Vaccine Development for Falciparum Malaria in Pregnant Women and Their Offspring

描述（由申请人提供）：疟疾影响着几乎一半的世界人口，每年造成100多万人死亡。非洲疟疾流行地区的幼儿死亡率最高，因为他们的免疫系统不成熟。全球控制该疾病的努力取得了有限的成功，尚未批准临床使用疫苗。因此，迫切需要使用新方法发现新的候选疫苗，特别是针对代表关键目标群体的母亲和婴儿。Michelow博士对拟议的指导职业发展奖的研究目标是为育龄妇女发现新的抗疟疾疫苗，以保护她们非常脆弱的后代在婴儿期早期免受严重或致命的疟疾的侵害。在博士的指导下。布朗大学的Kurtis和Friedman博士。Duffy和Fried来自NIH/NIAID疟疾免疫学和疫苗学实验室，他们是国际知名的研究人员，他计划通过鉴定经胎盘获得的疟疾抗体来发现新的疫苗靶点，这种抗体介导婴儿对严重或致命疟疾的抵抗力。本提案的目的是确定保守的恶性疟原虫抗原，这些抗原在分娩时获得的静脉血中的IgG抗体中被唯一识别，这些静脉血中的IgG抗体来自婴儿在出生后第一年患有轻度或无临床疟疾的母亲，而来自婴儿因疟疾而患有严重疾病或死亡的母亲的IgG抗体则无法识别。Michelow博士的团队将利用他们已经从坦桑尼亚Muheza的一个大型纵向队列（n=739）收集的血浆样本和流行病学数据。为了实现这些目标，他们提出了三个特定目标，即1)发现，2)验证和3)降低恶性疟原虫候选疫苗抗原。这种以患者为导向的转化策略的优势在于，他们将在发现疫苗表位的最早阶段使用具有自然获得的疟疾抗体的母亲和婴儿的血浆。基于Kurtis博士开创的成功方法，他们将对来自患有严重疟疾的婴儿母亲与患有轻度或无疟疾的婴儿母亲的精选血浆进行差异高通量全蛋白质组筛选。为此，他们将使用新生产的恶性疟原虫（3D7）疟疾基因组DNA T7噬菌体展示文库以及野生型血期互补DNA T7噬菌体文库。然后，候选疫苗抗原将通过测试来自同一人群的母亲和婴儿的大型独立队列来验证，以确定哪种特定的疟疾抗体最可靠地预测更好的疟疾结果。他们将采用混合效应逻辑回归模型来解释重复测量和混杂变量，以及Cox比例风险生存模型来比较时间和预定义终点。然后，通过生物信息学和表面定位研究，以及对血液阶段候选抗原的入侵和生长抑制试验进行功能评估，对主要候选抗原进行筛选。Michelow博士之前在儿科传染病和热带医学方面的临床培训，他对肺炎或先天性梅毒儿童诊断测试的研究，以及他在糖基化病毒感染的新型免疫疗法生产的实验室工作，为他提出的研究项目奠定了坚实的基础。在导师的指导下，他将通过严谨、机械和创造性的探究方法，将基础科学概念转化为相关的人类干预和治疗，弥合基础科学与以患者为导向的研究之间的差距。他计划通过在以下三个关键领域获得关键的新技能来实现他的目标：1)疫苗免疫学，2)高级分子方法，以及3)应用生物统计学，流行病学和人口研究。具体而言，他将接受以下方面的培训：实施创新的基于噬菌体的分子筛选战略、选择和测试最佳疟疾疫苗表位、培养和基因操纵疟疾寄生虫、进行基于细胞的感染分析、查询疟疾基因组/蛋白质组数据库、使用复杂的细胞成像技术、利用先进的统计方法为复杂数据建模，以解释混杂变量和重复措施；并强调生物伦理问题的重要性。拟议的研究经验将使Michelow博士为实现其长期职业目标做好准备，即成为疟疾疫苗发现领域假设驱动的转化研究领域的熟练研究者。理性识别的一个或多个

DESCRIPTION (provided by applicant): Malaria affects almost one-half of the world's population and causes more than one million deaths annually. Young children in malaria endemic areas of Africa have the highest mortality 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 using novel approaches, especially for mothers and infants who represent key target groups. Dr. Michelow's research goal for the proposed Mentored Career Development Award is to discover new anti-malarial vaccines for women of childbearing age in order to protect their highly vulnerable offspring from severe or fatal malaria in early infancy. Under the mentorship of Drs. Kurtis and Friedman from Brown University, and Drs. Duffy and Fried from the NIH/NIAID Laboratory of Malaria Immunology and Vaccinology, who are internationally renowned investigators, he plans to test the hypothesis that novel vaccine targets can be discovered by identifying transplacentally acquired malarial antibodies that mediate infants' resistance to severe or fatal malaria. The objective of this proposal is to identify conserved Plasmodium falciparum antigens that are uniquely recognized by IgG antibodies in venous blood obtained at delivery from mothers whose infants survived their first year of life with mild or no clinical malaria, but that are not recognized by IgG antibodies from mothers whose infants suffered severe disease or death due to malaria. Dr. Michelow's team will capitalize on plasma samples and epidemiological data that they already collected from a large well-characterized longitudinal cohort in Muheza, Tanzania (n=739). In order to achieve these objectives, they propose three Specific Aims that are directed at 1) discovering, 2) validating and 3) downselecting P. falciparum candidate vaccine antigens. The strength of this patient-oriented translational strategy derives from the fact that they will use plasma of mothers and infants with naturally acquired malarial antibodies at the earliest stage of vaccine epitope discovery. Based on the successful approach pioneered by Dr. Kurtis, they will perform a differential high throughput whole proteome screen on select groups of pooled plasma from mothers of infants with severe malaria vs. mothers of infants with mild or no malaria. They will use a newly produced P. falciparum (3D7) malaria genomic DNA T7 phage display library as well as a wild type blood-stage complementary DNA T7 phage library for this purpose. Candidate vaccine antigens will then be validated by testing a large independent cohort of mothers and infants from the same population to determine which specific malarial antibodies most reliably predict better malaria outcomes. They will employ mixed effects logistic regression modeling to account for repeated measures and confounding variables as well as the Cox proportional hazards survival model to compare time to predefined endpoints. Lead candidate antigens will then be downselected using bioinformatics and surface localization studies, as well as functional evaluations, using invasion and growth inhibition assays for blood stage candidates. Dr. Michelow's previous clinical training in Pediatric Infectious Diseases and Tropical Medicine, his research on diagnostic tests for children with pneumonia or congenital syphilis, and his laboratory work on production of novel immunotherapeutics for glycosylated virus infections, have laid a solid foundation for his proposed research project. Under the guidance of his mentors, he will bridge the gap between basic science and patient-oriented research by applying rigorous, mechanistic and creative methods of enquiry to translate basic science concepts into relevant human interventions and therapies. He plans to accomplish his goals by acquiring critical new skills in the following three key areas: 1) vaccine immunology, 2) advanced molecular methods, and 3) applied biostatistics, epidemiology and human population research. Specifically, he will be trained in methods to implement innovative phage-based molecular screening strategies, select and test optimal malaria vaccine epitopes, cultivate and genetically manipulate malaria parasites, perform cell-based infection assays, interrogate the malaria genome/proteome databases, use sophisticated cell imaging technologies, model complex data using advanced statistical methods to account for confounding variables and repeated measures, and reinforce importance of bioethical issues. The proposed research experiences will prepare Dr. Michelow to achieve his long-term career goal of becoming a skilled investigator in hypothesis-driven translational research in the field of malaria vaccine discovery. One or more rationally identified lead candidate vaccine epitopes from the current proposal will form the basis of his R01 application. His objectives will be to 1) confirm the relevance of the antigen/s derived from native P. falciparum strains from Tanzania, 2) conduct animal studies to study effectiveness and mechanisms of action of new vaccines, and 3) establish a Phase I healthy human volunteer vaccine study. Dr. Michelow and his team of highly accomplished investigators are committed to the mission of developing new effective malaria vaccines using creative strategies.