Papillomavirus Virion Proteins and Vaccines

乳头瘤病毒（pv）感染动物和人的上皮，通常在感染部位诱导良性增殖（疣或尖锐湿疣）。然而，由人类乳头瘤病毒（hpv）亚群，特别是HPV16引起的病变可发生恶性进展，这些hpv可引起宫颈癌和其他几种上皮恶性肿瘤。我们目前的研究主要关注于HPV疫苗和其他感染抑制策略的开发以及HPV生命周期的阐明。我们以前开发了一种有效的策略来产生高滴度的感染性乳头瘤病毒颗粒，这些颗粒可以转导封装的标记质粒，称为假病毒。假病毒感染模仿HPV感染的早期步骤，因此可用于研究这些事件以及可能抑制它们的干预措施。我们的体内研究也表明，假病毒在保留其上皮性的同时取消了真正hpv的严格物种特异性。这些特性使我们能够开发出hpv的第一个宫颈阴道挑战模型。该系统允许在体内探索建立感染所涉及的步骤。我们发现，雌性小鼠生殖道的感染，即使是单层宫颈内膜细胞，也需要病毒与基底膜（BM）结合，这只能在足以暴露于基底膜的微创伤后发生。由于肝素酶的治疗可以防止肝素的结合和感染，病毒粒子可以与肝素硫酸化的蛋白聚糖结合。bm结合的病毒经历酶介导的构象变化，导致L2次要衣壳蛋白的表位暴露。成功的上皮细胞感染只发生在脑转移相关的改变之后。正在进行的实验利用体内系统来研究当前HPV疫苗预防感染的机制，并帮助开发第二代HPV疫苗。在与约翰霍普金斯大学的同事合作中，我们发现一种基于l2的候选疫苗可能有潜力成为泛hpv疫苗，因为它可以诱导多种hpv的中和。

Papillomaviruses (PVs) infect the epithelia of animals and man, where they generally induce benign proliferation (warts or condylomata) at the site of infection. However, lesions induced by a subset of human papillomaviruses (HPVs), especially HPV16, can undergo malignant progression, and these HPVs cause cervical cancer and several other epithelial malignancies. Our current research is primarily concerned with development of vaccines and other infection inhibition strategies against HPV and elucidation of the HPV life cycle. We previously developed an efficient strategy for generating high titers of infectious papillomavirus particles that transduce encapsidated marker plasmids, designated pseudoviruses. Pseudovirus infection mimics the early steps in HPV infection and can therefore be used to study these events as well as interventions that may inhibit them. Our in vivo studies have also shown the pseudoviruses abrogate the strict species-specificity of authentic HPVs while retaining their epitheliotropism. These properties enabled us to develop the first cervicovaginal challenge model for HPVs. This system permits in vivo exploration of the steps involved in establishing infection. We have found that the infection of the female mouse genital tract, even of monolayer endocervical cells, requires binding of the virus to the basement membrane (BM), which can only occur following microtrauma sufficient to expose to the BM. The virions bind to heparan sulfated proteoglycans in the BM, as heparanase treatment prevents both BM binding and infection. The BM-bound virus undergoes an enzymatically mediated conformational change, leading to exposure of an epitope in the L2 minor capsid protein. Successful infection of epithelial cells only occurs after the BM-associated changes. Ongoing experiments are utilizing the in vivo system to study the mechanisms by which the current HPV vaccine prevents infection as well as to help develop second generation HPV vaccines. In collaboration with colleagues at Johns Hopkins, we have found that a candidate L2-based vaccine may have potential as a pan-HPV vaccine, as it can induce neutralization of a broad range of HPVs.