Mapping the antibody response to Trypanosoma brucei variant surface glycoprotein

项目总结 布鲁氏锥虫是人和动物非洲锥虫病的病原体，是毁灭性的疾病。 这危及公共健康，并对撒哈拉以南非洲的经济发展构成重大障碍。这个 胞外寄生虫通过以下方式在其哺乳动物宿主的血液和组织中维持感染 周期性地“切换”其致密的变异表面糖蛋白(VSG)外壳。从基因组库中摘录 在2000个VSG编码基因中，寄生虫在感染过程中会改变其表达的VSG外壳。在此之前 宿主抗体反应可以清除表达一种VSG的群体，寄生虫将表达切换到新的 VSG，使其在一段时间内对宿主抗体不可见。这一过程不断发生，使寄生虫 以维持慢性感染。因此，抗体和VSG之间的相互作用代表着一个关键的 在这种感染中的接口。尽管它很重要，但支配VSG抗体识别的原则仍然存在 人们对此知之甚少。在这里，我们建议研究抗体-VSG界面在感染期间的高 使用一种称为噬菌体免疫沉淀测序的高通量表位映射方法进行解析 (PhIP-seq)。使用噬菌体展示文库，其中包含来自曾经注释过的每个VSG的多肽，我们将测量 在慢性感染期间对VSG的抗体反应，同时使用高通量 我们实验室开发了一种测序方法来跟踪感染过程中表达的VSG。在第一个目标中，我们将 描述慢性实验性感染期间抗VSG抗体的动态和靶点。在 第二个目的，我们将使用PhIP-seq来绘制自然人类感染中的VSG表位图。拟议的研究将 进一步加深我们对抗VSG抗体反应的理解，同时建立布鲁氏毛滴虫作为一种易处理的模型 对抗原性不同的病原体的抗体反应的研究。从长远来看，这项工作可能会让 诊断或预防一种重要的被忽视的热带疾病的战略。

PROJECT SUMMARY Trypanosoma brucei is a causative agent of human and animal African trypanosomiasis, devastating diseases that endanger public health and present a major barrier to economic development in sub-Saharan Africa. The extracellular parasite manages to sustain an infection in the blood and tissues of its mammalian host by periodically “switching” its dense variant surface glycoprotein (VSG) coat. Drawing from a genomic repertoire of ~2000 VSG-encoding genes, the parasite changes its expressed VSG coat throughout infection. Before the host antibody response can clear a population expressing one VSG, the parasite switches expression to a new VSG, rendering it invisible to host antibody for a time. This process occurs continually and allows the parasite to maintain a chronic infection. The interaction between antibody and VSG, therefore, represents a critical interface in this infection. Despite its importance, the principles governing antibody recognition of VSG remain poorly understood. Here we propose to investigate the antibody-VSG interface during infection in high resolution using a high-throughput epitope mapping approach called phage immunoprecipitation sequencing (PhIP-seq). Using a phage display library containing peptides from every VSG ever annotated, we will measure antibody responses to VSG during chronic infections, while simultaneously using a high-throughput sequencing method developed by our lab to track the VSGs expressed during infection. In the first aim, we will characterize the dynamics and targets of anti-VSG antibody during chronic experimental infections. In the second aim, we will use PhIP-seq to map VSG epitopes in natural human infections. The proposed study will further our understanding of anti-VSG antibody responses while establishing T. brucei as a tractable model for the study of antibody responses to antigenically variable pathogens. Long term, this work could inform strategies for diagnosis or prevention of an important neglected tropical disease.