白念珠菌在肠腔中的增殖与局部IgA抗体分泌的关系

Observation on the secretion of specific IgA antibody to Candida albicans in intestine

目的 观察白念珠菌(白念菌)在肠腔内增殖与局部粘膜免疫反应的关系。方法 采用无特殊病原菌动物经口喂入白念菌,在不同时相处死后,观察肠内白念菌总数及肠粘膜表面白念菌粘附数量;取肠系膜淋巴结做白念菌选择培养,观察移位体内发生率;采用Brdu体内掺入显示局部粘膜淋巴细胞的增殖情况;流式细胞计数潘伊尔氏结细胞表面IgA(SmIgA)阳性率;免疫组化染色后计数固有层中IgA浆细胞数量变化;ELISA法测定肠粘液中特异抗白念菌IgA含量。结果 肠内白念菌总量及粘膜表面粘附数量随给菌后时间延长而明显下降;移位主要发生于给菌后早期;给菌后固有层淋巴细胞增殖活跃,分泌IgA浆细胞数量明显增加;粘液层中特异抗白念菌IgA含量在给菌后上升明显。结论 带菌动物首次白念菌肠内给入后以固有层中淋巴细胞反应为主,增殖及分化均增加;白念菌总量和粘附数量减少与局部粘膜免疫反应及特异IgA抗体含量上升的关系十分密切。

Objective To observe the relationship between proliferation of Candida albicans in the intestinal lumen and the mucosal secretory IgA response to the microbes. Methods After Candida albicans were inoculated into the specific pathogen free mice, the total amount of Candidas in cecum and the amount of which attached to the mucosal membrane were counted at different interent intervals. The lymphocyte proliferation in Peyer's patch(PP) and in lamina proper(LP) was shown by BrdU incorporation, meanwhile B cells isotype switch in PP was investigated. IgA plasma cells were shown by immunohistochemical staining. Specific IgA antibodies to Candida albicans were measured with ELISA. Results From the third day to the fourteenth day after Candidas inoculation, the amount of Candidas colonization in lumen and that attached to mucosal membrane reduced sharply.Candidatranslocation into MLN happened in the early time after inoculation and were not found in the later time. At meanwhile same time the content of specific IgA increased obviously. Increasing of the proliferation and differentiation of lymphocytes in LP were found. Conclusions Lymphocyts in LP play an important role on the mucosal immunity of SPF mice when they are first inoculated with Candidas. The reducing amount of Candidas in intestine is related to increasing of the specific IgA antibodies in the intestinal mucus.