Multi-target blood stage vaccine against Plasmodium falciparum

项目摘要 这项申请的总体目标是推动PfCDPK5和PfGARP作为候选疫苗 恶性疟疾。恶性疟原虫影响着世界上近一半的人口，并导致更多的 每年有超过50万人死亡。非洲疟疾流行地区的幼儿死亡率最高 这是因为他们的免疫系统不成熟。全球控制该疾病的努力有限 成功，目前还没有疫苗被批准用于临床。因此，有一种迫切的、未得到满足的需求 发现新的候选疫苗。预防儿童疟疾的疫苗是当务之急，因为 5岁的儿童非常容易感染这种疾病。在最近的研究中，我们的实验室发现了Schizont 出口抗原-1(PfSEA-1)，一种244 kDa的寄生虫抗原，对寄生虫从受感染的红色 血细胞(IRBC)，这是作为一篇全面的，全文的研究文章发表在《科学》杂志上的。 在一种平行的方法中，我们筛选了从寄生虫构建的噬菌体展示cdna文库。 用抗体阳性选择在我们坦桑尼亚野外现场分离的有/没有培养适应的分离株 从有抵抗力的两岁儿童那里收集抗体，用从易感儿童那里收集的抗体进行阴性选择。 我们鉴定了几个编码恶性疟原虫谷氨酸到达蛋白的独立cdna克隆。 (PfGARP)和植物样钙依赖蛋白激酶(PfCDPK5)是由 有抵抗力但不敏感的血清中的抗体。我们的初步数据显示PfGARP和PfCDPK5 分别对侧红细胞和出口中寄生虫的发展至关重要)。PfGARP在细胞表面的表达 滋养体感染的红细胞和PfCDPK5在裂殖子从红细胞破裂时表达。 在体外，针对PfGARP和PfCDPK5的抗体可阻止寄生虫生长高达99%，而PfGARP和PfCDPK5同源疫苗 CDPK5可保护小鼠免受寄生虫血症的侵袭，延长感染致死性伯氏疟原虫的小鼠的存活时间。 我们的疫苗发现计划还确定了几个已知的侵袭配体(MSP-4和MSP-7 在本申请中统称为MSP)，我们将使用CDPK5评估这些候选疫苗为 单一融合蛋白(PfCDPK5-MSP4和PfCDPK5-MSP7)与PfGARP的联合应用 在小鼠疫苗试验中使用多种佐剂系统。将对铅融合抗原进行进一步评估 TFRs耗尽法在小鼠模型中的细胞免疫应答。这项研究的成果 将成为一种佐剂优化的三价疫苗，用于应对Aotus/P.恶性疟原虫的挑战和1期临床 人体试验，目标是进入、细胞内发育和寄生虫循环的退出。

Project Summary The overall aim of this application is to advance PfCDPK5 and PfGARP as vaccine candidates for falciparum malaria. P.falciparum malaria affects almost one-half of the world's population and causes more than 500,000 deaths annually. Young children in malaria endemic areas of Africa have the highest mortality rate because of their immature immune systems. Global efforts to control the disease have had limited success, and no vaccine has yet been approved for clinical use. Therefore, there is an urgent, unmet need to discover new vaccine candidates. A vaccine against childhood malaria is a priority because children below the age of 5 years are highly vulnerable to the disease. In recent studies, our laboratory discovered Schizont Egress Antigen-1 (PfSEA-1), a 244-kDa-parasite antigen that is crucial for parasite egress from an infected red blood cell (iRBC), which was published as a comprehensive, full-length Research Article in Science. In a parallel approach, we have screened phage display cDNA libraries constructed from parasites isolated at our Tanzanian field site with/without culture adaptation using positive selection with antibodies pooled from resistant two-year-olds and negative selection with antibodies pooled from susceptible children. We identified several independent cDNA clones encoding plasmodium falciparum glutamic acid reach protein (PfGARP) and plant-like calcium-dependent protein kinase (PfCDPK5) that were uniquely recognized by antibodies in resistant, but not susceptible sera. Our preliminary data demonstrate that PfGARP and PfCDPK5 is critical for parasite development in side RBC and egress respectively). PfGARP expresses on the surface of the trophozoite infected RBC and PfCDPK5 is expressed by merozoites as they rupture from erythrocytes. Antibodies against PfGARP and PfCDPK5 block parasite growth up to 99% in vitro, and ortholog vaccine of CDPK5 protect mice from parasitemia, and extend the survival of mice challenged with lethal P. berghei ANKA. Our vaccine discovery program has also identified several known invasion ligands (MSP-4 and MSP-7 collectively referred to as MSPs) In this application, we will evaluate these vaccine candidates with CDPK5 as single fusion protein (PfCDPK5-MSP4 & PfCDPK5-MSP7) in combination with PfGARP in in vitro assays and using multiple adjuvant systems in murine vaccine trials. The lead fusion antigen will be further evaluated for cell mediated immune response using TFRS depletion method in murine model. The deliverables from this study will be an adjuvant optimized tri-valent vaccine ready for Aotus/ P. falciparum challenge and Phase-1 clinical trial in human that targets the entry, intracellular development, and the exit of the parasite cycle in .