T淋巴细胞活化与蛋氨酸腺苷转移酶的表达

Expression of methionine adenosyltransferase and T lymphocyte activation

目的 :检测人外周血 T细胞 (PBT)在不同刺激时蛋氨酸腺苷转移酶 (MAT) m RNA的表达和细胞内 MAT活性的变化。 方法 :半定量 PCR和 MAT酶活性检测法。 结果 :人 PBT只表达 MAT- 。经 IL - 2、PHA和抗 CD3抗体刺激后 ,人PBT MAT- m RNA的表达分别增加 (8.9± 2 .1)、(7.7± 1.9)和 (8.0± 1.8)倍 ,表达高峰分别出现在刺激后 8、4和 8h;MAT- 活性在 48h内持续升高 ,分别是未刺激时的 4、3.9和 3.3倍。 S-腺苷蛋氨酸 (SAM)能低水平增加人 T细胞产生的IL - 2和 IFN,0 .1m g/ ml SAM能反馈抑制 PHA和抗 CD3抗体诱导的 MAT- 的表达和活性 ,以及 PHA和抗 CD3抗体诱导的 IL - 2和 IFN产生 ,但对细胞增殖无影响。结论 :MAT参与 T细胞的活化过程 ,大剂量 SAM可能通过对细胞内物质的过甲基化抑制 PHA和抗 CD3抗体介导的 T细胞活化。

Objective: To study the expression and activity changes of methionine adenosyltransferase (MAT) in human peripheral T lymphocytes. Methods: The expression of MAT mRNA was detected by RT-PCR and the activity of MAT was measured. Results: After stimulated by IL-2, PHA and anti-CD3 antibody, MAT-Ⅱ gene expression increased by (8.9± 2.1), (7.7±1.9) and (8.0±1.8) times, respectively, and the expression peak was at 8, 4 and 8 h,respectively; MAT activity continuously increased in 48 h. S-adenosylmethioinie (SAM) moderately induced IL-2 and IFN secretion by human T cells. SAM(0.1 mg/ml) downregulated the expression and activity of MAT-Ⅱ and the secretion of IL-2 and IFN induced by PHA or anti-CD3 antibody in human T cells. Conclusion:MAT is involved in the activation of T lymphocytes, and high dose of SAM may also inhibit its activation through PHA and anti-CD3 antibody.