Many mammals exhibit a periparturient relaxation of previously established immune responses (PPRI) to gastrointestinal nematodes culminating in increased worm burdens. It has been suggested that the extent of PPRI may have a nutritional basis as it is considerably augmented when protein supply is scarce. Subsequent studies have shown that increased dietary protein intake can ameliorate this phenomenon. However, this effect is often confounded with increased food intake and thus increased energy levels. Herein, we aimed to dissect the effects of protein and energy nutrition on the immune status and resistance to re-infection with gastrointestinal nematodes in the periparturient host. The lactating, Nippostrongylus brasiliensis re-infected rat was utilised as an established model for mammalian PPRI. Experimental animals were assigned to restricted feeding regimens designed to achieve four pre-determined levels of crude protein (CP) at one of two levels of metabolisable energy (ME) and parasitological and immunological measurements taken at either day 6 or day 9 post re-infection. We clearly show that increased supply of dietary CP, but not increased dietary ME, significantly reduced worm burdens. The increased magnitude of worm expulsion with increased dietary CP supply strongly correlated with mucosal mast cell accumulation in the small intestine. In addition, increased CP and not ME supply increased mucosal eosinophil numbers. Furthermore, increased CP led to higher levels of total IgG at high ME only and there were interactive effects of CP and ME on serum levels of IgG1 and IgG2a. Perhaps surprisingly, CP nutrition did not affect expression of either Th1 (IFN-γ) or Th2 (IL-4, IL-13) cytokines in the mesenteric lymph nodes. These data emphasise the role of immunonutrition, and particularly dietary protein, in combating infectious disease such as gastrointestinal parasitism.

中文翻译：

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剖析蛋白质与能量宿主营养对哺乳期间胃肠道寄生虫免疫表达的影响。

许多哺乳动物表现出先前建立的对胃肠道线虫的免疫反应 (PPRI) 的围产期松弛，最终导致蠕虫负担增加。有人提出 PPRI 的程度可能有营养基础，因为当蛋白质供应稀缺时它会大大增加。随后的研究表明，增加膳食蛋白质摄入量可以改善这种现象。然而，这种影响往往与食物摄入量的增加以及能量水平的增加相混淆。在此，我们旨在剖析蛋白质和能量营养对围产期宿主免疫状态和抵抗胃肠线虫再感染的影响。哺乳期的巴西日圆线虫再感染大鼠被用作哺乳动物 PPRI 的既定模型。实验动物被分配到限制性喂养方案中，该方案旨在在重新感染后第 6 天或第 9 天进行的两个代谢能 (ME) 水平和寄生虫学和免疫学测量中的一个达到四个预先确定的粗蛋白 (CP) 水平. 我们清楚地表明，增加膳食 CP 的供应，但不增加膳食 ME，显着降低了蠕虫负担。随着膳食CP供应的增加，蠕虫排出量的增加与小肠粘膜肥大细胞的积累密切相关。此外，增加的 CP 而不是 ME 供应增加了粘膜嗜酸性粒细胞数量。此外，仅在高 ME 时，CP 增加会导致总 IgG 水平升高，并且 CP 和 ME 对 IgG1 和 IgG2a 的血清水平有交互作用。也许令人惊讶的是，CP 营养不影响肠系膜淋巴结中 Th1 (IFN-γ) 或 Th2 (IL-4, IL-13) 细胞因子的表达。这些数据强调了免疫营养，尤其是膳食蛋白质在对抗传染病（如胃肠道寄生虫）中的作用。