抑制吲哚胺2,3-双加氧酶活性促进慢性粒细胞白血病源树突状细胞的功能

Inhibition of indoleamine 2,3-dioxygenase activity promotes function of dendritic cells derived from chronic myeloid leukemia

目的:研究吲哚胺2,3-双加氧酶(indoleamine2,3-dioxygenase,IDO)在慢性粒细胞性白血病源性树突状细胞(dendritic cells derived from chronic myeloid leukemia,CML-DCs)中的表达,及抑制IDO活性对CML-DCs免疫刺激功能的影响。方法:RT-PCR检测17例患者CML-DCs的IDO mRNA的表达情况,流式细胞仪检测CML-DCs免疫表型。在有或无IDO抑制剂1-甲基色氨酸(1-methyltroptophan,1-MT)作用下,分别以不成熟CML-DCs(imDCs)和成熟CML-DCs(mDCs)为刺激细胞,完全缓解期(complete remission,CR)CML患者外周T淋巴细胞为反应细胞建立混合淋巴细胞反应体系,ELISA法检测CML-DCs上清液IL-12水平,MTT法检测CML-DCs刺激自体T淋巴细胞的增殖能力。结果:随着CML-DCs的诱导分化和成熟,IDO mRNA表达逐渐上调;经TNF-α诱导的DCs免疫表型除CD1a外,CD80、CD86、CD83、HLA-DR的表达均明显上调(P<0.05),且上述分子的表达不受1-MT的影响。用1-MT抑制IDO活性后的imDCs和mDCs,其IL-12水平均明显增加(P<0.05,P<0.01),且激发自体T淋巴细胞增殖的能力也明显增强(P<0.05,P<0.01)。结论:抑制IDO活性可提高CML-DCs的IL-12分泌水平,增强其对自体T细胞增殖的刺激能力,IDO对DCs的负性调节为白血病生物治疗提供了新的思路。

Objective： To investigate the expression of indoleamine 2,3-dioxygenase （IDO） in dendritic cells derived from chronic myeloid leukemia （CML-DCs） and to study the influence of IDO inhibition on the function of CML-DCs. Methods： The expression of IDO mRNA in dendritic cells derived from 17 patients with chronic myeloid leukemia was detected by RT-PCR. The phenotypes of CML-DCs were analyzed by flow cytometry. The immature CML-DCs （imDCs） and the mature CML-DCs （mDCs） were used as stimulating cells and autologous T-lymphoeytes were used as reactive cells for a mixed lymphocyte reaction system. IL-12 concentration was detected by ELISA kit; mix lymphocyte reaction was ana- lyzed by MTT assay. Results： It was demonstrated that DCs derived from bone marrow mononuclear cells of CML dis- played a typical morphology of DCs. Expressions of co-stimulatory molecules on DCs, such as CD80, CD86, CD83 and HLA-DR, except for CD1 a, were obviously higher after maturation （P 〈 0.05） and were not influenced by 1-Methyhrop- tophan（ 1-MT, an inhibitor of IDO）. Inhibition IDO activity in mature and immature DCs by 1-MT significantly enhanced their abilities to activate T cells proliferation and to produce IL-12 （P 〈 0.05 ,P 〈 0.01 ）. Conclusion： Inhibition of IDO activity in CML-DCs can increase their abilities to produce IL-12 and activate autologous T cells. Negative regulation of DCs by IDO paves a way for DC-based leukemia immunotherapy.