Plasmodium vivax recombinant CS protein vaccine

描述(申请人提供)：间日疟原虫(PV)是人类疟疾的第二大最常见原因，估计每年造成7000万至1亿例疟疾病例。在非洲大陆以外，光伏是分布最广的疟疾寄生虫。它与恶性疟原虫(Pf)共存，并造成显著的发病率和巨大的经济负担。PV每年在旅行者中造成的疟疾病例与PF一样多，PF是世界上导致疟疾的最常见原因。在过去的十年中，抗药性光伏病毒出现在新几内亚岛上，并已蔓延到其他地区。在发展中国家的旅行者和军人中，以及在出现地方性PV的国家的人群中，PV疫苗有着巨大的潜在市场。大多数疟疾疫苗的开发工作都集中在开发针对PF的疫苗上。相比之下，光伏疫苗的研究一直被忽视，主要是因为缺乏体外培养光伏的能力施加了技术限制。然而，在全世界大多数疟疾流行地区，肺结核病和小儿麻痹症共存，这一事实对部署仅对肺鼠疫有效的疫苗构成了技术和伦理上的限制。在过去的几年里，我们在哥伦比亚的合作伙伴将大量精力集中在光伏研究上。他们已经建立了生产PV SPZ的能力，成功地用这些SPZ挑战Aotus猴子，并在Aotus猴子和人类身上进行PV疫苗试验。他们还确定了包含重要抗体和主要候选PV抗原环子孢子蛋白(PvCSP)上T细胞表位的新结构域。在这里，我们建议生产、纯化和生化鉴定一组基于PvCSP的rec蛋白，并评估它们在Aotus猴身上的免疫原性和保护效果。之所以选择PvCSP，是因为它的PF同源蛋白(PfCSP)是唯一被证明能重复保护人类的PF蛋白，抗PvCSP的单抗在被动转移中保护猴子，出于商业原因，我们认为疫苗必须至少针对红斑狼疮前阶段。由于其能够产生大量分泌的、易于纯化的rec蛋白，因此巴斯德毕赤酵母表达系统将用于生产PV CS蛋白。这将包括PvCSP的整个氨基和整个羧基区域，以及PvCSP重复区域的两个已知的主要变体，从而包括PvCSP的两个主要变体上的所有已知抗体和T细胞表位。从来没有生产或测试过这样的PvCSP免疫原。该项目将提供REC蛋白和工艺开发信息，可用于选择在GMP条件下生产用于临床试验的REC蛋白。蛋白潜力(REC蛋白生产、工艺开发、向GMP生产过渡、疟疾疫苗开发和临床试验)与哥伦比亚的团队(有关PvCSP的免疫学专业知识以及进行Aotus猴子保护研究和人类临床试验的能力)之间的联系，提供了将这些蛋白质从概念迅速带入临床和现场，并最终进入光伏疫苗的大市场的能力。

DESCRIPTION (provided by applicant): Plasmodium vivax (Pv) is the second most common cause of malaria in humans, being responsible for an estimated 70-100 million cases annually. Outside the African continent Pv is the most widely distributed malaria parasite. It co-exists with P. falciparum (Pf) and is responsible for significant morbidity and a substantial economic burden. Pv is responsible annually for as many cases of malaria in travelers as is Pf, the most common cause of malaria in the world. During the last decade, drug resistant Pv emerged on the island of New Guinea and has spread to other areas. There is a huge potential market for a Pv vaccine in travelers and military from the developing world, and among populations in countries with endemic Pv. Most malaria vaccine development efforts have been focused on developing a Pf specific vaccine. In contrast, Pv vaccine research has been neglected, mainly because of technical restrictions imposed by the lack of capacity to culture Pv in vitro. However, the fact that Pf and Pv co-exist in most malaria endemic areas worldwide presents technical and ethical constraints for the deployment of a vaccine effective only against Pf. During the past several yrs our partners in Colombia have concentrated significant effort on Pv studies. They have established the capacity to produce Pv spz, to successfully challenge Aotus monkeys with these spz, and to conduct Pv vaccine trials in Aotus monkeys and humans. They have also identified new domains containing functionally important antibody and T cell epitopes on a major candidate Pv antigen, the circumsporozoite protein (PvCSP). Here we propose to produce, purify, and biochemically characterize a set of rec proteins based on the PvCSP, and assess them for immunogenicity and protective efficacy in Aotus monkeys. The PvCSP is chosen because its Pf orthologue (PfCSP) is the only Pf protein ever shown to reproducibly protect humans, a monoclonal antibody against PvCSP protects monkeys in passive transfer, and for commercial reasons we believe the vaccine must be at a minimum directed against the pre-erythrocytic stages of Pv. Because of its capacity to produce large quantitities of secreted, easily purified rec proteins, the Pichia pastoris expression system will be used to produce the Pv CS proteins. These will encompass the entire amino and the entire carboxy regions of the PvCSP plus the two known major variant forms of the PvCSP repeat domains, thereby including all known antibody and T cell epitopes on the two major variants of the PvCSP. No such PvCSP immunogens have ever been produced or tested. This project will provide rec proteins and process development information that can be used for the choice of manufacturing under GMP conditions a rec protein for clinical trials. The association between Protein Potential (rec protein production, process development, and transition to GMP manufacturing, malaria vaccine development and clinical trials) and the group in Colombia (immunological expertise regarding PvCSP and capacity to conduct Aotus monkey protection studies, and human clinical trials), provides the capacity to take these proteins rapidly from concept to the clinic and field and eventually to the large market for a Pv vaccine.