Deciphering the roles of RIFIN and STEVOR parasite antigens in severe malaria pathogenesis via transcriptomics and immune profiling

项目总结 尽管进行了数十年的研究，恶性疟疾仍在继续导致数十万儿童死亡 每年在撒哈拉沙漠以南的非洲地区。严重疟疾的脆弱性是复杂的，既涉及宿主也涉及寄生虫 各种因素。A型血是严重疟疾的既定危险因素，而O型血与 针对复杂症状的保护。这种现象的确切机制尚不完全清楚。 但可能涉及由特定寄生虫抗原介导的相互作用。RIFIN和STEVOR是高度多样化的 显示在受感染的红细胞表面的寄生虫蛋白家族。最近的实验室研究 提示这些抗原可能通过多种机制加重疟疾的严重程度，包括坚持 与附近的红细胞形成“花环”，包裹寄生虫，保护其免受免疫清除。 某些RIFIN优先与A型红细胞结合。STEVOR具有类似的绑定首选项 血糖素C，另一种红细胞表面蛋白。这些耐人寻味的发现表明，RIFIN和 STEVOR可能是恶性疟原虫毒力的核心，并导致对严重疾病的易感性差异。 血型之间的差异。尽管在体外有希望与严重的疟疾脆弱性有关，但巨大的 到目前为止，RIFIN和STEVOR家族的多样性阻碍了对它们的全面研究 临床感染中的抗原。该提案的目标是确定符合以下条件的RIFIN和STEVOR亚型 与非洲儿童的严重疟疾有关。我们将采集儿童的血液和血清样本 马里、马拉维和乌干达的严重或非严重疟疾，代表撒哈拉以南非洲的三个地区 具有不同的疟疾传播模式。在目标1中，我们将鉴定rif和stevor转录本在 使用无参考RNA-Seq的个体血液样本，然后比较转录亚群的丰度 严重疟疾和非严重疟疾之间的区别。在目标2中，我们将分析针对全面的 RIFIN和STEVOR变异体微阵列识别重症疟疾儿童免疫“缺口”的比较 到非严重疟疾。优先表达和/或不表达的RIFIN和STEVOR抗原亚型 在严重疟疾感染中识别的血清可能是发病的重要介质。RIFIN 在A型血的重症病例中占主导地位可能是这一群体脆弱性的关键方面。建议数 AIMS将有助于阐明RIFIN和STEVOR在严重疟疾发病中的作用，并向 开发量身定制的疫苗和疗法，以保护撒哈拉以南非洲最危险的儿童。这个 申请者将发展和应用转录学、免疫流行病学和国际 临床研究设计和管理，对他作为21世纪分子的预期职业生涯至关重要 流行病学家。

PROJECT SUMMARY Despite decades of research, Plasmodium falciparum malaria continues to kill hundreds of thousands of children in sub-Saharan Africa each year. Vulnerability to severe malaria is complex, involving both host and parasite factors. Blood type A is an established risk factor for severe malaria, whereas blood type O is associated with protection from complicated symptoms. The exact mechanism of this phenomenon is incompletely understood but may involve interactions mediated by particular parasite antigens. RIFINs and STEVORs are highly diverse parasite protein families that are displayed on the surface of infected red blood cells. Recent laboratory studies suggest that these antigens may exacerbate malaria severity through multiple mechanisms, including adherence to nearby red blood cells to form “rosettes” that envelop the parasite and protect it from immune clearance. Certain RIFINs bind preferentially to type A red blood cells. STEVORs have a similar binding preference for glycophorin C, another red blood cell surface protein. These intriguing findings suggest that RIFINs and STEVORs may be central to P. falciparum virulence and drive differences in susceptibility to severe disease between blood types. Despite promising in vitro links to severe malaria vulnerability, the immense diversity of the RIFIN and STEVOR families has so far precluded the comprehensive study of these antigens in clinical infections. The goal of this proposal is to identify RIFIN and STEVOR subtypes that are associated with severe malaria in African children. We will obtain blood and serum samples from children with severe or non-severe malaria in Mali, Malawi, and Uganda, representing three regions of sub-Saharan Africa with distinct malaria transmission patterns. In Aim 1, we will identify the expressed rif and stevor transcripts in individual blood samples using reference-free RNA-Seq, then compare the abundance of transcript subgroups between severe and non-severe malaria. In Aim 2, we will profile antibody responses against a comprehensive microarray of RIFIN and STEVOR variants to identify immune “gaps” in children with severe malaria compared to non-severe malaria. RIFIN and STEVOR antigen subtypes that were preferentially expressed and/or not serorecognized in severe malaria infections may be important mediators of pathogenesis. RIFINs that predominate in severe cases with blood type A may be critical aspects of this group’s vulnerability. The proposed aims will help clarify the role of RIFINs and STEVORs in severe malaria pathogenesis and inform the development of tailored vaccines and therapeutics to protect the most at-risk children in sub-Saharan Africa. The applicant will develop and apply hands-on skills in transcriptomics, immunoepidemiology, and international clinical research design and management, critical to his intended career as a 21st century molecular epidemiologist.