Project 1

摘要 病毒性呼吸道感染是导致早期生命的主要发病率和死亡率的原因。婴儿占到了 流感住院患者中有相当大的比例，被认为是最高风险群体。除 急性发病率，对流感的初始免疫反应塑造/影响免疫系统并影响后续 对流感感染和疫苗接种的反应，这往往会引起偏向于 目前出现的第一个流感抗原表位遇到。相比之下，婴儿感染SARS-CoV-2是 与老年人相比，一般情况下病情较轻，病情较轻。这是值得注意的，并表明有独特的 婴儿免疫系统对SARS-CoV-2的反应特点，与对其他病毒的反应比较 呼吸道病毒，这可以被用来提高我们对早期生命免疫的理解。 在这些观察的基础上，我们假设早期的病毒性呼吸道感染会引起病毒特异性。 免疫反应导致不同的免疫发育轨迹。为了解决这一假设，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；以及作为参考III)没有这两种感染的健康婴儿。在急性感染之后，儿童 将进行为期三年的纵向跟踪，并根据流感和 接种新冠肺炎疫苗。 我们设计了以下具体目标：目标1.明确血液转录免疫的差异 感染SARS-CoV-2的婴儿与感染流感的婴儿之间的特征。我们将评估以下方面的差异 两种急性病毒感染SARS-CoV-2与婴儿流感之间的免疫特征；ii)原发 急性感染与初级疫苗接种，以及iii)初始(初级反应)和随后的 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。 目的2.确定对流感病毒的抗体反应的大小、免疫优势模式和呼吸 和SARS-CoV-2抗体反应的进化。首先，我们将定义抗体反应的进化 在婴儿初次感染和随后接种疫苗时对流感病毒的抵抗力(S)。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的抗体反应(S)。另外， 我们将比较两种病毒对感染和接种疫苗的主要免疫反应。目标 3.高通量纵向评估B细胞对流感和SARS-CoV-2的反应。我们将表演 使用10x基因组学Drop-Seq平台进行多变量分析的高通量单细胞分析 在可变基因库、细胞表面表型、转录组和免疫球蛋白水平上的单个B细胞 专一性。

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.