Exogenous IL-7 increases recent thymic emigrants in peripheral lymphoid tissue without enhanced thymic function
Exogenous IL-7 increases recent thymic emigrants in peripheral lymphoid tissue without enhanced thymic function
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DOI：
10.1182/blood-2003-10-3635
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发表时间：
2004-08-15
期刊：
影响因子：
20.3
通讯作者：
Gress, RE
中科院分区：
文献类型：
--
作者：
Chu, YW;Memon, SA;Gress, RE
白细胞介素7（IL-7）在维持T细胞稳态的胸腺依赖性和胸腺非依赖性途径中至关重要。T细胞受体（TCR）重排切除环（TRECs）已被用作评估人类胸腺功能的近期胸腺移出（RTEs）的标志物。为了研究IL-7对RTE的胸腺和外周效应，我们测量了IL-7处理的小鼠中的TREC含量和外周初始T细胞亚群和周转。胸腺完整小鼠短期给予IL-7导致总TREC数量增加，与RTE蓄积一致。TREC频率的降低归因于继发于细胞更新增加的稀释。值得注意的是，IL-7给药胸腺切除小鼠导致TREC频率降低和总TREC数量增加的模式，与IL-7处理的胸腺完整小鼠相似。在胸腺完整和胸腺切除小鼠中，IL-7治疗后观察到外周免疫器官中幼稚细胞和RTE分布的不同模式以及CD 11a表达的改变。这些结果表明：（1）总TREC数量而非TREC频率准确地反映了RTE的定量变化;（2）短期IL-7给药导致RTE在外周免疫器官中优先蓄积，这是总外周淋巴池中TREC增加的原因;（3）没有证据表明短期IL-7给药可调节胸腺功能。(C)2004年，美国血液学会。
Interleukin 7 (IL-7) is critical in maintaining thymic-dependent and thymic-independent pathways of T-cell homeostasis. T-cell receptor (TCR) rearrangement excision circles (TRECs) have been used as markers for recent thymic emigrants (RTEs) in assessing human thymic function. To study the thymic and peripheral effects of IL-7 on RTEs, we measured TREC content and peripheral naive T-cell subsets and turnover in IL-7-treated mice. Short-term administration of IL-7 into thymus-intact mice resulted in increased total TREC numbers, consistent with RTE accumulation. Decreases in TREC frequency were attributable to dilution secondary to increased cell turnover. Significantly, IL-7 administration into thymectomized mice resulted in patterns of decreased TREC frequency and increased total TREC number similar to those in IL-7-treated thymus-intact mice. Distinct patterns of naive cell and RTE distribution among peripheral immune organs and altered expression of CD11a were observed following IL-7 treatment in thymus-intact and thymectomized mice. These results demonstrate (1) that total TREC number and not TREC frequency accurately reflects quantitative changes in RTEs; (2) that short-term IL-7 administration results in preferential accumulations of RTEs among peripheral immune organs, accounting for the increase in TRECs in the total peripheral lymphoid pool; and (3) no evidence for regulation of thymic function by short-term IL-7 administration. (C) 2004 by The American Society of Hematology.