Drivers of strain-specific and strain-transcendent antimalarial immunity in childhood

项目摘要/摘要 尽管最近取得了进展，但在撒哈拉以南非洲，恶性疟原虫造成的疟疾负担仍然存在 高得令人无法接受。疫苗提供了对疟疾产生持续保护的最大潜力，但 唯一获得许可的疟疾疫苗有效期很短，效果不是很好。几十年的研究一直是 无法生产出接近自然获得性免疫(NAI)效力的可行疫苗， 在许多流行地区，对成人的症状性疾病提供了几乎完全的保护。奈氏 疟疾是一个复杂的疾病，发展缓慢。抗体是NAI的关键效应者，并最终克服高 在宿主-寄生虫相互作用中起重要作用的PF抗原进化的遗传多样性程度。这种多样性可能 NAI发展缓慢和目前疫苗的相对无效是其根本原因。虽然人们对它的理解很松散 不断增加的PF累积暴露会带来更大的免疫力，但根本问题仍然存在 无人接听。这个项目的目的是(1)确定数量、时间和遗传因素的影响 儿童时期血液期感染对NAI的影响；以及(2)为了确定数量的影响， 儿童时期接触PF的时机和遗传组成对抗体谱的影响，以及抗体是如何 回应与豁免权有关。我们处于独特的地位，通过利用广泛的 一组现有的样本和数据，来自乌干达多个密集跟踪的儿童早期队列 拥有一支经验丰富的合作者团队，在疟疾流行病学、统计学、基因组学和 免疫学。在目标1中，我们将首先对我们的 系统识别潜在选择下的抗原变异体的队列。这些抗原和其他抗原 从现有数据中识别，将使用高度多路复用的深度对所有感染时间点进行深度测序 测序。我们将使用详细的临床数据来量化抗寄生虫和抗病免疫，并结合 这些数据用来检验关于暴露和免疫之间关系的3个基本假设。在……里面 目的2，我们将使用超高通量Long在我们的队列中纵向评估对PF的抗体反应 多肽阵列，靶向整个基因组，包括所有已识别的抗原变体。我们将确定 来自这些实验和目标1的关键抗原的序列，并进一步评估抗体反应 使用定制的蛋白质阵列，并使用功能分析进行实验验证。利用这些数据，我们将测试 另外3个假设。在本项目结束时，我们将确定推动 NAI的发展，包括菌株特异性免疫与超越性免疫的作用以及对 与免疫力最相关的抗原性变异，因此最适合纳入疟疾疫苗。

Project Summary/Abstract Despite recent gains, the burden of malaria caused by P. falciparum (Pf) in sub-Saharan Africa remains unacceptably high. Vaccines offer the greatest potential to produce sustained protection against malaria, but the only licensed vaccine for malaria is short lived and only modestly effective. Decades of research have been unable to produce a feasible vaccine which approaches the efficacy of naturally acquired immunity (NAI), which provides nearly complete protection against symptomatic disease in adults in many endemic areas. NAI to malaria is complex slow to develop. Antibodies are key effectors of NAI, and eventually overcome the high degree of genetic diversity evolved by Pf antigens important in host-parasite interactions. This diversity may underlie the slow development of NAI and relative inefficacy of current vaccines. While it is loosely understood that increasing cumulative exposure to Pf leads to greater immunity, fundamental questions remain unanswered. The aims of this project are (1) to determine the effect of the number, timing, and genetic composition of blood stage Pf infections on NAI in childhood; and (2) to determine the effect of the number, timing, and genetic composition of exposure to Pf in childhood on the antibody repertoire, and how antibody responses relate to immunity. We are in a unique position to achieve these aims by leveraging an extensive set of existing samples and data from multiple intensively followed early childhood cohorts in Uganda along with a team of experienced collaborators with expertise in malaria epidemiology, statistics, genomics, and immunology. In Aim 1, we will initially perform whole genome sequencing on a subset of Pf infections in our cohorts to systematically identify antigenic variants under potential selection. These antigens, along with others identified from existing data, will be deep sequenced from all infected time points using highly multiplexed deep sequencing. We will quantify anti-parasite and anti-disease immunity using detailed clinical data, and combine these data to test 3 fundamental hypotheses regarding the relationship between exposure and immunity. In Aim 2, we will longitudinally evaluate antibody responses to Pf in our cohorts using ultra-high throughput long peptide arrays, targeting the entire genome including all identified antigenic variants. We will identify sequences of key antigens from these experiments and from Aim 1, and further evaluate antibody responses using custom protein arrays with experimental validation using functional assays. Using these data, we will test an additional 3 hypotheses. At the conclusion of this project, we will have identified fundamental factors driving the development of NAI, including the role of strain-specific vs. transcendent immunity and the identification of antigenic variants most associated with immunity and thus most appropriate for inclusion in a malaria vaccine.