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

摘要 人类通过饮用水、空气和食物暴露于砷， 发病率和死亡率。沿着免疫功能受损，增加了对肺炎的易感性 在暴露于高水平砷的儿童中观察到。肺炎是一个主要的全球健康问题 仅在美国就占儿科住院病例的70%。流行病学研究表明， 呼吸道疫苗在砷暴露儿童中的有效性。虽然疫苗的有效性在很大程度上取决于 宿主的免疫功能，最近的证据表明，肠道微生物组也可能发挥作用。但 砷暴露儿童免疫功能和微生物组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损害疫苗的保护作用， 肺炎链球菌是肺炎最常见的细菌。科学假设是， 儿童早期和子宫内砷暴露会通过免疫调节异常导致适应性免疫改变 淋巴细胞的发育和功能。这些免疫细胞中的损伤是导致 保护免受上呼吸道感染（如S.肺炎），因为疫苗PCV 10效力降低， 测量S。肺炎鼻咽（NP）携带和抗PCV循环抗体滴度。我们也 砷会破坏肠道微生物组，这可能会改变疫苗的效力，因为适应性T细胞 发展在目标1中，我们检验了以下假设： (1-2年）导致（a）PCV 10加强剂量后PCV 10抗体应答受损，和（B） 影响NP微生物群多样性和S.肺炎携带我们将测量PCV 10滴度和NP 使用qRT-PCR和全长16 s rRNA测序检测载体。在目标2中，我们检验了改变 免疫功能和发育与早期砷暴露有关， 宿主免疫这些措施包括PBMC免疫生物标志物和功能性免疫测定，包括： a）细胞表面标志物（CSM = T、B、NK、单核细胞/树突细胞、记忆效应T细胞）和Th细胞 使用11色流式细胞术检测T细胞亚群（Th 1、Th 2、Th 4、Th 17、Treg）; B）T细胞增殖; c）离体细胞因子 生产在目标3中，我们检验了功能性肠道微生物组成差异的假设， 受免疫发育和免疫功能的影响。我们将评估肠道细菌微生物组， 鸟枪宏基因组学及其与以下各项的相关性：a）PCV 10滴度和肺炎球菌携带（Aim 1）以及B） 免疫标志物/功能的变化（目的2）。这项研究将在孟加拉国的400名儿童中进行 年龄在1至2岁之间。参与儿童的母亲是出生队列的一部分， 在整个怀孕期间，儿童在子宫内接触砷的特征非常明显。这些 研究将为PCV疫苗反应的改变和肠道微生物组的重要性提供新的证据。 与砷有关的不良健康后果。

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.