单唾液酸四己糖神经节苷脂(GM1)作为T细胞活化标志的探讨

目的:比较、分析单唾液酸四己糖神经节苷脂(GM1)和CD69分子在人外周血γδT和CD3 T细胞上的表达规律。方法:用抗CD3单克隆抗体(mAb)和结核杆菌抗原(MtbAg)等刺激剂分别刺激人外周血单个核细胞(PBMC),部分实验组同时使用信号转导途径阻断剂处理。用流式细胞术检测不同时相γδT和CD3 T细胞上GM1和CD69分子的表达率。结果:MtbAg刺激PBMC后0.5h,γδT细胞上即表达GM1,随着时间的推移表达水平持续升高;而CD69的表达出现在刺激后的3h,于24h达高峰,然后逐渐下降,72h明显降低,6d时已接近静止状态。抗CD3mAb刺激的CD3 T细胞上,GM1和CD69表达的规律类似于γδT细胞。PD98059和LY294002均能够阻断MtbAg刺激所致的γδT细胞上GM1的表达,PMA能够促进GM1的表达。结论:GM1可作为一种新的T细胞活化的标志,其与早期短暂表达的CD69分子有不同的表达规律。GM1的表达可能与RasErk通路、PI3K和PKC有关。

Exploration of ganglioside GM1 as an activation marker on T cells

AIM: To compare and analyze the patterns of ganglioside GM1 and CD69 expressions on activated gammadeltaT cells and CD3(+) T cells from human peripheral blood. METHODS: PBMCs were stimulated in vitro with anti-CD3 mAb or Mycobacterium tuberculosis antigen (Mtb-Ag). In some experimental groups, PBMCs were pretreated with different inhibitors of signal transduction pathway before stimulation. The expressions of GM1 or CD69 on gammadeltaT and CD3(+) T cells at different time points after stimulation were measured by flow cytometry (FCM). RESULTS: GM1 appeared on gammadeltaT cells at 30 min after stimulation with Mtb-Ag and retained a higher level with the lapse of time; whereas CD69 expression appeared at 3 h after stimulation and reached peak at 24 h, and then decreased gradually to the resting level on day 6 after stimulation. The expressions of CD69 and GM1 on CD3(+) T cells stimulated with anti-CD3 mAb were similar to those on gammadeltaT cells. The expression of GM1 on gammadeltaT cells was inhibited by pretreatment with PD98059 or LY294002. PMA increased the expression of GM1. CONCLUSION: GM1 can serve as a novel marker of activated T cells. During the activation of T cells, the dynamic expression of GM1 was different from that of CD69, a very early activation antigen. The Ras-Erk signal transduction pathway and PI3K and PKC might be involved in the expression of GM1.