PD-L1阻断对慢性髓系白血病源性树突状细胞的功能影响

程序性死亡-1配体-1(PD-L1)作为近年来发现的B7家族新的成员,已被证实有免疫负调节作用,白血病源性树突状细胞(DC)高表达PD-L1可能是影响其功能的原因之一,本研究试图阻断PD-L1在DC上的表达以增强白血病源性DC的免疫刺激功能。应用人rhGM-CSF、rhIL-4及TNF-α细胞因子组合诱导慢性髓系白血病细胞(CML)分化DC,观察给予加或不加PD-L1单克隆抗体对DC的影响。应用流式细胞术检测DC免疫表型及PD-L1,MTT法检测DC刺激自体T淋巴细胞的增殖能力,ELISA法测定上清液中IFN-γ、IL-2和IL-10的水平。结果显示,负性调节分子PD-L1随着慢性髓系白血病源性树突状细胞(CML-DC)成熟表达不断升高,阻断PD-L1能增强CML-DC刺激自体T淋巴细胞增殖的能力,促进T细胞分泌IFN-γ和IL-2并抑制IL-10的产生(p<0.05)。结论:阻断PD-L1可增强白血病源性DC的功能,为白血病DC瘤苗治疗技术提供了新的方法。

Effect of PD-L1 Blockade on Function of Dendritic Cells Derived from Chronic Myelocytic Leukemia

Programmed death-1 ligand-1(PD-L1) is a recently identified member of the B7 family molecules and is shown to mediate the inhibition of immune responses. This study was purposed to enhance the weak immunological function of dendritic cells (DCs) derived from the patients with chronic myelocytic leukemia (CML) by blockade of the expression of PD-L1. Bone marrow mononuclear cells (BMMNCs) of CML patients were induced into DCs in the presence of cytokine cocktail of rhGM-CSF, rhIL-4 and TNF-alpha. The phenotypes of DCs were detected by flow cytometry, mixed lymphocyte reaction was analyzed by MTT assay and IFN-gamma, IL-2 and IL-10 in the cell culture supernant were detected by ELISA. The results showed that the expression of PD-L1 on CML-DCs was upregulated with the maturation of CML-DCs. PD-L1-blockaded DCs could enhance T lymphocyte proliferation, increase the secretion of IL-2 and IFN-gamma, and inhibit the production of IL-10. Taken together, PD-L1-blockaded DCs originated from CML cells had more potent immunostimulatory capability. It is concluded that PD-L1 blockaded can enhance the function of CML-DCs. This approach presents new possibilities for achieving anti-tumor immunity by DC-based vaccination.