Samstag Y, Bader A, Meuer S C
Abteilung Angewandte Immunologie, Deutsches Krebsforschungszentrum, Heidelberg, FRG.
J Immunol. 1991 Aug 1;147(3):788-94.
We investigated early activation events after T cell triggering via the Ag receptor (TCR/CD3) complex as compared to activation via the CD2 surface molecule. To this end, resting peripheral human T lymphocytes were preincubated with 32P-orthophosphate and subsequently exposed to mitogenic mAb directed at either TCR/CD3 or CD2 for varying time periods. Cells were lysed and postnuclear lysates subjected to two-dimensional-gel electrophoresis (IEF and SDS-PAGE). As early as 10 min after stimulation through CD2, dephosphorylation of a cytosolic 19-kDa protein was observed. In contrast, this protein remained phosphorylated in unstimulated as well as CD3 activated T cells. Phosphoprotein (pp) 19 dephosphorylation was transient because, at later time points (2-4 h) after CD2 triggering, this protein was phosphorylated again. Phosphoaminoacid analysis indicated that pp19 is dephosphorylated on serine residues. Identical results were obtained using a CD2+ but TCR/CD3- human NK cell clone indicating that pp19 dephosphorylation occurs independent of surface expression of a TCR/CD3 complex. These data show that, in addition to protein phosphorylation events, serine dephosphorylation is involved in T cell triggering. More important, a selective signaling mechanism appears to be linked to T cell activation through the CD2 pathway.
我们研究了经抗原受体（TCR/CD3）复合物触发T细胞后与经CD2表面分子激活相比的早期激活事件。为此，将静息的外周血人T淋巴细胞与32P-正磷酸盐预孵育，随后在不同时间段内用针对TCR/CD3或CD2的促有丝分裂单克隆抗体处理。细胞裂解后，核后裂解物进行二维凝胶电泳（IEF和SDS-PAGE）。早在通过CD2刺激后10分钟，就观察到一种19 kDa胞质蛋白的去磷酸化。相比之下，该蛋白在未刺激的以及CD3激活的T细胞中仍保持磷酸化状态。磷蛋白（pp）19的去磷酸化是短暂的，因为在CD2触发后的后期时间点（2 - 4小时），该蛋白再次被磷酸化。磷酸氨基酸分析表明pp19在丝氨酸残基上去磷酸化。使用CD2 +但TCR/CD3 - 的人NK细胞克隆获得了相同的结果，表明pp19的去磷酸化独立于TCR/CD3复合物的表面表达而发生。这些数据表明，除了蛋白质磷酸化事件外，丝氨酸去磷酸化也参与T细胞触发。更重要的是，一种选择性信号传导机制似乎与通过CD2途径的T细胞激活相关。
