青春型双歧杆菌对哮喘儿童树突状细胞功能的影响

目的研究青春型双歧杆菌对过敏性哮喘儿童外周血单个核细胞来源的树突状细胞（dendritic calls，DC）表面共刺激分子表达及其细胞因子分泌的影响。方法从15例过敏性哮喘儿童和15例非哮喘儿童的外周血单个核细胞诱导生成未成熟DC．与青春型双歧杆菌共培养48小时后．用流式细胞仪检测DC表面CD86和HLA-DR分子的表达，用ELISA方法检测培养上清中自细胞介素（IL）-10、IL-12和IFN-γ的水平。结果经双歧杆菌刺激后，哮喘儿童DC表面CD86表达明显增高（P〈0．05），DC分泌IL-12和IFN-γ水平明显增高；而双歧杆菌刺激对非哮喘儿童的CD86和HLA-DR表达无明显影响，但可使其DC分泌IL-12及IL-10水平明显增高。结论青春型双歧杆菌既可以通过上调CD86的表达，促进DC成熟；又可刺激DC分泌IL-12和IFN-γ，改变Th2优势分化，纠正Th1/Th2失衡，这可能是益生菌防治变态反应性疾病的机制之一。

Effects of Bifidobacterium Adolescent on the Function of Dendritic Cells of the Children with Allergic Asthma

Objective To evaluate the effects of Bifidobacterium adolescent on the function of dendritic cells（DC） derived from peripheral blood mononuclear cells （PBMC） of the children with allergic asthma. Methods The PBMC-derived DC were proliferated in the presence of granulocyte macrophage-colony stimulating factor （GM-CSF） and interleukin-4 （IL-4） from 15 patients with allergic asthma and 15 normal children, and then the immature DC were cocultured with the Bifidobacterium adolescent for 48 h. The expression of CD86 and HLA-DR of DC were measured by flow cytometer. The IL-10, IL-12, and IFN-γ levels of culture supernatant were measured by ELISA. Results After the preproeessing with Bifidobacterium adolescent, the expression of CD86 on the DC, and secretion IL-12 and IFN-γ from the patients with allergic asthma were significantly increased （P 〈 0.05）. The preprocessing with the Bifidobacterium adolescent has no effects on the expression of CD86 and HLA-DR on the DC of the eontrol group, but could increased the level of IL-12 and IL-10 significantly. Conclusions The Bifutobacterium adolescent can not only stimulate the maturation of DC from the patients with allergic asthma by up-regulating the expression of CD86, but also stimulate the DC to secret the IL-12 and IFN-γ It may alter Th2 dominant differentiation and retrieve the Th1/Th2 imbalance in allergic asthma.