新疆野生荒漠肉苁蓉醇提物调节小鼠DCs成熟对Th1/Th2的免疫增强作用

旨在探讨新疆野生荒漠肉苁蓉醇提物（ethanol extracts of wild Cistanche deserticola，EEWCD）调节Th1/Th2免疫反应的特点及初步的作用机制。采用卵清白蛋白（ovalbumin，OVA）为抗原，研究EEWCD对小鼠体液免疫，细胞免疫，细胞因子分泌，树突状细胞（dendritic cells，DCs）的成熟和调节性T细胞（regulatory T cell，Treg）等的影响。EEWCD低、中、高剂量（分别记作L、M、H）分别与OVA混合，ICR小鼠随机分为0.9% NaCl、EEWCD、OVA、OVA-EEWCD-L、OVA-EEWCD-M、OVA-EEWCD-H和OVA-铝佐剂免疫组。皮下免疫2次，间隔2周。小鼠免疫后，ELISA法检测抗体滴度及分型，MTT检测脾细胞增殖水平，FACS检测CD4⁺ IL-4、CD4⁺IFN-γ和CD8⁺ IFN-γ的水平，以及DCs表面分子与Treg表达水平。结果显示，EEWCD提高了OVA特异性IgG抗体2~3倍；在初次免疫后21 d显著促进IgG₁和IgG_2a的表达水平（P<0.05）；显著促进OVA特异性脾细胞增殖以及T/B细胞的活化（P<0.05）；显著促进CD4⁺ IL-4、CD4⁺ IFN-γ和CD8⁺ IFN-γ的分泌（P<0.05）。同时，EEWCD也显著促进了DCs的CD40、CD80、CD86和MHCⅡ的表达（P<0.05），下调了Treg的水平（P<0.05）。EEWCD-M为最佳剂量。监测免疫后小鼠行为及体重，小鼠行为没有异常，且同一时间点各组体重之间差异不显著（P>0.05）。综上表明，EEWCD能够促进OVA特异性的Th₁/Th₂免疫反应，尤其促进Th₁型反应，具有良好的免疫调节活性，其作用机制可能为通过激活DCs的成熟，促进IL-4和IFN-γ的分泌，降低Treg的水平调节Th₁/Th₂免疫反应的动态平衡。

Immune Enhancement Activities of Ethanolic Extract from Wild Cistanche deserticola with Dual Th1 and Th2 Response by Promoting DCs Maturation in Mice

The study aimed to determine immune enhancement activities of ethanolic extract from wild C.deserticola with dual Th₁ and Th₂ responses by promoting DCs maturation in mice.OVA was used as antigen,three different doses of EEWCD(low,medium,high)were combined with OVA in 0.9%NaCl.ICR mice were randomly separated into seven groups,0.9%NaCl group,EEWCD group,OVA group,OVA-EEWCD-L group,OVA-EEWCD-M group,OVA-EEWCD-H group,and OVA-Alum group.ICR mice were subcutaneously injected twice with a 2-week interval.After vaccination,IgG titers,IgG subclasses were detected by ELISA,splenocyte proliferation was performed with MTT method,cytokine,DCs surface markers and Treg frequency were tested by FACS.The data showed that EEWCD significantly enhanced the serum IgG titers and IgG subclasses(P<0.05).Meanwhile,EEWCD significantly promoted OVA-specific splenocyte proliferation and T/B-proliferation(P<0.05).EEWCD also could significantly promote the level of CD4⁺IL-4,CD4⁺IFN-γand CD8⁺IFN-γ(P<0.05).Furthermore,the expression levels of CD40,CD80,CD86 and MHC-II in DCs were significantly improved(P<0.05),whereas the frequency of Treg was significantly decreased(P<0.05).EEWCD-M showed remarkable immunomodulatory activity.No abnormal behavior and significant difference in mice body weight were observed(P>0.05).The data showed that subcutaneous administration of EEWCD significantly enhanced Th₁/Th₂ immune responses by promoting DCs maturation and reducing the frequency of Treg.