Expanding the breadth, magnitude, and durability of PfSPZ vaccines by creating multi-strain vaccines, designer hybrid and genetically altered parasite vaccines and use of a unique adjuvant.

基于恶性疟原虫（Pf）子孢子（SPZ）的疫苗已经显示出优异的安全性和疫苗效力 (VE)在非洲、欧洲和美国进行的超过25项临床试验中; 3期评估将于2020年中期开始。 我们在未来十年的目标是开发、许可和部署下一代PfSPZ疫苗， 增加了VE的广度、量级和/或耐久性，并降低了商品成本。第一代和第二代 无菌的、纯化的、冷冻保存的PfSPZ疫苗，无论是辐射减毒的、化学减毒的还是遗传减毒的， 由Pf of the West（W.）非洲Pf株，NF 54。总体而言，东（E.）非洲的Pf菌株 与NF 54的遗传距离远于W.非洲菌株和亚洲菌株在基因上要远得多 比任何非洲Pf菌株都要多。因此，用E. E. 非洲将比用W.非洲菌株NF 54。同样，免疫接种 在亚洲的亚洲株Pf可能比用W.非洲菌株如NF 54。 在这个项目中，我们将确定，表征和优化PfSPZ生产从E。非洲和亚洲菌株 我们过去遇到的问题之一是无法生产大量的第五阶段 配子母细胞/培养物和PfSPZ/蚊子，来自除NF 54之外的任何Pf品系。我们已经确定了一个亚洲人（泰国人） 菌株NHP 4026是良好的V期配子母细胞和PfSPZ生产者，尽管不如NF 54好。到 实现奇偶校验，并理想地超过阶段V配子体和PfSPZ生产，我们将基因工程E。 非洲和亚洲的Pf通过过量表达PfAP 2-G转录因子，这是性阶段的关键调节因子 发展我们将单独使用这些新菌株，或使用已成功用于小泰勒虫的菌株 (East海岸热）疫苗和Prevnar，肺炎链球菌疫苗在世界范围内使用，我们 将寄生虫混合制成疫苗鸡尾酒在一种疫苗中生产多株Pf将是一个更大的挑战。 比生产单一菌株更昂贵。因此，我们将通过遗传杂交产生杂交寄生虫， 所需的遗传/蛋白质组多样性在一个单一的Pf寄生虫。这将为如何 产生PfSPZ免疫原，保护免受全球Pf多样性。我们建议调高 通过选择感染性更强的PfSPZ，确定对任何剂量PfSPZ的免疫应答的强度/效力 并通过遗传改变产生晚期抑制复制成分PfSPZ， 比目前的早期捕获辐射表达更多的抗原和更多的每一种抗原， 遗传减毒PfSPZ。佐剂往往提供了最直接的途径，以增加耐久性 疫苗。我们已经确定了一种糖脂佐剂，可以增加小鼠免疫球蛋白的效力和持久性。 疟疾SPZ疫苗。在这个项目中，我们将确定这种佐剂对免疫原性的影响。 我们在非人类灵长类动物中评估的杂交和迟捕菌株。目标是提供 PfSPZ候选疫苗准备进行进一步的下游工艺开发和未来的临床评价。

Plasmodium falciparum (Pf) sporozoite (SPZ)-based vaccines have shown excellent safety and vaccine efficacy (VE) in more than 25 clinical trials in Africa, Europe, and the US; Phase 3 assessment will begin in mid 2020. Our goal during the next decade is to develop, license, and deploy next generation PfSPZ vaccines with increased breadth, magnitude, and/or durability of VE and decreased cost of goods. The 1st and 2nd generation aseptic, purified, cryopreserved PfSPZ vaccines, whether radiation-, chemo-, or genetically-attenuated are composed of Pf of the West (W.) African strain of Pf, NF54. In general East (E.) African strains of Pf are more distant genetically from NF54 than are W. African strains, and Asian strains are much more distant genetically from NF54 than are any African Pf strains. Thus, it is possible that immunizing with an E. African strain in E. Africa will be more protective than immunizing with the W. African strain, NF54. Likewise, immunizing with an Asian strain of Pf in Asia will likely be more protective than immunizing with a W. African strain like NF54. In this project we will identify, characterize and optimize PfSPZ production from E. African and Asian strains of Pf. One of the problems we have had in the past is the inability to produce large numbers of stage V gametocytes/ culture and PfSPZ/ mosquito from any Pf strain except NF54. We have identified an Asian (Thai) strain, NHP4026, that is a good stage V gametocyte and PfSPZ producer, although not as good as NF54. To achieve parity and ideally exceed stage V gametocyte and PfSPZ production, we will genetically engineer the E. African and Asian Pf by overexpressing PfAP2-G a transcription factor that is a key regulator of sexual stage development. We will use these new strains alone or as has been successfully shown for the Theilera parva (East Coast Fever) vaccine in Africa and Prevnar, the Streptococcus pneumoniae vaccine used worldwide, we will mix the parasites to create a vaccine cocktail. Producing multiple strains of Pf in a vaccine will be more expensive than producing a single strain. Thus, we will produce hybrid parasites by genetic crossing to include the desired genetic/ proteomic diversity in a single Pf parasite. This will provide proof of concept for how to generate PfSPZ immunogens protecting against global Pf diversity. We propose to increase the magnitude/potency of the immune response to any dose of PfSPZ by selecting for PfSPZ that are more infective to hepatocytes and by creating through genetic alteration, late arresting replication component PfSPZ that express many more antigens and more of each antigen than do current early arresting radiation- and genetically-attenuated PfSPZ. Adjuvants have often provided the most direct route to increasing the durability of vaccines. We have identified a glycolipid adjuvant that increases the potency and durability of murine malaria SPZ vaccines. In this project we will determine the impact of this adjuvant on the immunogenicity of the hybrid and late arresting strains we develop by assessing in non-human primates. The goal is to provide PfSPZ vaccine candidate(s) poised for further downstream process development and future clinical evaluation.