Single-Cell Analysis To Define Protective and Tolerizing Immune Cell Populations in the Human Placenta

母体对妊娠的免疫适应需要维持免疫能力， 半同种异体胎儿的特异性耐受。免疫适应不良与几种 不利的妊娠结果，对产妇和后代的健康产生短期和长期影响。 孕妇在怀孕期间暴露于胎儿-胎盘抗原是公认的;然而，许多问题 关于抗原呈递和由此产生的适应性免疫应答的性质仍然存在争议。们逗得哈哈 从头适应性免疫应答需要专职抗原呈递细胞（APC）的活化， 特别是树突状细胞（DC）。重要的是，DC还可以诱导T细胞耐受，从而在避免不必要的免疫应答中发挥关键作用。这通常是在预防对自身抗原的反应的背景下研究的，也与保护胎儿免受母体排斥有关。目前尚不清楚人类胎盘和蜕膜中的APC如何提供抗感染的保护，同时防止对胎儿的免疫反应。理解人类生殖中的保护和耐受的一个主要障碍是关于这些APC的功能概况及其个体间变异的有限信息。我们建议在母血、胎盘、蜕膜和脐带血中定义人APC亚群，以检验以下假设：参与人类生殖的APC由几个亚群组成，这些亚群在功能上专门用于保护或耐受。为了实现这一点，我们将利用单细胞分析领域的最新技术进步，即高- 三维细胞术和单细胞基因表达分析，以剖析功能异质性内 这个免疫区。我们的实验室已经开发并验证了多重28色荧光细胞仪 分析，其询问细胞表型、活化和功能能力（即耗竭的表达） 标记物、抑制性受体、共刺激分子）。我们将使用这些检测来确定 细胞的组成和能力直接离体。这些实验将提供关键的洞察力， 在妊娠期间，DC在健康人类生殖组织中的功能特化，并且还提供了 为将来研究先兆子痫等病理学奠定了基础。

Maternal immune adaptation to pregnancy requires maintenance of immune competence with concurrent specific tolerance of the semi-allogeneic fetus. Immune maladaptation has been associated with several adverse pregnancy outcomes, with both short- and long-term impact on maternal and offspring health. Maternal exposure to fetal-placental antigens during pregnancy is well-established; however, many questions remain about the nature of both antigen presentation and the resultant adaptive immune response. Eliciting a de novo adaptive immune response requires the activation of professional antigen presenting cells (APCs), especially dendritic cells (DCs). Importantly, DCs can also induce T cell tolerance and thus play a critical role in avoiding unwanted immune responses. This has been typically studied in the context of preventing responses against self-antigens and is also relevant for protection of the fetus from maternal rejection. It remains unknown how APCs in the human placenta and decidua provide protection against infection and at the same time prevent immune responses against the fetus. A major roadblock to understanding protection and tolerance in human reproduction is the limited information about the functional profile of these APCs, and their inter-individual variation. We propose to define human APC subsets in maternal blood, placenta, decidua, and umbilical cord blood to test the hypothesis that APCs involved in human reproduction consist of several subsets that are functionally specialized to contribute to either protection or tolerance. To accomplish this, we will take advantage of recent technological advances in the field of single-cell analysis, namely high- dimensional cytometry and single-cell gene expression analysis to dissect the functional heterogeneity within this immune compartment. Our lab has developed and validated multiple 28-color fluorescence cytometry assays, which interrogate cell phenotype, activation, and functional capacity (i.e. expression of exhaustion markers, inhibitory receptors, co-stimulatory molecules). We will employ these assays to determine the composition and capabilities of cells directly ex vivo. These experiments will provide critical insight to define functional specialization of DCs in healthy human reproductive tissues during pregnancy and also provide the basis to study pathologies such as preeclampsia in the future.