Project 1

摘要 病毒性呼吸道感染是生命早期主要发病率和死亡率的原因。婴儿占 流感住院的比例很大，被认为是最高的高危人群。除了有 急性发病率，对流感的初始免疫反应形成/印记免疫系统，并影响随后的 对流感感染和疫苗接种的反应，这往往会引起体液反应， 在遇到的第一个流感抗原中存在的表位。相比之下，婴儿的SARS-CoV-2感染 一般较轻，不像老年人那么严重。这是值得注意的，并表明有独特的 婴儿免疫系统对SARS-CoV-2的反应与对其他病毒的反应相比， 呼吸道病毒，这可以用来提高我们对早期生命免疫力的理解。 基于这些观察结果，我们假设早期病毒性呼吸道感染引起病毒特异性 导致不同免疫发育轨迹的免疫反应。为了解决这个问题，我们 将比较三个纵向队列：i）感染SARS-CoV-2的婴儿; ii）感染流感的婴儿 病毒;和作为参照的iii）没有这两种感染的健康婴儿。急性感染后，儿童 将纵向随访三年，并在流感背景下评估免疫应答， COVID-19疫苗接种。 我们设计了以下具体目标：目标1。定义血液转录免疫的差异 SARS-CoV-2婴儿与流感感染婴儿的特征。我们将评估 免疫签名之间：i）两个急性病毒感染SARS-CoV-2与流感在婴儿; ii）原发性 急性感染与初次接种，以及iii）初始（初次应答）和后续（初次应答）之间 疫苗接种（召回反应）。将免疫特征与抗体谱和B细胞反应相关联。 目标2.确定流感病毒抗体应答的强度、免疫优势模式和呼吸 和对SARS-CoV-2的抗体应答的演变。首先，我们将定义抗体应答的演变 婴儿在初次感染和随后接种疫苗时对流感病毒的敏感性。其次，我们将定义 婴儿在初次感染和随后接种疫苗时对SARS-CoV-2的抗体应答。此外，本发明还 我们将比较感染与接种两种病毒的初级免疫应答。目的 3. B细胞对流感和SARS-CoV-2应答的高通量纵向评价。我们将执行 使用10 xGenomics drop-seq平台进行多变量分析的高通量单细胞测定 单个B细胞在可变基因库、细胞表面表型、转录组和IG水平的表达 的特异性

ABSTRACT Viral respiratory infections are responsible for major morbidity and mortality in early life. Infants account for a significant proportion of influenza hospitalizations and are considered a top high-risk group. In addition to the acute morbidity, initial immune responses to influenza shape/imprint the immune system and affect subsequent responses to influenza infections and vaccinations, which tend to induce humoral responses skewed towards epitopes present in the first influenza antigen encountered. In contrast, SARS-CoV-2 infection in infants is generally mild and less severe than in older individuals. This is remarkable and suggests that there are unique features on how the infant immune system responds to SARS-CoV-2, compared to its responses against other respiratory viruses, that can be leveraged to improve our understanding of early life immunity. On the basis of these observations, we hypothesize that early life viral respiratory infections elicit virus-specific immune responses that lead to distinct immune developmental trajectories. To address this hypothesis, we will compare three longitudinal cohorts: i) infants infected with SARS-CoV-2; ii) infants infected with influenza virus; and as reference iii) healthy infants with none of those two infections. After the acute infections, children will be followed longitudinally for three years and immune responses assessed in the context of influenza and COVID-19 vaccinations. We designed the following specific aims: Aim 1. Define the differences of blood transcriptional immune signatures in infants with SARS-CoV-2 versus infants with influenza infection. We will assess the differences in immune signatures between: i) the two acute viral infections SARS-CoV-2 versus influenza in infants; ii) primary acute infection versus primary vaccination, and iii) between initial (primary responses) and subsequent vaccinations (recall responses). Will correlate immune signatures with antibody profiles and B cell responses. Aim 2. Define the magnitude, immunodominance pattern and breath of the antibody responses to influenza virus and evolution of antibody responses to SARS-CoV-2. First, we will define the evolution of the antibody responses to influenza virus in infants upon initial infection and subsequent vaccination(s). Second, we will define the antibody responses to SARS-CoV-2 in infants upon initial infection and subsequent vaccination(s). Additionally, we will compare primary immune responses to infection versus vaccination with each of the two viruses. Aim 3. High-throughput longitudinal evaluation of B cell responses to influenza and SARS-CoV-2. We will perform high-throughput single cell assays using the 10xGenomics drop-seq platform to perform multi-variate analyses of single B cells at the level of the variable gene repertoire, cell-surface phenotype, transcriptome, and Ig specificity.