Guerin S, Mari B, Belhacene N, Rossi B, Peyron J F, Auberger P
Faculté de Médecine, INSERM U364, Nice, France.
Cell Immunol. 1997 Jan 10;175(1):85-91. doi: 10.1006/cimm.1996.1045.
Human immature thymocytes express significant levels of the CD10 (endopeptidase 24.11) cell surface antigen. We report here that IOB5, an anti-CD10 mAb, as well as the phorbol ester PMA down-regulate CD10 activity at the surface of human thymocytes. The kinetics of CD10 modulation were drastically different for both effectors, indicating different regulatory mechanisms. We also demonstrated that intact human thymocytes hydrolyze thymopentin and that CD10 significantly participates in this process. Finally, we found that thymopentin and to a lesser extent phosphoramidon, a specific endopeptidase 24.11 inhibitor, induced up-regulation of CD4 and CD8 molecules at the thymocyte cell surface. In view of these results, we suggest that down-regulation of endopeptidase 24.11 at the thymocyte cell surface might reduce its activity toward thymic factors possibly involved in the regulation of thymocyte functions.
人类未成熟胸腺细胞表达显著水平的CD10（内肽酶24.11）细胞表面抗原。我们在此报告，抗CD10单克隆抗体IOB5以及佛波酯PMA可下调人类胸腺细胞表面的CD10活性。两种效应物对CD10调节的动力学有显著差异，表明存在不同的调节机制。我们还证明完整的人类胸腺细胞可水解胸腺五肽，且CD10在这一过程中发挥重要作用。最后，我们发现胸腺五肽以及在较小程度上的磷酰胺素（一种特异性内肽酶24.11抑制剂）可诱导胸腺细胞表面CD4和CD8分子上调。鉴于这些结果，我们认为胸腺细胞表面内肽酶24.11的下调可能会降低其对可能参与胸腺细胞功能调节的胸腺因子的活性。
