Developmental Exposures to Arsenic: Pneumonia, Immunity, and Microbiomes (DEAPIM)

摘要 人群通过饮用水、空气和食物暴露于砷与显著相关 发病率和死亡率。伴随着免疫功能的损害，肺炎的易感性增加 在接触高水平砷的儿童中观察到了这种情况。肺炎是一个主要的全球健康问题。 仅在美国就占儿科住院人数的70%。流行病学研究表明， 呼吸道疫苗对砷暴露儿童的疗效。虽然疫苗的效力在很大程度上取决于 宿主免疫功能方面，最近的证据表明，肠道微生物群也可能起作用。然而， 砷暴露儿童免疫功能与微生物群对疫苗应答的相互关系 没有被研究过。早期接触砷很可能会危及预防流感的疫苗。 肺炎链球菌，肺炎最常见的细菌来源。科学的前提是 儿童早期和宫内砷暴露导致适应性免疫功能改变 淋巴细胞的发育和功能。这些免疫细胞的损伤是导致 预防由于疫苗PCV10效力降低而引起的上呼吸道感染(如肺炎链球菌)，如 用肺炎链球菌鼻咽(NP)携带率和抗PCV循环抗体效价测定。我们也 假设砷破坏肠道微生物群，这可能会改变疫苗的效力，因为适应性T细胞改变 发展。在目标1中，我们测试了儿童在宫内和早期接触砷的假设 (1-2年)导致(A)在加强剂量PCV10后PCV10抗体反应受损，以及(B) 影响NP微生物区系多样性和肺炎链球菌携带。我们将测量PCV10滴度和NP 载体采用qRT-PCR和全长16S rRNA测序。在目标2中，我们测试了这样的假设 免疫功能和发育与早期生活中的砷暴露有关，导致损害 宿主豁免权。这些措施包括PBMC免疫生物标记物和功能免疫分析，包括： A)细胞表面标记(CSM=T、B、NK、单核/树突状细胞、记忆效应T细胞)和Th细胞 11色流式细胞术检测T细胞亚群(Th1、Th2、Th4、Th17、Treg)；b)T细胞增殖；c)体外细胞因子 制作。在目标3中，我们测试了这样一个假设，即肠道功能微生物组成的差异是 受免疫发育和免疫功能的影响。我们将通过以下方法评估肠道细菌微生物群 鸟枪式元基因组学及其与PCV10滴度和肺炎球菌携带率(Aim1和b)的相关性 免疫标记物/功能的变化(目标2)。这项研究将在孟加拉国的400名儿童中进行 年龄在1到2岁之间。参与的孩子的母亲是出生队列的一部分，并被跟踪 在整个怀孕期间，儿童在宫内暴露于砷的特点非常好。这些 研究将为改变PCV疫苗反应和肠道微生物群的重要性提供新的证据 与砷相关的不良健康后果。

ABSTRACT Exposure of human populations to arsenic via drinking water, air, and food is associated with significant morbidity and mortality. Along with impairments in immune function, an increased susceptibility to pneumonia has been observed in children exposed to high levels of arsenic. Pneumonia is a major global health concern accounting for 70% of pediatric hospitalizations in the US alone. Epidemiological studies indicate a decrease in the efficacy of respiratory vaccines in arsenic-exposed children. While vaccine efficacy is largely dependent on host immune function, recent evidence indicates that the gut microbiome may also play a role. However, the interrelationship of immune function and the microbiome on vaccine response in arsenic-exposed children has not been studied. It is likely that early exposures to arsenic compromise vaccines protecting against Streptococcus pneumoniae, the most common bacterial cause of pneumonia. The Scientific Premise is that Early life and in utero arsenic exposure in children leads to alterations in adaptive immunity via dysregulation of lymphocyte development and function. The impairment in these immune cells is responsible for decreases in protection from upper airway infections (such as S. pneumoniae) due to decreased vaccine PCV10 efficacy, as measured by S. pneumoniae nasopharyngeal (NP) carriage and anti-PCV circulating antibody titers. We also posit that arsenic disrupts the gut microbiome which may alter vaccine efficacy, due to altered adaptive T cell development. In Aim 1, we test the hypothesis that arsenic exposure in utero and during early life in children (1-2 year) leads to (a) impaired PCV10 antibody responses following a booster dose of PCV10, and (b) influences the NP microbiota diversity and the S. pneumoniae carriage. We will measure PCV10 titers and NP carriage using qRT-PCR and full length 16s rRNA sequencing. In Aim 2, we test the hypothesis that alterations in immune function and development are associated with early life arsenic exposure, leading to compromised host immunity. These measures include PBMC immune biomarkers and functional immune assays including: a) cell surface markers (CSM = T, B, NK, monocyte/dendritic cells, memory effector T cells) and the Th cell subsets (Th1, Th2, Th4, Th17, Treg) using 11-color flow cytometry; b) T cell proliferation; c) ex vivo cytokine production. In Aim 3 we test the hypothesis that differences in functional gut microbial composition are influenced by immune development and immune function. We will assess the gut bacterial microbiome by shotgun metagenomics and correlations with; a) PCV10 titers and the pneumococcal carriage (Aim1) and b) changes in immune markers/function (Aim 2). The study will be conducted among 400 children in Bangladesh ages between 1 and 2 years. Mothers of the participating children are part of a birth cohort and are followed throughout their pregnancy, and children are extremely well characterized for arsenic exposure in utero. These studies will provide new evidence on altered PCV vaccine response and the importance of the gut microbiome in adverse health outcomes associated with arsenic.