枸杞多糖调控口蹄疫重组腺病毒疫苗诱导DC及T细胞亚群的研究

Study on Lycium Barbarum Polysaccharides Regulating DC and T Cell Subsets Induced by Recombinant Adenovirus Vaccine of Foot-and-Mouth Disease

近年来,随着许多病毒性疾病的发展,社会对于新型疫苗的研发迫在眉睫。与传统疫苗相比,新型疫苗具有安全可靠的优点,但其免疫原性较弱的特点也十分突出,因此,研究出安全稳定有效的免疫调节剂来增强疫苗的免疫效果成为研究学者们共同的关注点。枸杞是传统的名贵补益中药,枸杞多糖(Lycium barbarum polysaccharide,LBP)是其中的主要生物活性成分,具有免疫调节、抗肿瘤、抗衰老等多种生物学作用。本研究通过体内实验观察LBP对口蹄疫重组腺病毒疫苗(rAd5VP1)诱导小鼠脾脏树突状细胞(Dendritic cells,DC)成熟、辅助性T细胞1(T helper cells 1,Th1)、辅助性T细胞2(T helper cells 2,Th2)、滤泡辅助性T细胞(T follicular helper cells,Tfh)及调节性T细胞(Regulatory T cells,Treg)分化的免疫调节作用,为阐明LBP免疫调节的新机制提供实验依据。6周龄的雌性BALB/c小鼠随机分为5组,每组5只,所有小鼠均行腹腔注射rAd5VP1,同时分别给予低剂量(10mg/kg·d)、中剂量(20mg/kg·d)、高剂量(40mg/kg·d)的LBP,阴性对照组和阳性对照组分别给予磷酸盐缓冲液(Phosphate buffer solution,PBS)和脂多糖(Lipopolysaccharide,LPS)(1mg/kg·d)。免疫7d后,应用流式细胞术(Flow cytometry,FCM)检测小鼠脾脏DC(CD11c+MHCⅡ+CD86+)、Th1细胞(CD4+IFN-γ+)、Th2细胞(CD4+IL-4+)、Tfh细胞(CD4+CXCR5+)及Treg细胞(CD4+CD25+FoxP3+)的数量与比例。结果表明,与PBS组相比,LBP能明显诱导DC的成熟,DC表面的共刺激分子CD86的表达量明显升高;LBP能明显促进Th2细胞、Tfh细胞的分化,LBP对Th1细胞的分化无明显影响,LBP能抑制Treg细胞的分化。本研究证实LBP作为疫苗免疫调节剂,可调控DC及Th细胞亚群的分化而发挥免疫调节作用,为LBP的免疫调节机制提供理论依据。

In recent years,with the emerging of many viral diseases,the development of new vaccines is immi- nent.Compared with traditional vaccines,the new vaccines have the advantages of safety and reliability,but their immunogenicity is very weak.Therefore,it is a common concern for researchers to study safe,stable and effective immunomodulators to enhance the immune effect of vaccines.Lycium barbarum is a traditional Chinese herbal medicine.Lycium barbarum polysaccharide(LBP)is one of the main biological active components,with various biological functions such as immune regulation,anti-tumor and anti-aging.In this study,we investigated the immunoregulation effect of LBP on the maturation of mouse spleen dendritic cells(DC),differentiation of T helper cells 1(Th1),T helper cells 2(Th2),follicular helper T cells(Tfh)and Regulatory T cells(Treg) induced by foot and mouth disease recombinant adenovirus vaccine(rAd5VP1).Six weeks old female BALB/c mice were randomly divided into 5 groups,5 mice in each group.All mice were administrated by intraperitoneal injection with rAd5VP1.Mice were given once a day for 7 days with low dose LBP(10mg / kg·d),medium dose LBP(20mg/kg·d),and high dose LBP(40mg/kg · d).Negative control group and positive control group were injected with the same volume of PBS and lipopolysaccharide(LBP,1mg / kg·d),respectively.Senven days after immunization,DC(CD11c+MHCⅡ+CD86+),Th1 cells(CD4^+IFN-γ^+),Th2 cells(CD4^+IL-4^+),Tfh cells(CD4^+CXCR5^+)and Treg cells(CD4^+CD25^+FoxP3^+)from spleen were examined by flow cytometry.The results showed that compared with the PBS group,LBP could significantly promote the maturation of DC.The expression of CD86 on the surface of DC obviously was increased.LBP could significantly promote the dif- ferentiation of Th2 cells and Tfh cells,but has no significant effect on the differentiation of Th1 cells.LBP can inhibit the differentiation of Treg cells.It is suggested that LBP can regulate the differentiation of DC and T helper cells(Th)subsets and play an immunomodulatory role,which provided the theoretical basis for the new mechanism of LBP immunoregulation.