Protective role of small intestinal mucin producing cells against intestinal helminths

为了确定小肠杯状细胞粘蛋白的质/量变化在粘膜防御中的重要性，实验主要从以下两点着手：1)建立对不同肠蠕虫选择性驱逐的动物模型。2)建立杯状细胞粘蛋白保护作用的体内外检测系统。动物模型的建立用重组鼠IL-3同时感染鼠鼠S. ratti（Sr）和brasiliensis（Nb）后，只排出Sr，而不排出Nb与肠道肥大细胞增多症有关。在肥大细胞缺陷的W/W^<nu>小鼠中，Sr感染时间非常长，而W/W^<nu>小鼠中Nb的排出仅延迟48小时。骨髓移植可使W/W^<nu>小鼠Sr的延迟排出正常化，而Nb的延迟排出不正常。蒙古沙鼠同时感染Nb和Sr或委内瑞拉沙鼠后，圆线虫存活超过2个月，而Nb在3周内排出。因此，这3种模型可作为对肠道蠕虫选择性驱逐的动物模型。将13日龄的“受损”Nb成虫经十二指肠内植入正常受体大鼠体内，诱导杯状细胞增生和粘蛋白糖端改变，并在5天内将所有植入的蠕虫排出体外。当将7天大的“正常”蠕虫植入这些杯状细胞发生变化的大鼠体内时，所有植入的“正常”蠕虫都在48小时内被排出，这些蠕虫本应寄生10天以上。当同样的实验在低胸腺rnu/rnu大鼠中进行时，“受损”蠕虫的十二指肠内植入诱导了杯状细胞粘蛋白糖末端的改变，而不是细胞的增生，并伴有蠕虫的完全排出。随后植入的“正常”蠕虫在48小时内被排出体外。这些结果表明，一旦Nb虫受到宿主T细胞介导的免疫损伤，它们可以在没有T细胞帮助的情况下诱导杯状粘蛋白糖末端的改变，一旦这种改变被诱导，改变的粘蛋白可以选择性地对Nb起屏障作用，防止其附着在粘膜上。少

To determine possible importance of qualitative/quantitative changes of small intestinal goblet cell mucins in the mucosal defense, experiments were focused on the following 2 points:1) Establishment of animal models showing selective expulsion against different intestinal helminths. 2) Development of in vivo and in vitro assay system to measure protective role of goblet cell mucins.Establishment of animal modelsWhen nude mice were infected concurrently with S. ratti(Sr) and N. brasiliensis(Nb) and then trated with recombinant murine IL-3, only Sr, but not Nb, was expelled in association with intestinal mastocytosis. Sr infection was extremely prolonged in mast cell-deficient W/W^<nu> mice, though expulsion of Nb from W/W^<nu> mice delayed only 48 hrs. Delayed expulsion of Sr, but not of Nb, from W/W^<nu> mice was normalized by bone marrow grafting. After concurrent infection with Nb and Sr or S. venezuelensis in Mongolian gerbils, Strongyloides spp. survive over 2 mo. while Nb expelle … More d within 3 weeks. Thus, these 3 models can be used as the animal model showing selective expulsion against intestinal helminths.Development of assay system to assess protective role of goblet cell mucinsGoblet cell hyperplasia and alterations of sugar terminals of mucins were induced and all implanted worms were expelled within 5 days when 13 day-old "Damaged" Nb adult worms were implanted intraduodenally into normal recipient rats. When 7 day-old "Normal" worms were implanted into these rats having goblet cell changes, all implanted "Normal" worms, which were supposed to parasitize over 10 days, were expelled within 48 hr. When the same experiment was carried out using hypothymic rnu/rnu rats, alterations of sugar terminals of goblet cell mucins, but not hyperplasia of the cells, was induced by intraduodenal implantation of "Damaged" worms in association with complete expulsion of the worms. Subsequently implanted "Normal" worms were expelled within 48 hrs. These results imply that once Nb worms were damaged by host's T cell-mediated immunity, they can induce alteration of sugar terminals of goblet mucins without T cell help and that once such changes were induced, altered mucin can act selective barrier against Nb to prevent attachment to the mucosa. Less