A Novel Approach to RSV Vaccination

描述(由申请人提供)： 呼吸道合胞病毒(RSV)是一种副粘病毒，基本上感染所有两岁以下的人。首次感染的婴儿最容易受到下呼吸道感染，表现为毛细支气管炎和肺炎，但老年人和免疫功能低下的患者也会经历严重的呼吸道合胞病毒病。此外，这种病毒会在一生中频繁地再次感染健康的、具有免疫能力的人。血清阳性的成年人和年龄较大的儿童的疾病通常仅限于上呼吸道，但在每次再感染时观察到显著的病毒脱落，从而使病毒保持在免疫人群中。对RSV感染的免疫反应相对无效的原因尚不清楚，但这种病原体较差的免疫原性迄今阻碍了开发安全有效的RSV疫苗的努力。目前还没有针对RSV的治疗方法，只有针对RSV F蛋白的人源化单抗形式的一过性预防。在RSV疫苗设计的一种新方法中，我们使用了来自禽类副粘病毒的病毒载体，新城疫病毒(NDV)，因为它被认为是哺乳动物产生干扰素的非常强的触发因素，正如预期的那样，将编码RSV F基因的重组新城疫病毒(NDV-F)滴入小鼠鼻内诱导的干扰素是同等剂量RSV的1000倍，并且在NDV-F免疫小鼠3周后获得保护，免受活病毒攻击。此外，正如我们所希望的那样，新城疫病毒-F诱导的RSV-F蛋白特异性记忆CD8 T细胞明显多于RSV本身。这一结果现在已经在另外两种啮齿动物(栗鼠和棉鼠)上重现。为了测试NDV-F疫苗候选的安全性、有效性和建立长期保护，我们提出了以下目标：1)产生优化的NDV-F疫苗候选。2)评估新城疫病毒F蛋白免疫后棉花大鼠T和B细胞对HRSV F蛋白的反应、对活病毒攻击的保护、组织病理学和免疫记忆。3)评估牛在新城疫病毒FB免疫后T和B细胞对BRSV F蛋白的反应、对活病毒攻击的保护、组织病理学和免疫记忆。4)在GMP条件下大规模生产遗传稳定的新城疫病毒F。有大量证据表明，鼻腔接种疫苗可能是预防呼吸道病毒的最有效手段。我们的实验室正在努力开发一种针对呼吸道合胞病毒的鼻内疫苗，这种病毒是儿童鼻和肺部感染的主要原因。这种方法包括使用对人类无害的新城疫病毒(NDV)传递RSV片段，供免疫系统处理。这一想法在小鼠身上效果很好；一剂疫苗可以保护动物免受后来感染RSV的影响。在这项提议中，我们将在棉鼠和牛身上测试这种疫苗的安全性和有效性，这两种动物都患有这种病毒的类似疾病。如果它看起来安全有效，我们可以将其用于人体试验。

DESCRIPTION (provided by applicant): Respiratory syncytial virus (RSV) is a paramyxovirus that infects essentially all persons by their second birthday. Infants experiencing their first infection are most susceptible to lower airway infection in the form of bronchiolitis and pneumonia, but older adults and immunocompromised patients also experience severe RSV disease. In addition, this virus frequently reinfects healthy, immunocompetent individuals throughout life. Disease in seropositive adults and older children is usually limited to the upper airway, but significant virus shedding has been observed at each reinfection thus maintaining the virus within an immune population. The reason for this relatively ineffective immune response to RSV infection is not well understood, but the poor immunogenicity of this pathogen has so far confounded attempts to develop a safe and effective RSV vaccine. Currently there is no treatment for RSV, only transient prophylaxis in the form of a humanized monoclonal antibody targeting the RSV F protein. In a new approach to RSV vaccine design we made use of a viral vector derived from an avian paramyxovirus, Newcastle disease virus (NDV), chosen because it is known to be a very strong trigger for IFN-¿/¿ production in mammalian species As expected, intranasal instillation of recombinant NDV encoding the RSV F gene (NDV-F) into mice induced 1000 times more IFN-¿/¿ than did an equivalent dose of RSV, and 3 weeks after NDV-F priming mice were protected from live virus challenge. In addition, as we had hoped, NDV-F priming elicited significantly more RSV F protein-specific memory CD8+ T cells than did RSV itself. This result has now been reproduced in two additional rodent species (chinchillas and cotton rats).To test the NDV-F vaccine candidate for safety, efficacy, and establishment of long-lived protection we propose the following aims: 1) Generation of an optimized NDV-F vaccine candidate. 2) Assessment of T and B cell responses to the HRSV F protein following NDV-F priming, protection from live virus challenge, histopathology, and immunological memory in the cotton rat. 3) Assessment of T and B cell responses to the BRSV F protein following NDV-FB priming, protection from live virus challenge, histopathology, and immunological memory in the cow. 4) Large scale production of genetically stable NDV-F under GMP conditions. There is a large body of evidence to suggest that vaccinations placed in the nose may be the most effective means of protection against respiratory viruses. Our laboratory is working to develop an intranasal vaccine against respiratory syncytial virus, a virus responsible for the majority of nose and lung infections in children. The approach involves using Newcastle disease virus (NDV), which is not harmful to humans, to deliver pieces of RSV for processing by the immune system. This idea has worked very well in mice; one dose of the vaccine protects the animals from being infected later with RSV. In this proposal we will test this vaccine for safety and effectiveness in cotton rats and cattle, the animals who suffer a similar disease with this virus. If it appears safe and effective, we can move this into human trials.