Animal Health, Scottish Agricultural College (SAC), Edinburgh, UK.
Int J Parasitol. 2012 Dec;42(13-14):1127-34. doi: 10.1016/j.ijpara.2012.09.010. Epub 2012 Oct 23.
The degree of periparturient relaxation of immunity to gastrointestinal parasites has a nutritional basis, as overcoming protein scarcity through increased protein supply improves lactational performance, enhances local immune responses and reduces worm burdens. Herein lactating rats, re-infected with Nippostrongylus brasiliensis, are used to test the hypothesis that a similar and rapid improvement of immunity can be achieved through reducing nutrient demand at times of dietary protein scarcity. Reducing litter size from 12 to three pups during lactation resulted, as expected, in cessation of maternal body weight loss and increased pup body weight gain compared with dams which continued to nurse 12 pups. This increase in performance concurred with a rapid decrease in parasitism; within 3 days post nutrient reduction, a 87% reduction in the number of worm eggs found in the colon and 83% reduction in worm burdens was observed, which concurred with increased local immune responses, i.e. 70% more mast cells and 44% more eosinophils in the small intestinal mucosa, to levels similar to those in dams nursing three pups throughout. However, there were no concurrent changes in goblet cell hyperplasia, serum anti-N. brasiliensis-specific antibody levels or mRNA expression of IL-4, IL-10 or IL-13 in the mesenteric lymph nodes. To our knowledge the current study is the first to employ a litter reduction strategy to assess the rate of immune improvement upon overcoming nutrient scarcity in a non-ruminant host. These data support the hypothesis that periparturient relaxation of immunity to gastrointestinal nematodes can be reduced by restoring nutrient adequacy and, importantly, that this improvement can occur very rapidly.
围产期对胃肠道寄生虫免疫力的放松程度具有营养基础，因为通过增加蛋白质供应来克服蛋白质短缺会改善哺乳期表现，增强局部免疫反应并减少蠕虫负担。在此，我们使用再次感染巴西日圆线虫的哺乳期大鼠来检验这样一种假设，即在饮食蛋白质缺乏时，通过降低营养需求可以实现类似的、快速的免疫改善。与继续哺乳 12 只幼崽的母鼠相比，哺乳期将窝仔数从 12 只减少到 3 只，正如预期的那样，导致母体体重停止下降，幼崽体重增加。这种性能的提高与寄生虫感染的迅速减少同时发生；在减少营养后 3 天内，结肠中的蠕虫卵数量减少了 87%，蠕虫负担减少了 83%，这与局部免疫反应的增加相一致，即小肠黏膜中的肥大细胞增加了 70%，嗜酸性粒细胞增加了 44%，达到了与哺乳期仅哺乳 3 只幼崽的母鼠相似的水平。然而，肠系膜淋巴结中杯状细胞增生、抗巴西日圆线虫特异性抗体水平或 IL-4、IL-10 或 IL-13 的 mRNA 表达没有同时发生变化。据我们所知，这项研究首次采用减少窝仔数的策略来评估非反刍动物宿主在克服营养缺乏时免疫改善的速度。这些数据支持这样一种假设，即通过恢复营养充足度可以减少围产期对胃肠道线虫免疫力的放松，并且重要的是，这种改善可以非常迅速地发生。
