Mucosal microbiome and vaccine responses in HIV-exposed African infants

项目摘要 感染艾滋病毒的母亲所生的婴儿通过母乳喂养感染艾滋病毒的风险很高。然而，世界卫生组织 建议对感染艾滋病毒的婴儿进行纯母乳喂养，因为替代喂养与高 发病率和死亡率。虽然抗逆转录病毒治疗可以减少传播，但与 那就是异性性行为。因此，接触艾滋病毒的母乳喂养的婴儿是艾滋病毒的重要目标群体。 疫苗。与未接触艾滋病毒的婴儿相比，暴露于艾滋病毒的婴儿表现出不同的疫苗反应。动物模型 已经证明，某些T细胞亚群的发育，无论是在粘膜中还是在系统中，都是 由肠道中特定微生物的存在决定，在确定适应性时可能很重要 豁免权。在人类中，有许多理由假设接触艾滋病毒的肠道微生物群没有受到感染。 (HEU)婴儿与未接触HIV的婴儿(HU)不同，因为他们的母亲改变了肠道 微生物群，他们在怀孕和产后接触抗生素和抗逆转录病毒药物。这 该提案验证了一种假设，即在母乳喂养的HEU婴儿中，肠道微生物群在多样性上有所不同， HU婴儿的结构和功能，以及特定的胃肠道微生物图谱 对儿童早期疫苗有免疫反应。这项提案将利用已经获得资金的、正在进行的队列 旨在确定与纯母乳喂养相关的免疫保护相关因素，婴儿 队列，即招募500名感染艾滋病毒的母亲和她们的母乳喂养的婴儿，以及150名艾滋病毒阴性的母亲- 婴儿配对控制。作为婴儿研究的一部分，正在进行全面的样本和数据收集 详细的免疫学评估，包括疫苗反应。这项提议将利用现有的 通过16S分析150例HEU和75例HU婴儿肠道微生物组的结构和样本 RRNA测序及其在母乳喂养婴儿出生前9个月，即出生第一周的继承 (在开始复方新诺明预防之前)、7、15和36周龄(目标1)。这项研究将与 应用鸟枪式元基因组学、蛋白质组学和蛋白质组学的微生物组成及其相应功能(目标2) 代谢组学，对150名HIV感染婴儿接种卡介苗后T细胞反应的研究。最后，将翻译成 将测试肠道微生物及其副产品之间的关联，以确定其在疫苗免疫中的致病作用 通过用我们初步数据中的特定生物体、蛋白质和代谢物来定植无菌小鼠 目标2，然后使用最先进的四聚体技术(AIM)评估他们对卡介苗的后续反应 3)。目标3还将深入探讨微生物组-疫苗免疫原性相互作用的机制 肠系膜淋巴结和外周的全局性B和T细胞亚群。这项研究汇集了 临床、临床前、免疫学、质谱学和微生物组分析。这一联合方法将是 用于详细研究肠道微生物群改变HEU免疫反应的机制 从而改进了针对这些脆弱新生儿的艾滋病毒疫苗的开发。

Project Summary Infants born to HIV-infected mothers are at high risk for HIV acquisition via breastfeeding. Yet, the WHO recommends exclusive breastfeeding for HIV-exposed infants since replacement feeding is associated with high morbidity and mortality. Although antiretroviral therapy can reduce transmission, the risk is high compared to that of heterosexual sex. Therefore, HIV-exposed, breastfed infants are an important target group for an HIV vaccine. HIV-exposed infants display altered vaccine responses compared to unexposed infants. Animal models have demonstrated that the development of certain T cell subsets, both in the mucosa and systemically, is determined by the presence of specific microbes in the gut, and may be important in determining adaptive immunity. In humans, there are many reasons to postulate that the gut microbiome of HIV-exposed uninfected (HEU) infants differs from that of HIV-unexposed (HU) infants, since their mothers have altered gut microbiome, and they are exposed to antibiotics and antiretrovirals during pregnancy and postpartum. This proposal tests the hypothesis that in HEU infants who are breastfed, the gut microbiome differs in diversity, structure and function, from that of HU infants, and that specific gastrointestinal microbial profiles correlate with immune response to early childhood vaccines. This proposal will utilize an already funded, ongoing cohort designed to identify correlates of immune protection associated with exclusive breastfeeding, the InFANT cohort, that is enrolling 500 HIV-infected mothers and their breastfed infants, and 150 HIV-negative mother- infant pair controls. As part of the InFANT study, comprehensive sample and data collection is occurring with detailed immunological assessments including vaccine responses. This proposal will utilize the existing infrastructure and samples to characterize the infant gut microbiome of 150 HEU versus 75 HU infants via 16S rRNA sequencing, and its succession in the first 9 months of life in breastfed infants, i.e. in the first week of life (prior to initiation of cotrimoxazole prophylaxis), 7, 15 and 36 weeks of age (Aim 1). The study will relate the microbial composition and its corresponding function (Aim 2) using shotgun metagenomics, proteomics, and metabolomics, to T cellular responses to BCG vaccination in 150 HIV-exposed infants. Finally, will translate associations between gut microbes and their byproducts will be tested for causative roles in vaccine immunity by colonizing germ free mice with specific organisms, proteins and metabolites from our preliminary data and Aim 2, and then assessing their consequent response to BCG using state-of-the-art tetramer technology (Aim 3). Aim 3 will also delve into mechanisms of microbiome-vaccine immunogenicity interactions by assessing global B and T cell subsets in the mesenteric lymph nodes and periphery. This study brings together experts in clinical, pre-clinical, immunologic, mass-spectrometric and microbiome analyses. This joint approach will be used to investigate in detail the mechanisms through which gut microbiome alters immune responses of HEU infants, leading to improved development of HIV vaccines for these vulnerable neonates.