Modulation of the B cell response to dengue virus infection by Plasmodium falciparum co-infection

项目摘要。 这个职业发展奖的主要目标是PI从一个成功的过渡， 指导一名独立的研究科学家，研究贫困影响的疾病的免疫生物学， 例如登革热和疟疾。PI和指导团队设计了培训计划 包括具体的目标，将提供PI进行国际实践经验， 研究，专业技能，使用大规模细胞仪进行免疫学研究，熟练管理复杂的 数据和专业知识在适应性免疫的发展。为了实现这些目标，该团队已 制定了一项研究计划，以调查观察到，许多发烧的肯尼亚儿童，与PCR- 证实的登革病毒（DENV）病毒血症，在感染后1个月未产生血清抗DENV IgG。这 抗体对感染的低反应性是出乎意料的。由于疟原虫的高传播率 在该地区的恶性疟原虫（Pf）疟疾，同时感染DENV和 Pf（DENV/Pf共感染），以及已发表的Pf介导的对Pf免疫受损的证据，我们假设 在DENV/Pf共感染期间，Pf介导的B细胞失调引导抗原刺激的 DENV幼稚B细胞成熟为非典型记忆B细胞，其反应性较低 刺激，导致抗DENV IgG的发育受损或快速丧失，特别是降低 亲合力抗体较低亲合力抗DENV抗体的丧失可能影响抗体依赖性疾病的风险。 增强DENV感染，这可能影响临床疾病的表现。调查这一 假设，我们提出了两个目标，将调查两个儿童急性发热性疾病队列。在目标1中，我们 调查与寄生虫血症相关的DENV/Pf合并感染儿童的临床疾病谱， 病毒血症和抗DENV IgG的产生。我们将使用PCR检测亚显微Pf寄生虫血症， 这可能影响临床疾病或抗DENV抗体的产生。我们将描述临床 疾病的感染，并制定急性发热性疾病严重程度评分，以评估疾病的严重程度， 感染性病原学我们将纵向描述感染后抗DENV的发展， IgG。在目标2中，我们将描述急性DENV单独或DENV/Pf共刺激后的记忆B细胞应答。 感染我们将使用质谱细胞术来表征外周B细胞群随时间的变化， 进行全血刺激实验以探测外周B细胞对抗原暴露的反应。 总之，收集的数据将回答并发Pf感染是否会损害 抗DENV抗体以抗原非特异性方式应答。结果可能会提出这样一个问题： Pf合并感染是否以及如何影响疫苗引起的血清抗体应答，这将提供 在规划DENV和可能的其他疫苗的未来部署中的重要考虑因素。

Project Abstract. The primary goal of this Career Development Award is the successful transition of the PI from being a mentored to an independent research scientist, studying the immunobiology of diseases of poverty affecting children, such as dengue fever and malaria. The PI and mentoring team have designed a training plan consisting of specific objectives that will provide the PI with practical experience conducting international research, specialized skill using mass cytometry for immunologic research, proficiency in managing complex data, and expertise in the development of adaptive immunity. To achieve these objectives, the team has developed a research plan to investigate the observation that many febrile Kenyan children, with PCR- confirmed dengue virus (DENV) viremia, did not develop serum anti-DENV IgG by 1 month after infection. This antibody hyporesponsiveness to infection was unexpected. Due to the high transmission of Plasmodium falciparum (Pf) malaria in the region, observations of children with simultaneous infection with both DENV and Pf (DENV/Pf co-infection), and published evidence of impaired immunity to Pf mediated by Pf, we hypothesize that during DENV/Pf co-infection, Pf-mediated B cell dysregulation steers antigen-stimulated maturation of DENV-naïve B cells toward becoming atypical memory B cells, which are less responsive to stimulation, leading to impaired development of or rapid loss of anti-DENV IgG, particularly lower avidity antibodies. Loss of lower avidity anti-DENV antibodies may affect the risk of antibody-dependent enhancement of DENV infection, which may affect manifestations of clinical disease. To investigate this hypothesis, we propose two aims that will investigate two child acute febrile illness cohorts. In Aim 1, we will investigate the clinical disease spectrum of DENV/Pf co-infected children in relation to parasitemia, viremia, and development of anti-DENV IgG. We will use PCR to detect sub-microscopic Pf parasitemia, which may influence clinical disease or anti-DENV antibody development. We will characterize the clinical disease by infection and develop an acute febrile illness severity score to assess disease severity irrespective of infectious etiology. And we will characterize, longitudinally, the post-infectious development of anti-DENV IgG. In Aim 2, we will profile the memory B cell response after acute DENV solo- or DENV/Pf co- infection. We will use mass cytometry to characterize changes in peripheral B cell populations over time, and perform whole blood stimulation experiments to probe responses of peripheral B cells to antigen exposure. Together, the data collected will answer the question of whether concurrent Pf infection impairs development of anti-DENV antibody responses in an antigen non-specific manner. The results may raise the question of whether and how Pf co-infection might affect vaccine-elicited serum antibody responses, which will provide important considerations in the planning for future deployment of DENV, and possibly other, vaccines.