派尔斑滤泡辅助性T细胞在轮状病毒感染时的变化研究

摘要

目的 研究派尔斑滤泡辅助性T细胞(follicular helper T cells,Tfh细胞)在轮状病毒感染时的变化.方法 KM小鼠以灌胃方式感染轮状病毒,随机分为初次感染组和再次感染组,同时设立给予生理盐水的对照组.在感染前(0 d)和感染后1、3、7、10 d等时间点,应用流式细胞术观察派尔斑Tfh细胞的比例;实时荧光定量RT-PCR和Western blot分别检测Bcl-6基因mRNA和蛋白表达水平.ELISA检测小肠黏膜轮状病毒特异性IgA的水平.结果 与对照组比较,初次感染组派尔斑Tfh细胞的比例在轮状病毒感染3 d(P<0.05)开始显著增加;7 d(P<0.05)增加达峰值;10 d(P<0.05)开始下降.与对照组(P<0.05)和初次感染组(P<0.05)比较,再次感染组派尔斑Tfh细胞比例在各时间点均显著增加,且增加幅度先增大后减小.与对照组比较,初次感染组(P<0.05)和再次感染组(P<0.05)Bcl-6基因mRNA和蛋白表达水平在感染后各个时间点均显著提高,其中再次感染组提高的幅度更明显.另外,与对照组(P<0.05)和初次感染组(P<0.05)比较,再次感染组轮状病毒特异性IgA的水平在感染后各个时间点均显著增加,且IgA水平与派尔斑Tfh细胞变化呈正相关.结论轮状病毒感染时派尔斑Tfh细胞显著增加,且再次感染时该变化与黏膜免疫应答密切相关.%Objective To investigate the changes of follicular helper T cells ( Tfh) in Peyer′s pat-ches during rotavirus infection. Methods KM mice were randomly divided into control group, primary in-fection group and secondary infection group. Those in control group were injected with normal saline, while the others were infected with rotavirus by intragastric administration for one or two times. Flow cytometry, real-time RT-PCR and Western blot were respectively performed to measure the percentages of Tfh in Peyer′s patches, the expression of Bcl-6 at mRNA and protein levels before (0 d) and after infection (1 d, 3 d, 7 d, 10 d) . The levels of rotavirus-specific IgA were detected by ELISA. Results Firstly, compared with control group, the percentages of Tfh in Peyer′s patches in primary infection group were significantly in-creased at 3 d (P<0. 05), reached the peak at 7 d (P<0. 05), and decreased at 10 d (P<0. 05). Com-pared with control group (P<0. 05) and primary infection group (P<0. 05), the percentages of Tfh in Pey-er′s patches in secondary infection group were significantly increased at every time point after infection, the extent of which increased initially and decreased afterwards. Secondly, compared with control group, the ex-pression of Bcl-6 gene at mRNA and protein levels in both primary infection group (P<0. 05) and secondary infection group (P<0. 05) were significantly increased at every time point. The expression of Bcl-6 at both mRNA and protein levels in secondary infection group were higher than those in primary infection group. Ad-ditionally, compared with control group (P<0. 05) and primary infection group (P<0. 05), the levels of ro-tavirus-specific IgA in secondary infection group were significantly increased at every time point after infec-tion. The levels of IgA were positively correlated the changes of Tfh in Peyer′s patches. Conclusion There is a significant increase in Tfh in Peyer′s patches during rotavirus infection and the increase of Tfh during secondary infection is closely related to the mucosal immune responses.