Regulatory T lymphocytes (Treg) play a vital role in the protection of the organism against autoimmune pathology. It is therefore paradoxical that comparatively large numbers of Treg were found in the thymus of type I diabetes‐prone NOD mice. The Treg population in the thymus is composed of newly developing cells and cells that had recirculated from the periphery back to the thymus. We here demonstrate that exceptionally large numbers of Treg develop in the thymus of young, but not adult, NOD mice. Once emigrated from the thymus, an unusually large proportion of these Treg is activated in the periphery, which causes a particularly abundant accumulation of recirculating Treg in the thymus. These cells then rapidly inhibit de novo development of Treg. The proportions of developing Treg thus reach levels similar to or lower than those found in most other, type 1 diabetes‐resistant, inbred mouse strains. Thus, in adult NOD mice the particularly large Treg‐niche is actually composed of mostly recirculating cells and only few newly developing Treg.

中文翻译：

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再循环细胞迅速抑制了年轻 NOD 小鼠中调节性 T 细胞的稳健胸内发育

调节性 T 淋巴细胞 (Treg) 在保护生物体免受自身免疫病理学方面的影响中起着至关重要的作用。因此，在 I 型糖尿病易感 NOD 小鼠的胸腺中发现相对大量的 Treg 是矛盾的。胸腺中的 Treg 群由新发育的细胞和从外周循环回到胸腺的细胞组成。我们在这里证明了在年轻的 NOD 小鼠的胸腺中发育异常大量的 Treg，但不是成年的 NOD 小鼠。一旦从胸腺移出，这些 Treg 的异常大比例在外周被激活，这导致胸腺中循环 Treg 的特别丰富的积累。然后这些细胞迅速抑制 Treg 的从头发育。因此，发育中 Treg 的比例达到与大多数其他 1 型糖尿病抗性近交小鼠品系相似或更低的水平。因此，在成年 NOD 小鼠中，特别大的 Treg-niche 实际上主要由循环细胞和少数新发育的 Treg 组成。