Enhancing potency of the MERS vaccine by a novel ASP-1+alum adjuvant combination

 描述（由申请人提供）：致命传染病在全球范围内的反复爆发，加剧了开发新的和改进的疫苗以对抗其传播的紧迫性。不幸的是，目前的许多疫苗或正在开发的疫苗诱导次优免疫应答，并且需要大剂量抗原、多次免疫或定期加强以提供长期保护。已知佐剂组合可以增加疫苗的功效和安全性，促进剂量节省，并且可能有助于更快速和持久的针对病原体的免疫保护，特别是靶向多种受体和途径的那些。然而，迄今为止的研究都集中在单个佐剂上;现在需要更深入地了解联合佐剂产生效果的机制。目前，含铝佐剂（明矾）是最受欢迎的，因为它们具有强大而持久的免疫刺激作用和长期的安全记录;它们也很便宜。但这些佐剂主要促进Th 2偏向的体液免疫应答，而不是靶向细胞内病原体的疫苗所需的强Th 1和/或CD 8+细胞介导的免疫应答。为了满足这一需求，我们建议测试一种新的佐剂组合-一种新型蛋白佐剂（ASP-1）和传统的佐剂明矾，并研究当与中东呼吸综合征（MERS）冠状病毒（MERS-CoV）的刺突（S）蛋白中的受体结合结构域（RBD）一起配制时，它诱导其效果的机制，MERS冠状病毒是一种具有高死亡率和高流行潜力的病毒病原体。ASP-1佐剂是旋毛虫的一种天然分泌蛋白，对先天性细胞具有内在的免疫刺激特性，可以促进对几种可溶性疫苗候选抗原以及商业灭活病毒疫苗的平衡抗体应答和Th 1偏向性细胞应答。当与商业三价流感疫苗组合时，其还促进剂量节省，并且在针对同源或异源流感病毒攻击的一次免疫后赋予年轻和年老成年小鼠保护。同样重要的是，疫苗接种期间产生的抗体不会限制其在任何测试环境中的效用或佐剂性。我们将通过比较与MERS-RBD配制时的体内免疫原性来研究ASP- 1和明矾之间的物理结合对其佐剂性的影响（此处吸附至明矾可能是必需的）。在鉴定最有效的ASP- 1/明矾/RBD制剂后，我们将确定这种新型佐剂组合的体外和体内作用机制，以确定各种先天和适应性细胞类型、趋化因子、以及它们在注射部位和引流淋巴结中刺激的细胞因子，其负责增强由ASP-1和明矾佐剂的MERS-RBD疫苗。展望未来，我们希望开发一种安全用于人类的高效佐剂组合，这种组合将以最少量的疫苗免疫原增强针对各种病原体的独特免疫反应。

 DESCRIPTION (provided by applicant): The recurrent outbreak of deadly infectious diseases worldwide heightens the urgency to develop new and improved vaccines to combat their spread. Unfortunately, many of the current vaccines, or those in development, induce suboptimal immune responses and require large antigen doses, multiple immunizations, or periodic boosting to provide long-term protection. It is known that adjuvant combinations can increase the efficacy and safety of vaccines, promote dose sparing, and, possibly, contribute to more rapid and durable immune protection against pathogensin particular those that target multiple receptors and pathways. Studies to date, however, have focused on individual adjuvants; needed now is a deeper understanding of the mechanisms by which combination adjuvants produce their effects. At this time, aluminum-containing adjuvants (alum) are the most popular because of their strong and long-lasting immunostimulatory effects and long-standing safety record; they are also low-cost. But these adjuvants promote primarily Th2-biased humoral immune responses, not the strong Th1 and/or CD8+ cell-mediated immune responses needed for vaccines targeting intracellular pathogens. To meet this need, we propose to test a new adjuvant combinationa novel protein adjuvant (ASP-1) and the traditional adjuvant alumand study the mechanisms by which it induces its effects when formulated with the receptor-binding domain (RBD) in the spike (S) protein of Middle East respiratory syndrome (MERS) coronavirus (MERS-CoV), a viral pathogen with a high mortality rate and high pandemic potential. The ASP-1 adjuvant, a naturally occurring secreted protein of Onchocerca volvulus shown to have intrinsic immunostimulatory properties on innate cells, can promote a balanced antibody response and Th1-biased cellular responses to several soluble vaccine candidate antigens, as well as commercial inactivated viral vaccines. It also promotes dose sparing when combined with a commercial trivalent influenza vaccine, and confers protection in young and aged adult mice after one immunization against homologous or heterologous influenza virus challenge. As important, antibodies produced to it during vaccinations do not limit its utility or adjuvanticity n any setting tested. We will study the effect of the physical association between ASP- 1 and alum on their adjuvanticity (adsorption to alum is possibly essential here) by comparing the immunogenicity in vivo when formulated with MERS-RBD. Upon identification of the most effective ASP- 1/alum/RBD formulation, we will determine the mechanism of action of this novel adjuvant combination, both in vitro and in vivo, to determine the precise interactions among the various innate and adaptive cell types, chemokines, and cytokines that they stimulate in the injection site and in the draining lymph nodes responsible for potentiating the enhanced immunogenicity elicited by the ASP-1 and alum-adjuvanted MERS-RBD vaccine. Looking forward, we hope to develop a highly effective adjuvant combination safe for use in humans, one that will boost distinctive immune responses against various pathogens with a minimal amount of the vaccine immunogen.