Development of a Tetravalent Dengue Vaccine that Links Innate and Adaptive Immuni

描述（由申请人提供）：我们建议使用一种新的策略开发四价登革热（DEN）疫苗，该策略将确保对DEN病毒感染的广泛保护。登革热是由四种蚊媒血清学相关的黄病毒引起的疾病，DEN疫苗的开发特别具有挑战性，因为不同DEN血清型/病毒的连续感染可导致DEN出血热（DHF）或登革热休克综合征（DSS），两者都是危及生命的。由于这种现象，有效和安全的疫苗需要是四价的，并同时提供对所有四种DEN病毒的保护性免疫。迄今为止，由于干扰、免疫原性差和产生不平衡的免疫应答的问题，开发四价活疫苗或减毒疫苗的尝试失败了。在这里，我们提出了一种创新的DEN疫苗策略，旨在克服这些限制。我们的方法涉及通过将保护性抗原与Toll样受体（TLR）配体连接，将重组蛋白混合物靶向抗原呈递细胞。TLR与其相关配体的接合触发先天免疫系统并引发一系列影响适应性免疫应答的事件。这消除了对疫苗制剂中通常使用的佐剂或载体的需要，并通过增强免疫原性而不增加毒性来增加疫苗效力。通过这种策略，我们成功开发了流感和西尼罗河（WN）候选疫苗，这些疫苗可以经济地生产，诱导有效的抗体应答，在小鼠模型中有效，并且不需要佐剂。该提案的目标是通过工程化四种单价融合蛋白来开发四价DEN疫苗，所述单价融合蛋白由来自每种DEN病毒的包膜蛋白的DEN EIII结构域与细菌鞭毛蛋白（一种有效的TLR 5配体）融合组成。为了评估DEN病毒类型特异性中和抗体的诱导，将在小鼠中检查对每种单价候选疫苗的免疫应答的效力和特异性。这些单价研究将指导临床前四价制剂的鉴定，该制剂将涉及所有四种融合蛋白的混合物，其比例为诱导公平免疫应答所必需的比例。将在小鼠中优化四价组合，并在非人灵长类动物攻毒模型中进行测试，作为概念验证。我们假设，所有四种单价蛋白的鸡尾酒制剂将诱导平衡的四价免疫应答，并提供针对所有四种DEN病毒的类型特异性保护，而没有产生可能增强DEN感染并导致DHF的抗体的风险。

DESCRIPTION (provided by applicant): We propose to develop a tetravalent dengue (DEN) vaccine using a novel strategy that will ensure broad protection against DEN virus infection. The disease dengue is caused by four mosquito-borne serologically related flaviviruses and development of a DEN vaccine has been particularly challenging because sequential infection by different DEN serotypes/viruses can lead to DEN hemorrhagic fever (DHF) or dengue shock syndrome (DSS), both of which are life-threatening. As a consequence of this phenomenon, an efficacious and safe vaccine needs to be tetravalent and provide protective immunity simultaneously against all four DEN viruses. Attempts at developing a tetravalent live or attenuated vaccine have thus far failed due to problems with interference, poor immunogenicity and generation of an imbalanced immune response. Here, we present an innovative DEN vaccine strategy designed to overcome these limitations. Our approach involves targeting a mixture of recombinant proteins to antigen-presenting cells by linking a protective antigen to a Toll-like receptor (TLR) ligand. Engagement of a TLR with its associated ligand triggers the innate immune system and initiates a series of events that impact the adaptive immune response. This eliminates the need for adjuvants or carriers typically used in vaccine formulations and increases vaccine potency by enhancing immunogenicity without increasing toxicity. With this strategy, we have successfully developed influenza and West Nile (WN) vaccine candidates that can be produced economically, induce potent antibody responses, are efficacious in mouse models and do not require adjuvant. The goal of this proposal is to develop a tetravalent DEN vaccine by engineering four monovalent fusion proteins comprised of the DEN EIII domain of the envelope protein from each DEN virus fused to bacterial flagellin, a potent TLR5 ligand. To assess induction of DEN virus type-specific neutralizing antibodies, the efficacy and specificity of the immune response to each monovalent vaccine candidate will be examined in mice. These monovalent studies will guide identification of a preclinical tetravalent formulation that will involve a mixture of all four fusion proteins at ratios necessary to induce an equitable immune response. A tetravalent combination will be optimized in mice and tested in a non-human primate challenge model as proof-of-concept. We hypothesize that a cocktail formulation of all four monovalent proteins will induce a balanced tetravalent immune response and provide type-specific protection against all four DEN viruses without the risk of producing antibodies that may enhance DEN infection and lead to DHF.