Therapeutic/preventive vaccination against MusPV

描述(申请人提供)：虽然大多数人乳头瘤病毒(HPV)感染都是短暂的，但有一部分人会变得慢性并可能进展为恶性肿瘤，HIV感染者的发生率要高得多。只有12种高危HPV类型会致癌，但仅HPV16一种就导致了90%的肛门癌、头颈癌和50%的宫颈癌。此外，“低风险”的HPV类型会对HIV阳性患者产生相当大的发病率。不幸的是，两种获得许可的HPV疫苗都不能有效地治疗现有的感染，持续的HPV感染和疾病仍然非常普遍和有问题。尽管进行了HAART，但HIV+患者表现出比健康人更多的慢性和进行性HPV感染，并显著增加了HPV相关癌症的风险。HPV感染的不良结局与HIV+患者的CD4T细胞免疫功能下降有关。目前的非特异性尖锐湿疣治疗经常失败。因此，我们的目标是开发一种治疗性疫苗，在HIV背景下治疗慢性HPV感染，尽管CD4T细胞帮助减少。最近，一种实验室小鼠乳头瘤病毒(MusPV)被发现并进行了序列测定。已发表的研究表明，MusPV感染在免疫缺陷小鼠中持续存在，但在免疫能力强的小鼠中8周内被清除，这种情况与CD4T细胞免疫受损患者与健康人的HPV疾病密切相关。因此，我们假设小鼠的CD4T细胞免疫受损将允许慢性MusPV感染，我们建议确定MusPV感染的持久性与CD4T细胞免疫之间的关系。我们将探讨CD4T细胞耗竭对慢性MusPV感染和乳头状瘤发生发展的影响。一些研究表明，通过体内电穿孔进行免疫将改善DNA疫苗的交付和效果。此外，将E6和E7病毒癌蛋白融合到热休克蛋白钙网蛋白(CRT)中，可以显著增强抗原特异性CD8T细胞依赖性细胞免疫的诱导，即使在CD4T细胞耗尽的动物中也是如此。用融合了HPV16E6、E7和衣壳蛋白L2(pNGVL4a-CRTE6E7L2，(PVX01))的CRT表达DNA免疫小鼠，既能诱导抗肿瘤免疫，又能诱导L2特异性中和抗体。我们假设，通过体内电穿孔给CD4T细胞耗竭的小鼠接种MusPV版本的PVX01DNA将消除慢性乳头瘤病毒病并激发保护性免疫。因此，在这里，我们建议表征体内电穿孔版本的PVX01 DNA疫苗产生的免疫反应，包括对病毒攻击的保护，以及它对CD4T细胞耗尽小鼠慢性MusPV感染的治疗效果。有效治疗艾滋病毒阳性患者的HPV疾病，以及保护他们免受各种HPV感染的能力，仍然是一个重要的未得到满足的医疗需求。当前提议的成功实施将为未来通过电穿孔提供的PVX01 DNA疫苗过渡到临床试验奠定重要基础，该疫苗适用于HPV16+肿瘤和HIV合并感染的患者。

DESCRIPTION (provided by applicant): While most human papillomavirus (HPV) infections are short-lived, a subset become chronic and can progress to malignancy, with much greater frequency in HIV infected individuals. Only a dozen 'high risk' HPV types cause cancer but HPV16 alone is responsible for >90% of anal cancer, head and neck cancer and 50% of cervical cancer. Further, 'low risk' HPV types produce considerable morbidity for HIV+ patients. Unfortunately, neither licensed HPV vaccine is effective for treatment of existing infections, and persistent HPV infection and disease remain very prevalent and problematic. HIV+ patients exhibit more chronic and progressive HPV infections than healthy individuals despite HAART, and are at significantly elevated risk for HPV-associated cancers. Poor outcomes of HPV infection are associated with declining CD4 T cell immunity in HIV+ patients. Current non-specific wart treatments frequently fail. Therefore our objective is to develop a therapeutic vaccine to treat chronic HPV infections in the context of HIV despite reduced CD4 T cell help. Recently a laboratory mouse papillomavirus (MusPV) was discovered and sequenced. Published studies suggest that MusPV infection persists in immunodeficient mice but is cleared by 8 weeks in immune competent mice, a situation that closely parallels HPV disease in patients with compromised CD4 T cell immunity versus healthy individuals. We therefore hypothesize that compromised CD4 T cell immunity in mice will permit chronic MusPV infection, and we propose to determine the relationship between persistence of MusPV infection and CD4 T cell immunity. We will explore the impact of CD4 T cell depletion on the development of chronic MusPV infection and papillomas. Several studies indicate that immunization via in vivo electroporation will improve DNA vaccine delivery and efficacy. Furthermore, fusion of the E6 and E7 viral oncoproteins to a heat shock protein, calreticulin (CRT), profoundly enhances the induction of antigen-specific CD8 T cell dependent cellular immunity, even in CD4 T cell-depleted animals. Vaccination of mice with a DNA expressing CRT fused to HPV16 E6, E7 and capsid protein L2 (pNGVL4a-CRTE6E7L2, (PVX01)) induces both antitumor immunity and L2-specific neutralizing antibodies. We hypothesize that vaccination of CD4 T cell-depleted mice with a MusPV version of PVX01 DNA via in vivo electroporation will eliminate chronic papillomavirus disease and elicit protective immunity. Thus, here we propose to characterize the immune response generated by in vivo electroporation of the MusPV version of PVX01 DNA vaccine, including protection from viral challenge, and its therapeutic effect against chronic MusPV infection in CD4 T cell-depleted mice. An effective treatment for HPV disease in HIV+ patients, and the ability to protect them from diverse HPV infections, remains an important unmet medical need. Successful implementation of the current proposal will serve as an important foundation for future transition of the PVX01 DNA vaccine delivered by electroporation to clinical trials in patients with HPV16+ neoplasia and HIV co-infection.