Douch P G, Morum P E, Rabel B
Wallaceville Animal Research Centre, AgResearch, Upper Hutt, New Zealand.
Int J Parasitol. 1996 Feb;26(2):205-11. doi: 10.1016/0020-7519(95)00120-4.
The presence of larval migration inhibitory (LMI) compounds in the gastrointestinal mucus of nematode resistant sheep has been shown previously to be associated with increased numbers of gastrointestinal mucus of nematode resistant sheep has been shown previously to be associated with increased numbers of gastrointestinal mucosal mast cells (MMC) and globule leukocytes (GL). This experiment was designed to determine if LMI compounds were secreted by MMC/GL in response to nematode antigenic challenge and if so, could secretion account for levels observed in mucus. Romney sheep were immunized by repeated cycles of infection with Trichostrongylus colubriformis or Haemonchus contortus larvae and anthelmintic treatment. After slaughter, gastrointestinal tissue was taken for examination of histology and mucus anti-parasite activity. Segments of small intestine were ligatured to form sacs which were incubated with exsheathed nematode larvae or larval excretory/secretory antigens. Tissue slices from small intestine or abomasum were also incubated with nematode larvae or antigens. After homologous challenge, levels of leukotrienes secreted into small intestinal tissue sacs were significantly higher than levels in heterologously challenged sacs or unimmunized sheep intestinal sacs challenged with larvae of any nematode species (279.4 +/- 33.7, 141.0 +/- 27.8 and 39.5 +/- 15.2 ng h-1 respectively). Tissue slices gave a similar pattern of leukotriene secretion. LMI activity was also significantly elevated in intestinal sacs from immunized sheep challenged homologously with nematode larvae or antigen (64 +/- 10 and 68 +/- 14% respectively cf. heterologous challenge 32 +/- 10% and unimmunized sheep sacs 15 +/- 6%). Histological examination of abomasal and small intestinal sections showed that immunized sheep had significantly greater numbers of MMC/GL than unimmunized sheep. MMC/GL isolated and purified from immunized sheep secreted leukotrienes and compounds having LMI activity when cultured with homologous nematode larvae or antigens. Secretion of leukotrienes and molecules having LMI activity from MMC/GL could account for the levels of these substances observed in small intestine mucus.
先前已表明，抗线虫绵羊胃肠道黏液中存在幼虫迁移抑制（LMI）化合物，这与抗线虫绵羊胃肠道黏液数量增加有关，且与胃肠道黏膜肥大细胞（MMC）和球状白细胞（GL）数量增多有关。本实验旨在确定LMI化合物是否由MMC/GL响应线虫抗原攻击而分泌，若如此，其分泌是否能解释黏液中观察到的水平。罗姆尼绵羊通过反复感染蛇形毛圆线虫或捻转血矛线虫幼虫并进行驱虫治疗来免疫。屠宰后，取胃肠道组织进行组织学检查和黏液抗寄生虫活性检测。将小肠段结扎形成囊袋，与脱鞘线虫幼虫或幼虫排泄/分泌抗原一起孵育。小肠或皱胃的组织切片也与线虫幼虫或抗原一起孵育。同源攻击后，分泌到小肠组织囊袋中的白三烯水平显著高于异源攻击囊袋或用任何线虫物种幼虫攻击的未免疫绵羊肠囊袋中的水平（分别为279.4±33.7、141.0±27.8和39.5±15.2 ng h-1）。组织切片呈现出类似的白三烯分泌模式。在用线虫幼虫或抗原同源攻击的免疫绵羊的肠囊中，LMI活性也显著升高（分别为64±10和68±14%，而异源攻击为32±10%，未免疫绵羊囊袋为15±6%）。对皱胃和小肠切片的组织学检查表明，免疫绵羊的MMC/GL数量明显多于未免疫绵羊。从免疫绵羊中分离纯化的MMC/GL在与同源线虫幼虫或抗原一起培养时会分泌白三烯和具有LMI活性的化合物。MMC/GL分泌白三烯和具有LMI活性的分子可以解释在小肠黏液中观察到的这些物质的水平。
