第三类先天淋巴细胞（ILC3）是固有免疫中的新细胞类群，它们可产生IL-17, IL-22等细胞因子，在肠道及粘膜相关淋巴组织的免疫防御、稳态平衡和组织修复过程中起到重要的作用。ILC3包含多个亚群，均源自胚胎肝脏或成体骨髓内的前驱细胞，但各亚群具体的分化过程有所不同。目前对于这些分化途径以及分化所需关键因子的认识仍然有限。我们的前期工作发现骨髓内的ILC前驱细胞中有一个亚群表达ILC3发育和功能相关的重要基因，包括细胞因子受体IL1R1。本项目将利用IL1R1以及决定ILC发育的关键转录因子Id2作为生物标记，研究共表达两者的骨髓细胞是否为ILC3前驱细胞，解析它们在小鼠不同发育阶段和不同器官的组成和特性，并阐明IL1R1信号通路在该群细胞的生成及分化中的作用。研究ILC3的发育途径有助于我们了解ILC3分化和成熟所必须的条件，为进一步研究ILC3相关疾病和开发治疗手段提供依据。

Group 3 innate lymphoid cells is a new member of innate immunity. They produce IL-17 and IL-22, and play important roles in the defense, homeostasis and repair of intestine and mucosal tissues. Group 3 ILC comprises several subsets that are all derived from fetal liver or bone marrow progenitor cells, whereas the differentiation pathways differ among these subsets. Howerver, the exact developmental pathways and the essential regulators along these pathways are still unclear. Our previous work discovered that a subset of the bone marrow ILC progenitors expresses ILC3 related genes including receptor for cytokine IL-1. Using IL-1R1 and Id2 (a critical ILC regulator) as biomarker, we aim to investigate whether Id2+IL1R1+ bone marrow cells are ILC3 prognenitors, to study the distribution of these cells in lymphoid and non-lymphoid tissue, the composition of the cells at different developmental stages as well as the role of IL1R1 in the generation of this population and differentiation of ILC3. Study on the developmental pathway of ILC3 will lead to a better understanding of the requirement for ILC3 differentiation and provide foundations for further studies of ILC3 related diseases and therapeutics.