Garnier Romain, Cheung Christopher K, Watt Kathryn A, Pilkington Jill G, Pemberton Josephine M, Graham Andrea L
Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.
Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
Ecol Lett. 2017 Feb;20(2):175-183. doi: 10.1111/ele.12719.
In many wild animal populations, hosts are at risk of parasites and malnutrition and resource costs of defence may be difficult to afford. We postulate that proteins, important in homeostasis and immunity, play a complex but central role in condition dependence and resource costs of mammalian immune defence. To test this, we measured plasma concentrations of albumin, total proteins. Self-reactive antibodies and parasite-specific IgG in female Soay sheep. Using a principal component analysis, we found a new metric of condition reflecting individual variation in acquisition, assimilation and/or recycling of plasma proteins that predicted overwinter survival. Controlling for this metric, an age-dependent trade-off between antibody titres and protein reserves emerged, indicating costs of mounting an antibody response: younger individuals survived best when prioritising immunity while older individuals fared better when maintaining high-protein nutritional plane. These findings suggest fascinating roles for protein acquisition and allocation in influencing survival in wild animal populations.
在许多野生动物种群中，宿主面临寄生虫和营养不良的风险，防御所需的资源成本可能难以承受。我们推测，在体内平衡和免疫中起重要作用的蛋白质，在哺乳动物免疫防御的条件依赖性和资源成本方面发挥着复杂但核心的作用。为了验证这一点，我们测量了雌性索艾羊血浆中白蛋白、总蛋白、自身反应性抗体和寄生虫特异性IgG的浓度。通过主成分分析，我们发现了一个反映血浆蛋白获取、同化和/或循环利用个体差异的新的身体状况指标，该指标可以预测越冬存活率。控制这个指标后，抗体滴度和蛋白质储备之间出现了年龄依赖性的权衡，这表明产生抗体反应是有成本的：年轻个体优先考虑免疫时存活率最高，而年长个体保持高蛋白营养水平时情况更好。这些发现表明，蛋白质的获取和分配在影响野生动物种群生存方面发挥着引人入胜的作用。
