树突状细胞诱导抗曲霉菌的Th免疫及皮质类固醇对其影响的研究

目的　研究树突状细胞 (DC)在抗曲霉菌免疫中的作用以及皮质类固醇如何在DC水平影响机体的抗曲霉菌免疫。方法　通过体外培养小鼠骨髓DC ,用麦氏比浊法检测DC对灭活曲霉菌孢子的吞噬量。酶联免疫吸附测定 (ELISA)检测DC以及脾脏T细胞分泌的细胞因子。结果　小鼠骨髓DC能高效吞噬加热灭活的曲霉菌孢子 ,皮质类固醇氢化可的松 (HC)抑制DC吞噬曲霉菌孢子的能力。DC受曲霉菌孢子刺激时分泌白细胞介素 12 (IL 12 )和干扰素γ(IFN γ) ,而不分泌白细胞介素 10 (IL 10 ) ,HC明显抑制DC分泌IL 12和IFN γ ,但不影响IL 10的分泌。给小鼠接种经灭活曲霉菌孢子冲击的DC后 ,其脾脏T细胞在体外受灭活曲霉菌孢子再刺激时分泌IFN γ ,而给小鼠接种经灭活曲霉菌孢子和HC联合冲击的DC后 ,其脾脏T细胞受灭活曲霉菌孢子再刺激时分泌IFN γ明显减少 ,IL 10却增加。结论　DC可能是抗曲霉菌免疫的效应细胞 ,并起始抗曲霉菌的Th1型免疫 ,HC抑制DC的这些功能 ,并使曲霉菌免疫偏向Th2型。经灭活曲霉菌孢子冲击的DC可能对增强免疫受损宿主抗曲霉菌免疫有作用。

Anti-aspergillus Th immunity induced by dendritic cells and the effect of hydrocortisone on it

OBJECTIVE: To investigate the role of dendritic cells (DCs) in host defense against aspergillus, and how corticosteroids hydrocortisone (HC) affects host anti-aspergillus immunity at the DCs level. METHODS: Mouse bone marrow-derived DCs were generated ex vivo and the uptake of inactivated Aspergillus fumigatus conidia (iAfc) by DCs was assayed using McFarland standard. Cytokine production by DCs or by splenic T cells were measured using ELISA method. RESULTS: DCs were capable of ingesting iAfc efficiently. HC significantly inhibited the capacity of DCs to phagocytose iAfc. After stimulated with iAfc in vitro, DCs secreted IL-12 and IFN-gamma, but did not secret IL-10. 10(-5) mol/L HC down-regulated IL-12 and IFN-gamma production by DCs, but it didn't affect IL-10 production. After the mice were inoculated with iAfc-pulsed DCs, their splenic T cells secreted IFN-gamma upon the re-stimulation with iAfc in vitro. In contrast, after the mice were inoculated with iAfc-HC-pulsed DCs, the splenic T cells showed significantly decreased IFN-gamma secretion upon the same stimulation, but the secretion of IL-10 was increased. CONCLUSIONS: DCs might act as effector cells in host defense against aspergillus, and initiate anti-aspergillus Th1 type immunity. HC inhibited the above functions of DCs and skew the immunity response towards Th2 type. iAfc-pulsed DCs might be useful for promoting the anti-aspergillus immunity of immunocompromised host.