Gastroenteritis virus infections in South African children: secretor status-linkedsusceptibility, prevalence and genetic diversity and humoral responses to norovirusinfection

摘要 诺如病毒、轮状病毒和腺病毒是小儿重症病毒性胃肠炎的主要病原 国际吧该项目旨在监测流行率、遗传多样性、主要和 这些病毒在南非（SA）的新菌株在5年的时间。该项目还 将研究诺如病毒感染的体液反应，并确定哪种诺如病毒 SA儿童在生命的头两年暴露于基因型， 产生抗体。我们将对儿童进行平行胃肠炎病毒监测1） （<5岁）因胃肠炎住院，2）11个哨点的废水流入物 污水处理厂在全国各地。主要诺如病毒的完整基因组， 轮状病毒和腺病毒基因型将通过下一代测序确定， 这些病毒的全球性出现和多样化。一种蛋白质微阵列方法将是 用于评估SA儿童中一系列诺如病毒基因型的抗体。干血斑 来自HIV暴露儿童的提交HIV检测的样本， 艾滋病毒检测已经完成。儿童将被分为从出生到2岁的五个年龄组 年龄。最初，我们将检测针对20种诺如病毒株的免疫反应， 最近在住院儿童和环境中传播。的范围 在项目期间，将扩大诺如病毒基因型，以反映在 临床和环境监测。此外，岩藻糖基转移酶2（FUT 2）分泌 将确定状态（与诺如病毒和轮状病毒易感性相关）， 更好地了解分泌状态与各种诺如病毒感染之间的联系， 轮状病毒基因型。最后，检测到的抗体的功能性将在以下方面进行评价： 它们的亲合力和阻断诺如病毒主要衣壳蛋白（VP 1）和 组织血型抗原将进行酶-VP 1融合蛋白免疫沉淀测定。 用于检测基因型特异性阻断抗体。血清阳性率和抗体 将在0-1个月（母体抗体）、2 - 4个月（母体抗体）和5个月（母体抗体）的5个年龄组之间比较特征。 6个月（母源抗体）、7-12个月、13-18个月和19-24个月。这个项目 应该产生有价值的数据，以更好地了解诺如病毒感染的多样性， 免疫反应，这些感染的幼儿。结合血清阳性率 在同一时期收集的临床和环境数据的结果将提供 关于环境毒株在诺如病毒暴露中的重要性的宝贵信息， 年幼的孩子。

Abstract Norovirus, rotavirus and adenovirus are the major causes of severe viral gastroenteritis in children worldwide. This project aims to monitor the prevalence, genetic diversity, predominant and emerging strains of these viruses in South Africa (SA) over a 5-year period. In addition, the project will investigate the humoral response to norovirus infections and determine to which norovirus genotypes children in SA are exposed to in the first two years of life, and when protective antibodies are generated. We will perform parallel gastroenteritis virus surveillance 1) in children (<5 years of age) hospitalised with gastroenteritis, and 2) in wastewater influent from 11 sentinel wastewater treatment plants across SA. Complete genomes of the predominant norovirus, rotavirus and adenovirus genotypes will be determined by next generation sequencing to study the global emergence and diversification of these viruses. A protein microarray approach will be used to evaluate antibodies to a range of norovirus genotypes in children in SA. Dried blood spot specimens from HIV exposed children that were submitted for HIV testing, will be accessed once HIV testing is complete. Children will be classified in five age groups between birth and 2 years of age. Initially we will characterise the immune response against 20 norovirus strains which circulated in hospitalised children and in the environment in the recent past. The range of norovirus genotypes will be expanded during the project to reflect the current strains detected in clinical and environmental surveillance. In addition, the fucosyltransferase 2 (FUT2) secretor status (which is linked to norovirus and rotavirus susceptibility) will be determined in an effort to better understand the link between secretor status and infection with various norovirus and rotavirus genotypes. Finally, the functionality of the detected antibodies will be evaluated in terms of their avidity and ability to block binding between the norovirus major capsid protein (VP1) and histo-blood group antigens. A luciferase-VP1 fusion protein immunoprecipitation assay will be used to detect genotype-specific blocking antibodies. Seroprevalence and antibody characteristics will be compared between the five age groups 0-1 month (maternal antibodies), 2- 6 months (maternal antibodies), 7-12 months, 13-18 months and 19-24 months. This project should generate valuable data to better understand the diversity of norovirus infections and the immune response to these infections in young children. The combination of seroprevalence results with clinical and environmental data collected during the same time period will provide valuable information on the importance of the environmental strains in norovirus exposure in young children.