Study on dendritic epidermal T cells in mice

成年小鼠表皮含有上皮γδ T细胞家族的成员，称为树突状表皮T细胞（DETC）。它们的发育和成熟一直是调查的对象，但细节仍不清楚。T细胞受体(TCR) ζ -链相关蛋白70 （ZAP-70）是TCR信号转导所需的蛋白酪氨酸激酶之一，在αβ T细胞的发育中起关键作用。在缺乏ZAP-70的小鼠中，αβ T细胞的胸腺发育在未成熟CD4^+CD8^+ TCR^<低>阶段完全停止。在这里，我们检测了在zap -70缺陷小鼠中DETC的发育和成熟是否被改变。免疫组化分析显示，ZAP-70^<-/->小鼠表皮层DETC数量减少，特征树突缺失或明显缩短。流式细胞术分析发现，γδ TCR和Thy-1.2在ZAP-70^<-/-> DETC上的表达水平低于ZAP-70^<+/-> DETC。在新制备的ZAP-70^<+/-> DETC中，几乎检测不到CD69的表达，而CD69阳性细胞则存在于ZAP-70^<+/-> DETC中。此外，ZAP-70^<-/->小鼠对抗cd3ε刺激的DETC增殖明显减少。这些结果表明，通过ZAP-70传递的TCR信号对于DETC的发育和功能成熟也是必不可少的。

Adult murine epidermis contains members of the epithelial γδ T-cell family called dendritic epidermal T cells (DETC). Their development and maturation have been subjects of investigations, but the details are still unclear. T cell receptor (TCR) zeta-chain associated protein-70 (ZAP-70), one of the protein tyrosine kinases required for TCR signaling, plays a pivotal role in the development of αβ T cells. In mice lacking ZAP-70, thymic development of αβ T cells was completely arrested at the immature CD4^+CD8^+ TCR^<low> stage. Here, we examined whether or not development and maturation of DETC were altered in ZAP-70-deficient mice. Immunohistochemical analyses of epidermal sheets revealed that the number of DETC was reduced and their characteristic dendrites were lost or markedly shortened in ZAP-70^<-/-> mice. In flow cytometric analyses, the expression levels of γδ TCR and Thy-1.2 on ZAP-70^<-/-> DETC were lower than those on ZAP-70^<+/-> DETC. The expression of a very early activation antigen, CD69, was hardly detected on the ZAP-70^<-/-> DETC, whereas CD69 positive cells were present in freshly prepared ZAP-70^<+/-> DETC. Furthermore, ZAP-70^<-/-> mice showed markedly reduced DETC proliferation in response to anti-CD3ε stimulation. These results indicate that the TCR signal via ZAP-70 is also essential for the development and the functional maturation of DETC.