摘要目的 探讨表达吲哚胺2,3-二氧化酶(IDO)的Kupffer细胞(KC)在体外对小鼠同种异体T淋巴细胞(TC)增殖的抑制作用.方法 用实时荧光定量PCR检测经IFN-γ处理或未处理的KC表达IDOmRNA和FasLmRNA的情况.用高压液相色谱仪分析IDO对色氨酸的分解作用以了解其活性.用3H嵌入增殖试验检测KC对同种异体TC增殖抑制情况.用流式细胞仪分析KC对同种异体TC细胞周期的影响和凋亡作用.结果 实时荧光定量PCR显示:经IFN-γ处理后小鼠KC表达IDO和FasL并且其表达在6 h后均达到高峰.IDO能降低培养基中色氨酸的浓度,提高其代谢产物犬尿氨酸浓度.表达IDO的KC能明显抑制同种异体TC的增殖,但1-甲基色氨酸和抗FasL抗体能部分阻断其增殖抑制作用,且存在剂量依赖关系.表达IDO和FasL的KC能阻滞同种异体TC于G1中期,诱导其凋亡.结论 除了FasL/Fas途径,IDO可能是KC抑制同种异体TC的增殖并诱导其凋亡的另一机制.

abstractsObjective To investigate kupffer cells (KCs) expressing indoleamine 2,3-dioxygenase(IDO)in the inhibition of allogeneic T-cell proliferation in vitro. Methods Real-time PCR was used to investigate the expression of IDO mRNA and FasL mRNA in KCs pretreated with or without IFNγ. High performance liquid chromatography was used to analyze the catabolism of tryptophan by IDO from KCs. Allogeneic T-cell response was used to confirm the inhibition of KCs in vitro. The proliferation of lymphocytes was detected using [3 H] thymidine incorporation. Cell cycle and lymphocyte apoptosis were evaluated by flow cytometric assay. Results Real-time PCR revealed IDO mRNA and FasL mRNA expression in KCs pretreated with IFN-γ. IDO catabolic effect was confirmed by a decrease in tryptophan and increase in kynurenine concentration. KCs expressing IDO and FasL from BABL/c mice acquire the ability to suppress the proliferation of T-cells from C57BL/6, which could be blocked by the addition of 1-methyl-tryptophan and anti-FasL antibody. The co-cultured T-cells with KCs expressing IDO and FasL could induce allogeneic T-cell apoptosis and exhibited cell-cycle arrest in G1. Conclusion In addition to the Fas/FasL pathway, IDO may also play an important role in KCs to inhibit allogeneic T-cell proliferation in vitro.