【摘要】 目的 研究经口感染弓形虫速殖子小鼠肠道粘膜组织诱导部位与效应部位T细胞亚群的变化,探讨肠道粘膜免疫应答机制。 方法 将6~7周龄BALB／c小鼠100只随机分为对照组和感染组。感染组灌胃接种RH株弓形虫速殖子5×104个／只,对照组给予等体积PBS。于感染后第2、4、6、8、10 d分别处死小鼠,分离Peyer’s patches(PP结)、肠系膜淋巴结(MLN)淋巴细胞、小肠上皮内淋巴细胞(IEL),用免疫细胞化学法检测CD4+、CD8+T细胞亚群。 结果感染组小鼠PP结CD4+T细胞有随感染天数增加呈升高趋势,第6、8、10 d显著高于对照组(P<0.01);CD8+T细胞亦有增高趋势,但与对照组相比差异无显著性(P>0.05);CD4+／CD8+比值第6 d起增高(P<0.05),第8 d最大(P<0.01),第10d回落(P<0.05)。MLN中T细胞亚群有较弱增高趋势,无统计学意义(P>0.05)。IEL CD4+、CD8+T细胞在第6、8、10 d均增高,其中CD8+T细胞增高显著(P<0.01);CD4+／CD8+比值第6 d开始下降,两组间差异有显著性(P<0.05)。 结论 诱导部位PP结CD4+T细胞明显增高,诱导对弓形虫抗原的处理、提呈作用;效应部位IELCD8+T细胞增殖明显,在清除虫体的过程中起主导作用。更多还原

【Abstract】 Objective To observe the T cell subsets variation within gut mucosa-associated tissues and mucosal immune response induced by Toxoplasma gondii tachyzoite in BALB/c mice. Methods 6- to 7-week-old BALB/c mice were divided into control group and infected group. The ascites containing tachyzoites of RH strain of infected mice were gathered and adjusted to contain 5×104 tachyzoites for each mouse of infected group by oral administration 0. 5 ml dose; the control group was given PBS solution instead. Five mice in each group were killed per time-point on day 2, 4, 6, 8, 10, respectively, after infection. The Peyers patches, mesenteric lymph node and intestinal mucosal epithelial tissues were prepared for the lymphocytes suspension and the changes of CD4+ and CD8+ T cells in these sites were determined by SABC immunohistochemistry. Results The CD4+ T subset of the Peyer s patches increased at the early stage of the infection, getting ifs the highest level on day 8 post infections and then decreased. The CD8+ T subset increased with no statistical difference. The two groups had significant difference on day 6, 8, 10 post infections a-bout the relative percentage of CD4+ and CD8+ T cells. For the mesenteric lymph node, there was no obvious change occurred. Intestinal epithelial had much more CD8+ T cells than other mucosal tissues. On day 6, 8, 10 post infections we observed the significant increasing for the proliferation of CD8+ T cells while the CD4+ T subset of the mucosal effector sites didn’t change greatly corresponding, so the ratio of CD4+ to CD8+ T cells was reversed with significance. Conclusion During the period of infection in the BALB/c mice orally administered with Toxoplasma, CD4+ T cell subset in the inductive sites just like Peyer’s patches was increasing obviously, which indicated the parasite antigen processing. On the other hand, CD8+ T cell subset of the effector sites was activated and enhanced its cytotoxicity which was primary immune components when eliminating the parasite.更多还原