THE APPLICATION OF THE DENDRITIC CELL GENE THERAPY IN TRANSPLANTATION FIELD -Induction of antigen-specific T cell proliferation by Indoleamine 2,3-dioxygenase cDNA-transfected dendritic cells-

目的：吲哚胺2,3-双加氧酶（IDO）是一种酶，参与色氨酸的分解代谢，并已被证明可以防止胎儿在怀孕期间的排斥反应，可能是通过抑制同种异体反应性T细胞。在本研究中，我们研究了转染IDO cDNA的树突状细胞在抗原特异性相互作用后是否抑制T细胞增殖。方法：采用重组腺病毒载体表达IDO，采用Western blot、免疫染色和犬尿氨酸测定证实IDO的表达和功能。通过FACS分析证实ido转染的XS106 DC克隆（来源于A/J小鼠）表面分子的表达。用ido表达的DC培养后检测同种异体T细胞增殖。结果：成功构建了表达IDO的重组腺病毒载体，并通过Western blot和免疫染色检测其基因表达。通过提高犬尿氨酸浓度证实了其分解代谢作用。结果表明，表达ido的XS106 DC对CD86、CDllc和CD69的表达没有改变。表达ido的DC与B6异体脾T细胞共培养后，T细胞的增殖明显受到抑制。结论：这些结果表明，DC中IDO的过表达可有效抑制T细胞增殖，并可能为防止器官移植的同种异体排斥反应提供新的免疫调节策略。

Purpose : Indoleamine 2,3-dioxygenase (IDO) is an enzyme, involved in the catabolism of tryptophan and has been show to prevent rejection of the fetus during pregnancy, probably by inhibiting alloreactive T cells. In the present study, we investigated whether DCs that are transfected with IDO cDNA in inhibition of T cell proliferation after antigen-specific interaction. Methods : IDO was expressed with a gene delivery system using a recombinantadenoviral vector and its expression and function were confirmed by Western blot, immunology staining and kynurenine assay. The expression of the surface molecular of the IDO-transfected XS106 DC clone (derived from A/J mice) was confirmed by FACS analysis. Alloreactive T cell proliferation was assayed after culture with IDO-expressed DC. Results : A recombinant adenoviral vector expressing IDO was successfully generated and its gene expression detected by Western blot and immune staining. Its catabolic effect was confirmed by increase the kynurenine concentration. It revealed that IDO-expressing XS106 DC were no changeable for CD86, CDllc and CD69 expression. After co-cultured IDO-expressing DC with B6 allogeneic splenic T cell, the proliferation of the T cell was inhibited significantly. Conclusions : These results suggest that over expression of the IDO in the DC was effective to inhibit T cell proliferation, and may expand a new immunomodulatory strategy to prevent the allo-rejection of the organ transplantation.