日本血吸虫虫卵抗原诱导CD4^＋CD25^＋ T细胞及其细胞因子表达

Production of CD4^+CD25^+ T cells induced by Schistosoma japonicum egg antigens and their cytokine

目的探讨日本血吸虫虫卵抗原诱导宿主免疫应答下调的机制。方法6～8周龄雌性BALB/c小鼠分为2组,实验组小鼠口服血吸虫虫卵10000个以及尾静脉注射可溶性虫卵抗原(SEA)200μg,每周免疫1次,共4次;对照组注射PBS。流式细胞仪检测SEA免疫小鼠CD4+CD25+T细胞数量;与CD4+CD25-T细胞共同培养,检测CD4+CD25+T细胞抑制功能;流式细胞仪检测CD4+CD25+T细胞表达IL-4、IL-10与IFN-γ水平;酶联免疫吸附试验检测静脉血IL-10和转化生长因子-β表达水平。结果实验组小鼠CD4+CD25+T细胞数量为14.7%,对照组为7.4%;实验组IL-10为29.2pg/ml,对照组为11.0pg/ml。与CD4+CD25-T细胞相比,CD4+CD25+T细胞主要合成IL-10及少量IFN-γ。CD4+CD25+T细胞显著抑制CD4+T细胞增殖。结论日本血吸虫虫卵抗原可能通过诱导CD4+CD25+T细胞和IL-10下调机体免疫应答。

Objective To explore the role of Sch istosoma japonicum egg antigens in host immune response. Methods Female BALB/c mice aged 6-8 weeks were divided into two groups. The mice in the experiment group were administrated with 10 000 eggs of S. japonicum orally and injected with 200 μg SEA via tail vein, once for a week. The mice in the control group were infected with PBS. The number of CD4^＋ CD25^＋ T cells was detected in a murine model treated by S. japonicum egg antigens, and the regulatory properties of CD4^＋ CD25^＋ T cells were assessed while CD4^＋ CD25^＋ T cells were coeultured with CD4^＋CD25-T cells. For the detection of routine TGF-β and IL-10, a DuoSet ELISA development kit was used. IL-4, IL-10 and IFN-γ were detected by using flow cytometry. Results The number of CD4^＋ CD25^＋ T cells and the level of IL-10 increased in mice treated with S. japonicurn egg antigens. CD4^＋ CD25^＋ T cells dramatically enhanced IL-10 production and decreased IFN-γ production compared with the CD4^＋ CD25^- population. CD4^＋ CD25^＋ T cells suppressed the proliferation of CD4^＋ T cells. Conclusion S. japonicum egg antigens downregulate the host immune response by inducing the production of CD4^＋ CD25^＋ T cells and IL-10.