The role of the thymus and recent thymic migrants in the maintenance of the adult peripheral lymphocyte pool.
The role of the thymus and recent thymic migrants in the maintenance of the adult peripheral lymphocyte pool.
复制标题
胸腺和最近的胸腺移民在维持成年外周淋巴细胞库中的作用。
DOI：
10.1084/jem.187.11.1839
复制
发表时间：
1998-06-01
影响因子：
15.3
通讯作者：
Miller, J F
中科院分区：
文献类型：
--
作者：
Berzins, S P;Boyd, R L;Miller, J F
胸腺对于T细胞最初向周围组织的迁移至关重要，但其在维持成年T细胞库方面的作用仍不明确。我们研究了T细胞输出速率的改变是否能成为控制周围T细胞库大小和组成的稳态调节机制的一部分。通过在肾包膜下移植新生胸腺，我们发现无论T细胞库是供应过剩（由胸腺移植导致）还是供应不足（由于新生期胸腺切除），宿主胸腺和移植胸腺的T细胞输出速率都是恒定的，并且周围T细胞库的大小保持不变。我们还追踪了近期胸腺迁出细胞（RTE），以确定它们被正常小鼠T细胞库接纳的程度。作为一个群体，RTE在表型上是成熟的，但与周围组织中的常驻T细胞不同，其释放时的CD4/CD8比值约为已建立的周围T细胞的两倍。这种输出比值与成熟胸腺区室中的T细胞相似，但在进入周围组织后不久，该比值下降，这表明CD4/CD8比值受到胸腺和周围组织的分别调节。RTE可能也会优先被纳入周围组织，导致常驻T细胞的移位，从而维持周围T细胞库的大小。尽管对于维持一个有功能的T细胞库并非至关重要，但在一个“已满”的周围T细胞库中接纳RTE将确保T细胞受体库保持多样性，并且T细胞群体包含广泛的初始T细胞以及记忆T细胞。
The thymus is essential for the initial seeding of T cells to the periphery, but its role in maintaining the adult T cell pool remains poorly defined. We investigated whether changes to the rate of T cell export could form part of the mechanism(s) controlling the homeostatic regulation of the size and composition of the peripheral T cell pool. Using neonatal thymi grafted under the kidney capsule, we found that irrespective of whether the pool was oversupplied (by thymic grafts) or undersupplied (due to neonatal thymectomy), the thymic export rate was constant from both the host and graft thymus, and the periphery remained constant in size. Recent thymic emigrants (RTE) were also tracked to determine the extent of their acceptance into the T cell pool of a normal mouse. As a population, RTE are phenotypically mature, but were distinct from resident T cells in the periphery, being released in a CD4/CD8 ratio approximately twice that of established peripheral T cells. This export ratio is similar to that of T cells in the mature thymic compartment, but soon after entry into the periphery, the ratio falls, indicating separate thymic and peripheral regulation of the CD4/CD8 ratio. RTE may also be preferentially incorporated into the periphery, causing displacement of resident T cells, thus maintaining the size of the peripheral pool. Although not vital for the maintenance of a functional T cell pool, the acceptance of RTE in a “full” peripheral pool would ensure that the T cell receptor repertoire is kept diverse and that the T cell population encompasses a broad range of naive as well as memory T cells.