Salamone M C, Rabinovich G A, Mendiguren A K, Salamone G V, Fainboim L
Division Inmunogenética, Hospital de Clínicas, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
J Leukoc Biol. 2001 Feb;69(2):207-14.
In the present study, we investigated the expression of human CD1d antigen on activated mature T cells. Expression of this glycoprotein was found to be highly regulated and dependent on PHA stimulation. Flow cytometry studies using the NOR3.2 antibody, which recognized CD1d under denaturing conditions, showed a clear increase in its expression after PHA stimulation. Expression of this molecule after PHA activation was confirmed by analysis of its corresponding transcript by RT-PCR. A single band representing mRNA for CD1d membrane isoform was observed in activated PBMC as well as in ER3 CD1D-transfected and MOLT-4, pre-T cell lines, which were used as controls. Western blot analysis revealed an activation-dependent increase in CD1d protein expression when PBMC and enriched T cells were activated for different time periods. Activation-dependent expression of CD1d antigen was also confirmed in allogenic-activated T cells, suggesting that this event could have biological significance. Finally, immunocytochemical studies showed the presence of this protein at the plasma membrane accompanied by a cytoplasmic and perinuclear distribution. Results presented herein provide the first experimental evidence showing that CD1d antigen is present on circulating, activated T lymphocytes, suggesting that its expression is dependent on the activation state of the cells. Elucidation of the molecular mechanisms implicated in the activation-dependent expression of this nonclassical antigen will provide new insights into the understanding of antigen presentation and immune regulation.
在本研究中，我们调查了人CD1d抗原在活化成熟T细胞上的表达。发现这种糖蛋白的表达受到高度调控且依赖于PHA刺激。使用在变性条件下识别CD1d的NOR3.2抗体进行的流式细胞术研究表明，PHA刺激后其表达明显增加。通过RT-PCR分析其相应转录本证实了PHA激活后该分子的表达。在活化的外周血单个核细胞（PBMC）以及用作对照的ER3 CD1D转染细胞和MOLT-4前T细胞系中观察到一条代表CD1d膜异构体mRNA的条带。蛋白质印迹分析显示，当PBMC和富集的T细胞在不同时间段被激活时，CD1d蛋白表达呈激活依赖性增加。在同种异体激活的T细胞中也证实了CD1d抗原的激活依赖性表达，表明这一事件可能具有生物学意义。最后，免疫细胞化学研究表明该蛋白存在于质膜上，并伴有细胞质和核周分布。本文给出的结果提供了首个实验证据，表明CD1d抗原存在于循环的活化T淋巴细胞上，提示其表达依赖于细胞的激活状态。阐明与这种非经典抗原的激活依赖性表达相关的分子机制将为理解抗原呈递和免疫调节提供新的见解。
