Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands.
J Exp Biol. 2013 Jul 15;216(Pt 14):2573-80. doi: 10.1242/jeb.083147. Epub 2013 Mar 26.
Trade-offs between immune function and other physiological and behavioural processes are central in ecoimmunology, but one important problem is how to distinguish a reallocation of resources away from the immune system from a reallocation or redistribution within the immune system. While variation in baseline values of individual immune parameters is well established, studies in wild animals on multiple parameters during an immune response are lacking. It also remains to be tested whether and how immune responses correlate with baseline values that vary, for example, over the course of an annual cycle. We studied immunological responses to an endotoxin challenge in skylarks (Alauda arvensis), a partial migrant bird breeding in temperate zones. We compared birds injected with the endotoxin LPS with un-injected controls, characterizing immunological responses with leukocyte profiles, titres of lytic enzymes and natural antibodies, and concentrations of haptoglobin and heat shock proteins. We did this in five annual-cycle stages to test whether the response varied throughout the year. The endotoxin challenge affected six of 10 measured parameters. Lysis titres and proportions of heterophils increased; haptoglobin concentrations and proportions of lymphocytes, basophils and eosinophils decreased. The variable effects on different immune components demonstrate the complexity of an immune response. We found no evidence that the response differed between annual-cycle stages. The response was independent of baseline measures taken directly upon capture in the field, indicating that birds were facing no immunological ceiling when mounting an immune response. Values of five parameters collected under field conditions were significantly related to values taken under standardized laboratory conditions. We conclude that multiple parts of the immune system are modulated during an immunological response and that responses are not re-organized throughout the annual cycle.
在生态免疫学中，免疫系统与其他生理和行为过程之间的权衡是核心问题，但一个重要问题是如何区分资源从免疫系统的重新分配与免疫系统内部的再分配或重新分布。虽然个体免疫参数的基线值变化已经得到很好的证实，但在野外动物中对免疫反应期间的多个参数进行研究还很缺乏。此外，还需要测试免疫反应是否以及如何与变化的基线值相关联，例如在一年的周期中。我们研究了在田雀（Alauda arvensis）中对内毒素挑战的免疫反应，田雀是一种在温带地区繁殖的部分迁徙鸟类。我们将接受内毒素 LPS 注射的鸟类与未接受注射的对照组进行比较，通过白细胞图谱、溶酶体酶和天然抗体的效价以及结合珠蛋白和热休克蛋白的浓度来描述免疫反应。我们在五个年周期阶段进行了这项研究，以测试全年的反应是否会发生变化。内毒素挑战影响了 10 个测量参数中的 6 个。溶酶体酶效价和异嗜粒细胞的比例增加；结合珠蛋白浓度以及淋巴细胞、嗜碱性粒细胞和嗜酸性粒细胞的比例降低。不同免疫成分的可变影响表明免疫反应的复杂性。我们没有发现反应在年周期阶段之间存在差异的证据。该反应与直接在野外捕获时进行的基线测量无关，这表明鸟类在进行免疫反应时没有免疫上限。在野外条件下收集的五个参数的值与在标准化实验室条件下收集的值显著相关。我们得出结论，免疫系统的多个部分在免疫反应过程中被调节，并且反应不会在整个年周期中重新组织。
