Data from: Measuring the immune system of the three-spined stickleback - examining natural variation in the laboratory and the wild

Current understanding of the immune system comes primarily from laboratory-based studies. There has been substantial interest in examining how it functions in the wild, but studies have been limited by a lack of appropriate assays and study species. The three-spined stickleback (Gasterosteus aculeatus L.) provides an ideal system in which to advance the study of wild immunology, but requires the development of suitable immune assays. We demonstrate that meaningful variation in the immune response of stickleback can be measured using real-time PCR to quantify the expression of eight genes, representing the innate response and Th1-, Th2- and Treg-type adaptive responses. Assays are validated by comparing the immune expression profiles of wild and laboratory-raised stickleback, and by examining variation across populations on North Uist, Scotland. We also compare the immune response potential of laboratory-raised individuals from two Icelandic populations by stimulating cells in culture. Immune profiles of wild fish differed from laboratory-raised fish from the same parental population, with immune expression patterns in the wild converging relative to those in the laboratory. Innate measures differed between wild populations, whilst the adaptive response was associated with variation in age, relative size of fish, reproductive status and S. solidus infection levels. Laboratory-raised individuals from different populations showed markedly different innate immune response potential. The ability to combine studies in the laboratory and in the wild underlines the potential of this toolkit to advance our understanding of the ecological and evolutionary relevance of immune system variation in a natural setting.

当前学界对免疫系统的认知主要源自实验室基础研究。尽管学界对探究免疫系统在自然野生环境中的运作机制已有广泛研究兴趣，但相关研究因缺乏适配的检测方法与研究物种而进展受限。三刺棘鱼（Gasterosteus aculeatus L.）为野生免疫学研究的推进提供了理想的研究体系，但仍需开发适配的免疫检测方法。本研究证实，可通过实时定量PCR（real-time PCR）量化8个基因的表达水平，以此检测三刺棘鱼免疫应答的显著差异，这8个基因分别对应天然免疫应答以及Th1型、Th2型与Treg型适应性免疫应答。本研究通过对比野生与实验室饲养的同亲本种群三刺棘鱼的免疫表达谱，并针对苏格兰北尤伊斯特岛不同种群的免疫差异展开分析，对上述检测方法进行了验证。此外，本研究通过体外细胞刺激实验，对比了两个冰岛种群实验室饲养个体的免疫应答潜能。研究结果显示，野生三刺棘鱼的免疫表达谱与同亲本实验室饲养个体存在显著差异，且相较于实验室饲养个体，野生个体的免疫表达模式更为趋同。天然免疫指标在野生种群间存在显著差异，而适应性免疫应答则与宿主年龄、相对体型、繁殖状态以及粗线绦虫（S. solidus）感染水平密切相关。不同种群的实验室饲养个体，其天然免疫应答潜能也存在显著差异。本研究可同时开展实验室与野外研究，这一优势凸显了该检测工具包的应用潜力，有助于我们进一步理解自然环境中免疫系统变异的生态学与进化意义。