感染肺炎链球菌的猕猴消化系统分泌型免疫球蛋白A的表达  

Expression of secretory immunoglobulin A in gastrointestinal tract of streptococcal pneumonia rhesus monkey

作　　者：陈恋[1] 罗启慧[1,2] 章瑶[1] 陈正礼[1,2] 程安春[1,2,3] 曾文[2] 

机构地区：[1]四川农业大学动物医学院动物疫病与人类健康四川省重点实验室,四川雅安625014 [2]四川农业大学实验动物工程技术中心/国家实验猕猴种源基地,四川雅安625014 [3]I~ll农业大学预防兽医研究所,四川成都611130

出　　处：《浙江大学学报（农业与生命科学版）》2012年第6期675-683,共9页Journal of Zhejiang University:Agriculture and Life Sciences

基　　金：四川省科技厅资助项目(2011JY0054);教育部“长江学者和创新团队发展计划”团队资助项目(IRT0848);四川省博士后引进专项资助项目(04310608);四川省国际科技合作与交流研究计划资助项目(2010HH0013)

摘　　要：采用免疫组织化学和原位杂交方法检测分泌型免疫球蛋白A(SIgA)在自发性感染肺炎链球菌的猕猴胃肠道以及肝脏、食管的表达变化,通过测定光密度值和表达面积比较感染前后的分泌变化,探讨SIgA在肺炎链球菌发病机制中的作用以及自发性肺炎链球菌性肺炎的病理特点.免疫组化结果显示,和健康组比较,SIgA在感染组的光密度值以及表达面积在各组织中均有下降趋势,其中在空肠阳性细胞的表达面积下降显著(P<0.05);原位杂交结果和免疫组化结果基本一致,感染组各组织阳性细胞表达面积均较健康组减少,其中空肠、盲肠以及胃组织差异显著(P<0.05),感染组光密度值较健康组高,但差异均不显著(P>0.05).阳性细胞的分布多集中于各胃肠段和食管的黏膜层,血管中可见较多阳性细胞,而肝脏中的阳性细胞多呈散在分布.其中,阳性细胞主要包括胃肠道黏膜层的淋巴细胞和肝细胞、血管内细胞以及炎性浸润细胞,部分腺体细胞、上皮细胞和食管黏膜层未角化上皮细胞也有阳性反应.上述结果表明,SIgA可通过以体液免疫为主的免疫机制帮助机体清除肺炎链球菌;SIgA作为黏膜免疫系统中重要的抗体分子在感染组组织中表达水平的降低可能是导致肺炎链球菌入侵机体从而引起感染的一个因素.Streptococcus pneumoniae is a conditional pathogenic bacteria which is associated with significant global morbidity and mortality. The main infection way is through mucosa system. Due to its variable serotype, there still have no effective method to prevent it. Secretory immunoglobulin A （SIgA） is the most important antibody secreted by plasmocytes and also the maximum in number, which can prevent bacterial adhesion to cells of host. Besides, secretory piece of SIgA can bind pneumococcal surface protein A, which help immune cells clear bacteria. Previous study showed that SIgA decreased when a host was infected with S. pneumoniae in the intestinal tract. SIgA could restrain bacteria being translocated to other organs and activate complement pathway, so when secretion decreased, host immune resistance become weakened, thus caused pathological changes. Corresponding to this research, increase of the antibody could help inhibit infection. This experiment aimed to investigate the expression condition of SIgA in intestinal mucosal immune system when rhesus monkeys were infected with S. pneumoniae spontaneously, and its role in the pathopoiesis of S. pneumoniae. Due to the high similarity of genes shared between human beings and rhesus monkeys, this experiment would also be helpful for the understanding of pneumonia happened on mankind. Three infected and three normal rhesus monkeys were blooded to death and obtained relative organs after anaesthesia. The changes of SIgA expression in esophago, jejunum, caecum, stomach and liver of rhesus monkeys were detected by immunohistochemistry and in situ hybridization on paraffin sections. Meanwhile, the images were collected, and the optical density value and positive cell area were detected by microscope. Immunohistochemistry results showed that the expression of SIgA in infected groups was smaller than that in normal ones, especially in jejunum where the expression was significantly reduced （P〈 0.05） （Table 1 and Fig. 1）. Similar results were

关 键 词：肺炎链球菌 分泌型免疫球蛋白A(SIgA) 猕猴 黏膜 免疫组化 原位杂交 

分 类 号：Q51[生物学—生物化学] S852.31[农业科学—基础兽医学]