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目的探讨CD4~+CD25~+调节性T细胞(Tregs)对日本血吸虫病疫苗保护性效果的影响及其机制。方法雌性BALB/c小鼠随机分成5组,即正常对照组、感染对照组、抗CD25单克隆抗体(anti-CD25 m Ab)组、谷胱甘肽-S-转移酶(Gluthatione-S-transferase,GST)免疫组和GST/anti-CD25 m Ab联合组。分别在感染后2、3、4、5周剖杀小鼠,收集脾细胞及培养上清,采用流式细胞术检测脾细胞中CD4~+CD25~+Tregs比例,双抗夹心ELISA法测定脾细胞培养上清中的IFN-γ、IL-2、IL-4、IL-5和TGF-β水平。感染后5周杀鼠,门静脉冲虫,统计每只小鼠虫荷及每克肝脏虫卵数;肝组织石蜡切片HE染色观察虫卵肉芽肿病理变化。结果感染后5周,GST免疫组小鼠减虫率为24.98%,而GST/anti-CD25 m Ab联合组减虫率达43.13%;GST免疫组小鼠脾细胞中CD4~+CD25~+Foxp3+比例显著高于感染对照组(P<0.05),而anti-CD25 m Ab组小鼠脾细胞中CD4~+CD25~+Foxp3+比例显著低于感染对照组(P<0.01)。使用anti-CD25 m Ab后2周,GST/anti-CD25 m Ab联合组小鼠脾细胞培养上清中IL-4、IL-5、IFN-γ和IL-2含量均较其他组高;各组小鼠肝脏病理变化和脾细胞培养上清中TGF-β水平间差异均无统计学意义(P均>0.05)。结论 GST疫苗可引起日本血吸虫感染宿主CD4~+CD25~+Tregs明显上升,从而导致其保护性效果欠佳;anti-CD25 m Ab部分封闭CD4~+CD25~+Tregs后有利于增强日本血吸虫病疫苗的免疫保护性效果,其机制可能与Th1、Th2型免疫反应增强有关。
Objective To investigate the effect of CD4 ~ + CD25 ~ + regulatory T cells (Tregs) on the protective effect of Schistosoma japonicum vaccine and its mechanism. Methods Female BALB / c mice were randomly divided into 5 groups: normal control group, infection control group, anti-CD25 m Ab group, Gluthatione-S-transferase , GST) and GST / anti-CD25 m Ab group. Mice were sacrificed at 2, 3, 4 and 5 weeks after infection respectively. Splenocytes and supernatants were collected. The proportion of CD4 ~ + CD25 ~ + Tregs in splenocytes was detected by flow cytometry. IFN-γ, IL-2, IL-4, IL-5 and TGF-β levels in cell culture supernatants. Rats were sacrificed 5 weeks after infection, and portal vein punctures were collected. The number of eggs per mouse and the number of eggs per gram of liver were counted. The pathological changes of the egg granulomas were observed by HE staining. Results The worm reduction rate of GST group was 24.98% at 5 weeks after infection, while the GST / anti-CD25 m Ab combined group was 43.13%. The percentage of CD4 ~ + CD25 ~ + Foxp3 + (P <0.05), while the proportion of CD4 ~ + CD25 ~ + Foxp3 + in splenocytes of anti-CD25 m Ab group was significantly lower than that of infected control group (P <0.01). The levels of IL-4, IL-5, IFN-γ and IL-2 in the spleen cell culture supernatant of GST / anti-CD25 m Ab group were higher than those of other groups after 2 weeks of anti-CD25 m Ab treatment. There was no significant difference between the pathological changes of liver and TGF-β in the spleen cell culture supernatant (all P> 0.05). Conclusions GST vaccine can cause significant increase of CD4 ~ + CD25 ~ + Tregs in Schistosoma japonicum infected host, resulting in poor protective effect. Anti-CD25 m Ab partial blocking of CD4 ~ + CD25 ~ + Tregs is beneficial to enhance immunity against Schistosoma japonicum The mechanism of immunosuppressive effects may be related to Th1 and Th2 immune responses.