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

项目总结/摘要 尽管最近取得了一些进展，但撒哈拉以南非洲的恶性疟原虫（Pf）造成的疟疾负担仍然很重， 不可接受的高。疫苗提供了最大的潜力，以产生对疟疾的持续保护，但 唯一获得许可的疟疾疫苗寿命很短，效力有限。几十年的研究 不能生产接近天然获得性免疫（NAI）功效的可行疫苗， 它在许多流行地区的成年人中提供了几乎完全的保护，使其免受有症状的疾病的侵害。nai 疟疾是复杂的，发展缓慢。抗体是NAI的关键效应物，并最终克服了NAI的高表达。 Pf抗原进化的遗传多样性程度在宿主-寄生虫相互作用中很重要。这种多样性可能 这是NAI发展缓慢和目前疫苗相对无效的原因。虽然它被松散地理解为 增加对Pf的累积接触会导致更大的免疫力，但基本问题仍然存在 无人回应本研究的目的是：（1）确定数量、时间和遗传因素的影响， 儿童期血液阶段Pf感染的组成对NAI的影响;和（2）确定数量的影响， 儿童期暴露于Pf的时间和遗传组成对抗体库的影响，以及抗体 答案与免疫力有关。我们处于一个独特的地位，通过利用广泛的 一组现有的样本和数据，来自乌干达沿着的多个密集跟踪的幼儿队列 与一组经验丰富的合作者，他们在疟疾流行病学、统计学、基因组学和 免疫学在目标1中，我们将首先在我们的研究中对Pf感染的子集进行全基因组测序。 在潜在选择下系统地鉴定抗原变体。这些抗原，沿着着其他抗原 从现有数据中识别，将使用高度多重深度测序技术从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量化抗寄生虫和抗病免疫，并将联合收割机 这些数据用于检验关于暴露与免疫力之间关系的3个基本假设。在 目的2，我们将纵向评估抗体反应，以Pf在我们的队列使用超高通量长 肽阵列，靶向整个基因组，包括所有鉴定的抗原变体。我们将确定 来自这些实验和来自Aim 1的关键抗原的序列，并进一步评估抗体应答 使用定制的蛋白质阵列，并使用功能测定进行实验验证。利用这些数据，我们将测试 三个假设。在本项目结束时，我们将确定驱动 NAI的发展，包括菌株特异性与超越性免疫的作用，以及 抗原变体与免疫性最相关，因此最适合包含在疟疾疫苗中。

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.