Identifying genetic determinants of Rotavirus Vaccine Failure in Malawian Children

项目摘要 轮状病毒是严重的儿童胃肠炎的主要原因，每年导致超过215，000人死亡。 年最近推出的口服轮状病毒活疫苗（RVV）在欧洲显示出90-95%的保护率， 美国，但在疾病负担最高的低收入国家，这一比例不到50%。生物 轮状病毒疫苗失败的原因尚不清楚，但可能包括微生物和宿主因素。 在马拉维，轮状病毒病的患病率很高，在进行了一项关键的安慰剂对照临床试验后， 试验中有中度血清转化，只有40%-50%。尽管疫苗覆盖率很高， 马拉维婴儿腹泻住院的主要原因。没有证据表明疫苗逃逸 然而，RVV失败的潜在解释包括：肠道/全身感染的影响， 微生物组、被动获得的母体抗体的干扰和/或遗传易感性，但 其中每一个的证据都是有限的。初步数据表明，血型抗原的突变可能 影响轮状病毒疫苗的失败，但这一假设尚未在非洲人群中得到很好的表征。 有更多的证据表明，低收入国家的高病原体负担可能会减少婴儿的死亡率。 对活疫苗的反应。为了充分了解RVV故障的原因，对主机和 需要微生物遗传因子。 为了阐明与轮状病毒疫苗低免疫原性和临床疫苗失败相关的遗传变异， 本研究将利用全基因组关联研究（GWAS）和转录组学分析。详细婴儿 将在基线时收集健康状况，并使用已建立的诊断测定法来表征血清学特征。 回复RVV评估接种疫苗时并发感染是否与RVV相关 失败，将筛选常见的病原体-使用商业上可用的诊断，新的CRISPR- Cas 13 a测定和宏基因组测序。本研究将利用前瞻性和回顾性 疫苗接种前与接种后婴儿的GWAS和转录组学分析相结合， 与RVV失败相关并预测RVV失败的遗传变异。 在GWAS中鉴定的遗传变异将经历改进的信号分辨率和功能。 通过多信号复合分析、大规模平行报告试验、体外分析和基因分析 使用CRISPR进行编辑。这项研究将在非洲产生第一个病毒性腹泻疾病的GWAS， 揭示轮状病毒的防御机制。 尽管广泛接种疫苗，轮状病毒仍然是严重危及生命的腹泻的主要原因， 马拉维婴儿。这项研究有可能确定宿主来源的签名，可以用于早期 RVV失败的预测因素，为免疫策略和疫苗开发的未来提供信息。

Project Summary Rotavirus is the leading cause of severe childhood gastroenteritis, resulting in over 215,000 deaths per year. The recently introduced live, oral rotavirus vaccine (RVV) demonstrated 90-95% protection in Europe and the US, but is less than 50% in low-income countries, where the disease burden is highest. The biological basis of rotavirus vaccine failure remains unknown but likely includes both microbial and host factors. In Malawi there is a high prevalence of rotavirus disease and after a pivotal placebo-controlled clinical trial there was modest seroconversion, only 40%-50%. Despite high vaccine coverage rotavirus remains the leading cause of diarrhea hospitalization among infants in Malawi. There is no evidence of vaccine escape however potential explanations for RVV failure include: effects of gut/systemic infection, variation in the microbiome, interference from passively acquired maternal antibodies, and/or genetic predisposition but evidence for each of these is limited. Preliminary data suggest that mutations in blood group antigens may influence rotavirus vaccine failure, but this hypothesis has not been well characterized in African populations. There is additional evidence that the high pathogen burden in low-income countries may be reducing infants' response to live vaccines. To fully understand the causes of RVV failure a robust investigation of host and microbial genetic factors is needed. To elucidate genetic variants linked to low rotavirus vaccine immunogenicity and clinical vaccine failure, this study will utilize a genome wide association study (GWAS) and transcriptomic analysis. Detailed infant health will be collected at baseline and established diagnostic assays will be used to characterize serological response to RVV. To assess whether concurrent infection at the time of vaccination is correlated with RVV failure, common pathogens will be screened for – using commercially available diagnostics, novel CRISPR- Cas13a assays, and metagenomic sequencing . This study will leverage prospective and retrospective collections combined with a GWAS and transcriptomic profiling of infants pre vs. post-vaccination to identify genetic variants that are associated with and predictive of RVV failure. The genetic variants identified in the GWAS will undergo improved signal resolution and functional analysis through Composite of Multiple Signals, Massively Parallel Report Assay, In vitro analysis, and gene editing using CRISPR. This study will produce the first GWAS of a viral diarrheal illness in Africa and may uncover mechanisms of defense to rotavirus. Despite widespread vaccination, rotavirus remains the main cause of severe life threatening diarrhea in Malawian infants. This study has the potential to identify host-derived signatures that can be used as early predictors of RVV failure, inform immunization strategies and the future of vaccine development.