中文摘要：

目的动态观察刚地弓形虫（简称弓形虫）可溶性速殖子抗原（STAg）鼻内免疫小鼠对小肠IgA分泌细胞（IgASCs）数量和分泌型IgA（sIgA）水平的影响。方法 5～6周龄BALB/c小鼠96只,随机均分为免疫组和对照组。免疫组小鼠用STAg（20μg/只,悬于20μl PBS）滴鼻免疫2次,间隔2周;对照组用等量PBS代替。末次免疫后1周,灌胃感染RH株弓形虫速殖子（1×10~4个/只,溶于0.5 ml PBS）,记录小鼠健康状况及体重。于感染后6、7、8、9、10和1 1 d随机处死每组小鼠各8只,免疫组化检测小鼠的十二指肠、空肠和回肠黏膜IgASCs数量,ELISA测定小肠冲洗液sIgA水平。结果感染后所有小鼠均发病,但免疫组症状较轻,体重增加幅度明显高于对照组（P〈0.05）,感染后第7天对照组小鼠死亡2只。两组小鼠小肠冲洗液sIgA水平均呈升高趋势,但免疫组高于对照组（P〈0.05）。十二指肠IgASCs数量,对照组的略有增加,而免疫组持续升高至9 d后维持较高水平为20.65±1.67,对照组为12.30±2.67,对照组和免疫组十二指肠IgASCs数量与小肠液sIgA水平的相关性分别为r=0.378（P〈0.05）和r=0.566（P〈0.05）。空肠IgASCs数量,对照组的呈下降趋势,免疫组的持续升高至9 d后略下降。对照组和免疫组空肠IgASCs数量与小肠液sIgA水平的相关性分别为r=-0.557（P〈0.05）和r=0.218（P〉0.05）。对照组回肠IgASCs数量持续下降,免疫组的始终保持较高水平,对照组和免疫组回肠IgASCs数量与小肠液sIgA水平的相关性分别为r=-0.685（P〈0.05）和r=-0.053（P〈0.05）。结论 STAg鼻内免疫能使经口感染弓形虫小鼠空肠和回肠IgASCs数量增加,小肠黏膜免疫屏障功能增强。

英文摘要：

Objective To investigate the kinetics of IgA secreting cells （IgASCs）and secretory IgA （sIgA）level in small intestine induced by intranasal immunization with Toxoplasma gondii soluble tachyzoite antigen （STAg）in mice. Methods Ninty-six 5 to 6-week old BALB/c mice were randomly divided into immunity and control groups.Mice of the immunity group were each intranasally immunized with STAg 20μg in 20μl PBS,twice at an interval of 2 weeks, while the control mice were each given 20μl PBS.All mice were challenged intragastrically with 1×10~4 tachyzoites in 05ml per mouse in 1 week after the last immunization.The body weight and infection incidence of mice were recorded.Eight mice of each group were sacrificed on the day 6,7,8,9,10 and 11 post infection,respectively.The quantity of IgASCs in mucosa of duodenum,jejunum and ileum was detected by immunohistochemistry.The sIgA in intestinal washes were determined by ELISA.Results All mice fell ill post infection,but the symptom of mice in the immunity group was milder,the increasing level of body weight of mice in the immunity group was higher considerably than that in the control group （P0.05）.Two mice died in control group on the 7th day after infection.sIgA level in intestinal washes increased continually in two groups,but the increasing level in the immunity group was higher than that of the control （P0.05）.The number of IgASCs in duodenum increased slightly in the control group,but increased continuously and maintained a high level after 9 d in the immunity group,for instance,20.65±1.67 in the immunity group and 12.30±2.67 in the control.The correlation of the sIgA level in intestinal washes and the quantitative change of IgASCs in duodenum was positive in the immunity group （r=0.566,P0.05）and the control （r=-0.378,P0.05）.The number of IgASCs in jejunum decreased in the control group but increased then slightly decreased after 9 d in the immunity group. Positive correlation between the sIgA level in intestinal washes and the quantitativ