Tissue-Specific Determinants of Adaptive NK Cell Responses - Myeloid Cells

Natural killer (NK) cells are circulating lymphocytes that possess both innate and adaptive features, the latter including antigen-specific clonal expansion and long-lived memory responses. Unlike other adaptive lymphocytes like T and B cells, NK cells are not thought to require priming in lymphoid organs during activation. However, although NK cells respond in multiple tissue sites during cytomegalovirus (CMV) infection, here we observed that early activation and virus-specific expansion occurs predominantly in the spleen. These splenic NK cells exhibited heightened TNF-a signaling, which we identify as a novel and critical regulator of both innate and adaptive responses through engagement of distinct NF-kB signaling arms downstream of TNFR2. These findings highlight the central role of the spleen as a lymphoid organ in facilitating the innate-to-adaptive transition NK cells undergo during viral infection, and provide insight into how we can better generate innate and adaptive NK cell immunity across diverse settings. Bulk RNA-Seq data of cDC1, pDC, red pulp macrophages from spleen at different time points post MCMV infection cDC1s (Lineage- XCR1+ CD11c+), red-pulp macrophages (Lineage- F4/80+ CD64+), and pDCs (Lineage- F4/80- B220+ BST2+ Ly6C+) were sorted from the spleens of uninfected wildtype mice, or those that were d1 or d2 p.i with MCMV. where Lineage refers to CD3, TCRb, CD19, NK1.1, Ly6G. In each independent experiment, RNA was isolated from sorted cells using the Arcturus PicoPure RNA Isolation Kit (ThermoFisher) in accordance with the manufacturer instructions.

自然杀伤细胞（NK细胞，Natural killer cells）是一类兼具固有免疫与适应性免疫特征的循环淋巴细胞，其适应性免疫特征包括抗原特异性克隆扩增与长效记忆应答。与T、B细胞等其他适应性淋巴细胞不同，学界此前认为NK细胞在激活过程中无需在次级淋巴器官中进行致敏。然而，尽管NK细胞在巨细胞病毒（CMV，cytomegalovirus）感染期间可在多个组织部位发挥免疫应答作用，但本研究观察到其早期激活与病毒特异性克隆扩增主要发生在脾脏中。这些脾脏NK细胞表现出增强的肿瘤坏死因子α（TNF-α，Tumor necrosis factor alpha）信号通路活性，本研究证实该活性可通过激活肿瘤坏死因子受体2（TNFR2，Tumor necrosis factor receptor 2）下游不同的核因子κB（NF-κB，Nuclear factor kappa-light-chain-enhancer of activated B cells）信号分支，同时调控固有免疫与适应性免疫应答，是一类新型关键调控因子。本研究结果凸显了脾脏作为次级淋巴器官，在介导NK细胞在病毒感染过程中完成固有免疫向适应性免疫转化过程中的核心作用，并为在多种场景下更高效诱导NK细胞的固有与适应性免疫应答提供了理论依据。

本数据集包含小鼠在鼠巨细胞病毒（MCMV，murine cytomegalovirus）感染后不同时间点的脾脏经典树突状细胞1型（cDC1）、浆细胞样树突状细胞（pDC）以及红髓巨噬细胞的批量RNA测序（Bulk RNA-Seq）数据。实验所分选的细胞包括：cDC1（谱系标记阴性、XCR1+ CD11c+）、红髓巨噬细胞（谱系标记阴性、F4/80+ CD64+）以及pDC（谱系标记阴性、F4/80- B220+ BST2+ Ly6C+），分选来源为未感染的野生型小鼠脾脏，以及感染MCMV后第1天（d1 p.i.）或第2天（d2 p.i.）的小鼠脾脏。其中谱系标记（Lineage）指CD3、TCRβ、CD19、NK1.1及Ly6G。每一次独立实验中，均按照生产商说明书的操作流程，使用Arcturus PicoPure RNA提取试剂盒（ThermoFisher）从分选得到的细胞中提取总RNA。