T Cell Zone Resident Macrophages Silently Dispose of Apoptotic Cells in the Lymph Node
T Cell Zone Resident Macrophages Silently Dispose of Apoptotic Cells in the Lymph Node
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DOI：
10.1016/j.immuni.2017.07.019
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发表时间：
2017-08-15
期刊：
影响因子：
32.4
通讯作者：
Bajenoff, Marc
中科院分区：
文献类型：
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作者：
Baratin, Myriam;Simon, Lea;Bajenoff, Marc
在淋巴结 (LN) 中，树突状细胞 (DC) 被认为可以处理凋亡细胞，这是其他组织中巨噬细胞的一种功能。我们发现位于 LN T 细胞区的 CX3CR1(+) MERTK+ 细胞群（之前被鉴定为 DC）是胞巨噬细胞。谱系追踪实验和盾嵌合体表明，这些 T 区巨噬细胞 (TZM) 是在子宫内接种的长寿巨噬细胞，并在出生后慢慢被血液单核细胞取代。对 TZM 和 DC 表达不同荧光蛋白的小鼠 LN 进行成像显示，TZM（而非 DC）是唯一的专业清道夫，以 CX3CR1 依赖性方式清除 LN T 细胞区中的凋亡细胞。此外，与其他巨噬细胞类似，TZM 在启动 CD4 T 细胞方面似乎效率低下。因此，LN 中的胞吞作用和 T 细胞激活是分别指定给巨噬细胞和 DC 的解偶联过程，对免疫稳态的维持具有影响。
In lymph nodes (LNs), dendritic cells (DCs) are thought to dispose of apoptotic cells, a function pertaining to macrophages in other tissues. We found that a population of CX3CR1(+) MERTK+ cells located in the T cell zone of LNs, previously identified as DCs, are efferocytic macrophages. Lineage-tracing experiments and shield chimeras indicated that these T zone macrophages (TZM) are long-lived macrophages seeded in utero and slowly replaced by blood monocytes after birth. Imaging the LNs of mice in which TZM and DCs express different fluorescent proteins revealed that TZM-and not DCs-act as the only professional scavengers, clearing apoptotic cells in the LN T cell zone in a CX3CR1-dependent manner. Furthermore, similar to other macrophages, TZM appear inefficient in priming CD4 T cells. Thus, efferocytosis and T cell activation in the LN are uncoupled processes designated to macrophages and DCs, respectively, with implications to the maintenance of immune homeostasis.