV载体，并在初步实验中将其用于接种已建立肿瘤（乳头状瘤）的兔子。与对照组相比，治疗产生了显著的治疗效果，包括在一些总乳头瘤负荷为4 cm3的兔子中，所有疾病完全和永久消退。这项应用的假设是，rVSV-E6疫苗可以改进，以诱导更快速和更普遍的回归。这是基于观察到原始疫苗表达的E6蛋白水平相对较低，并且由于初次接种诱导的vsv特异性中和抗体，使用相同的rVSV-E6再次接种可能无效。通过修饰E6基因编码泛素-E6融合蛋白（UbE6）也可以提高rVSV-E6的效力，基于我们的研究结果，使用CRPV DNA疫苗，UbE6融合基因明显比未融合的E6基因更有效。具体目的是在更大的群体规模和所有适当的对照中重复初步实验；确定是否可以使用高水平表达E6或表达UbE6的VSV载体，使用带有来自异源血清型的VSV包膜基因的高效VSV-E6增强载体，或使用完全异源的病毒载体（腺病毒），获得更快速和更普遍的肿瘤清除。我们将确定最有效的治疗性疫苗是否也能诱导保护性免疫。这项调查提供的数据可能有助于开发一种高效的人乳头瘤病毒疫苗，以保护妇女免受宫颈癌的侵害。

DESCRIPTION (provided by applicant): Human papillomavirus (HPV) infection of the cervix initiates the development of cervical cancer. Vaccination has the potential to prevent cervical cancer by preventing primary HPV infection and by eliminating persistent lesions. The ideal vaccine would induce therapeutic as well as protective immunity. The best animal model for therapeutic vaccine development is the cottontail rabbit papillomavirus (CRPV)-rabbit model. Live recombinant vesicular stomatitis viruses (rVSV) expressing foreign viral proteins have successfully protected animals against challenges with several human viruses. We recently generated an rVSV vector expressing the CRPV E6 tumor antigen and used it to vaccinate rabbits with well-established tumors (papillomas) in a preliminary experiment. The treatment induced dramatic therapeutic outcomes including the complete and permanent regression of all disease in some rabbits with a total papilloma burden of 4 cm3, as compared to no regression in the controls. The hypothesis of this application is that the rVSV-E6 vaccine can be improved to induce more rapid and more universal regression. It is based on the observation that the original vaccine expressed a relatively low level of E6 protein and that revaccination with the same rVSV-E6 was probably not effective, due to VSV-specific neutralizing antibodies induced by primary vaccination. The efficacy of the rVSV-E6 could also be improved by modifying the E6 gene to encode a ubiquitin-E6 fusion protein (UbE6), based on our findings, using CRPV DNA vaccines, that a UbE6 fused gene was markedly more effective than the unfused E6 gene. The specific aims are to repeat the preliminary experiment with larger group size and all appropriate controls; to determine if more rapid and more universal tumor clearance can be obtained using VSV vectors giving higher-level expression of E6 or expressing UbE6, using an efficient VSV-E6 boosting vector with the VSV envelope gene from a heterologous serotype, or using a completely heterologous viral vector (adenovirus). We will determine if the most effective therapeutic vaccine also induces protective immunity. The data provided by this investigation are likely to aid in the development a highly effective HPV vaccine to protect women against cervical cancer.