Han D, Plaisance S, Rubinstein E, Alileche A, Pottin-Clemenceau C, Kim T S, Cohen E P, Jasmin C, Azzarone B
INSERM U 268, Villejuif, France.
Eur J Immunol. 1995 Jul;25(7):1905-12. doi: 10.1002/eji.1830250717.
Mouse fibroblasts do not ordinarily express components for the interleukin-2 receptor (IL-2R alpha, beta, and gamma). An analysis of these cells by reverse transcription followed by polymerase chain reaction, however, indicates the presence of transcripts specific for the IL-2R beta and gamma genes. Transfection of the cDNA for the alpha chain of the human IL-2R into LTK- mouse fibroblast cell line (L3 cells) leads, in long-term cultures, to the formation of transcripts of endogenous mouse IL-2, IL-2R alpha and beta genes, as detected by Northern blotting. Based upon the results of the binding of 125I-labeled IL-2 to the transfected cells, three IL-2-binding proteins of 55 kDa, 65 kDa and 75 kDa were expressed by the transfected cells. The 65-kDa and 75-kDa proteins bound IL-2 in the presence of monoclonal antibodies for the IL-2R alpha chain. These polypeptides assembled to form high-affinity IL-2R, as shown by Scatchard binding analyses. The receptors were functionally active, since the expression of H-2k major histocompatibility complex antigens on the surface membranes of L3 cells was enhanced by exposing the cells to IL-2. Activation of the IL-2 gene was also observed in long-term cultures of L alpha beta cells, another LTK- transfectant expressing the human IL-2R alpha chain. This type of gene activation was not observed in LTK- fibroblasts transfected with cDNA for human IL-2 or IL-2R beta genes. In L3 and L alpha beta cells, transcription of the endogenous IL-2 gene was suppressed by cyclosporin A and enhanced by cycloheximide. These data may have implications for gene therapy of cancer cells.
小鼠成纤维细胞通常不表达白细胞介素-2受体（IL-2Rα、β和γ）的组分。然而，通过逆转录随后进行聚合酶链反应对这些细胞进行分析，结果表明存在IL-2Rβ和γ基因特异性的转录本。将人IL-2Rα链的cDNA转染到LTK⁻小鼠成纤维细胞系（L3细胞）中，经过长期培养，通过Northern印迹检测发现，内源性小鼠IL-2、IL-2Rα和β基因形成了转录本。根据125I标记的IL-2与转染细胞的结合结果，转染细胞表达了三种分子量分别为55 kDa、65 kDa和75 kDa的IL-2结合蛋白。在存在针对IL-2Rα链的单克隆抗体的情况下，65 kDa和75 kDa的蛋白能够结合IL-2。如Scatchard结合分析所示，这些多肽组装形成了高亲和力的IL-2R。这些受体具有功能活性，因为将L3细胞暴露于IL-2可增强其表面膜上H-2k主要组织相容性复合体抗原的表达。在另一种表达人IL-2Rα链的LTK⁻转染细胞Lαβ细胞的长期培养中，也观察到了IL-2基因的激活。在用人类IL-2或IL-2Rβ基因的cDNA转染的LTK⁻成纤维细胞中未观察到这种基因激活。在L3和Lαβ细胞中，内源性IL-2基因的转录受到环孢素A的抑制，并被环己酰亚胺增强。这些数据可能对癌细胞的基因治疗具有启示意义。
