Pernthaner A, Cabaj W, Shaw R J, Rabel B, Shirer C L, Stankiewicz M, Douch P G
AgResearch, Wallaceville Animal Research Centre, Upper Hutt, New Zealand.
Int J Parasitol. 1996 Apr;26(4):415-22. doi: 10.1016/0020-7519(96)00004-5.
Aspects of the local immune response to nematode challenge were investigated in vivo in isolated loops of the upper small intestine of mature sheep that were immunised by repeated infections with Trichostrongylus colubriformis infective larvae (L3). Groups of 3 sheep were challenged either through the loop (Group 1) or orally (Group 2) with T. colubriformis L3, the third group served as unchallenged controls (Group 3). Nematode specific antibody levels, mast cell proteinase levels (SMCP) and larval migration inhibition (LMI) activity were determined in loop secretions for 4 weeks after challenge. The intestinal loops remained functional throughout the experiment. Groups 1 and 2 were re-challenged 2 weeks after the first challenge, and all 3 Groups were slaughtered 2 weeks later. Histopathological examination showed elevated numbers of globule leukocytes (GL) in both the nematode-challenged loop and unchallenged small intestine of Group 1 and small intestine of Group 2 indicating that nematode infections induce the local appearance of large numbers of GL. Oral, but not loop challenge caused increased antibody levels in loop secretions when compared to unchallenged controls. Only loop-challenged sheep showed a peak in loop fluid SMCP levels 10-13 days after the first challenge which coincided with a peak in numbers of mucosal GL. The isolated loops of all 3 groups showed highly elevated numbers of eosinophils when compared to the intact small intestine. Loop fluid of all 3 groups showed a high level of LMI activity reflecting the high level of nematode-resistance induced by the immunisation procedures. Sheep in Groups 1 and 2 were both able to expel challenge infections, and when compared to Group 3, showed higher blastogenic activity of unstimulated cells derived from a mesenteric lymph node in the region of the challenged part of the intestine. The present experiment showed that surgically constructed intestinal loops provided a model system by which the substantial changes associated with the local intestinal immune response to challenge with T. colubriformis could be investigated.
在成熟绵羊的上段小肠分离肠袢中，对经蛇形毛圆线虫感染性幼虫（L3）反复感染免疫的绵羊，在体内研究了其对该线虫攻击的局部免疫反应的各个方面。将3只绵羊分为一组，通过肠袢（第1组）或经口（第2组）用蛇形毛圆线虫L3进行攻击，第三组作为未攻击的对照（第3组）。在攻击后4周内，测定肠袢分泌物中线虫特异性抗体水平、肥大细胞蛋白酶水平（SMCP）和幼虫移行抑制（LMI）活性。整个实验过程中肠袢保持功能正常。第1组和第2组在首次攻击后2周再次攻击，所有三组在2周后宰杀。组织病理学检查显示，第1组受线虫攻击的肠袢和未攻击的小肠以及第2组的小肠中，球样白细胞（GL）数量增加，表明线虫感染可诱导大量GL在局部出现。与未攻击的对照相比，经口而非通过肠袢攻击可使肠袢分泌物中的抗体水平升高。仅经肠袢攻击的绵羊在首次攻击后10 - 13天肠袢液SMCP水平出现峰值，这与黏膜GL数量的峰值一致。与完整小肠相比，所有三组的分离肠袢中嗜酸性粒细胞数量均显著增加。所有三组的肠袢液均显示出高水平的LMI活性，反映了免疫程序诱导的高水平线虫抗性。第1组和第2组的绵羊均能够排出攻击感染，并且与第3组相比，来自受攻击肠道区域肠系膜淋巴结的未刺激细胞显示出更高的增殖活性。本实验表明，手术构建的肠袢提供了一个模型系统，通过该系统可以研究与对蛇形毛圆线虫攻击的局部肠道免疫反应相关的实质性变化。
