CD4＋CD25＋Foxp3＋T—reg细胞在大鼠肝移植天然免疫耐受模型中的作用

CD4＋CD25 ＋ Foxp3＋ T-reg cells play an important role in na（i）ve immune tolerance in rat liver transplantation

目的 通过采用流式细胞技术对比分析研究,大鼠肝移植免疫耐受模型中CD4＋CD25＋Foxp3＋T＋reg细胞亚群的分布变化来研究揭示CD4＋CD25＋Foxp3＋T-reg细胞亚群在移植免疫耐受过程中发挥的重要作用.方法 通过改良的Kamada＂二袖套法＂建立两种不同种属大鼠的免疫耐受和急性免疫排斥模型,再通过流式细胞技术检测两个模型大鼠CD4＋CD25＋Foxp3＋T-reg细胞亚群分布有无区别.主要观察指标：两组肝移植大鼠的存活率比较,应用常规HE染色法观察移植肝组织病理学变化,检测CD4＋CD25＋Foxp3＋T-reg细胞亚群在两组大鼠,肝脏、外周血、胸腺和脾脏总单核细胞数中所占的百分比.RT-PCR检测移植肝脏Foxp3 mRNA的表达水平.结果 耐受组大鼠可以不服用任何免疫抑制药物而长期存活（〉2个月）,且排斥组大鼠最多只能存活7～10d,免疫耐受组在肝脏、外周血、脾脏和胸腺单核细胞中CD4＋CD25＋Foxp3＋T-reg细胞亚群所占的比例明显高于排斥组（P〈0.05）,且在移植肝脏中,免疫耐受组的Foxp3 mRNA表达含量明显高于排斥组.结论 在LEW→DA的大鼠免疫耐受模型中,CD4＋CD25＋Foxp3＋T-reg细胞亚群细胞数量和比例明显升高,提示CD4＋CD25＋Foxp3＋T-reg细胞亚群在移植免疫耐受过程中发挥着重要作用,从而为我们临床诱导免疫耐受提供一条新的思路.我们可以通过体外扩增抗原特异性的天然存在的调节性T细胞来抑制效应T细胞的激活和扩增,从而帮助诱导移植免疫耐受和抑制移植物排斥.

Objective To study the effect of CD4＋ CD25＋ Foxp3 ＋ T-reg cells in na（i）ve immune tolerance using a rat liver transplantation model, we monitored the changes of this population cell of CD4＋ CD25＋ Foxp3＋ T-reg cells in liver、thymus、spleen and blood by flow cytometry technique. Methods Na（i）ve immune tolerance model of rat liver transplantation was established （LEW→DA） ,The rejection group （DA→LEW） was used as the control group. CD4＋ CD25＋ Foxp3＋ T-reg cells were respectively extracted and measured in liver、thymus、 spleen and blood. Simultaneously, we recorded the survival rate of rats and liver graft pathological changes in every group. The expression level of Foxp3 mRNA in every group was monitored. Results DA rat in tolerance group could acquire long-time survival without any immunosuppressive drug. Compared with rejection group,CD4＋ CD25＋ Eoxp3＋ T-reg cells in tolerance group were significantly increased, especially in blood. The expression level of Foxp3 mRNA is significantly higher（P〈0. 05）. Conclusions In tolerance group （LEW→DA）, the number and percentage of CD4 ＋ CD25 ＋ Foxp3 ＋ T-reg cell were both significantly increased. It suggests that CD4 ＋ CD25 ＋ Foxp3 ＋ T-reg cells play an important role in na（i）ve immune tolerance model of rat liver transplantation. This new sight could lead to induction immune tolerance and suppression graft rejection.