Data from: Food limitation constrains host immune responses to nematode infections

Trade-offs in the allocation of finite energy resources among immunological defences and other physiological processes are believed to influence infection risk and disease severity in food-limited wildlife populations. However, this prediction has received little experimental investigation. Here we test the hypothesis that food limitation impairs the ability of wild field voles (Microtus agrestis) to mount an immune response against parasite infections. We conducted a replicated experiment on vole populations maintained in large outdoor enclosures during boreal winter, using food supplementation and antihelminthic treatment of intestinal nematodes. Innate immune responses against intestinal parasite infections were compared between food-supplemented and non-supplemented voles. Voles with high food availability mounted stronger immune responses against intestinal nematode infections than food-limited voles. No food effects were seen in immune responses to intracellular coccidian parasites, possibly due to their ability to avoid activation of innate immune pathways. Our findings demonstrate that food availability constrains vole immune responses against nematode infections, and support the concept that spatiotemporal heterogeneity in food availability creates variation in infectious disease susceptibility.

学界普遍认为，在有限能量资源分配于免疫防御与其他生理过程之间存在权衡，这会影响食物受限的野生动物种群的感染风险与疾病严重程度。然而，该预测尚未得到广泛的实验研究支持。本研究旨在验证这一假说：食物受限会削弱野生普通田鼠（Microtus agrestis）对抗寄生虫感染的免疫应答能力。我们在寒带冬季期间，于大型户外围栏内的田鼠种群中开展了重复实验，设置食物补充与肠道线虫抗蠕虫治疗两组处理。我们对比了食物补充组与食物受限组田鼠针对肠道寄生虫感染的先天免疫应答水平。结果显示，食物资源充足的田鼠，其对抗肠道线虫感染的免疫应答强度显著高于食物受限的田鼠。而针对细胞内球虫寄生虫的免疫应答则未受食物供应的影响，这可能是因为球虫能够规避先天免疫通路的激活。本研究结果表明，食物可获得性会限制田鼠对抗线虫感染的免疫应答，同时验证了“食物可获得性的时空异质性会导致传染病易感性产生差异”这一理论假说。