Department of Surgery, University of Oklahoma College of Medicine, Tulsa, OK, USA.
Hum Immunol. 2010 Apr;71(4):329-33. doi: 10.1016/j.humimm.2010.01.009. Epub 2010 Jan 25.
Interleukin (IL)-7 is a factor essential for mouse and human thymopoiesis. Mouse thymocytes have altered sensitivities to IL-7 at different developmental stages. CD4/CD8 double positive (DP) mouse thymocytes are shielded from the influence of IL-7 because of loss of CD127 (IL-7Ralpha). In this study, we assessed IL-7 receptor expression and IL-7 signaling in human thymocytes. We found human DP cells to be severely limited in their ability to phosphorylate STAT-5 in response to IL-7. The relative expression levels of the IL-7-inducible proteins Bcl-2 and Mcl-1 were also lower in human DP cells, consistent with a stage-specific decrease in IL-7 responsiveness. IL-7 responses were restored in a subset of cells that matured past the DP stage. Unlike the regulation of IL-7 signaling in mouse thymocytes, loss of IL-7 signaling in human DP cells was not due to absence of CD127, but instead correlated with downregulation of CD132 (common gamma chain).
白细胞介素（IL）-7 是小鼠和人类胸腺发生所必需的因子。小鼠胸腺细胞在不同发育阶段对 IL-7 的敏感性发生改变。由于 CD127（IL-7Ralpha）的丢失，CD4/CD8 双阳性（DP）小鼠胸腺细胞免受 IL-7 的影响。在这项研究中，我们评估了人胸腺细胞中 IL-7 受体表达和 IL-7 信号转导。我们发现人 DP 细胞对 IL-7 反应的 STAT-5 磷酸化能力受到严重限制。IL-7 诱导的蛋白 Bcl-2 和 Mcl-1 的相对表达水平在人 DP 细胞中也较低，与 IL-7 反应性的阶段特异性下降一致。在成熟超过 DP 阶段的细胞亚群中，IL-7 反应得到恢复。与小鼠胸腺细胞中 IL-7 信号转导的调节不同，人 DP 细胞中 IL-7 信号转导的缺失不是由于 CD127 的缺失，而是与 CD132（共同γ链）的下调相关。
